Merge PR #95: fix: refresh cooldown counts pending requests, button beside the title

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.claude/skills/ship/SKILL.md

@@ -24,7 +24,8 @@ Repo rules: `CONTRIBUTING.md`. Gitea: https://git.mariuszpacek.pl/mariusz.pacek/
    then `git push origin master` and delete the branch locally and on origin. Confirm CI is
    green on master. Gitea does not close an AGit PR merged by hand: ask the user to close it.
 6. Release and update only with the user's explicit approval for this one:
-   `scripts/release.sh vMAJOR.MINOR.PATCH` (patch for fixes, minor for features) tags master;
+   `scripts/release.sh vMAJOR.MINOR.PATCH` (patch for fixes, minor for features) waits for green
+   CI on master's head (no local check run), then tags master;
    wait until the Release run under `…/actions` is green (it publishes the images). Then on the
    Pi (`ssh <host>`, an alias while D7 is open): `cd /home/pi/home-pump && ./update.sh <version>`,
    watch `journalctl -t home-pump-gateway -f` and Grafana for one polling cycle (300 s) and

.gitea/workflows/ci.yml

@@ -1,3 +1,6 @@
+# One job: check.sh builds the three parts in parallel itself. The runner runs one job at a time
+# and its actions cache server is unreachable from job containers (ETIMEDOUT), so separate jobs
+# or setup-java/setup-node caches would only add waiting.
 name: CI
 
 on:

.gitea/workflows/release.yml

@@ -13,8 +13,20 @@ env:
 
 jobs:
   images:
-    name: Images
+    name: Image (${{ matrix.part }})
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # The Pi is arm64. Each Dockerfile builds on the runner's platform and only copies into
+          # the final stage, so the arm64 image needs no emulation.
+          - part: gateway
+            platforms: linux/arm64,linux/amd64
+          - part: backend
+            platforms: linux/amd64
+          - part: frontend
+            platforms: linux/amd64
 
     steps:
       - name: Checkout
@@ -31,26 +43,14 @@ jobs:
           username: ${{ gitea.repository_owner }}
           # The owner's token with package write access (the secret homelab-upgrade uses too).
           password: ${{ secrets.REGISTRY_TOKEN }}
-      # The Pi is arm64. Each Dockerfile builds on the runner's platform and only copies into the
-      # final stage, so the arm64 image needs no emulation.
-      - name: Gateway
+      # The registry cache keeps the Maven and npm layers between releases.
+      - name: Build and push
         uses: docker/build-push-action@v6
         with:
-          context: gateway
-          platforms: linux/arm64,linux/amd64
+          context: ${{ matrix.part }}
+          build-args: VERSION=${{ gitea.ref_name }}
+          platforms: ${{ matrix.platforms }}
           push: true
-          tags: ${{ env.IMAGES }}-gateway:${{ gitea.ref_name }},${{ env.IMAGES }}-gateway:latest
-      - name: Backend
-        uses: docker/build-push-action@v6
-        with:
-          context: backend
-          platforms: linux/amd64
-          push: true
-          tags: ${{ env.IMAGES }}-backend:${{ gitea.ref_name }},${{ env.IMAGES }}-backend:latest
-      - name: Frontend
-        uses: docker/build-push-action@v6
-        with:
-          context: frontend
-          platforms: linux/amd64
-          push: true
-          tags: ${{ env.IMAGES }}-frontend:${{ gitea.ref_name }},${{ env.IMAGES }}-frontend:latest
+          tags: ${{ env.IMAGES }}-${{ matrix.part }}:${{ gitea.ref_name }},${{ env.IMAGES }}-${{ matrix.part }}:latest
+          cache-from: type=registry,ref=${{ env.IMAGES }}-${{ matrix.part }}:buildcache
+          cache-to: type=registry,ref=${{ env.IMAGES }}-${{ matrix.part }}:buildcache,mode=max

backend/Dockerfile

@@ -8,6 +8,9 @@ COPY src src
 RUN mvn -B -q package -Dmaven.test.skip=true
 
 FROM eclipse-temurin:21-jre-alpine
+# The release tag, shown in /api/health; the release workflow passes it.
+ARG VERSION=dev
+ENV VERSION=$VERSION
 USER 10001:10001
 WORKDIR /app
 COPY --from=build /src/target/home-pump-backend-1.0.0.jar app.jar

backend/README.md

@@ -3,6 +3,43 @@
 The phone API in Kraków (ADR-008): live state from the gateway, history from InfluxDB, setpoint
 changes passed to the gateway. JSON under `/api/` only; the web UI is the frontend's (ADR-010).
 The records in `home.backend.domain` and the examples in `src/test/resources/api/` are the contract.
+`GET /api/energy/details` lists the Deye, Fronius and house meter values in labelled groups (a stale device has none); the label, unit and place of every field are the catalog in `EnergyDetailsService`: a new field is one line there.
+`GET /api/pi-sensor` is the BME280 sensor on the Raspberry Pi (the living room), example `src/test/resources/api/pi-sensor.json`:
+`time`, `stale`, `temperature` (°C), `humidity` (%), `pressure` (hPa). When it is stale (device down, no reading or older than 10 min)
+the three values are null (`pi-sensor-stale.json`).
+
+`GET /api/stats?range=7d|30d` (example `src/test/resources/api/stats.json`; 400 otherwise, 502 when InfluxDB is down) is the heat pump per local
+day (Europe/Warsaw, today included) from the raw `heat_pump` polls: `days[]` with `date`, `compressorHours`, `compressorStarts`, `cwuHours`, `coHours`,
+`heaterHours`, `avgOutdoorTemp`, `minCwuTemp`, `maxCwuTemp` (all null on a day without polls) and `totals` over the range. A poll holds its outputs
+until the next one, at most 600 s, so gaps add no hours; a start is a poll above 0 after a poll at 0, so the 300 s polling misses short cycles.
+
+`GET /api/battery` is the Deye battery, example `src/test/resources/api/battery.json`: live `socPct`, `powerW` (+ discharge / − charge), `voltageV`,
+`currentA`, `temperatureC`, `today` and `total` energy (`chargeKwh`, `dischargeKwh`), null when the Deye is stale (older than 10 min or down).
+The settings come from the gateway's slower `deye_settings` reading and are stale after 30 min (`battery-settings-stale.json`):
+`mode` (`touEnabled` with a Polish sentence), `schedule` (six slots, each from its start to the next one, the last wraps past midnight),
+`limits`, and `capacityKwh` = capacity in Ah x a nominal 51.2 V, since the inverter reports Ah only. When stale they are null (`schedule` empty).
+
+`/api/battery` also has `reserve` (`pct`, `floorPct`: the backup reserve of the app and the lowest the user may set) and `editable`:
+true when the gateway answers its `/battery/reserve`, i.e. it has battery commands on and `GATEWAY_TOKEN` is right; else `reserve` is null
+and `editable` false. `POST /api/battery/schedule` (examples `battery-schedule-request.json`, `battery-failed.json`) takes
+`{"enabled"?, "slots": [{"slot": 1-6, "from"?: "HH:MM", "socPct"?, "gridCharge"?}]}` and `POST /api/battery/reserve` takes `{"pct": 60}`.
+Same Origin, header and JSON rules as the other writes; `Remote-User` goes on as the requester. The gateway's verdict comes back as
+`{status, message, read}`: 200 applied, 422 rejected, 409 settings unknown or changed meanwhile, 429 too soon, 502 failed (`read` is what the
+inverter holds), 400 bad body, 503 gateway unreachable or without battery commands (ADR-013).
+
+`GET /api/audit?range=7d` (`24h`, `7d` default, `30d`; 400 otherwise, 502 when InfluxDB fails) is the change history, example
+`src/test/resources/api/audit.json`: the gateway's audit rows of the heat pump (`Dom_Pompa.setpoint_audit`) and the battery
+(`electricity.deye_settings_audit`), read only, as `entries` newest first: `time`, `source` (`heat_pump`, `battery`), `what` (Polish label;
+the Deye registers are named in `DeyeSettingLabels`), `oldValue`/`newValue` (whole numbers, null when not recorded), `unit` (`°C`, `%`,
+`HHMM`, `0/1`), `who` (`Remote-User` of the request; a restore is "automatycznie (przywrócenie)") and `status` (the gateway's: APPLIED, FAILED, REJECTED, CONFLICT, INVALID).
+
+`GET /api/weather` (example `src/test/resources/api/weather.json`) is the forecast of Open-Meteo for the house and the IMGW warnings that name
+Krosno (TERYT 1862 or the powiat 1807): `today`, `tomorrow`, `dayAfter` (`date`, `weatherCode` WMO, Polish `description`, `tMax`, `tMin`,
+`precipitationMm`, `sunshineHours`, `pvForecastKwh`), `now.temperature`, `warnings` (`event`, `level` 1-3, `from`, `to`, `text`; the ones that
+ended are dropped). `pvFactor` is kWh per MJ/m^2: the Deye plus Fronius energy of the past 14 complete days (from InfluxDB, daily maximum of
+`pv_today_kwh` and `energy_day_wh`) over the forecast radiation of the same days, so no tilt or azimuth is needed; `pvForecastKwh` is the factor
+times the day's radiation, and both are null with fewer than 5 days that have both values. The forecast is kept 30 min and the warnings 10 min;
+when a refresh fails the older answer is served with `stale` true. 503 only when there never was a forecast. The sources are public and need no key.
 
 Settings are environment variables (`.env` next to `compose.yaml`); the backend refuses to start
 without the two URLs.
@@ -16,7 +53,9 @@ Setpoint changes go only to the gateway; the user name from Traefik's `Remote-Us
 | `GATEWAY_TIMEOUT` | `5` | seconds |
 | `INFLUX_TIMEOUT` | `10` | seconds |
 | `GATEWAY_TOKEN` | unset | shared token for the gateway's `/commands`; without it the backend runs but `/api/setpoints` and `/api/presets/{id}` answer 503 |
-| `PRESETS_FILE` | built-in | JSON file replacing the presets: `[{"id", "name", "changes": [{"setpoint", "value", "hours"}]}]`, `hours` null means until changed; a bad file stops the start |
+| `WEATHER_LAT`, `WEATHER_LON` | `49.684`, `21.770` | where the house is (Krosno, ul. Szczepańcowa), for the forecast |
+| `WEATHER_TERYT` | `1862,1807` | comma-separated TERYT powiat codes whose IMGW warnings count |
+| `PRESETS_FILE` | built-in | JSON file replacing the presets: `[{"id", "name", "changes": [{"setpoint", "value", "hours"}]}]`, `hours` null means until changed; a bad file stops the start. A preset may also have `"until": "chosen"` (then no `hours`): the user picks the end, see below |
 
 ```bash
 mvn -f backend/pom.xml clean package
@@ -25,6 +64,28 @@ GATEWAY_URL=http://10.0.0.2:8080 INFLUX_URL=https://influxdb.example \
 docker compose -f backend/compose.yaml up --build              # with backend/.env; network home-pump
 ```
 
+`POST /api/presets/{id}` takes no body for an ordinary preset. A preset with `"until": "chosen"` (the built-in "Wyjazd")
+needs `{"until": "2026-11-02T18:00:00+01:00"}` (ISO-8601 with offset, example `src/test/resources/api/preset-away-request.json`):
+400 when it is missing, invalid, or sent to a preset that has none. Any preset also takes optional `"values"`
+(example `preset-away-values-request.json`): a whole number per setpoint of that preset, replacing the preset's value;
+the others keep it. 400 for a setpoint the preset does not change or a value outside the gateway's min, max and step
+(from `/commands`), checked before anything is sent; a held value that is not below the current one is 422. The gateway holds those changes until then without
+renewals (ADR-012) and rejects an end that is past or over 30 days away, or a change that does not lower the value (422).
+
+`POST /api/refresh` (same Origin, header and JSON rules; send `{}`) is the "Odśwież" button: it asks the gateway for one
+extra poll of every device and passes its answer through, example `src/test/resources/api/refresh.json`
+(`requested`, and `skipped` with `retryInSeconds` for devices polled within the last minute). Read-only; 503 when
+`GATEWAY_TOKEN` is not set or the gateway is unreachable.
+
+`POST /api/setpoints/{name}/restore` (same Origin, header and JSON rules as the other writes; send `{}`) ends the
+pending change of that setpoint now and answers with the gateway's verdict, example
+`src/test/resources/api/setpoint-restored.json`: 200 restored, 404 nothing pending, 409 the value was changed
+meanwhile (left alone, the restore is dropped), 429 too soon after the last write, 502 failed (the restore stays
+pending), 503 gateway unreachable.
+
 Publish no host port in production: only the frontend, behind Traefik, may reach the backend. It
 trusts `Remote-User` and has no login of its own, so a direct port would bypass Traefik's access
 rules (ADR-009).
+
+`/api/health` also carries `backendVersion` (the `VERSION` the image was built with, `dev` locally) and
+`gatewayVersion` (from the gateway's `/health`; null when it is unreachable or too old to report it).

backend/src/main/java/home/backend/Backend.java

@@ -4,20 +4,39 @@ import home.backend.adapters.config.PresetFile;
 import home.backend.adapters.gateway.GatewayHttpClient;
 import home.backend.adapters.gateway.GatewayHttpCommands;
 import home.backend.adapters.http.ApiServer;
+import home.backend.adapters.influx.InfluxAuditRepository;
 import home.backend.adapters.influx.InfluxHistoryRepository;
+import home.backend.adapters.influx.InfluxPvEnergy;
 import home.backend.adapters.influx.InfluxSettings;
+import home.backend.adapters.weather.ImgwClient;
+import home.backend.adapters.weather.OpenMeteoClient;
+import home.backend.adapters.weather.WeatherSettings;
+import home.backend.application.AuditService;
+import home.backend.application.BatteryService;
+import home.backend.application.EnergyDetailsService;
 import home.backend.application.EnergyService;
 import home.backend.application.HealthService;
 import home.backend.application.HeatPumpService;
 import home.backend.application.HistoryService;
+import home.backend.application.StatsService;
+import home.backend.application.LeaseRenewer;
+import home.backend.application.PiSensorService;
 import home.backend.application.SetpointService;
+import home.backend.application.WeatherService;
 
 import java.io.IOException;
+import java.net.URI;
 import java.time.Clock;
+import java.time.Duration;
+import java.util.Objects;
 
 /** Wires the adapters and services together; the only place that knows all of them. */
 final class Backend {
 
+    private static final Duration WEATHER_TIMEOUT = Duration.ofSeconds(10);
+    /** Warnings are optional, so a slow IMGW must not hold the forecast. */
+    private static final Duration WARNINGS_TIMEOUT = Duration.ofSeconds(3);
+
     private Backend() {
     }
 
@@ -28,14 +47,35 @@ final class Backend {
      */
     static ApiServer assemble(Settings settings, Clock clock) throws IOException {
         var gateway = new GatewayHttpClient(settings.gatewayUrl(), settings.gatewayTimeout());
-        var influx = new InfluxHistoryRepository(new InfluxSettings(settings.influxUrl(), settings.influxTimeout()));
-        var commands = new GatewayHttpCommands(settings.gatewayUrl(), settings.gatewayToken(),
-                settings.gatewayTimeout());
+        var influxSettings = new InfluxSettings(settings.influxUrl(), settings.influxTimeout());
+        var influx = new InfluxHistoryRepository(influxSettings);
+        var commands = commands(settings);
         var setpoints = new SetpointService(commands, PresetFile.load(settings.presetsFile()));
         return new ApiServer(settings.port(),
                 new HeatPumpService(gateway, clock),
                 new EnergyService(gateway, clock),
-                new HealthService(gateway, clock),
-                new HistoryService(influx, clock), setpoints);
+                new EnergyDetailsService(gateway, clock),
+                new HealthService(gateway, clock, Objects.requireNonNullElse(System.getenv("VERSION"), "dev")),
+                new HistoryService(influx, clock), setpoints, new PiSensorService(gateway, clock),
+                new BatteryService(gateway, commands, clock),
+                new AuditService(new InfluxAuditRepository(influxSettings), clock), new StatsService(influx, clock),
+                weather(influxSettings, clock), commands);
+    }
+
+    private static WeatherService weather(InfluxSettings influx, Clock clock) {
+        var place = WeatherSettings.fromEnvironment(System.getenv());
+        return new WeatherService(
+                new OpenMeteoClient(URI.create("https://api.open-meteo.com"), place, WEATHER_TIMEOUT),
+                new ImgwClient(URI.create("https://danepubliczne.imgw.pl"), place, WARNINGS_TIMEOUT),
+                new InfluxPvEnergy(influx), clock);
+    }
+
+    /** Keeps the gateway from restoring our setpoint changes while we are up (ADR-011). */
+    static LeaseRenewer leaseRenewer(Settings settings) {
+        return new LeaseRenewer(commands(settings));
+    }
+
+    private static GatewayHttpCommands commands(Settings settings) {
+        return new GatewayHttpCommands(settings.gatewayUrl(), settings.gatewayToken(), settings.gatewayTimeout());
     }
 }

backend/src/main/java/home/backend/Main.java

@@ -21,10 +21,14 @@ public final class Main {
             System.exit(2);
             return;
         }
+        Runtime.getRuntime().addShutdownHook(new Thread(server::stop));
         if (settings.gatewayToken() == null) {
             System.err.println("home-pump-backend: GATEWAY_TOKEN is not set, setpoint changes are disabled");
+        } else {
+            var renewer = Backend.leaseRenewer(settings);
+            Runtime.getRuntime().addShutdownHook(new Thread(renewer::close));
+            renewer.start();
         }
-        Runtime.getRuntime().addShutdownHook(new Thread(server::stop));
         server.start();
         System.out.println("home-pump-backend listening on port " + server.port());
     }

backend/src/main/java/home/backend/adapters/gateway/GatewayHttpClient.java

@@ -23,7 +23,7 @@ import java.util.stream.Collectors;
 /** Reads the gateway's {@code /health} and {@code /snapshot} over HTTP. */
 public class GatewayHttpClient implements GatewayClient {
 
-    private record Health(List<DeviceHealth> devices) {
+    private record Health(String version, List<DeviceHealth> devices) {
     }
 
     private record DeviceHealth(String name, String status, Instant lastSuccess, String lastError) {
@@ -61,7 +61,7 @@ public class GatewayHttpClient implements GatewayClient {
                         device.lastSuccess(), device.lastError(),
                         measurements.getOrDefault(device.name(), List.of())))
                 .toList();
-        return new GatewaySnapshot(devices);
+        return new GatewaySnapshot(health.version(), devices);
     }
 
     private static List<Measurement> measurements(DeviceReadings device) {

backend/src/main/java/home/backend/adapters/gateway/GatewayHttpCommands.java

@@ -3,10 +3,18 @@ package home.backend.adapters.gateway;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import home.backend.application.GatewayBattery;
 import home.backend.application.GatewayCommands;
+import home.backend.application.GatewayRefresh;
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
+import home.backend.domain.BatteryView.Reserve;
 import home.backend.domain.Command;
 import home.backend.domain.CommandResult;
+import home.backend.domain.RefreshResult;
+import home.backend.domain.RestoreResult;
 import home.backend.domain.SetpointState;
 
 import java.io.IOException;
@@ -15,23 +23,54 @@ import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
 import java.time.Duration;
+import java.time.Instant;
+import java.util.List;
 import java.util.Set;
 
-/** Sends commands to the gateway's {@code /commands} with the shared token (S6). */
-public class GatewayHttpCommands implements GatewayCommands {
+/** Calls the gateway's {@code /commands}, {@code /battery} and {@code /refresh} with the shared token (S6). */
+public class GatewayHttpCommands implements GatewayCommands, GatewayBattery, GatewayRefresh {
 
     /** The gateway answers a verdict with 200 (applied), 422 (rejected) or 502 (failed). */
     private static final Set<Integer> VERDICTS = Set.of(200, 422, 502);
 
+    /** Restore now: 200 restored, 404 nothing pending, 409 changed meanwhile, 429 too soon, 502 failed. */
+    private static final Set<Integer> RESTORE_VERDICTS = Set.of(200, 404, 409, 429, 502);
+
+    /** Battery change: 200 applied, 422 rejected, 409 stale or changed meanwhile, 429 too soon, 502 failed. */
+    private static final Set<Integer> BATTERY_VERDICTS = Set.of(200, 422, 409, 429, 502);
+
     @JsonInclude(JsonInclude.Include.NON_NULL)
-    private record Request(String setpoint, int value, Long minutes) {
+    private record ScheduleRequest(Boolean enabled, List<SlotRequest> slots) {
+    }
+
+    @JsonInclude(JsonInclude.Include.NON_NULL)
+    private record SlotRequest(int slot, Integer start, Integer soc, Boolean gridCharge) {
+    }
+
+    private record ReserveRequest(int pct) {
+    }
+
+    @JsonInclude(JsonInclude.Include.NON_NULL)
+    private record Request(String setpoint, int value, Long minutes, Instant until) {
+    }
+
+    private record RestoreRequest(String setpoint) {
+    }
+
+    private record Renewal(int renewed) {
     }
 
     private static final ObjectMapper JSON = new ObjectMapper()
             .registerModule(new JavaTimeModule())
+            .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
             .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
 
     private final URI endpoint;
+    private final URI renewEndpoint;
+    private final URI restoreEndpoint;
+    private final URI refreshEndpoint;
+    private final URI reserveEndpoint;
+    private final URI scheduleEndpoint;
     private final String token;
     private final Duration timeout;
     private final HttpClient http;
@@ -39,6 +78,11 @@ public class GatewayHttpCommands implements GatewayCommands {
     /** @param token null when not configured: every call then fails without touching the network */
     public GatewayHttpCommands(URI baseUri, String token, Duration timeout) {
         this.endpoint = baseUri.resolve("/commands");
+        this.renewEndpoint = baseUri.resolve("/commands/renew");
+        this.restoreEndpoint = baseUri.resolve("/commands/restore");
+        this.refreshEndpoint = baseUri.resolve("/refresh");
+        this.reserveEndpoint = baseUri.resolve("/battery/reserve");
+        this.scheduleEndpoint = baseUri.resolve("/battery/schedule");
         this.token = token;
         this.timeout = timeout;
         this.http = HttpClient.newBuilder().connectTimeout(timeout).build();
@@ -47,35 +91,84 @@ public class GatewayHttpCommands implements GatewayCommands {
     @Override
     public CommandResult apply(Command command) throws IOException {
         Long minutes = command.duration() == null ? null : command.duration().toMinutes();
-        byte[] body = JSON.writeValueAsBytes(new Request(command.setpoint(), command.value(), minutes));
+        byte[] body = JSON.writeValueAsBytes(new Request(command.setpoint(), command.value(), minutes, command.heldUntil()));
         HttpRequest.Builder request = request().header("Content-Type", "application/json")
                 .header("X-Requested-By", command.requestedBy())
                 .POST(HttpRequest.BodyPublishers.ofByteArray(body));
         return JSON.readValue(send(request, VERDICTS), CommandResult.class);
     }
 
+    @Override
+    public RestoreResult restore(String setpoint, String requestedBy) throws IOException {
+        byte[] body = JSON.writeValueAsBytes(new RestoreRequest(setpoint));
+        var request = request(restoreEndpoint).header("Content-Type", "application/json")
+                .header("X-Requested-By", requestedBy).POST(HttpRequest.BodyPublishers.ofByteArray(body));
+        return JSON.readValue(send(request, RESTORE_VERDICTS), RestoreResult.class);
+    }
+
     @Override
     public SetpointState setpoints() throws IOException {
         return JSON.readValue(send(request().GET(), Set.of(200)), SetpointState.class);
     }
 
+    @Override
+    public int renewLeases() throws IOException {
+        var request = request(renewEndpoint).POST(HttpRequest.BodyPublishers.noBody());
+        return JSON.readValue(send(request, Set.of(200)), Renewal.class).renewed();
+    }
+
+    @Override
+    public RefreshResult refresh() throws IOException {
+        var request = request(refreshEndpoint).POST(HttpRequest.BodyPublishers.noBody());
+        return JSON.readValue(send(request, Set.of(200)), RefreshResult.class);
+    }
+
+    @Override
+    public Reserve reserve() throws IOException {
+        return JSON.readValue(send(request(reserveEndpoint).GET(), Set.of(200)), Reserve.class);
+    }
+
+    @Override
+    public BatteryResult changeSchedule(BatteryChange change, String requestedBy) throws IOException {
+        var slots = change.slots().stream().map(slot -> new SlotRequest(slot.slot(),
+                slot.from() == null ? null : slot.from().getHour() * 100 + slot.from().getMinute(),
+                slot.socPct(), slot.gridCharge())).toList();
+        return battery(scheduleEndpoint, new ScheduleRequest(change.enabled(), slots), requestedBy);
+    }
+
+    @Override
+    public BatteryResult changeReserve(int pct, String requestedBy) throws IOException {
+        return battery(reserveEndpoint, new ReserveRequest(pct), requestedBy);
+    }
+
+    private BatteryResult battery(URI uri, Object body, String requestedBy) throws IOException {
+        var request = request(uri).header("Content-Type", "application/json").header("X-Requested-By", requestedBy)
+                .POST(HttpRequest.BodyPublishers.ofByteArray(JSON.writeValueAsBytes(body)));
+        return JSON.readValue(send(request, BATTERY_VERDICTS), BatteryResult.class);
+    }
+
     private HttpRequest.Builder request() throws IOException {
+        return request(endpoint);
+    }
+
+    private HttpRequest.Builder request(URI uri) throws IOException {
         if (token == null) {
             throw new IOException("GATEWAY_TOKEN is not set, commands are disabled");
         }
-        return HttpRequest.newBuilder(endpoint).timeout(timeout).header("Authorization", "Bearer " + token);
+        return HttpRequest.newBuilder(uri).timeout(timeout).header("Authorization", "Bearer " + token);
     }
 
     private byte[] send(HttpRequest.Builder request, Set<Integer> accepted) throws IOException {
         try {
-            var response = http.send(request.build(), HttpResponse.BodyHandlers.ofByteArray());
+            var built = request.build();
+            var response = http.send(built, HttpResponse.BodyHandlers.ofByteArray());
             if (!accepted.contains(response.statusCode())) {
-                throw new IOException("gateway /commands answered " + response.statusCode());
+                throw new IOException("gateway " + built.uri().getPath() + " answered " + response.statusCode());
             }
             return response.body();
         } catch (InterruptedException e) {
             Thread.currentThread().interrupt();
-            throw new IOException("interrupted while calling gateway /commands", e);
+            throw new IOException("interrupted while calling the gateway", e);
         }
     }
 }

backend/src/main/java/home/backend/adapters/http/ApiServer.java

@@ -9,15 +9,27 @@ import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpHandler;
 import com.sun.net.httpserver.HttpServer;
+import home.backend.application.AuditService;
+import home.backend.application.BatteryService;
+import home.backend.application.EnergyDetailsService;
 import home.backend.application.EnergyService;
+import home.backend.application.GatewayRefresh;
 import home.backend.application.HealthService;
 import home.backend.application.HeatPumpService;
 import home.backend.application.HistoryService;
+import home.backend.application.StatsService;
+import home.backend.application.PiSensorService;
 import home.backend.application.SetpointService;
+import home.backend.application.WeatherService;
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
 import home.backend.domain.CommandResult.Status;
 import home.backend.domain.PresetResult;
+import home.backend.domain.RestoreResult;
 
 import java.io.IOException;
+import java.time.OffsetDateTime;
+import java.time.format.DateTimeParseException;
 import java.net.InetSocketAddress;
 import java.net.URLDecoder;
 import java.nio.charset.StandardCharsets;
@@ -37,12 +49,30 @@ public class ApiServer {
             .disable(DeserializationFeature.ACCEPT_FLOAT_AS_INT)
             .disable(MapperFeature.ALLOW_COERCION_OF_SCALARS);
 
+    private record ReserveRequest(Integer pct) {
+    }
+
     private record SetpointRequest(String setpoint, Integer value, Double hours) {
     }
 
+    /** {@code values}: the user's own value per setpoint of the preset, by setpoint name. */
+    private record PresetRequest(String until, Map<String, Integer> values) {
+
+        PresetRequest {
+            if (values == null) {
+                values = Map.of();
+            } else if (values.containsValue(null)) {
+                throw new IllegalArgumentException("a value must be a number");
+            }
+        }
+    }
+
     private static final String UNREACHABLE = "gateway unreachable";
+    private static final String UNAVAILABLE = "battery changes are not available: gateway unreachable or not enabled";
     private static final String WRITE_MARKER = "home-pump";
     private static final String PRESETS_PATH = "/api/presets/";
+    private static final String SETPOINTS_PATH = "/api/setpoints/";
+    private static final Pattern RESTORE_PATH = Pattern.compile("/api/setpoints/([a-z_]{1,32})/restore");
     /** The user name Traefik's auth forwards; anything odd falls back to the default. */
     private static final String USER_HEADER = "Remote-User";
     private static final String DEFAULT_USER = "phone";
@@ -58,8 +88,11 @@ public class ApiServer {
     private final ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor();
 
     /** Binds the port now; 0 picks a free one. */
-    public ApiServer(int port, HeatPumpService heatPump, EnergyService energy, HealthService health,
-            HistoryService history, SetpointService setpoints) throws IOException {
+    public ApiServer(int port, HeatPumpService heatPump, EnergyService energy,
+            EnergyDetailsService energyDetails, HealthService health,
+            HistoryService history, SetpointService setpoints, PiSensorService piSensor,
+            BatteryService battery, AuditService audit, StatsService stats, WeatherService weather,
+            GatewayRefresh refresh) throws IOException {
         server = HttpServer.create(new InetSocketAddress(port), 0);
         server.setExecutor(executor);
         // Everything outside the API, with the security headers too: the web UI is the frontend's (ADR-010).
@@ -70,13 +103,36 @@ public class ApiServer {
         });
         api("/api/heat-pump", query -> heatPump.current());
         api("/api/energy", query -> energy.current());
+        api("/api/energy/details", query -> energyDetails.current());
+        api("/api/battery", query -> battery.current());
+        route("/api/battery/schedule", exchange -> handle(exchange, Map.of(
+                "POST", () -> guarded(exchange, body -> postSchedule(exchange, body, battery)))));
+        route("/api/battery/reserve", exchange -> handle(exchange, Map.of(
+                "POST", () -> guarded(exchange, body -> postReserve(exchange, body, battery)))));
+        route("/api/refresh", exchange -> handle(exchange, Map.of(
+                "POST", () -> guarded(exchange, body -> postRefresh(exchange, refresh)))));
+        api("/api/pi-sensor", query -> piSensor.current());
+        api("/api/weather", query -> weather.current());
         api("/api/health", query -> health.current());
         route("/api/history", exchange -> handleHistory(exchange, history));
+        route("/api/audit", exchange -> handleAudit(exchange, audit));
+        route("/api/stats", exchange -> handleStats(exchange, stats));
         route("/api/setpoints", exchange -> handle(exchange, Map.of(
                 "GET", () -> getSetpoints(exchange, setpoints),
                 "POST", () -> guarded(exchange, body -> postSetpoint(exchange, body, setpoints)))));
+        context(SETPOINTS_PATH, exchange -> {
+            var restore = RESTORE_PATH.matcher(exchange.getRequestURI().getPath());
+            if (restore.matches()) {
+                handle(exchange, Map.of("POST", () -> guarded(exchange,
+                        body -> postRestore(exchange, restore.group(1), setpoints))));
+            } else {
+                try (exchange) {
+                    exchange.sendResponseHeaders(404, -1);
+                }
+            }
+        });
         context(PRESETS_PATH, exchange -> handle(exchange, Map.of(
-                "POST", () -> guarded(exchange, body -> postPreset(exchange, setpoints)))));
+                "POST", () -> guarded(exchange, body -> postPreset(exchange, body, setpoints)))));
     }
 
     /** The JDK matches a context by prefix, so /api/heat-pumpX would reach /api/heat-pump. */
@@ -175,15 +231,71 @@ public class ApiServer {
         }
     }
 
-    private static void postPreset(HttpExchange exchange, SetpointService setpoints) throws IOException {
+    private static void postSchedule(HttpExchange exchange, byte[] body, BatteryService battery) throws IOException {
+        try {
+            var change = JSON.readValue(body, BatteryChange.class);
+            if (change == null) {
+                throw new IllegalArgumentException("a change is required");
+            }
+            var result = battery.changeSchedule(change, user(exchange));
+            send(exchange, batteryHttpStatus(result.status()), result);
+        } catch (JsonProcessingException | IllegalArgumentException e) {
+            send(exchange, 400, error("expected {\"enabled\"?, \"slots\": [{\"slot\", \"from\"?: \"HH:MM\", "
+                    + "\"socPct\"?, \"gridCharge\"?}]}"));
+        } catch (IOException e) {
+            send(exchange, 503, error(UNAVAILABLE));
+        }
+    }
+
+    private static void postReserve(HttpExchange exchange, byte[] body, BatteryService battery) throws IOException {
+        try {
+            var request = JSON.readValue(body, ReserveRequest.class);
+            if (request == null || request.pct() == null) {
+                throw new IllegalArgumentException("pct is required");
+            }
+            var result = battery.changeReserve(request.pct(), user(exchange));
+            send(exchange, batteryHttpStatus(result.status()), result);
+        } catch (JsonProcessingException | IllegalArgumentException e) {
+            send(exchange, 400, error("expected {\"pct\"}"));
+        } catch (IOException e) {
+            send(exchange, 503, error(UNAVAILABLE));
+        }
+    }
+
+    private static void postRefresh(HttpExchange exchange, GatewayRefresh refresh) throws IOException {
+        try {
+            send(exchange, 200, refresh.refresh());
+        } catch (IOException e) {
+            send(exchange, 503, error(UNREACHABLE));
+        }
+    }
+
+    private static void postRestore(HttpExchange exchange, String setpoint, SetpointService setpoints)
+            throws IOException {
+        try {
+            var result = setpoints.restore(setpoint, user(exchange));
+            send(exchange, restoreHttpStatus(result.outcome()), result);
+        } catch (IOException e) {
+            send(exchange, 503, error(UNREACHABLE));
+        }
+    }
+
+    private static void postPreset(HttpExchange exchange, byte[] body, SetpointService setpoints)
+            throws IOException {
         String id = exchange.getRequestURI().getPath().substring(PRESETS_PATH.length());
         try {
-            var result = setpoints.applyPreset(id, user(exchange));
+            var request = body.length == 0 ? new PresetRequest(null, null) : JSON.readValue(body, PresetRequest.class);
+            var until = request.until() == null ? null : OffsetDateTime.parse(request.until()).toInstant();
+            var result = setpoints.applyPreset(id, until, request.values(), user(exchange));
             if (result.isPresent()) {
                 send(exchange, presetHttpStatus(result.get().status()), result.get());
             } else {
                 send(exchange, 404, error("no such preset"));
             }
+        } catch (JsonProcessingException | DateTimeParseException | IllegalArgumentException e) {
+            send(exchange, 400, error("expected {\"until\": \"2026-11-02T18:00:00+01:00\"} for a preset that needs "
+                    + "an end time, else no body; optional \"values\": {\"cwu_comfort\": 12} within the limits "
+                    + "for setpoints of the preset"));
         } catch (IOException e) {
             send(exchange, 503, error(UNREACHABLE));
         }
@@ -197,6 +309,26 @@ public class ApiServer {
         };
     }
 
+    private static int batteryHttpStatus(BatteryResult.Status status) {
+        return switch (status) {
+            case APPLIED -> 200;
+            case REJECTED -> 422;
+            case STALE -> 409;
+            case TOO_SOON -> 429;
+            case FAILED -> 502;
+        };
+    }
+
+    private static int restoreHttpStatus(RestoreResult.Outcome outcome) {
+        return switch (outcome) {
+            case RESTORED -> 200;
+            case NOT_PENDING -> 404;
+            case CONFLICT -> 409;
+            case TOO_SOON -> 429;
+            case FAILED -> 502;
+        };
+    }
+
     private static int presetHttpStatus(PresetResult.Status status) {
         return switch (status) {
             case APPLIED -> 200;
@@ -223,6 +355,31 @@ public class ApiServer {
         }));
     }
 
+    private void handleAudit(HttpExchange exchange, AuditService audit) throws IOException {
+        handle(exchange, Map.of("GET", () -> {
+            Map<String, String> query = parseQuery(exchange.getRequestURI().getRawQuery());
+            try {
+                send(exchange, 200, audit.audit(query.get("range")));
+            } catch (IllegalArgumentException e) {
+                send(exchange, 400, error(e.getMessage()));
+            } catch (IOException e) {
+                send(exchange, 502, error("audit unavailable"));
+            }
+        }));
+    }
+
+    private void handleStats(HttpExchange exchange, StatsService stats) throws IOException {
+        handle(exchange, Map.of("GET", () -> {
+            try {
+                send(exchange, 200, stats.stats(parseQuery(exchange.getRequestURI().getRawQuery()).get("range")));
+            } catch (IllegalArgumentException e) {
+                send(exchange, 400, error(e.getMessage()));
+            } catch (IOException e) {
+                send(exchange, 502, error("stats unavailable"));
+            }
+        }));
+    }
+
     private interface Action {
         void run() throws IOException;
     }

backend/src/main/java/home/backend/adapters/influx/InfluxAuditRepository.java

@@ -0,0 +1,88 @@
+package home.backend.adapters.influx;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import home.backend.application.AuditRepository;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/** The gateway's audit measurements (S3) read from InfluxDB; never written. */
+public final class InfluxAuditRepository implements AuditRepository {
+
+    private static final ObjectMapper JSON = new ObjectMapper();
+
+    private final InfluxClient influx;
+
+    public InfluxAuditRepository(InfluxSettings settings) {
+        this.influx = new InfluxClient(settings);
+    }
+
+    @Override
+    public List<Row> heatPump(Instant from, Instant to) throws IOException {
+        return rows("Dom_Pompa", "setpoint_audit", "setpoint", from, to);
+    }
+
+    @Override
+    public List<Row> battery(Instant from, Instant to) throws IOException {
+        return rows("electricity", "deye_settings_audit", "register", from, to);
+    }
+
+    private List<Row> rows(String database, String measurement, String targetTag, Instant from, Instant to)
+            throws IOException {
+        String query = "SELECT * FROM \"" + measurement + "\" WHERE time >= " + from.toEpochMilli()
+                + "ms AND time < " + to.toEpochMilli() + "ms ORDER BY time DESC";
+        var rows = new ArrayList<Row>();
+        for (JsonNode result : results(influx.query(database, query))) {
+            for (JsonNode series : result.path("series")) {
+                for (JsonNode values : series.path("values")) {
+                    rows.add(row(series.path("columns"), values, targetTag));
+                }
+            }
+        }
+        return rows;
+    }
+
+    private static JsonNode results(String body) throws IOException {
+        JsonNode root;
+        try {
+            root = JSON.readTree(body);
+        } catch (JsonProcessingException e) {
+            throw new IOException("InfluxDB returned invalid JSON: " + e.getOriginalMessage(), e);
+        }
+        failOnError(root);
+        for (JsonNode result : root.path("results")) {
+            failOnError(result);
+        }
+        return root.path("results");
+    }
+
+    private static void failOnError(JsonNode node) throws IOException {
+        if (node.hasNonNull("error")) {
+            throw new IOException("InfluxDB query failed: " + node.get("error").asText());
+        }
+    }
+
+    private static Row row(JsonNode columns, JsonNode values, String targetTag) {
+        Map<String, JsonNode> byName = new HashMap<>();
+        for (int i = 0; i < columns.size(); i++) {
+            byName.put(columns.get(i).asText(), values.get(i));
+        }
+        return new Row(Instant.ofEpochMilli(byName.get("time").asLong()), text(byName.get(targetTag)),
+                text(byName.get("requested_by")), text(byName.get("status")),
+                number(byName.get("old_value")), number(byName.get("new_value")));
+    }
+
+    private static String text(JsonNode node) {
+        return node == null || node.isNull() ? "" : node.asText();
+    }
+
+    private static Double number(JsonNode node) {
+        return node == null || !node.isNumber() ? null : node.asDouble();
+    }
+}

backend/src/main/java/home/backend/adapters/influx/InfluxClient.java

@@ -0,0 +1,47 @@
+package home.backend.adapters.influx;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URLEncoder;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.nio.charset.StandardCharsets;
+
+/** Read-only queries to InfluxDB 1.x over its HTTP {@code /query} endpoint; times come back in epoch ms. */
+final class InfluxClient {
+
+    private final InfluxSettings settings;
+    private final HttpClient http;
+
+    InfluxClient(InfluxSettings settings) {
+        this.settings = settings;
+        this.http = HttpClient.newBuilder().connectTimeout(settings.requestTimeout()).build();
+    }
+
+    String query(String database, String query) throws IOException {
+        HttpRequest request = HttpRequest.newBuilder(queryUri(database, query))
+                .timeout(settings.requestTimeout())
+                .GET()
+                .build();
+        try {
+            HttpResponse<String> response = http.send(request, HttpResponse.BodyHandlers.ofString());
+            if (response.statusCode() != 200) {
+                throw new IOException("InfluxDB answered HTTP " + response.statusCode());
+            }
+            return response.body();
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new IOException("InfluxDB request interrupted", e);
+        }
+    }
+
+    private URI queryUri(String database, String query) {
+        String base = settings.baseUri().toString().replaceAll("/+$", "");
+        return URI.create(base + "/query?db=" + encode(database) + "&epoch=ms&q=" + encode(query));
+    }
+
+    private static String encode(String value) {
+        return URLEncoder.encode(value, StandardCharsets.UTF_8);
+    }
+}

backend/src/main/java/home/backend/adapters/influx/InfluxHistoryRepository.java

@@ -1,16 +1,12 @@
 package home.backend.adapters.influx;
 
+import home.backend.application.HeatPumpSamples;
 import home.backend.application.HistoryRepository;
+import home.backend.domain.HeatPumpSample;
 import home.backend.domain.HistoryView.Point;
 import home.backend.domain.Series;
 
 import java.io.IOException;
-import java.net.URI;
-import java.net.URLEncoder;
-import java.net.http.HttpClient;
-import java.net.http.HttpRequest;
-import java.net.http.HttpResponse;
-import java.nio.charset.StandardCharsets;
 import java.time.Duration;
 import java.time.Instant;
 import java.util.List;
@@ -20,14 +16,12 @@ import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executors;
 
 /** History from InfluxDB 1.x over its HTTP {@code /query} endpoint (ADR-005, ADR-008). */
-public final class InfluxHistoryRepository implements HistoryRepository {
+public final class InfluxHistoryRepository implements HistoryRepository, HeatPumpSamples {
 
-    private final InfluxSettings settings;
-    private final HttpClient http;
+    private final InfluxClient influx;
 
     public InfluxHistoryRepository(InfluxSettings settings) {
-        this.settings = settings;
-        this.http = HttpClient.newBuilder().connectTimeout(settings.requestTimeout()).build();
+        this.influx = new InfluxClient(settings);
     }
 
     @Override
@@ -57,39 +51,19 @@ public final class InfluxHistoryRepository implements HistoryRepository {
                 .toList();
     }
 
+    @Override
+    public List<HeatPumpSample> samples(Instant from, Instant to) throws IOException {
+        String query = InfluxSamples.query(from.toEpochMilli(), to.toEpochMilli());
+        return InfluxSamples.parse(influx.query(SeriesSources.LEGACY, query));
+    }
+
     private Map<Long, Double> part(Source source, Instant from, Instant to, long stepMinutes) throws IOException {
         String query = source.query(from.toEpochMilli(), to.toEpochMilli(), stepMinutes);
-        return InfluxResponse.parse(fetch(source.database(), query));
+        return InfluxResponse.parse(influx.query(source.database(), query));
     }
 
     private static long stepMinutes(Instant from, Instant to, int maxPoints) {
         long stepMillis = Math.ceilDiv(Duration.between(from, to).toMillis(), maxPoints);
         return Math.max(1, Math.ceilDiv(stepMillis, Duration.ofMinutes(1).toMillis()));
     }
-
-    private String fetch(String database, String query) throws IOException {
-        HttpRequest request = HttpRequest.newBuilder(queryUri(database, query))
-                .timeout(settings.requestTimeout())
-                .GET()
-                .build();
-        try {
-            HttpResponse<String> response = http.send(request, HttpResponse.BodyHandlers.ofString());
-            if (response.statusCode() != 200) {
-                throw new IOException("InfluxDB answered HTTP " + response.statusCode());
-            }
-            return response.body();
-        } catch (InterruptedException e) {
-            Thread.currentThread().interrupt();
-            throw new IOException("InfluxDB request interrupted", e);
-        }
-    }
-
-    private URI queryUri(String database, String query) {
-        String base = settings.baseUri().toString().replaceAll("/+$", "");
-        return URI.create(base + "/query?db=" + encode(database) + "&epoch=ms&q=" + encode(query));
-    }
-
-    private static String encode(String value) {
-        return URLEncoder.encode(value, StandardCharsets.UTF_8);
-    }
 }

backend/src/main/java/home/backend/adapters/influx/InfluxPvEnergy.java

@@ -0,0 +1,51 @@
+package home.backend.adapters.influx;
+
+import home.backend.application.PvEnergyRepository;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.Map;
+import java.util.TreeMap;
+
+/** Daily PV energy: the Deye's and the Fronius's own day counters, each read as the day's maximum. */
+public final class InfluxPvEnergy implements PvEnergyRepository {
+
+    private static final ZoneId ZONE = ZoneId.of("Europe/Warsaw");
+    private static final String DATABASE = "electricity";
+
+    private final InfluxClient influx;
+
+    public InfluxPvEnergy(InfluxSettings settings) {
+        this.influx = new InfluxClient(settings);
+    }
+
+    @Override
+    public Map<LocalDate, Double> dailyKwh(LocalDate from, LocalDate to) throws IOException {
+        Map<LocalDate, Double> deye = dailyMax("deye", "pv_today_kwh", from, to);
+        Map<LocalDate, Double> fronius = dailyMax("fronius", "energy_day_wh", from, to);
+        Map<LocalDate, Double> total = new TreeMap<>();
+        deye.forEach((day, kwh) -> {
+            Double wh = fronius.get(day);
+            if (wh != null) {
+                total.put(day, kwh + wh / 1000);
+            }
+        });
+        return total;
+    }
+
+    private Map<LocalDate, Double> dailyMax(String measurement, String field, LocalDate from, LocalDate to)
+            throws IOException {
+        String query = "SELECT max(\"" + field + "\") FROM \"" + measurement + "\" WHERE time >= "
+                + millis(from) + "ms AND time < " + millis(to) + "ms GROUP BY time(1d) fill(none) tz('Europe/Warsaw')";
+        Map<LocalDate, Double> days = new TreeMap<>();
+        InfluxResponse.parse(influx.query(DATABASE, query)).forEach((start, max) ->
+                days.put(Instant.ofEpochMilli(start).atZone(ZONE).toLocalDate(), max));
+        return days;
+    }
+
+    private static long millis(LocalDate day) {
+        return day.atStartOfDay(ZONE).toInstant().toEpochMilli();
+    }
+}

backend/src/main/java/home/backend/adapters/influx/InfluxSamples.java

@@ -0,0 +1,58 @@
+package home.backend.adapters.influx;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import home.backend.domain.HeatPumpSample;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+
+/** The raw {@code heat_pump} rows of an InfluxDB 1.x query. */
+final class InfluxSamples {
+
+    private static final ObjectMapper JSON = new ObjectMapper();
+
+    private InfluxSamples() {
+    }
+
+    static String query(long fromMs, long toMs) {
+        return "SELECT output_compressor, output_cwu, output_co, output_heater, outdoor_temp, cwu_temp"
+                + " FROM \"heat_pump\" WHERE time >= " + fromMs + "ms AND time < " + toMs + "ms";
+    }
+
+    /** The rows of {@link #query}, as returned (ascending); empty when there is no data. */
+    static List<HeatPumpSample> parse(String body) throws IOException {
+        JsonNode root;
+        try {
+            root = JSON.readTree(body);
+        } catch (JsonProcessingException e) {
+            throw new IOException("InfluxDB returned invalid JSON: " + e.getOriginalMessage(), e);
+        }
+        failOnError(root);
+        List<HeatPumpSample> samples = new ArrayList<>();
+        for (JsonNode result : root.path("results")) {
+            failOnError(result);
+            for (JsonNode series : result.path("series")) {
+                for (JsonNode row : series.path("values")) {
+                    samples.add(new HeatPumpSample(Instant.ofEpochMilli(row.get(0).asLong()),
+                            number(row, 1), number(row, 2), number(row, 3), number(row, 4),
+                            number(row, 5), number(row, 6)));
+                }
+            }
+        }
+        return samples;
+    }
+
+    private static Double number(JsonNode row, int column) {
+        return row.get(column).isNumber() ? row.get(column).asDouble() : null;
+    }
+
+    private static void failOnError(JsonNode node) throws IOException {
+        if (node.hasNonNull("error")) {
+            throw new IOException("InfluxDB query failed: " + node.get("error").asText());
+        }
+    }
+}

backend/src/main/java/home/backend/adapters/influx/SeriesSources.java

@@ -8,7 +8,7 @@ import java.util.Map;
 /** Where each series lives in InfluxDB. A fixed table: no query is built from user input. */
 final class SeriesSources {
 
-    private static final String LEGACY = "Dom_Pompa";
+    static final String LEGACY = "Dom_Pompa";
     private static final String ELECTRICITY = "electricity";
 
     private static final Map<Series, List<Source>> SOURCES = Map.ofEntries(

backend/src/main/java/home/backend/adapters/weather/HttpJson.java

@@ -0,0 +1,42 @@
+package home.backend.adapters.weather;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+
+/** GET of a public JSON document, with a timeout on connecting and on the whole request. */
+final class HttpJson {
+
+    private static final ObjectMapper JSON = new ObjectMapper();
+
+    private final HttpClient http;
+    private final Duration timeout;
+
+    HttpJson(Duration timeout) {
+        this.http = HttpClient.newBuilder().connectTimeout(timeout).build();
+        this.timeout = timeout;
+    }
+
+    JsonNode get(URI uri) throws IOException {
+        HttpRequest request = HttpRequest.newBuilder(uri).timeout(timeout).GET().build();
+        try {
+            HttpResponse<String> response = http.send(request, HttpResponse.BodyHandlers.ofString());
+            if (response.statusCode() != 200) {
+                throw new IOException(uri.getHost() + " answered HTTP " + response.statusCode());
+            }
+            return JSON.readTree(response.body());
+        } catch (JsonProcessingException e) {
+            throw new IOException(uri.getHost() + " returned invalid JSON: " + e.getOriginalMessage(), e);
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new IOException("request to " + uri.getHost() + " interrupted", e);
+        }
+    }
+}

backend/src/main/java/home/backend/adapters/weather/ImgwClient.java

@@ -0,0 +1,76 @@
+package home.backend.adapters.weather;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import home.backend.application.WarningSource;
+import home.backend.domain.WeatherView.Warning;
+
+import java.io.IOException;
+import java.net.URI;
+import java.time.DateTimeException;
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.time.OffsetDateTime;
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * IMGW's public list of meteorological warnings, kept to those naming one of our TERYT areas. A warning
+ * that is malformed (no degree or times) is left out rather than failing the others.
+ */
+public final class ImgwClient implements WarningSource {
+
+    private static final ZoneId POLAND = ZoneId.of("Europe/Warsaw");
+    private static final DateTimeFormatter TIME = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
+
+    private final HttpJson http;
+    private final URI uri;
+    private final List<String> teryt;
+
+    public ImgwClient(URI baseUri, WeatherSettings place, Duration timeout) {
+        this.http = new HttpJson(timeout);
+        this.uri = URI.create(baseUri.toString().replaceAll("/+$", "") + "/api/data/warningsmeteo");
+        this.teryt = place.teryt();
+    }
+
+    @Override
+    public List<Warning> warnings() throws IOException {
+        JsonNode root = http.get(uri);
+        if (!root.isArray()) {
+            throw new IOException("IMGW returned no list of warnings");
+        }
+        List<Warning> ours = new ArrayList<>();
+        for (JsonNode item : root) {
+            if (covers(item.path("teryt"))) {
+                warning(item).ifPresent(ours::add);
+            }
+        }
+        return ours;
+    }
+
+    private boolean covers(JsonNode codes) {
+        for (JsonNode code : codes) {
+            if (teryt.contains(code.asText())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static Optional<Warning> warning(JsonNode item) {
+        try {
+            return Optional.of(new Warning(item.path("nazwa_zdarzenia").asText(),
+                    Integer.parseInt(item.path("stopien").asText()),
+                    time(item.path("obowiazuje_od")), time(item.path("obowiazuje_do")),
+                    item.path("tresc").asText()));
+        } catch (NumberFormatException | DateTimeException e) {
+            return Optional.empty();
+        }
+    }
+
+    private static OffsetDateTime time(JsonNode text) {
+        return LocalDateTime.parse(text.asText(), TIME).atZone(POLAND).toOffsetDateTime();
+    }
+}

backend/src/main/java/home/backend/adapters/weather/OpenMeteoClient.java

@@ -0,0 +1,68 @@
+package home.backend.adapters.weather;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import home.backend.application.ForecastSource;
+import home.backend.domain.Forecast;
+import home.backend.domain.Forecast.DailyForecast;
+
+import java.io.IOException;
+import java.net.URI;
+import java.time.DateTimeException;
+import java.time.Duration;
+import java.time.LocalDate;
+import java.util.Map;
+import java.util.TreeMap;
+
+/** Open-Meteo (free, no key): daily values for the past 14 days and the next 4, and the temperature now. */
+public final class OpenMeteoClient implements ForecastSource {
+
+    private static final String DAILY = "weather_code,temperature_2m_max,temperature_2m_min,precipitation_sum,"
+            + "shortwave_radiation_sum,sunshine_duration";
+
+    private final HttpJson http;
+    private final URI uri;
+
+    public OpenMeteoClient(URI baseUri, WeatherSettings place, Duration timeout) {
+        this.http = new HttpJson(timeout);
+        this.uri = URI.create(baseUri.toString().replaceAll("/+$", "") + "/v1/forecast?latitude="
+                + place.latitude() + "&longitude=" + place.longitude() + "&daily=" + DAILY
+                + "&current=temperature_2m&timezone=Europe%2FWarsaw&past_days=14&forecast_days=4");
+    }
+
+    @Override
+    public Forecast forecast() throws IOException {
+        JsonNode root = http.get(uri);
+        JsonNode daily = root.path("daily");
+        JsonNode dates = daily.path("time");
+        if (!dates.isArray() || dates.isEmpty()) {
+            throw new IOException("Open-Meteo returned no daily forecast");
+        }
+        Map<LocalDate, DailyForecast> days = new TreeMap<>();
+        for (int i = 0; i < dates.size(); i++) {
+            days.put(date(dates.get(i).asText()), new DailyForecast(
+                    integer(daily, "weather_code", i), number(daily, "temperature_2m_max", i),
+                    number(daily, "temperature_2m_min", i), number(daily, "precipitation_sum", i),
+                    number(daily, "shortwave_radiation_sum", i), number(daily, "sunshine_duration", i)));
+        }
+        JsonNode now = root.path("current").path("temperature_2m");
+        return new Forecast(now.isNumber() ? now.asDouble() : null, days);
+    }
+
+    private static LocalDate date(String text) throws IOException {
+        try {
+            return LocalDate.parse(text);
+        } catch (DateTimeException e) {
+            throw new IOException("Open-Meteo returned a bad date: " + text, e);
+        }
+    }
+
+    private static Double number(JsonNode daily, String name, int i) {
+        JsonNode value = daily.path(name).path(i);
+        return value.isNumber() ? value.asDouble() : null;
+    }
+
+    private static Integer integer(JsonNode daily, String name, int i) {
+        JsonNode value = daily.path(name).path(i);
+        return value.isNumber() ? value.asInt() : null;
+    }
+}

backend/src/main/java/home/backend/adapters/weather/WeatherSettings.java

@@ -0,0 +1,35 @@
+package home.backend.adapters.weather;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Where the house is and which IMGW areas (TERYT powiat codes) count as ours. Krosno is a city with
+ * powiat rights, 1862; 1807 is the surrounding powiat krośnieński, which warnings may name instead.
+ */
+public record WeatherSettings(double latitude, double longitude, List<String> teryt) {
+
+    public static WeatherSettings fromEnvironment(Map<String, String> env) {
+        return new WeatherSettings(
+                coordinate(env, "WEATHER_LAT", 49.684, 90),
+                coordinate(env, "WEATHER_LON", 21.770, 180),
+                List.of(env.getOrDefault("WEATHER_TERYT", "1862,1807").strip().split("\\s*,\\s*")));
+    }
+
+    private static double coordinate(Map<String, String> env, String name, double fallback, double limit) {
+        String value = env.get(name);
+        if (value == null || value.isBlank()) {
+            return fallback;
+        }
+        try {
+            double number = Double.parseDouble(value.strip());
+            if (Math.abs(number) <= limit) {
+                return number;
+            }
+        } catch (NumberFormatException e) {
+            // reported below with the same message
+        }
+        throw new IllegalArgumentException(name + " must be a number from -" + limit + " to " + limit
+                + ", got: " + value);
+    }
+}

backend/src/main/java/home/backend/application/AuditRepository.java

@@ -0,0 +1,17 @@
+package home.backend.application;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.List;
+
+/** The gateway's audit rows in InfluxDB (S3), read only. */
+public interface AuditRepository {
+
+    /** One audited write as recorded; {@code target} is the setpoint name or the Deye register. */
+    record Row(Instant time, String target, String requestedBy, String status, Double oldValue, Double newValue) {
+    }
+
+    List<Row> heatPump(Instant from, Instant to) throws IOException;
+
+    List<Row> battery(Instant from, Instant to) throws IOException;
+}

backend/src/main/java/home/backend/application/AuditService.java

@@ -0,0 +1,70 @@
+package home.backend.application;
+
+import home.backend.application.AuditRepository.Row;
+import home.backend.domain.AuditEntry;
+import home.backend.domain.AuditView;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.stream.Stream;
+
+/** S3: who changed what and when, from the gateway's audit rows of the heat pump and of the battery. */
+public class AuditService {
+
+    private static final String DEFAULT_RANGE = "7d";
+    private static final Map<String, Duration> RANGES =
+            Map.of("24h", Duration.ofHours(24), "7d", Duration.ofDays(7), "30d", Duration.ofDays(30));
+    private static final Map<String, String> SETPOINTS = Map.of(
+            "cwu_economy", "Ciepła woda – oszczędnie", "cwu_comfort", "Ciepła woda – komfort",
+            "co_economy", "Ogrzewanie – oszczędnie", "co_comfort", "Ogrzewanie – komfort");
+    private static final String RESTORE_USER = "restore";
+    private static final String RESTORE_LABEL = "automatycznie (przywrócenie)";
+
+    private final AuditRepository repository;
+    private final Clock clock;
+
+    public AuditService(AuditRepository repository, Clock clock) {
+        this.repository = repository;
+        this.clock = clock;
+    }
+
+    /**
+     * @param range {@code 24h}, {@code 7d} or {@code 30d}; null means 7d
+     * @throws IllegalArgumentException for an unknown range
+     */
+    public AuditView audit(String range) throws IOException {
+        Duration length = RANGES.get(range == null ? DEFAULT_RANGE : range);
+        if (length == null) {
+            throw new IllegalArgumentException("unknown range: " + range);
+        }
+        Instant to = clock.instant();
+        Instant from = to.minus(length);
+        var heatPump = repository.heatPump(from, to).stream().map(AuditService::heatPumpEntry);
+        var battery = repository.battery(from, to).stream().map(AuditService::batteryEntry);
+        return new AuditView(Stream.concat(heatPump, battery)
+                .sorted(Comparator.comparing(AuditEntry::time).reversed())
+                .toList());
+    }
+
+    private static AuditEntry heatPumpEntry(Row row) {
+        return entry(AuditEntry.HEAT_PUMP, row, SETPOINTS.getOrDefault(row.target(), row.target()), "°C");
+    }
+
+    private static AuditEntry batteryEntry(Row row) {
+        var label = DeyeSettingLabels.of(row.target());
+        return entry(AuditEntry.BATTERY, row, label.what(), label.unit());
+    }
+
+    private static AuditEntry entry(String source, Row row, String what, String unit) {
+        return new AuditEntry(row.time(), source, what, whole(row.oldValue()), whole(row.newValue()), unit,
+                RESTORE_USER.equals(row.requestedBy()) ? RESTORE_LABEL : row.requestedBy(), row.status());
+    }
+
+    private static Integer whole(Double value) {
+        return value == null ? null : (int) Math.round(value);
+    }
+}

backend/src/main/java/home/backend/application/BatteryService.java

@@ -0,0 +1,114 @@
+package home.backend.application;
+
+import home.backend.application.SnapshotFields.Live;
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
+import home.backend.domain.BatteryView;
+import home.backend.domain.BatteryView.Energy;
+import home.backend.domain.BatteryView.Limits;
+import home.backend.domain.BatteryView.Mode;
+import home.backend.domain.BatteryView.Reserve;
+import home.backend.domain.BatteryView.Slot;
+import home.backend.domain.GatewaySnapshot;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.IntStream;
+
+import static home.backend.application.SnapshotFields.on;
+import static home.backend.application.SnapshotFields.whole;
+
+/** F7: the Deye's battery now, and how it is set up. */
+public class BatteryService {
+
+    /** The settings are read every 10 minutes; three missed reads and they are not current. */
+    private static final Duration SETTINGS_MAX_AGE = Duration.ofMinutes(30);
+    private static final int SLOTS = 6;
+    /** The nominal voltage of a 16-cell lithium pack; the Deye reports capacity in Ah only. */
+    private static final double NOMINAL_VOLTS = 51.2;
+
+    private final GatewayClient gateway;
+    private final GatewayBattery battery;
+    private final Clock clock;
+
+    public BatteryService(GatewayClient gateway, GatewayBattery battery, Clock clock) {
+        this.gateway = gateway;
+        this.battery = battery;
+        this.clock = clock;
+    }
+
+    public BatteryResult changeSchedule(BatteryChange change, String user) throws IOException {
+        return battery.changeSchedule(change, user);
+    }
+
+    public BatteryResult changeReserve(int pct, String user) throws IOException {
+        return battery.changeReserve(pct, user);
+    }
+
+    /** Asked on its own: a gateway without battery commands still serves the live view. */
+    private Reserve reserve() {
+        try {
+            return battery.reserve();
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    public BatteryView current() throws IOException {
+        GatewaySnapshot snapshot = gateway.snapshot();
+        Live deye = SnapshotFields.live(snapshot, "deye", "deye", clock.instant());
+        Live settings = SnapshotFields.live(snapshot, "deye-settings", "deye_settings", clock.instant(),
+                SETTINGS_MAX_AGE);
+        Map<String, Double> d = deye.fields();
+        Map<String, Double> s = settings.fields();
+        boolean settingsStale = settings.source().stale();
+        Reserve reserve = reserve();
+        return new BatteryView(deye.source().time(), deye.source().stale(),
+                d.get("battery_soc_pct"), d.get("battery_power_w"), d.get("battery_voltage_v"),
+                d.get("battery_current_a"), d.get("battery_temperature_c"), capacityKwh(s),
+                new Energy(d.get("battery_charge_today_kwh"), d.get("battery_discharge_today_kwh")),
+                new Energy(d.get("battery_charge_total_kwh"), d.get("battery_discharge_total_kwh")),
+                settingsStale ? null : mode(s), settingsStale ? List.of() : schedule(s),
+                settingsStale ? null : limits(s), settings.source().time(), settingsStale, reserve, reserve != null);
+    }
+
+    private static Double capacityKwh(Map<String, Double> settings) {
+        Double ah = settings.get("battery_capacity_ah");
+        return ah == null ? null : Math.round(ah * NOMINAL_VOLTS) / 1000.0;
+    }
+
+    private static Mode mode(Map<String, Double> s) {
+        boolean tou = on(s, "tou_enabled");
+        return new Mode(tou, tou ? "Harmonogram: bateria pracuje według przedziałów"
+                : "Rezerwa na awarię: bateria nie rozładowuje się na co dzień");
+    }
+
+    /** Slot n runs from its start to the start of slot n + 1; the last one wraps to the first.
+     * No schedule at all when a start is missing. */
+    private static List<Slot> schedule(Map<String, Double> s) {
+        boolean complete = IntStream.rangeClosed(1, SLOTS).allMatch(n -> whole(s, "prog" + n + "_start_hhmm") != null);
+        if (!complete) {
+            return List.of();
+        }
+        return IntStream.rangeClosed(1, SLOTS).mapToObj(n -> {
+            String prefix = "prog" + n + "_";
+            String next = "prog" + (n % SLOTS + 1) + "_start_hhmm";
+            return new Slot(time(whole(s, prefix + "start_hhmm")), time(whole(s, next)),
+                    whole(s, prefix + "power_w"), whole(s, prefix + "soc_pct"), on(s, prefix + "grid_charge"));
+        }).toList();
+    }
+
+    private static String time(int hhmm) {
+        return "%02d:%02d".formatted(hhmm / 100, hhmm % 100);
+    }
+
+    private static Limits limits(Map<String, Double> s) {
+        return new Limits(whole(s, "max_charge_current_a"), whole(s, "max_discharge_current_a"),
+                whole(s, "shutdown_soc_pct"), whole(s, "low_soc_pct"), whole(s, "restart_soc_pct"),
+                on(s, "grid_charge_enabled"), whole(s, "grid_charge_current_a"),
+                whole(s, "grid_charge_start_soc_pct"));
+    }
+}

backend/src/main/java/home/backend/application/Cached.java

@@ -0,0 +1,80 @@
+package home.backend.application;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.ZoneId;
+
+/**
+ * One remote answer kept for a while, and no longer than its local day when a zone is given. When a refresh
+ * fails the older answer is served marked stale, and the source is left alone for a short back-off so a
+ * source that is down does not make every request wait for its timeout.
+ */
+final class Cached<T> {
+
+    interface Fetch<T> {
+        T fetch() throws IOException;
+    }
+
+    record Entry<T>(T value, boolean stale) {
+    }
+
+    private static final Duration BACK_OFF = Duration.ofSeconds(60);
+
+    private final Duration ttl;
+    private final ZoneId dayZone;
+    private final Clock clock;
+    private final Fetch<T> source;
+    private T value;
+    private Instant fetchedAt;
+    private Instant failedAt;
+
+    Cached(Duration ttl, Clock clock, Fetch<T> source) {
+        this(ttl, null, clock, source);
+    }
+
+    /** @param dayZone the answer expires at midnight of this zone even before the ttl, or null */
+    Cached(Duration ttl, ZoneId dayZone, Clock clock, Fetch<T> source) {
+        this.ttl = ttl;
+        this.dayZone = dayZone;
+        this.clock = clock;
+        this.source = source;
+    }
+
+    /** @throws IOException when the refresh fails or is backing off, and there is nothing older to serve */
+    synchronized Entry<T> get() throws IOException {
+        Instant now = clock.instant();
+        if (value != null && now.isBefore(expiry())) {
+            return new Entry<>(value, false);
+        }
+        if (failedAt != null && now.isBefore(failedAt.plus(BACK_OFF))) {
+            return older(new IOException("source failed recently, not retrying yet"));
+        }
+        try {
+            value = source.fetch();
+            fetchedAt = now;
+            failedAt = null;
+            return new Entry<>(value, false);
+        } catch (IOException e) {
+            failedAt = now;
+            return older(e);
+        }
+    }
+
+    private Entry<T> older(IOException failure) throws IOException {
+        if (value == null) {
+            throw failure;
+        }
+        return new Entry<>(value, true);
+    }
+
+    private Instant expiry() {
+        Instant byTtl = fetchedAt.plus(ttl);
+        if (dayZone == null) {
+            return byTtl;
+        }
+        Instant midnight = fetchedAt.atZone(dayZone).toLocalDate().plusDays(1).atStartOfDay(dayZone).toInstant();
+        return midnight.isBefore(byTtl) ? midnight : byTtl;
+    }
+}

backend/src/main/java/home/backend/application/DayTally.java

@@ -0,0 +1,96 @@
+package home.backend.application;
+
+import home.backend.domain.HeatPumpSample;
+import home.backend.domain.StatsView.Day;
+import home.backend.domain.StatsView.Totals;
+
+import java.time.Duration;
+import java.time.LocalDate;
+
+/** What the heat pump did over some span of polls; days are added up into the totals. */
+final class DayTally {
+
+    private double compressorSeconds;
+    private double cwuSeconds;
+    private double coSeconds;
+    private double heaterSeconds;
+    private int starts;
+    private int samples;
+    private double outdoorSum;
+    private int outdoorCount;
+    private Double minCwu;
+    private Double maxCwu;
+
+    void sample(HeatPumpSample s) {
+        samples++;
+        if (s.outdoorTemp() != null) {
+            outdoorSum += s.outdoorTemp();
+            outdoorCount++;
+        }
+        if (s.cwuTemp() != null) {
+            minCwu = lower(minCwu, s.cwuTemp());
+            maxCwu = higher(maxCwu, s.cwuTemp());
+        }
+    }
+
+    /** The outputs of {@code s} held for {@code held}. */
+    void hold(HeatPumpSample s, Duration held) {
+        double seconds = held.toMillis() / 1000.0;
+        compressorSeconds += on(s.compressor()) ? seconds : 0;
+        cwuSeconds += on(s.cwu()) ? seconds : 0;
+        coSeconds += on(s.co()) ? seconds : 0;
+        heaterSeconds += on(s.heater()) ? seconds : 0;
+    }
+
+    void start() {
+        starts++;
+    }
+
+    void add(DayTally other) {
+        compressorSeconds += other.compressorSeconds;
+        cwuSeconds += other.cwuSeconds;
+        coSeconds += other.coSeconds;
+        heaterSeconds += other.heaterSeconds;
+        starts += other.starts;
+        samples += other.samples;
+        outdoorSum += other.outdoorSum;
+        outdoorCount += other.outdoorCount;
+        if (other.minCwu != null) {
+            minCwu = lower(minCwu, other.minCwu);
+            maxCwu = higher(maxCwu, other.maxCwu);
+        }
+    }
+
+    Day day(LocalDate date) {
+        if (samples == 0) {
+            return new Day(date, null, null, null, null, null, null, null, null);
+        }
+        return new Day(date, hours(compressorSeconds), starts, hours(cwuSeconds), hours(coSeconds),
+                hours(heaterSeconds), avgOutdoor(), minCwu, maxCwu);
+    }
+
+    Totals totals() {
+        return new Totals(hours(compressorSeconds), starts, hours(cwuSeconds), hours(coSeconds),
+                hours(heaterSeconds), avgOutdoor(), minCwu, maxCwu);
+    }
+
+    static boolean on(Double output) {
+        return output != null && output > 0;
+    }
+
+    private static Double lower(Double known, double value) {
+        return known == null ? value : Math.min(known, value);
+    }
+
+    private static Double higher(Double known, double value) {
+        return known == null ? value : Math.max(known, value);
+    }
+
+    private Double avgOutdoor() {
+        return outdoorCount == 0 ? null : Math.round(outdoorSum / outdoorCount * 10) / 10.0;
+    }
+
+    private static double hours(double seconds) {
+        return Math.round(seconds / 3600 * 100) / 100.0;
+    }
+}

backend/src/main/java/home/backend/application/DeyeSettingLabels.java

@@ -0,0 +1,48 @@
+package home.backend.application;
+
+import java.util.Optional;
+
+/** Polish name and unit of the Deye program registers and of the app's reserve, as the gateway audits them. */
+final class DeyeSettingLabels {
+
+    record Label(String what, String unit) {
+    }
+
+    private static final int TOU_ENABLE = 146;
+    private static final int FIRST_START = 148;
+    private static final int FIRST_SOC = 166;
+    private static final int FIRST_GRID_CHARGE = 172;
+    private static final int SLOTS = 6;
+
+    private DeyeSettingLabels() {
+    }
+
+    static Label of(String register) {
+        if ("reserve".equals(register)) {
+            return new Label("Rezerwa baterii", "%");
+        }
+        int address;
+        try {
+            address = Integer.parseInt(register);
+        } catch (NumberFormatException e) {
+            return unknown(register);
+        }
+        if (address == TOU_ENABLE) {
+            return new Label("Harmonogram baterii", "0/1");
+        }
+        return slot(address, FIRST_START, "start", "HHMM")
+                .or(() -> slot(address, FIRST_SOC, "poziom", "%"))
+                .or(() -> slot(address, FIRST_GRID_CHARGE, "ładowanie z sieci", "0/1"))
+                .orElseGet(() -> unknown(register));
+    }
+
+    private static Label unknown(String register) {
+        return new Label("Rejestr " + register, "");
+    }
+
+    private static Optional<Label> slot(int address, int first, String what, String unit) {
+        return address >= first && address < first + SLOTS
+                ? Optional.of(new Label("Przedział " + (address - first + 1) + ": " + what, unit))
+                : Optional.empty();
+    }
+}

backend/src/main/java/home/backend/application/EnergyDetailsService.java

@@ -0,0 +1,157 @@
+package home.backend.application;
+
+import home.backend.application.SnapshotFields.Live;
+import home.backend.domain.EnergyDetails;
+import home.backend.domain.EnergyDetails.Device;
+import home.backend.domain.EnergyDetails.Group;
+import home.backend.domain.EnergyDetails.Item;
+import home.backend.domain.GatewaySnapshot;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.IntStream;
+
+/**
+ * F7 details: the Deye, Fronius and house meter fields worth a look, grouped and labelled. The
+ * catalog below is the only place that knows a field's label, unit and place; showing a new field
+ * is one line here.
+ */
+public class EnergyDetailsService {
+
+    /** A gateway field shown as {@code label}; {@code scale} turns the stored unit into {@code unit}. */
+    private record Field(String key, String label, String unit, int digits, double scale) {
+    }
+
+    private record Spec(String id, String name, String measurement, List<GroupSpec> groups) {
+    }
+
+    /** {@code measurement} is null for the device's own one. */
+    private record GroupSpec(String title, String measurement, List<Field> fields) {
+    }
+
+    // Each helper returns the fields it stands for, so a group can mix single fields and phase triples.
+    private static Field[] field(String key, String label, String unit, int digits) {
+        return new Field[] {new Field(key, label, unit, digits, 1)};
+    }
+
+    private static Field[] kwhFromWh(String key, String label, int digits) {
+        return new Field[] {new Field(key, label, "kWh", digits, 0.001)};
+    }
+
+    /** L1 to L3 of one quantity; {@code key} holds %d for the phase number. */
+    private static Field[] phases(String key, String label, String unit, int digits) {
+        return IntStream.rangeClosed(1, 3)
+                .mapToObj(n -> new Field(key.formatted(n), label + " L" + n, unit, digits, 1)).toArray(Field[]::new);
+    }
+
+    private static GroupSpec group(String title, Field[]... parts) {
+        return groupOf(null, title, parts);
+    }
+
+    /** A group whose fields come from another measurement of the same device. */
+    private static GroupSpec groupOf(String measurement, String title, Field[]... parts) {
+        return new GroupSpec(title, measurement, Arrays.stream(parts).flatMap(Arrays::stream).toList());
+    }
+
+    private static final List<Spec> CATALOG = List.of(
+            new Spec("deye", "Falownik Deye", "deye", List.of(
+                    group("Bateria",
+                            field("battery_soc_pct", "Naładowanie", "%", 0),
+                            field("battery_power_w", "Moc", "W", 0),
+                            field("battery_voltage_v", "Napięcie", "V", 1),
+                            field("battery_current_a", "Prąd", "A", 1),
+                            field("battery_temperature_c", "Temperatura", "°C", 1)),
+                    group("Sieć",
+                            field("grid_power_w", "Moc razem", "W", 0),
+                            phases("grid_power_l%d_w", "Moc", "W", 0),
+                            phases("grid_voltage_l%d_v", "Napięcie", "V", 1),
+                            field("grid_frequency_hz", "Częstotliwość", "Hz", 2)),
+                    group("Odbiór domu",
+                            field("load_power_w", "Moc razem", "W", 0),
+                            phases("load_power_l%d_w", "Moc", "W", 0)),
+                    group("Panele PV",
+                            field("pv1_power_w", "PV1 moc", "W", 0),
+                            field("pv1_voltage_v", "PV1 napięcie", "V", 1),
+                            field("pv1_current_a", "PV1 prąd", "A", 1),
+                            field("pv2_power_w", "PV2 moc", "W", 0),
+                            field("pv2_voltage_v", "PV2 napięcie", "V", 1),
+                            field("pv2_current_a", "PV2 prąd", "A", 1)),
+                    group("Dziś",
+                            field("pv_today_kwh", "Produkcja PV", "kWh", 1),
+                            field("load_today_kwh", "Zużycie domu", "kWh", 1),
+                            field("grid_bought_today_kwh", "Pobrano z sieci", "kWh", 1),
+                            field("grid_sold_today_kwh", "Oddano do sieci", "kWh", 1),
+                            field("battery_charge_today_kwh", "Bateria naładowana", "kWh", 1),
+                            field("battery_discharge_today_kwh", "Bateria rozładowana", "kWh", 1)),
+                    group("Od początku",
+                            field("pv_total_kwh", "Produkcja PV", "kWh", 0),
+                            field("load_total_kwh", "Zużycie domu", "kWh", 0),
+                            field("grid_bought_total_kwh", "Pobrano z sieci", "kWh", 0),
+                            field("grid_sold_total_kwh", "Oddano do sieci", "kWh", 0),
+                            field("battery_charge_total_kwh", "Bateria naładowana", "kWh", 0),
+                            field("battery_discharge_total_kwh", "Bateria rozładowana", "kWh", 0)),
+                    group("Falownik",
+                            field("inverter_power_w", "Moc wyjściowa", "W", 0),
+                            field("inverter_temperature_c", "Temperatura", "°C", 1),
+                            field("heatsink_temperature_c", "Radiator", "°C", 1)))),
+            new Spec("fronius", "Falownik Fronius", "fronius", List.of(
+                    group("Teraz", field("pv_power_w", "Moc PV", "W", 0)),
+                    group("Produkcja",
+                            kwhFromWh("energy_day_wh", "Dziś", 1),
+                            kwhFromWh("energy_year_wh", "Ten rok", 0),
+                            kwhFromWh("energy_total_wh", "Od początku", 0)))),
+            new Spec("house-meter", "Licznik domu", "PRAD2", List.of(
+                    group("Moc czynna",
+                            field("total_power_active", "Razem", "W", 0),
+                            phases("p%d_power_active", "Moc", "W", 0)),
+                    group("Napięcie", phases("p%d_voltage", "Napięcie", "V", 1)),
+                    group("Prąd", phases("p%d_current", "Prąd", "A", 2)),
+                    group("Współczynnik mocy", phases("p%d_power_factor", "cos φ", "", 2)),
+                    group("Sieć", field("frequency", "Częstotliwość", "Hz", 2)),
+                    group("Energia od początku",
+                            field("import_energy_active", "Pobrana", "kWh", 0),
+                            field("export_energy_active", "Oddana", "kWh", 0)),
+                    groupOf("house_meter_phases", "Energia na fazę",
+                            phases("l%d_import_energy_active_kwh", "Pobrana", "kWh", 0),
+                            phases("l%d_export_energy_active_kwh", "Oddana", "kWh", 0)))));
+
+    private final GatewayClient gateway;
+    private final Clock clock;
+
+    public EnergyDetailsService(GatewayClient gateway, Clock clock) {
+        this.gateway = gateway;
+        this.clock = clock;
+    }
+
+    public EnergyDetails current() throws IOException {
+        GatewaySnapshot snapshot = gateway.snapshot();
+        return new EnergyDetails(CATALOG.stream().map(spec -> device(spec, snapshot)).toList());
+    }
+
+    private Device device(Spec spec, GatewaySnapshot snapshot) {
+        Live live = SnapshotFields.live(snapshot, spec.id(), spec.measurement(), clock.instant());
+        List<Group> groups = spec.groups().stream()
+                .map(g -> group(g, g.measurement() == null ? live.fields() : fieldsOf(snapshot, spec.id(), g)))
+                .filter(g -> !g.items().isEmpty()).toList();
+        return new Device(spec.id(), spec.name(), live.source().time(), live.source().stale(), groups);
+    }
+
+    private Map<String, Double> fieldsOf(GatewaySnapshot snapshot, String device, GroupSpec group) {
+        return SnapshotFields.live(snapshot, device, group.measurement(), clock.instant()).fields();
+    }
+
+    private static Group group(GroupSpec spec, Map<String, Double> fields) {
+        List<Item> items = spec.fields().stream().filter(f -> fields.containsKey(f.key()))
+                .map(f -> new Item(f.label(), scaled(fields.get(f.key()), f), f.unit(), f.digits())).toList();
+        return new Group(spec.title(), items);
+    }
+
+    /** Rounded to the shown precision, so a conversion leaves no binary noise such as 4.3999999. */
+    private static double scaled(double value, Field f) {
+        double factor = Math.pow(10, f.digits());
+        return Math.round(value * f.scale() * factor) / factor;
+    }
+}

backend/src/main/java/home/backend/application/EnergyService.java

@@ -1,26 +1,21 @@
 package home.backend.application;
 
+import home.backend.application.SnapshotFields.Live;
 import home.backend.domain.EnergyView;
 import home.backend.domain.EnergyView.Source;
 import home.backend.domain.EnergyView.Today;
 import home.backend.domain.GatewaySnapshot;
-import home.backend.domain.GatewaySnapshot.Measurement;
 
 import java.io.IOException;
 import java.time.Clock;
 import java.time.Instant;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 import java.util.stream.Stream;
 
 /** F7: house electricity from the Deye inverter and the Fronius PV inverter. */
 public class EnergyService {
 
-    /** One inverter's fields; empty when it is stale, so nothing old is shown as current. */
-    private record Inverter(Source source, Map<String, Double> fields) {
-    }
-
     private final GatewayClient gateway;
     private final Clock clock;
 
@@ -31,8 +26,8 @@ public class EnergyService {
 
     public EnergyView current() throws IOException {
         GatewaySnapshot snapshot = gateway.snapshot();
-        Inverter deye = inverter(snapshot, "deye");
-        Inverter fronius = inverter(snapshot, "fronius");
+        Live deye = SnapshotFields.live(snapshot, "deye", "deye", clock.instant());
+        Live fronius = SnapshotFields.live(snapshot, "fronius", "fronius", clock.instant());
         Map<String, Double> d = deye.fields();
         Map<String, Double> f = fronius.fields();
 
@@ -46,13 +41,6 @@ public class EnergyService {
                 d.get("load_power_w"), today);
     }
 
-    private Inverter inverter(GatewaySnapshot snapshot, String name) {
-        Optional<Measurement> reading = SnapshotFields.find(snapshot, name, name);
-        boolean stale = SnapshotFields.stale(SnapshotFields.device(snapshot, name), reading, clock.instant());
-        Source source = new Source(name, reading.map(Measurement::time).orElse(null), stale);
-        return new Inverter(source, stale ? Map.of() : reading.get().fields());
-    }
-
     private static Instant oldest(List<Source> sources) {
         return sources.stream().map(Source::time).flatMap(Stream::ofNullable).min(Instant::compareTo).orElse(null);
     }

backend/src/main/java/home/backend/application/ForecastSource.java

@@ -0,0 +1,11 @@
+package home.backend.application;
+
+import home.backend.domain.Forecast;
+
+import java.io.IOException;
+
+/** The weather forecast service: the past 14 days and the next 3. */
+public interface ForecastSource {
+
+    Forecast forecast() throws IOException;
+}

backend/src/main/java/home/backend/application/GatewayBattery.java

@@ -0,0 +1,19 @@
+package home.backend.application;
+
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
+import home.backend.domain.BatteryView.Reserve;
+
+import java.io.IOException;
+
+/** Battery settings through the gateway, which checks every change (ADR-013). */
+public interface GatewayBattery {
+
+    /** @throws IOException when the gateway has no battery commands, or cannot be reached */
+    Reserve reserve() throws IOException;
+
+    /** A verdict, even a negative one; IOException only when no verdict could be obtained. */
+    BatteryResult changeSchedule(BatteryChange change, String requestedBy) throws IOException;
+
+    BatteryResult changeReserve(int pct, String requestedBy) throws IOException;
+}

backend/src/main/java/home/backend/application/GatewayCommands.java

@@ -2,6 +2,7 @@ package home.backend.application;
 
 import home.backend.domain.Command;
 import home.backend.domain.CommandResult;
+import home.backend.domain.RestoreResult;
 import home.backend.domain.SetpointState;
 
 import java.io.IOException;
@@ -12,5 +13,11 @@ public interface GatewayCommands {
     /** A verdict, even a negative one; IOException only when no verdict could be obtained. */
     CommandResult apply(Command command) throws IOException;
 
+    /** Ends the pending change of a setpoint now; a verdict like {@link #apply}. */
+    RestoreResult restore(String setpoint, String requestedBy) throws IOException;
+
     SetpointState setpoints() throws IOException;
+
+    /** Keeps the gateway's live restores alive; returns how many it extended. */
+    int renewLeases() throws IOException;
 }

backend/src/main/java/home/backend/application/GatewayRefresh.java

@@ -0,0 +1,11 @@
+package home.backend.application;
+
+import home.backend.domain.RefreshResult;
+
+import java.io.IOException;
+
+/** Asks the gateway for fresh readings; it decides which devices may be polled again yet. */
+public interface GatewayRefresh {
+
+    RefreshResult refresh() throws IOException;
+}

backend/src/main/java/home/backend/application/HealthService.java

@@ -1,5 +1,6 @@
 package home.backend.application;
 
+import home.backend.domain.GatewaySnapshot;
 import home.backend.domain.GatewaySnapshot.DeviceSnapshot;
 import home.backend.domain.HealthView;
 import home.backend.domain.HealthView.DeviceHealth;
@@ -13,19 +14,21 @@ public class HealthService {
 
     private final GatewayClient gateway;
     private final Clock clock;
+    private final String version;
 
-    public HealthService(GatewayClient gateway, Clock clock) {
+    public HealthService(GatewayClient gateway, Clock clock, String version) {
         this.gateway = gateway;
         this.clock = clock;
+        this.version = version;
     }
 
     public HealthView current() {
         try {
-            List<DeviceHealth> devices = gateway.snapshot().devices().stream()
-                    .map(HealthService::health).toList();
-            return new HealthView(clock.instant(), true, devices);
+            GatewaySnapshot snapshot = gateway.snapshot();
+            List<DeviceHealth> devices = snapshot.devices().stream().map(HealthService::health).toList();
+            return new HealthView(clock.instant(), true, devices, version, snapshot.version());
         } catch (IOException e) {
-            return new HealthView(clock.instant(), false, List.of());
+            return new HealthView(clock.instant(), false, List.of(), version, null);
         }
     }
 

backend/src/main/java/home/backend/application/HeatPumpSamples.java

@@ -0,0 +1,13 @@
+package home.backend.application;
+
+import home.backend.domain.HeatPumpSample;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.List;
+
+/** The heat pump polls stored in InfluxDB, oldest first. */
+public interface HeatPumpSamples {
+
+    List<HeatPumpSample> samples(Instant from, Instant to) throws IOException;
+}

backend/src/main/java/home/backend/application/LeaseRenewer.java

@@ -0,0 +1,53 @@
+package home.backend.application;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Tells the gateway now and then that we are still here (ADR-011): while it hears us, our setpoint
+ * changes stay; once we or the tunnel are gone for 15 minutes, it restores them on its own.
+ */
+public class LeaseRenewer implements AutoCloseable {
+
+    /** A third of the gateway's lease, so two renewals in a row may fail. */
+    public static final Duration PERIOD = Duration.ofMinutes(5);
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(LeaseRenewer.class);
+
+    private final GatewayCommands gateway;
+    private final ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor(
+            Thread.ofVirtual().name("lease-renewal").factory());
+
+    public LeaseRenewer(GatewayCommands gateway) {
+        this.gateway = gateway;
+    }
+
+    public void start() {
+        start(PERIOD);
+    }
+
+    void start(Duration period) {
+        scheduler.scheduleWithFixedDelay(this::renew, 0, period.toMillis(), TimeUnit.MILLISECONDS);
+    }
+
+    /** A failure is logged and retried next cycle; an exception would end the schedule for good. */
+    void renew() {
+        try {
+            int renewed = gateway.renewLeases();
+            LOGGER.debug("renewed {} lease(s)", renewed);
+        } catch (IOException | RuntimeException e) {
+            LOGGER.warn("could not renew the gateway leases, retrying in {}: {}", PERIOD, e.toString());
+        }
+    }
+
+    @Override
+    public void close() {
+        scheduler.shutdownNow();
+    }
+}

backend/src/main/java/home/backend/application/PiSensorService.java

@@ -0,0 +1,27 @@
+package home.backend.application;
+
+import home.backend.application.SnapshotFields.Live;
+import home.backend.domain.PiSensorView;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.util.Map;
+
+/** The BME280 on the Pi, read by the gateway every 5 minutes. */
+public class PiSensorService {
+
+    private final GatewayClient gateway;
+    private final Clock clock;
+
+    public PiSensorService(GatewayClient gateway, Clock clock) {
+        this.gateway = gateway;
+        this.clock = clock;
+    }
+
+    public PiSensorView current() throws IOException {
+        Live live = SnapshotFields.live(gateway.snapshot(), "bme280", "MEASUREMENT", clock.instant());
+        Map<String, Double> f = live.fields();
+        return new PiSensorView(live.source().time(), live.source().stale(),
+                f.get("temperature"), f.get("humidity"), f.get("pressure"));
+    }
+}

backend/src/main/java/home/backend/application/PvEnergyRepository.java

@@ -0,0 +1,12 @@
+package home.backend.application;
+
+import java.io.IOException;
+import java.time.LocalDate;
+import java.util.Map;
+
+/** What the panels produced, from InfluxDB. */
+public interface PvEnergyRepository {
+
+    /** Deye plus Fronius kWh per local day from {@code from} up to {@code to}; days missing either are absent. */
+    Map<LocalDate, Double> dailyKwh(LocalDate from, LocalDate to) throws IOException;
+}

backend/src/main/java/home/backend/application/SetpointService.java

@@ -7,15 +7,20 @@ import home.backend.domain.Preset.Change;
 import home.backend.domain.PresetResult;
 import home.backend.domain.PresetResult.ChangeResult;
 import home.backend.domain.PresetResult.ChangeStatus;
+import home.backend.domain.RestoreResult;
 import home.backend.domain.Setpoint;
 import home.backend.domain.SetpointState;
 import home.backend.domain.SetpointsView;
 
 import java.io.IOException;
 import java.time.Duration;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
 
 /** F3: change setpoints directly or through a preset; the gateway enforces the limits (S1). */
 public class SetpointService {
@@ -38,48 +43,86 @@ public class SetpointService {
         return gateway.apply(new Command(setpoint, value, duration(hours), user));
     }
 
+    /** Puts the value from before the pending change back now, instead of waiting for its end. */
+    public RestoreResult restore(String setpoint, String user) throws IOException {
+        return gateway.restore(setpoint, user);
+    }
+
     /**
      * Empty if there is no such preset. A preset that does not fit the gateway's limits writes nothing.
      * IOException only when no change was attempted; once writing starts, trouble is reported per change.
+     *
+     * @param until the end the user chose; required by a held preset, not allowed for any other
+     * @param values the user's own value for some of the preset's setpoints (any preset); the rest keep the
+     *               preset's value
+     * @throws IllegalArgumentException when {@code until} does not match what the preset needs, or a value is
+     *                                  for a setpoint the preset does not change or outside the gateway's limits
      */
-    public Optional<PresetResult> applyPreset(String id, String user) throws IOException {
+    public Optional<PresetResult> applyPreset(String id, Instant until, Map<String, Integer> values, String user)
+            throws IOException {
         Optional<Preset> preset = presets.stream().filter(p -> p.id().equals(id)).findFirst();
         if (preset.isEmpty()) {
             return Optional.empty();
         }
-        List<Change> changes = preset.get().changes();
+        if (preset.get().isHeld() != (until != null)) {
+            throw new IllegalArgumentException(preset.get().isHeld() ? "preset " + id + " needs an end time"
+                    : "preset " + id + " has no end time to choose");
+        }
+        List<Change> changes = withValues(preset.get().changes(), values);
         List<Setpoint> limits = gateway.setpoints().setpoints();
-        List<ChangeResult> checked = changes.stream().map(c -> check(c, limits)).toList();
+        requireWithinLimits(values, limits);
+        List<ChangeResult> checked = changes.stream().map(c -> check(c, preset.get().isHeld(), limits)).toList();
         if (checked.stream().anyMatch(r -> r.status() == ChangeStatus.REJECTED)) {
             return Optional.of(PresetResult.of(checked));
         }
-        return Optional.of(PresetResult.of(run(changes, user)));
+        return Optional.of(PresetResult.of(run(changes, until, user)));
     }
 
-    private List<ChangeResult> run(List<Change> changes, String user) {
+    private static List<Change> withValues(List<Change> changes, Map<String, Integer> values) {
+        Set<String> own = changes.stream().map(Change::setpoint).collect(Collectors.toSet());
+        if (!own.containsAll(values.keySet())) {
+            throw new IllegalArgumentException("values may only be for the setpoints the preset changes: " + own);
+        }
+        return changes.stream().map(c -> new Change(c.setpoint(), values.getOrDefault(c.setpoint(), c.value()),
+                c.hours())).toList();
+    }
+
+    private static void requireWithinLimits(Map<String, Integer> values, List<Setpoint> limits) {
+        for (Setpoint limit : limits) {
+            Integer value = values.get(limit.name());
+            if (value != null && !limit.allows(value)) {
+                throw new IllegalArgumentException(limit.name() + " must be " + limit.min() + "–" + limit.max()
+                        + " in steps of " + limit.step());
+            }
+        }
+    }
+
+    private List<ChangeResult> run(List<Change> changes, Instant until, String user) {
         List<ChangeResult> results = new ArrayList<>();
         for (Change change : changes) {
             boolean stopped = !results.isEmpty() && results.getLast().status() != ChangeStatus.APPLIED;
-            results.add(stopped ? ChangeResult.notAttempted() : attempt(change, user));
+            results.add(stopped ? ChangeResult.notAttempted() : attempt(change, until, user));
         }
         return results;
     }
 
-    private ChangeResult attempt(Change change, String user) {
+    private ChangeResult attempt(Change change, Instant until, String user) {
         try {
-            return ChangeResult.of(apply(change.setpoint(), change.value(), change.hours(), user));
+            var command = until == null ? new Command(change.setpoint(), change.value(), duration(change.hours()), user)
+                    : new Command(change.setpoint(), change.value(), null, until, user);
+            return ChangeResult.of(gateway.apply(command));
         } catch (IOException e) {
             return new ChangeResult(ChangeStatus.UNKNOWN, "no answer from the gateway", null);
         }
     }
 
     /** REJECTED with the reason, or NOT_ATTEMPTED (nothing is sent if any change is rejected). */
-    private static ChangeResult check(Change change, List<Setpoint> limits) {
-        String problem = problem(change, limits);
+    private static ChangeResult check(Change change, boolean held, List<Setpoint> limits) {
+        String problem = problem(change, held, limits);
         return problem == null ? ChangeResult.notAttempted() : new ChangeResult(ChangeStatus.REJECTED, problem, null);
     }
 
-    private static String problem(Change change, List<Setpoint> limits) {
+    private static String problem(Change change, boolean held, List<Setpoint> limits) {
         Optional<Setpoint> known = limits.stream().filter(s -> s.name().equals(change.setpoint())).findFirst();
         if (known.isEmpty()) {
             return "preset sets " + change.setpoint() + ", which the gateway does not know";
@@ -88,6 +131,11 @@ public class SetpointService {
             return "preset sets " + change.setpoint() + " to " + change.value() + ", outside the gateway's limits "
                     + known.get().min() + "–" + known.get().max() + " step " + known.get().step();
         }
+        // The gateway refuses a held raise too; asking first keeps a preset from stopping half way.
+        if (held && known.get().value() != null && change.value() >= known.get().value()) {
+            return "preset sets " + change.setpoint() + " to " + change.value() + ", which is not below the current "
+                    + known.get().value();
+        }
         return null;
     }
 

backend/src/main/java/home/backend/application/SnapshotFields.java

@@ -1,5 +1,6 @@
 package home.backend.application;
 
+import home.backend.domain.EnergyView.Source;
 import home.backend.domain.GatewaySnapshot;
 import home.backend.domain.GatewaySnapshot.DeviceSnapshot;
 import home.backend.domain.GatewaySnapshot.Measurement;
@@ -25,8 +26,28 @@ final class SnapshotFields {
 
     /** A reading is stale when the device link is down, it is missing, or it is older than twice a cycle. */
     static boolean stale(Optional<DeviceSnapshot> device, Optional<Measurement> reading, Instant now) {
+        return stale(device, reading, now, MAX_AGE);
+    }
+
+    static boolean stale(Optional<DeviceSnapshot> device, Optional<Measurement> reading, Instant now,
+            Duration maxAge) {
         return device.isEmpty() || !device.get().up() || reading.isEmpty()
-                || Duration.between(reading.get().time(), now).compareTo(MAX_AGE) > 0;
+                || Duration.between(reading.get().time(), now).compareTo(maxAge) > 0;
+    }
+
+    /** One device's fields; empty when it is stale, so nothing old is shown as current. */
+    record Live(Source source, Map<String, Double> fields) {
+    }
+
+    static Live live(GatewaySnapshot snapshot, String device, String measurement, Instant now) {
+        return live(snapshot, device, measurement, now, MAX_AGE);
+    }
+
+    static Live live(GatewaySnapshot snapshot, String device, String measurement, Instant now, Duration maxAge) {
+        Optional<Measurement> reading = find(snapshot, device, measurement);
+        boolean stale = stale(device(snapshot, device), reading, now, maxAge);
+        Source source = new Source(device, reading.map(Measurement::time).orElse(null), stale);
+        return new Live(source, stale ? Map.of() : reading.get().fields());
     }
 
     static Optional<Measurement> find(GatewaySnapshot snapshot, String device, String measurement) {

backend/src/main/java/home/backend/application/StatsService.java

@@ -0,0 +1,89 @@
+package home.backend.application;
+
+import home.backend.domain.HeatPumpSample;
+import home.backend.domain.StatsView;
+import home.backend.domain.StatsView.Day;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * F2: the heat pump's work per local day over the last 7 or 30 days. A poll is taken to hold its
+ * outputs until the next poll, but at most {@link #MAX_HOLD}, so a gap in the data adds no hours.
+ */
+public class StatsService {
+
+    static final ZoneId ZONE = ZoneId.of("Europe/Warsaw");
+    static final Duration MAX_HOLD = Duration.ofSeconds(600);
+    private static final Map<String, Integer> RANGE_DAYS = Map.of("7d", 7, "30d", 30);
+
+    private final HeatPumpSamples repository;
+    private final Clock clock;
+
+    public StatsService(HeatPumpSamples repository, Clock clock) {
+        this.repository = repository;
+        this.clock = clock;
+    }
+
+    /**
+     * @param range {@code 7d} or {@code 30d}
+     * @throws IllegalArgumentException for an unknown range
+     */
+    public StatsView stats(String range) throws IOException {
+        Integer length = range == null ? null : RANGE_DAYS.get(range);
+        if (length == null) {
+            throw new IllegalArgumentException("unknown range: " + range);
+        }
+        Instant now = clock.instant();
+        LocalDate first = now.atZone(ZONE).toLocalDate().minusDays(length - 1);
+        Map<LocalDate, DayTally> tallies = new TreeMap<>();
+        for (int i = 0; i < length; i++) {
+            tallies.put(first.plusDays(i), new DayTally());
+        }
+        tally(repository.samples(first.atStartOfDay(ZONE).toInstant(), now), now, tallies);
+
+        DayTally all = new DayTally();
+        List<Day> days = new ArrayList<>();
+        tallies.forEach((date, tally) -> {
+            days.add(tally.day(date));
+            all.add(tally);
+        });
+        return new StatsView(range, days, all.totals());
+    }
+
+    private static void tally(List<HeatPumpSample> samples, Instant now, Map<LocalDate, DayTally> tallies) {
+        HeatPumpSample previous = null;
+        for (int i = 0; i < samples.size(); i++) {
+            HeatPumpSample s = samples.get(i);
+            DayTally day = tallies.get(s.t().atZone(ZONE).toLocalDate());
+            day.sample(s);
+            if (previous != null && previous.compressor() != null && previous.compressor() == 0
+                    && DayTally.on(s.compressor())) {
+                day.start();
+            }
+            previous = s;
+            hold(s, i + 1 < samples.size() ? samples.get(i + 1).t() : now, tallies);
+        }
+    }
+
+    /** Adds the time {@code s} was in force to the days it falls in; a stretch over midnight is split. */
+    private static void hold(HeatPumpSample s, Instant next, Map<LocalDate, DayTally> tallies) {
+        Instant end = Duration.between(s.t(), next).compareTo(MAX_HOLD) > 0 ? s.t().plus(MAX_HOLD) : next;
+        Instant at = s.t();
+        while (at.isBefore(end)) {
+            LocalDate date = at.atZone(ZONE).toLocalDate();
+            Instant midnight = date.plusDays(1).atStartOfDay(ZONE).toInstant();
+            Instant stop = midnight.isBefore(end) ? midnight : end;
+            tallies.get(date).hold(s, Duration.between(at, stop));
+            at = stop;
+        }
+    }
+}

backend/src/main/java/home/backend/application/WarningSource.java

@@ -0,0 +1,12 @@
+package home.backend.application;
+
+import home.backend.domain.WeatherView.Warning;
+
+import java.io.IOException;
+import java.util.List;
+
+/** Weather warnings that cover the house, whether in force now or announced. */
+public interface WarningSource {
+
+    List<Warning> warnings() throws IOException;
+}

backend/src/main/java/home/backend/application/WeatherService.java

@@ -0,0 +1,98 @@
+package home.backend.application;
+
+import home.backend.application.Cached.Entry;
+import home.backend.domain.Forecast;
+import home.backend.domain.Forecast.DailyForecast;
+import home.backend.domain.PvCalibration;
+import home.backend.domain.WeatherCodes;
+import home.backend.domain.WeatherView;
+import home.backend.domain.WeatherView.Day;
+import home.backend.domain.WeatherView.Now;
+import home.backend.domain.WeatherView.Warning;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.LocalDate;
+import java.time.ZoneId;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/** Forecast, PV estimate and warnings, each kept for a while so the phones do not load the sources. */
+public class WeatherService {
+
+    private static final ZoneId ZONE = ZoneId.of("Europe/Warsaw");
+    private static final int CALIBRATION_DAYS = 14;
+
+    private record Calibrated(Forecast forecast, Double factor) {
+    }
+
+    private final Clock clock;
+    private final PvEnergyRepository pv;
+    private final Cached<Calibrated> forecast;
+    private final Cached<List<Warning>> warnings;
+
+    public WeatherService(ForecastSource forecastSource, WarningSource warningSource, PvEnergyRepository pv,
+            Clock clock) {
+        this.clock = clock;
+        this.pv = pv;
+        this.forecast = new Cached<>(Duration.ofMinutes(30), ZONE, clock, () -> calibrated(forecastSource.forecast()));
+        this.warnings = new Cached<>(Duration.ofMinutes(10), clock, warningSource::warnings);
+    }
+
+    /** @throws IOException when there is no forecast at all; warnings alone may be missing. */
+    public WeatherView current() throws IOException {
+        Entry<Calibrated> weather = forecast.get();
+        Entry<List<Warning>> warned = warnings();
+        LocalDate today = LocalDate.now(clock.withZone(ZONE));
+        Calibrated w = weather.value();
+        return new WeatherView(clock.instant(),
+                day(w, today), day(w, today.plusDays(1)), day(w, today.plusDays(2)),
+                new Now(w.forecast().temperature()), inForce(warned.value()), w.factor(),
+                weather.stale() || warned.stale());
+    }
+
+    private Entry<List<Warning>> warnings() {
+        try {
+            return warnings.get();
+        } catch (IOException e) {
+            return new Entry<>(List.of(), true);
+        }
+    }
+
+    private List<Warning> inForce(List<Warning> all) {
+        return all.stream().filter(w -> w.to().toInstant().isAfter(clock.instant())).toList();
+    }
+
+    private Calibrated calibrated(Forecast fetched) {
+        LocalDate today = LocalDate.now(clock.withZone(ZONE));
+        Map<LocalDate, Double> radiation = new HashMap<>();
+        fetched.days().forEach((date, day) -> {
+            if (day.radiationMj() != null) {
+                radiation.put(date, day.radiationMj());
+            }
+        });
+        try {
+            var measured = pv.dailyKwh(today.minusDays(CALIBRATION_DAYS), today);
+            return new Calibrated(fetched, PvCalibration.factor(measured, radiation));
+        } catch (IOException e) {
+            return new Calibrated(fetched, null);
+        }
+    }
+
+    private static Day day(Calibrated w, LocalDate date) throws IOException {
+        DailyForecast d = w.forecast().days().get(date);
+        if (d == null) {
+            throw new IOException("forecast has no " + date);
+        }
+        Double kwh = w.factor() == null || d.radiationMj() == null ? null : round(w.factor() * d.radiationMj());
+        Double sunshine = d.sunshineSeconds() == null ? null : round(d.sunshineSeconds() / 3600);
+        return new Day(date, d.weatherCode(), WeatherCodes.describe(d.weatherCode()), d.tMax(), d.tMin(),
+                d.precipitationMm(), sunshine, kwh);
+    }
+
+    private static double round(double value) {
+        return Math.round(value * 10) / 10.0;
+    }
+}

backend/src/main/java/home/backend/domain/AuditEntry.java

@@ -0,0 +1,14 @@
+package home.backend.domain;
+
+import java.time.Instant;
+
+/**
+ * One audited write. {@code unit} is "°C", "%", "HHMM" (a clock time written as 1830) or "0/1" (off/on);
+ * the values are null when the gateway did not record them.
+ */
+public record AuditEntry(Instant time, String source, String what, Integer oldValue, Integer newValue,
+        String unit, String who, String status) {
+
+    public static final String HEAT_PUMP = "heat_pump";
+    public static final String BATTERY = "battery";
+}

backend/src/main/java/home/backend/domain/AuditView.java

@@ -0,0 +1,7 @@
+package home.backend.domain;
+
+import java.util.List;
+
+/** The audited writes of the heat pump and the battery, newest first. */
+public record AuditView(List<AuditEntry> entries) {
+}

backend/src/main/java/home/backend/domain/BatteryChange.java

@@ -0,0 +1,19 @@
+package home.backend.domain;
+
+import java.time.LocalTime;
+import java.util.List;
+
+/**
+ * A change of the Time of Use switch and of single program slots (1 to 6); a null field stays as it is.
+ * The gateway checks every rule (ADR-013).
+ */
+public record BatteryChange(Boolean enabled, List<Slot> slots) {
+
+    public BatteryChange {
+        slots = slots == null ? List.of() : List.copyOf(slots);
+    }
+
+    /** {@code from} is the slot's start, to the minute. */
+    public record Slot(int slot, LocalTime from, Integer socPct, Boolean gridCharge) {
+    }
+}

backend/src/main/java/home/backend/domain/BatteryResult.java

@@ -0,0 +1,13 @@
+package home.backend.domain;
+
+import java.util.Map;
+
+/**
+ * The gateway's verdict on a battery change, passed on unchanged. REJECTED: refused by the rules, nothing
+ * written. STALE: the inverter's settings are unknown or changed meanwhile, nothing written. TOO_SOON: S4.
+ * FAILED: a write or its read-back went wrong; {@code read} has the registers as read back.
+ */
+public record BatteryResult(Status status, String message, Map<Integer, Integer> read) {
+
+    public enum Status { APPLIED, REJECTED, STALE, TOO_SOON, FAILED }
+}

backend/src/main/java/home/backend/domain/BatteryView.java

@@ -0,0 +1,39 @@
+package home.backend.domain;
+
+import java.time.Instant;
+import java.util.List;
+
+/**
+ * The Deye's battery (F7), read-only. Power in W, + discharge / − charge. The live values
+ * ({@code time}, {@code stale}) come from the Deye's readings and are null when stale; the settings
+ * ({@code settingsTime}, {@code settingsStale}: mode, schedule, limits, capacity) come from their own,
+ * slower reading and are null (empty schedule) when stale. The capacity assumes the nominal 51.2 V.
+ * {@code reserve} is the app's backup reserve (ADR-013) and {@code editable} says the gateway accepts
+ * changes; they are null and false when it does not.
+ */
+public record BatteryView(Instant time, boolean stale, Double socPct, Double powerW, Double voltageV,
+        Double currentA, Double temperatureC, Double capacityKwh, Energy today, Energy total, Mode mode,
+        List<Slot> schedule, Limits limits, Instant settingsTime, boolean settingsStale, Reserve reserve,
+        boolean editable) {
+
+    /** The share of the battery kept for a power cut, and the lowest the user may set. */
+    public record Reserve(int pct, int floorPct) {
+    }
+
+    /** Battery energy in kWh. */
+    public record Energy(Double chargeKwh, Double dischargeKwh) {
+    }
+
+    /** Time of use on means the battery follows the schedule; off means backup only. */
+    public record Mode(boolean touEnabled, String description) {
+    }
+
+    /** A program slot, {@code from} and {@code to} as HH:MM; it runs until the next slot starts. */
+    public record Slot(String from, String to, int powerW, int socPct, boolean gridCharge) {
+    }
+
+    public record Limits(Integer maxChargeA, Integer maxDischargeA, Integer shutdownSocPct,
+            Integer lowSocPct, Integer restartSocPct, boolean gridChargeEnabled, Integer gridChargeCurrentA,
+            Integer gridChargeStartSocPct) {
+    }
+}

backend/src/main/java/home/backend/domain/Command.java

@@ -1,9 +1,18 @@
 package home.backend.domain;
 
 import java.time.Duration;
+import java.time.Instant;
 
-/** Set a setpoint; with a duration the gateway restores the old value afterwards, else it stays. */
-public record Command(String setpoint, int value, Duration duration, String requestedBy) {
+/**
+ * Set a setpoint. With a duration the gateway restores the old value afterwards; with
+ * {@code heldUntil} it holds a lowering value until then without renewals (ADR-012); else it stays
+ * while the backend renews the lease (ADR-011).
+ */
+public record Command(String setpoint, int value, Duration duration, Instant heldUntil, String requestedBy) {
+
+    public Command(String setpoint, int value, Duration duration, String requestedBy) {
+        this(setpoint, value, duration, null, requestedBy);
+    }
 
     /** The gateway refuses longer boosts too; we refuse first, so the phone gets a clear 400. */
     public static final int MAX_HOURS = 72;

backend/src/main/java/home/backend/domain/EnergyDetails.java

@@ -0,0 +1,22 @@
+package home.backend.domain;
+
+import java.time.Instant;
+import java.util.List;
+
+/**
+ * Every value the energy devices report, grouped for a details panel (F7). A device without a
+ * fresh reading has {@code stale} true and no groups; a field the device did not report is absent.
+ */
+public record EnergyDetails(List<Device> devices) {
+
+    /** One device; {@code id} is the gateway's device name. */
+    public record Device(String id, String name, Instant time, boolean stale, List<Group> groups) {
+    }
+
+    public record Group(String title, List<Item> items) {
+    }
+
+    /** A value in {@code unit}, to be shown with {@code digits} decimals. */
+    public record Item(String label, double value, String unit, int digits) {
+    }
+}

backend/src/main/java/home/backend/domain/Forecast.java

@@ -0,0 +1,13 @@
+package home.backend.domain;
+
+import java.time.LocalDate;
+import java.util.Map;
+
+/** What the forecast service says: the temperature now and a record per calendar day, past days included. */
+public record Forecast(Double temperature, Map<LocalDate, DailyForecast> days) {
+
+    /** Radiation in MJ/m² per day, sunshine in seconds; any value may be missing. */
+    public record DailyForecast(Integer weatherCode, Double tMax, Double tMin, Double precipitationMm,
+            Double radiationMj, Double sunshineSeconds) {
+    }
+}

backend/src/main/java/home/backend/domain/GatewaySnapshot.java

@@ -4,8 +4,9 @@ import java.time.Instant;
 import java.util.List;
 import java.util.Map;
 
-/** The gateway's latest state of every device, as the backend sees it. */
-public record GatewaySnapshot(List<DeviceSnapshot> devices) {
+/** The gateway's latest state of every device, as the backend sees it.
+ * The version is the gateway's release tag, null for a gateway that does not report it yet. */
+public record GatewaySnapshot(String version, List<DeviceSnapshot> devices) {
 
     public record DeviceSnapshot(String name, boolean up, Instant lastSuccess, String lastError,
             List<Measurement> measurements) {

backend/src/main/java/home/backend/domain/HealthView.java

@@ -3,8 +3,10 @@ package home.backend.domain;
 import java.time.Instant;
 import java.util.List;
 
-/** Health of the chain phone → backend → gateway → devices (F5). */
-public record HealthView(Instant time, boolean gatewayReachable, List<DeviceHealth> devices) {
+/** Health of the chain phone → backend → gateway → devices (F5), with the deployed versions.
+ * The gateway's version is null when it is unreachable or too old to report it. */
+public record HealthView(Instant time, boolean gatewayReachable, List<DeviceHealth> devices,
+        String backendVersion, String gatewayVersion) {
 
     public record DeviceHealth(String name, boolean up, Instant lastSuccess, String lastError) {
     }

backend/src/main/java/home/backend/domain/HeatPumpSample.java

@@ -0,0 +1,8 @@
+package home.backend.domain;
+
+import java.time.Instant;
+
+/** One poll of the heat pump from InfluxDB; a field the poll did not carry is null. */
+public record HeatPumpSample(Instant t, Double compressor, Double cwu, Double co, Double heater,
+        Double outdoorTemp, Double cwuTemp) {
+}

backend/src/main/java/home/backend/domain/PiSensorView.java

@@ -0,0 +1,11 @@
+package home.backend.domain;
+
+import java.time.Instant;
+
+/**
+ * The BME280 sensor on the Raspberry Pi: °C, % and hPa. When it is stale (device down, no reading
+ * or older than 2 × 300 s) the values are null and {@code stale} is true; {@code time} is null
+ * without any reading.
+ */
+public record PiSensorView(Instant time, boolean stale, Double temperature, Double humidity, Double pressure) {
+}

backend/src/main/java/home/backend/domain/Preset.java

@@ -1,9 +1,19 @@
 package home.backend.domain;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
+
 import java.util.List;
 
-/** A named one-tap bundle of setpoint changes (F3), e.g. boost or away. */
-public record Preset(String id, String name, List<Change> changes) {
+/**
+ * A named one-tap bundle of setpoint changes (F3), e.g. boost or away. {@code until} is null, or
+ * {@link #CHOSEN}: the user picks the end on a calendar and the gateway holds the changes until
+ * then without renewals (ADR-012).
+ */
+public record Preset(String id, String name, @JsonInclude(JsonInclude.Include.NON_NULL) String until,
+        List<Change> changes) {
+
+    public static final String CHOSEN = "chosen";
 
     /** {@code hours} null means "until changed back". */
     public record Change(String setpoint, int value, Double hours) {
@@ -18,6 +28,11 @@ public record Preset(String id, String name, List<Change> changes) {
         }
     }
 
+    @JsonIgnore
+    public boolean isHeld() {
+        return CHOSEN.equals(until);
+    }
+
     public Preset {
         if (id == null || id.isBlank() || name == null || name.isBlank()) {
             throw new IllegalArgumentException("a preset needs an id and a name");
@@ -25,5 +40,11 @@ public record Preset(String id, String name, List<Change> changes) {
         if (changes == null || changes.isEmpty()) {
             throw new IllegalArgumentException("preset " + id + " has no changes");
         }
+        if (until != null && !until.equals(CHOSEN)) {
+            throw new IllegalArgumentException("preset " + id + ": until can only be \"" + CHOSEN + "\"");
+        }
+        if (CHOSEN.equals(until) && changes.stream().anyMatch(change -> change.hours() != null)) {
+            throw new IllegalArgumentException("preset " + id + " is held until a chosen time, so no hours");
+        }
     }
 }

backend/src/main/java/home/backend/domain/PvCalibration.java

@@ -0,0 +1,32 @@
+package home.backend.domain;
+
+import java.time.LocalDate;
+import java.util.Map;
+
+/**
+ * The PV output per unit of radiation, found from past days instead of the panels' tilt and azimuth:
+ * measured kWh over forecast MJ/m², summed over the days that have both.
+ */
+public final class PvCalibration {
+
+    static final int MIN_DAYS = 5;
+
+    private PvCalibration() {
+    }
+
+    /** Null with fewer than {@value MIN_DAYS} days having both values or no radiation at all. */
+    public static Double factor(Map<LocalDate, Double> measuredKwh, Map<LocalDate, Double> radiationMj) {
+        double kwh = 0;
+        double mj = 0;
+        int days = 0;
+        for (var day : measuredKwh.entrySet()) {
+            Double radiation = radiationMj.get(day.getKey());
+            if (radiation != null) {
+                kwh += day.getValue();
+                mj += radiation;
+                days++;
+            }
+        }
+        return days < MIN_DAYS || mj <= 0 ? null : kwh / mj;
+    }
+}

backend/src/main/java/home/backend/domain/RefreshResult.java

@@ -0,0 +1,10 @@
+package home.backend.domain;
+
+import java.util.List;
+
+/** The gateway's answer to a refresh: the devices it will poll again, and those polled too recently. */
+public record RefreshResult(List<String> requested, List<Skipped> skipped) {
+
+    public record Skipped(String device, long retryInSeconds) {
+    }
+}

backend/src/main/java/home/backend/domain/Restore.java

@@ -2,6 +2,9 @@ package home.backend.domain;
 
 import java.time.Instant;
 
-/** A boost the gateway will undo at {@code due}, unless someone changed the register meanwhile. */
+/**
+ * A change the gateway will undo at {@code due} (null: until changed), unless someone changed the
+ * register meanwhile. It also undoes it when we stop renewing the lease (ADR-011).
+ */
 public record Restore(String setpoint, int register, int originalValue, int appliedValue, Instant due) {
 }

backend/src/main/java/home/backend/domain/RestoreResult.java

@@ -0,0 +1,11 @@
+package home.backend.domain;
+
+/** The gateway's answer to "restore now", passed on to the phone unchanged. */
+public record RestoreResult(Outcome outcome, String message) {
+
+    /**
+     * NOT_PENDING: nothing to restore. CONFLICT: the register was changed meanwhile, so it was left alone.
+     * TOO_SOON: the gateway's rate limit. FAILED: the restore stays pending and is retried.
+     */
+    public enum Outcome { RESTORED, NOT_PENDING, CONFLICT, TOO_SOON, FAILED }
+}

backend/src/main/java/home/backend/domain/StatsView.java

@@ -0,0 +1,19 @@
+package home.backend.domain;
+
+import java.time.LocalDate;
+import java.util.List;
+
+/**
+ * Heat pump work per local day (F2). Hours are approximated from the polls, starts are counted
+ * between polls, so short cycles are missed. A day without polls has null values.
+ */
+public record StatsView(String range, List<Day> days, Totals totals) {
+
+    public record Day(LocalDate date, Double compressorHours, Integer compressorStarts, Double cwuHours,
+            Double coHours, Double heaterHours, Double avgOutdoorTemp, Double minCwuTemp, Double maxCwuTemp) {
+    }
+
+    public record Totals(double compressorHours, int compressorStarts, double cwuHours, double coHours,
+            double heaterHours, Double avgOutdoorTemp, Double minCwuTemp, Double maxCwuTemp) {
+    }
+}

backend/src/main/java/home/backend/domain/WeatherCodes.java

@@ -0,0 +1,37 @@
+package home.backend.domain;
+
+/** WMO weather interpretation codes as Polish text. */
+public final class WeatherCodes {
+
+    private WeatherCodes() {
+    }
+
+    public static String describe(Integer code) {
+        if (code == null) {
+            return "Brak danych";
+        }
+        return switch (code) {
+            case 0 -> "Bezchmurnie";
+            case 1 -> "Przeważnie słonecznie";
+            case 2 -> "Częściowe zachmurzenie";
+            case 3 -> "Pochmurno";
+            case 45, 48 -> "Mgła";
+            case 51, 53, 55 -> "Mżawka";
+            case 56, 57 -> "Marznąca mżawka";
+            case 61 -> "Słaby deszcz";
+            case 63 -> "Deszcz";
+            case 65 -> "Silny deszcz";
+            case 66, 67 -> "Marznący deszcz";
+            case 71 -> "Słaby śnieg";
+            case 73 -> "Śnieg";
+            case 75 -> "Intensywny śnieg";
+            case 77 -> "Ziarna śnieżne";
+            case 80, 81 -> "Przelotny deszcz";
+            case 82 -> "Ulewa";
+            case 85, 86 -> "Przelotny śnieg";
+            case 95 -> "Burza";
+            case 96, 99 -> "Burza z gradem";
+            default -> "Brak danych";
+        };
+    }
+}

backend/src/main/java/home/backend/domain/WeatherView.java

@@ -0,0 +1,27 @@
+package home.backend.domain;
+
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.util.List;
+
+/**
+ * Weather at the house: three days, the temperature now and the IMGW warnings in force or announced.
+ * {@code pvFactor} (kWh per MJ/m² of forecast radiation) and every {@code pvForecastKwh} are null while
+ * there are too few measured days to calibrate. {@code stale} means part of it is an older answer
+ * because a source could not be reached.
+ */
+public record WeatherView(Instant time, Day today, Day tomorrow, Day dayAfter, Now now,
+        List<Warning> warnings, Double pvFactor, boolean stale) {
+
+    public record Day(LocalDate date, Integer weatherCode, String description, Double tMax, Double tMin,
+            Double precipitationMm, Double sunshineHours, Double pvForecastKwh) {
+    }
+
+    public record Now(Double temperature) {
+    }
+
+    /** {@code level} is IMGW's degree 1 to 3. */
+    public record Warning(String event, int level, OffsetDateTime from, OffsetDateTime to, String text) {
+    }
+}

backend/src/main/resources/presets-default.json

@@ -7,6 +7,7 @@
   {
     "id": "away",
     "name": "Wyjazd",
+    "until": "chosen",
     "changes": [
       { "setpoint": "cwu_comfort", "value": 10, "hours": null },
       { "setpoint": "co_comfort", "value": 15, "hours": null }

backend/src/test/java/home/backend/BackendTest.java

@@ -151,6 +151,11 @@ class BackendTest {
         assertServesExactly("/api/heat-pump", "heat-pump");
     }
 
+    @Test
+    void servesPiSensorFromTheGatewayReadings() throws Exception {
+        assertServesExactly("/api/pi-sensor", "pi-sensor");
+    }
+
     @Test
     void servesEnergyFromTheGatewayReadings() throws Exception {
         assertServesExactly("/api/energy", "energy");

backend/src/test/java/home/backend/adapters/config/PresetFileTest.java

@@ -28,8 +28,8 @@ class PresetFileTest {
         var presets = PresetFile.load(null);
 
         assertEquals(List.of(
-                new Preset("cwu-now", "Ciepła woda teraz", List.of(new Change("cwu_economy", 45, 2.0))),
-                new Preset("away", "Wyjazd", List.of(new Change("cwu_comfort", 10, null),
+                new Preset("cwu-now", "Ciepła woda teraz", null, List.of(new Change("cwu_economy", 45, 2.0))),
+                new Preset("away", "Wyjazd", "chosen", List.of(new Change("cwu_comfort", 10, null),
                         new Change("co_comfort", 15, null)))), presets);
     }
 
@@ -39,7 +39,7 @@ class PresetFileTest {
                 [{"id": "bath", "name": "Kąpiel", "changes": [{"setpoint": "cwu_economy", "value": 48, "hours": 1.5}]}]
                 """));
 
-        assertEquals(List.of(new Preset("bath", "Kąpiel", List.of(new Change("cwu_economy", 48, 1.5)))), presets);
+        assertEquals(List.of(new Preset("bath", "Kąpiel", null, List.of(new Change("cwu_economy", 48, 1.5)))), presets);
     }
 
     @Test
@@ -51,6 +51,8 @@ class PresetFileTest {
                 "[{\"id\": \"\", \"name\": \"A\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 15}]}]",
                 "[{\"id\": \"a\", \"name\": \"A\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 15, \"hours\": 0}]}]",
                 "[{\"id\": \"a\", \"name\": \"A\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 15, \"hours\": 73}]}]",
+                "[{\"id\": \"a\", \"name\": \"A\", \"until\": \"tomorrow\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 15}]}]",
+                "[{\"id\": \"a\", \"name\": \"A\", \"until\": \"chosen\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 15, \"hours\": 2}]}]",
                 "[{\"id\": \"a\", \"name\": \"A\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 15}]},"
                         + "{\"id\": \"a\", \"name\": \"B\", \"changes\": [{\"setpoint\": \"co_comfort\", \"value\": 16}]}]")) {
             Path file = file(json);

backend/src/test/java/home/backend/adapters/gateway/GatewayHttpClientTest.java

@@ -86,6 +86,20 @@ class GatewayHttpClientTest {
         assertEquals(645.0, device(devices, "deye").measurements().get(0).fields().get("grid_power_w"));
     }
 
+    @Test
+    void readsTheGatewayVersion() throws Exception {
+        serveFiles(200, "health-all-up.json", "snapshot-all-up.json");
+
+        assertEquals("v1.2.1", client.snapshot().version());
+    }
+
+    @Test
+    void anOldGatewayWithoutVersionHasNullVersion() throws Exception {
+        serveFiles(503, "health-one-down.json", "snapshot-one-down.json");
+
+        assertNull(client.snapshot().version());
+    }
+
     @Test
     void aDownDeviceAnswering503IsStillASnapshot() throws Exception {
         serveFiles(503, "health-one-down.json", "snapshot-one-down.json");

backend/src/test/java/home/backend/adapters/gateway/GatewayHttpCommandsTest.java

@@ -2,9 +2,15 @@ package home.backend.adapters.gateway;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.sun.net.httpserver.HttpExchange;
 import com.sun.net.httpserver.HttpServer;
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
+import home.backend.domain.BatteryView;
 import home.backend.domain.Command;
 import home.backend.domain.CommandResult.Status;
+import home.backend.domain.RefreshResult;
+import home.backend.domain.RestoreResult.Outcome;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -18,6 +24,7 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Duration;
 import java.time.Instant;
+import java.time.LocalTime;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -32,7 +39,7 @@ class GatewayHttpCommandsTest {
     private static final ObjectMapper JSON = new ObjectMapper();
     private static final Path CONTRACT = Path.of("../gateway/src/test/resources/commands");
 
-    private record Seen(String method, String authorization, String requestedBy, String body) {
+    private record Seen(String method, String path, String authorization, String requestedBy, String body) {
     }
 
     private final List<Seen> seen = new ArrayList<>();
@@ -59,16 +66,20 @@ class GatewayHttpCommandsTest {
     }
 
     private void answerCommands() {
-        server.createContext("/commands", exchange -> {
-            seen.add(new Seen(exchange.getRequestMethod(),
-                    exchange.getRequestHeaders().getFirst("Authorization"),
-                    exchange.getRequestHeaders().getFirst("X-Requested-By"),
-                    new String(exchange.getRequestBody().readAllBytes(), StandardCharsets.UTF_8)));
-            byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
-            exchange.sendResponseHeaders(status, bytes.length);
-            exchange.getResponseBody().write(bytes);
-            exchange.close();
-        });
+        for (String path : List.of("/commands", "/battery", "/refresh")) {
+            server.createContext(path, this::answer);
+        }
+    }
+
+    private void answer(HttpExchange exchange) throws IOException {
+        seen.add(new Seen(exchange.getRequestMethod(), exchange.getRequestURI().getPath(),
+                exchange.getRequestHeaders().getFirst("Authorization"),
+                exchange.getRequestHeaders().getFirst("X-Requested-By"),
+                new String(exchange.getRequestBody().readAllBytes(), StandardCharsets.UTF_8)));
+        byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
+        exchange.sendResponseHeaders(status, bytes.length);
+        exchange.getResponseBody().write(bytes);
+        exchange.close();
     }
 
     private GatewayHttpCommands commands(String token) {
@@ -95,6 +106,15 @@ class GatewayHttpCommandsTest {
         assertEquals(contractJson("request-boost.json"), contractJson(seen.getFirst().body()));
     }
 
+    @Test
+    void aHeldChangeSendsTheEndAsUntil() throws Exception {
+        serve(200, contract("response-applied.json"));
+
+        commands("s3cret-token").apply(new Command("cwu_comfort", 10, null, Instant.parse("2026-11-02T17:00:00Z"), "phone"));
+
+        assertEquals(contractJson("request-held.json"), contractJson(seen.getFirst().body()));
+    }
+
     @Test
     void awayHasNoMinutes() throws Exception {
         serve(200, contract("response-applied.json"));
@@ -136,6 +156,172 @@ class GatewayHttpCommandsTest {
         assertEquals(8, state.restores().getFirst().originalValue());
     }
 
+    @Test
+    void anUntilChangedRestoreHasNoDue() throws Exception {
+        serve(200, "{\"setpoints\":[],\"restores\":[{\"setpoint\":\"cwu_comfort\",\"register\":4144,"
+                + "\"originalValue\":45,\"appliedValue\":10,\"leaseUntil\":\"2026-10-24T10:15:00Z\"}]}");
+
+        assertNull(commands("s3cret-token").setpoints().restores().getFirst().due());
+    }
+
+    @Test
+    void restorePostsTheSetpointWithTokenAndUser() throws Exception {
+        serve(200, contract("response-restored.json"));
+
+        var result = commands("s3cret-token").restore("cwu_economy", "anna");
+
+        assertEquals(Outcome.RESTORED, result.outcome());
+        assertEquals("POST", seen.getFirst().method());
+        assertEquals("/commands/restore", seen.getFirst().path());
+        assertEquals("Bearer s3cret-token", seen.getFirst().authorization());
+        assertEquals("anna", seen.getFirst().requestedBy());
+        assertEquals(contractJson("request-restore.json"), contractJson(seen.getFirst().body()));
+    }
+
+    @Test
+    void aConflictOnRestoreIsAVerdictNotAnError() throws Exception {
+        serve(409, contract("response-restore-conflict.json"));
+
+        assertEquals(Outcome.CONFLICT, commands("s3cret-token").restore("cwu_economy", "anna").outcome());
+    }
+
+    @Test
+    void everyRestoreStatusOfTheGatewayIsAVerdict() throws Exception {
+        var expected = java.util.Map.of(404, Outcome.NOT_PENDING, 429, Outcome.TOO_SOON, 502, Outcome.FAILED);
+        for (var entry : expected.entrySet()) {
+            serve(entry.getKey(), "{\"outcome\":\"" + entry.getValue() + "\",\"message\":\"x\"}");
+
+            assertEquals(entry.getValue(), commands("s3cret-token").restore("cwu_economy", "anna").outcome());
+        }
+    }
+
+    @Test
+    void restoreFailsWithoutAVerdictOrToken() {
+        serve(503, "{\"error\":\"x\"}");
+        assertThrows(IOException.class, () -> commands("s3cret-token").restore("cwu_economy", "anna"));
+
+        var seenBefore = seen.size();
+        assertThrows(IOException.class, () -> commands(null).restore("cwu_economy", "anna"));
+        assertEquals(seenBefore, seen.size());
+    }
+
+    @Test
+    void renewPostsToRenewWithTheTokenAndReturnsHowManyWereExtended() throws Exception {
+        serve(200, "{\"renewed\":2}");
+
+        assertEquals(2, commands("s3cret-token").renewLeases());
+
+        assertEquals("POST", seen.getFirst().method());
+        assertEquals("/commands/renew", seen.getFirst().path());
+        assertEquals("Bearer s3cret-token", seen.getFirst().authorization());
+    }
+
+    @Test
+    void renewFailsOnAnyOtherStatusOrWithoutToken() {
+        serve(503, "{\"error\":\"x\"}");
+        assertThrows(IOException.class, () -> commands("s3cret-token").renewLeases());
+
+        var seenBefore = seen.size();
+        assertThrows(IOException.class, () -> commands(null).renewLeases());
+        assertEquals(seenBefore, seen.size());
+    }
+
+    @Test
+    void refreshPostsToRefreshWithTheTokenAndParsesTheAnswer() throws Exception {
+        serve(200, Files.readString(Path.of("src/test/resources/api/refresh.json")));
+
+        var result = commands("s3cret-token").refresh();
+
+        assertEquals("POST", seen.getFirst().method());
+        assertEquals("/refresh", seen.getFirst().path());
+        assertEquals("Bearer s3cret-token", seen.getFirst().authorization());
+        assertEquals(List.of("deye", "house-meter"), result.requested());
+        assertEquals(new RefreshResult.Skipped("heat-pump", 41), result.skipped().getFirst());
+    }
+
+    @Test
+    void refreshFailsOnAnyOtherStatusOrWithoutToken() {
+        serve(401, "{\"error\":\"x\"}");
+        assertThrows(IOException.class, () -> commands("s3cret-token").refresh());
+
+        var seenBefore = seen.size();
+        assertThrows(IOException.class, () -> commands(null).refresh());
+        assertEquals(seenBefore, seen.size());
+    }
+
+    @Test
+    void readsTheBatteryReserveWithTheToken() throws Exception {
+        serve(200, contract("battery-reserve.json"));
+
+        var reserve = commands("s3cret-token").reserve();
+
+        assertEquals(new BatteryView.Reserve(50, 30), reserve);
+        assertEquals("GET", seen.getFirst().method());
+        assertEquals("/battery/reserve", seen.getFirst().path());
+        assertEquals("Bearer s3cret-token", seen.getFirst().authorization());
+    }
+
+    @Test
+    void sendsAScheduleChangeAsTheGatewayExpectsIt() throws Exception {
+        serve(200, contract("response-battery-applied.json"));
+        var change = new BatteryChange(true, List.of(new BatteryChange.Slot(2, LocalTime.of(9, 30), 90, true),
+                new BatteryChange.Slot(3, null, 85, null)));
+
+        var result = commands("s3cret-token").changeSchedule(change, "anna");
+
+        assertEquals(BatteryResult.Status.APPLIED, result.status());
+        assertEquals(java.util.Map.of(167, 90, 172, 1), result.read());
+        assertEquals("POST", seen.getFirst().method());
+        assertEquals("/battery/schedule", seen.getFirst().path());
+        assertEquals("Bearer s3cret-token", seen.getFirst().authorization());
+        assertEquals("anna", seen.getFirst().requestedBy());
+        assertEquals(contractJson("request-battery-schedule.json"), contractJson(seen.getFirst().body()));
+    }
+
+    @Test
+    void sendsAReserveChange() throws Exception {
+        serve(200, contract("response-battery-applied.json"));
+
+        commands("s3cret-token").changeReserve(60, "anna");
+
+        assertEquals("/battery/reserve", seen.getFirst().path());
+        assertEquals(contractJson("{\"pct\":60}"), contractJson(seen.getFirst().body()));
+    }
+
+    @Test
+    void everyBatteryStatusOfTheGatewayIsAVerdict() throws Exception {
+        var expected = java.util.Map.of(422, BatteryResult.Status.REJECTED, 409, BatteryResult.Status.STALE,
+                429, BatteryResult.Status.TOO_SOON, 502, BatteryResult.Status.FAILED);
+        for (var entry : expected.entrySet()) {
+            serve(entry.getKey(), "{\"status\":\"" + entry.getValue() + "\",\"message\":\"x\",\"read\":{}}");
+
+            assertEquals(entry.getValue(), commands("s3cret-token").changeReserve(60, "anna").status());
+        }
+    }
+
+    @Test
+    void aFailedBatteryWriteCarriesWhatWasRead() throws Exception {
+        serve(502, contract("response-battery-failed.json"));
+
+        var result = commands("s3cret-token").changeSchedule(new BatteryChange(null, null), "anna");
+
+        assertEquals(BatteryResult.Status.FAILED, result.status());
+        assertEquals(java.util.Map.of(167, 80), result.read());
+    }
+
+    @Test
+    void batteryCallsFailWithoutAVerdictOrToken() {
+        for (int status : List.of(400, 401, 404, 503)) {
+            serve(status, "{\"error\":\"x\"}");
+            assertThrows(IOException.class, () -> commands("s3cret-token").reserve(), "GET " + status);
+            assertThrows(IOException.class, () -> commands("s3cret-token").changeReserve(60, "anna"), "POST " + status);
+        }
+        var seenBefore = seen.size();
+        assertThrows(IOException.class, () -> commands(null).reserve());
+        assertThrows(IOException.class, () -> commands(null).changeReserve(60, "anna"));
+        assertEquals(seenBefore, seen.size());
+    }
+
     @Test
     void aSetpointNotReadYetStaysNullInsteadOfZero() throws Exception {
         serve(200, "{\"setpoints\":[{\"name\":\"co_comfort\",\"register\":4132,\"min\":5,\"max\":25,\"step\":1,"

backend/src/test/java/home/backend/adapters/http/ApiServerTest.java

@@ -2,24 +2,42 @@ package home.backend.adapters.http;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import home.backend.application.AuditRepository;
+import home.backend.application.AuditService;
+import home.backend.application.BatteryService;
+import home.backend.application.EnergyDetailsService;
 import home.backend.application.EnergyService;
 import home.backend.adapters.config.PresetFile;
 import home.backend.application.GatewayClient;
+import home.backend.application.GatewayBattery;
 import home.backend.application.GatewayCommands;
 import home.backend.application.SetpointService;
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
+import home.backend.domain.BatteryView.Reserve;
 import home.backend.domain.Command;
 import home.backend.domain.CommandResult;
 import home.backend.domain.CommandResult.Status;
+import home.backend.domain.RefreshResult;
+import home.backend.domain.RestoreResult;
+import home.backend.domain.RestoreResult.Outcome;
 import home.backend.domain.Restore;
 import home.backend.domain.Setpoint;
 import home.backend.domain.SetpointState;
 import home.backend.application.HealthService;
 import home.backend.application.HeatPumpService;
 import home.backend.application.HistoryRepository;
+import home.backend.application.HeatPumpSamples;
 import home.backend.application.HistoryService;
+import home.backend.application.StatsService;
+import home.backend.application.PiSensorService;
+import home.backend.application.WeatherService;
+import home.backend.domain.Forecast;
 import home.backend.domain.GatewaySnapshot;
 import home.backend.domain.GatewaySnapshot.DeviceSnapshot;
 import home.backend.domain.GatewaySnapshot.Measurement;
+import home.backend.domain.WeatherView.Warning;
+import home.backend.domain.HeatPumpSample;
 import home.backend.domain.HistoryView.Point;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
@@ -35,11 +53,14 @@ import java.net.http.HttpResponse;
 import java.nio.charset.StandardCharsets;
 import java.time.Clock;
 import java.time.Instant;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.TreeMap;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -54,10 +75,18 @@ class ApiServerTest {
     private GatewaySnapshot snapshot;
     private boolean gatewayDown;
     private boolean historyDown;
+    private boolean auditDown;
+    private HeatPumpSamples samples;
     private RuntimeException gatewayBug;
     private final List<Command> sent = new ArrayList<>();
     private Status verdict;
+    private Outcome restoreOutcome;
+    private int refreshes;
+    private final List<String> restored = new ArrayList<>();
     private boolean commandsDown;
+    private boolean batteryDown;
+    private BatteryResult.Status batteryVerdict;
+    private final List<String> batterySent = new ArrayList<>();
     private int answersBeforeDrop;
     private ApiServer server;
 
@@ -81,7 +110,18 @@ class ApiServerTest {
                     new Point(Instant.parse("2026-10-23T11:00:00Z"), 38.5),
                     new Point(Instant.parse("2026-10-23T12:00:00Z"), 44.2));
         };
+        samples = (from, to) -> {
+            if (historyDown) {
+                throw new IOException("influx down");
+            }
+            return List.of(
+                    new HeatPumpSample(Instant.parse("2026-10-23T10:00:00Z"), 0.0, 0.0, 0.0, 0.0, 8.0, 44.0),
+                    new HeatPumpSample(Instant.parse("2026-10-23T10:05:00Z"), 100.0, 100.0, 0.0, 0.0, 8.5, 43.0),
+                    new HeatPumpSample(Instant.parse("2026-10-23T10:10:00Z"), 100.0, 0.0, 0.0, 100.0, 9.0, 45.0),
+                    new HeatPumpSample(Instant.parse("2026-10-23T10:15:00Z"), 0.0, 0.0, 0.0, 0.0, 9.0, 46.0));
+        };
         verdict = Status.APPLIED;
+        restoreOutcome = Outcome.RESTORED;
         answersBeforeDrop = Integer.MAX_VALUE;
         GatewayCommands commands = new GatewayCommands() {
             @Override
@@ -98,6 +138,15 @@ class ApiServerTest {
                 };
             }
 
+            @Override
+            public RestoreResult restore(String setpoint, String requestedBy) throws IOException {
+                if (commandsDown) {
+                    throw new IOException("tunnel down");
+                }
+                restored.add(setpoint + " by " + requestedBy);
+                return new RestoreResult(restoreOutcome, "restored to 8");
+            }
+
             @Override
             public SetpointState setpoints() throws IOException {
                 if (commandsDown) {
@@ -109,11 +158,63 @@ class ApiServerTest {
                         new Setpoint("cwu_comfort", 4144, 5, 48, 1, 45)),
                         List.of(new Restore("cwu_economy", 4143, 8, 45, Instant.parse("2026-10-24T12:00:00Z"))));
             }
+
+            @Override
+            public int renewLeases() {
+                return 0;
+            }
+        };
+        batteryDown = false;
+        batteryVerdict = BatteryResult.Status.APPLIED;
+        GatewayBattery batteryCommands = new GatewayBattery() {
+            @Override
+            public Reserve reserve() throws IOException {
+                if (batteryDown) {
+                    throw new IOException("gateway /battery/reserve answered 404");
+                }
+                return new Reserve(50, 30);
+            }
+
+            @Override
+            public BatteryResult changeSchedule(BatteryChange change, String requestedBy) throws IOException {
+                return answer("schedule " + change + " by " + requestedBy);
+            }
+
+            @Override
+            public BatteryResult changeReserve(int pct, String requestedBy) throws IOException {
+                return answer("reserve " + pct + " by " + requestedBy);
+            }
+
+            private BatteryResult answer(String what) throws IOException {
+                if (batteryDown) {
+                    throw new IOException("tunnel down");
+                }
+                batterySent.add(what);
+                return switch (batteryVerdict) {
+                    case APPLIED -> new BatteryResult(batteryVerdict, "applied", Map.of(167, 90));
+                    case FAILED -> new BatteryResult(batteryVerdict,
+                            "registers not as written: [167]; not retried", Map.of(167, 80));
+                    default -> new BatteryResult(batteryVerdict, "nope", Map.of());
+                };
+            }
         };
         Clock clock = Clock.fixed(HEALTH_TIME, ZoneOffset.UTC);
         server = new ApiServer(0, new HeatPumpService(gateway, clock), new EnergyService(gateway, clock),
-                new HealthService(gateway, clock), new HistoryService(history, clock),
-                new SetpointService(commands, PresetFile.load(null)));
+                new EnergyDetailsService(gateway, clock),
+                new HealthService(gateway, clock, "v1.3.0"), new HistoryService(history, clock),
+                new SetpointService(commands, PresetFile.load(null)), new PiSensorService(gateway, clock),
+                new BatteryService(gateway, batteryCommands, clock),
+                new AuditService(auditRows(), clock), new StatsService(samples, clock),
+                new WeatherService(() -> exampleForecast(), () -> List.of(exampleWarning()),
+                        (from, to) -> exampleMeasuredPv(), clock),
+                () -> {
+                    if (commandsDown) {
+                        throw new IOException("tunnel down");
+                    }
+                    refreshes++;
+                    return new RefreshResult(List.of("deye", "house-meter"),
+                            List.of(new RefreshResult.Skipped("heat-pump", 41)));
+                });
         server.start();
     }
 
@@ -122,6 +223,27 @@ class ApiServerTest {
         server.stop();
     }
 
+    private AuditRepository auditRows() {
+        return new AuditRepository() {
+            @Override
+            public List<Row> heatPump(Instant from, Instant to) throws IOException {
+                if (auditDown) {
+                    throw new IOException("influx down");
+                }
+                return List.of(
+                        new Row(Instant.parse("2026-10-24T08:00:00Z"), "cwu_economy", "restore", "APPLIED", 45.0, 8.0),
+                        new Row(Instant.parse("2026-10-23T07:00:00Z"), "co_comfort", "mariusz", "REJECTED", null, 22.0));
+            }
+
+            @Override
+            public List<Row> battery(Instant from, Instant to) {
+                return List.of(
+                        new Row(Instant.parse("2026-10-24T09:30:00Z"), "reserve", "mariusz", "APPLIED", 50.0, 60.0),
+                        new Row(Instant.parse("2026-10-23T18:00:00Z"), "174", "mariusz", "FAILED", 0.0, 1.0));
+            }
+        };
+    }
+
     private static GatewaySnapshot exampleSnapshot() {
         Map<String, Double> pump = new HashMap<>(Map.of("outdoor_temp", 4.3, "indoor_temp", 21.2,
                 "co_buffer_temp", 16.9, "cwu_temp", 13.6, "ground_in_temp", 16.0, "ground_out_temp", 14.3,
@@ -133,18 +255,46 @@ class ApiServerTest {
                 "output_circulation", 0.0, "output_ground", 0.0, "output_cwu", 0.0));
         Instant pumpTime = Instant.parse("2026-10-23T22:13:35Z");
         Instant energyTime = Instant.parse("2026-10-23T22:26:00Z");
-        Map<String, Double> deye = Map.of("pv1_power_w", 0.0, "pv2_power_w", 0.0, "pv_today_kwh", 29.9,
+        Map<String, Double> deye = new HashMap<>(Map.of("pv1_power_w", 0.0, "pv2_power_w", 0.0, "pv_today_kwh", 29.9,
                 "grid_power_w", 645.0, "battery_power_w", -24.0, "battery_soc_pct", 99.0,
                 "load_power_w", 570.0, "grid_bought_today_kwh", 16.8, "grid_sold_today_kwh", 22.3,
-                "load_today_kwh", 24.2);
-        return new GatewaySnapshot(List.of(
+                "load_today_kwh", 24.2));
+        deye.putAll(Map.of("battery_voltage_v", 56.49, "battery_current_a", -0.05, "battery_temperature_c", 19.2,
+                "battery_charge_today_kwh", 0.5, "battery_discharge_today_kwh", 0.1,
+                "battery_charge_total_kwh", 453.7, "battery_discharge_total_kwh", 162.1));
+        return new GatewaySnapshot("v1.2.1", List.of(
                 new DeviceSnapshot("heat-pump", true, pumpTime, null,
                         List.of(new Measurement("Dom_Pompa", "heat_pump", pump, energyTime))),
                 new DeviceSnapshot("deye", true, energyTime, null,
                         List.of(new Measurement("home", "deye", deye, energyTime))),
                 new DeviceSnapshot("fronius", true, energyTime, null,
                         List.of(new Measurement("home", "fronius",
-                                Map.of("pv_power_w", 0.0, "energy_day_wh", 4400.0), energyTime)))));
+                                Map.of("pv_power_w", 0.0, "energy_day_wh", 4400.0), energyTime))),
+                new DeviceSnapshot("house-meter", true, energyTime, null,
+                        List.of(new Measurement("electricity", "PRAD2", Map.of("p1_voltage", 235.69,
+                                "p1_current", 0.32, "p1_power_active", 55.94, "p1_power_factor", 0.75,
+                                "frequency", 50.01, "import_energy_active", 67514.27), energyTime))),
+                new DeviceSnapshot("deye-settings", true, energyTime, null,
+                        List.of(new Measurement("electricity", "deye_settings", deyeSettings(), energyTime))),
+                new DeviceSnapshot("bme280", true, energyTime, null,
+                        List.of(new Measurement("measurement", "MEASUREMENT",
+                                Map.of("temperature", 20.17, "humidity", 45.82, "pressure", 985.8), energyTime)))));
+    }
+
+    /** The settings read from the inverter on 2026-10-24: time of use off, six 4-hour slots. */
+    private static Map<String, Double> deyeSettings() {
+        Map<String, Double> settings = new HashMap<>(Map.of("battery_capacity_ah", 280.0, "tou_enabled", 0.0,
+                "max_charge_current_a", 80.0, "max_discharge_current_a", 120.0, "shutdown_soc_pct", 20.0,
+                "low_soc_pct", 35.0, "restart_soc_pct", 50.0, "grid_charge_enabled", 1.0,
+                "grid_charge_current_a", 40.0, "grid_charge_start_soc_pct", 30.0));
+        double[] starts = {100, 500, 900, 1300, 1700, 2100};
+        for (int slot = 1; slot <= 6; slot++) {
+            settings.put("prog" + slot + "_start_hhmm", starts[slot - 1]);
+            settings.put("prog" + slot + "_power_w", 10000.0);
+            settings.put("prog" + slot + "_soc_pct", 80.0);
+            settings.put("prog" + slot + "_grid_charge", 0.0);
+        }
+        return settings;
     }
 
     private HttpResponse<String> get(String path) throws Exception {
@@ -153,6 +303,10 @@ class ApiServerTest {
         return client.send(request, HttpResponse.BodyHandlers.ofString());
     }
 
+    private static String awayRequest() throws IOException {
+        return example("preset-away-request").toString();
+    }
+
     private static JsonNode example(String name) throws IOException {
         try (InputStream in = ApiServerTest.class.getResourceAsStream("/api/" + name + ".json")) {
             return JSON.readTree(in);
@@ -178,16 +332,21 @@ class ApiServerTest {
         assertMatchesExample("/api/energy", "energy");
     }
 
+    @Test
+    void energyDetailsMatchExample() throws Exception {
+        assertMatchesExample("/api/energy/details", "energy-details");
+    }
+
     @Test
     void healthMatchesExample() throws Exception {
-        snapshot = new GatewaySnapshot(List.of(snapshot.devices().get(0),
+        snapshot = new GatewaySnapshot("v1.2.1", List.of(snapshot.devices().get(0),
                 new DeviceSnapshot("deye", false, null, "connect timed out", List.of())));
         assertMatchesExample("/api/health", "health");
     }
 
     @Test
     void heatPumpWithoutReadingMatchesUnreadExample() throws Exception {
-        snapshot = new GatewaySnapshot(List.of());
+        snapshot = new GatewaySnapshot("v1.2.1", List.of());
         assertMatchesExample("/api/heat-pump", "heat-pump-unread");
     }
 
@@ -198,25 +357,205 @@ class ApiServerTest {
         Measurement deye = devices.get(1).measurements().get(0);
         devices.set(1, new DeviceSnapshot("deye", true, old, null,
                 List.of(new Measurement("home", "deye", deye.fields(), old))));
-        snapshot = new GatewaySnapshot(devices);
+        snapshot = new GatewaySnapshot("v1.2.1", devices);
         assertMatchesExample("/api/energy", "energy-deye-stale");
     }
 
+    @Test
+    void batteryMatchesExample() throws Exception {
+        assertMatchesExample("/api/battery", "battery");
+    }
+
+    @Test
+    void batteryWithStaleSettingsMatchesExample() throws Exception {
+        Instant old = Instant.parse("2026-10-23T21:00:00Z");
+        List<DeviceSnapshot> devices = new ArrayList<>(snapshot.devices());
+        devices.set(devices.size() - 2, new DeviceSnapshot("deye-settings", true, old, null,
+                List.of(new Measurement("electricity", "deye_settings", deyeSettings(), old))));
+        snapshot = new GatewaySnapshot("v1.2.1", devices);
+        assertMatchesExample("/api/battery", "battery-settings-stale");
+    }
+
+    @Test
+    void batteryWithoutGatewayCommandsIsNotEditable() throws Exception {
+        batteryDown = true;
+
+        var body = JSON.readTree(get("/api/battery").body());
+
+        assertTrue(body.get("reserve").isNull());
+        assertEquals(false, body.get("editable").asBoolean());
+        assertEquals(99.0, body.get("socPct").asDouble());
+    }
+
+    @Test
+    void scheduleChangeGoesToTheGatewayWithTheUserAndAnswersWithTheVerdict() throws Exception {
+        var response = post("/api/battery/schedule", example("battery-schedule-request").toString(),
+                "Remote-User", "anna");
+
+        assertEquals(200, response.statusCode());
+        assertEquals(List.of("schedule " + new BatteryChange(true, List.of(
+                new BatteryChange.Slot(2, java.time.LocalTime.of(9, 30), 90, true),
+                new BatteryChange.Slot(3, null, 85, null))) + " by anna"), batterySent);
+        assertEquals(JSON.readTree("{\"status\":\"APPLIED\",\"message\":\"applied\",\"read\":{\"167\":90}}"),
+                JSON.readTree(response.body()));
+    }
+
+    @Test
+    void reserveChangeGoesToTheGateway() throws Exception {
+        var response = post("/api/battery/reserve", example("battery-reserve-request").toString());
+
+        assertEquals(200, response.statusCode());
+        assertEquals(List.of("reserve 60 by phone"), batterySent);
+    }
+
+    @Test
+    void batteryStatusFollowsTheGatewaysVerdict() throws Exception {
+        var expected = Map.of(BatteryResult.Status.REJECTED, 422, BatteryResult.Status.STALE, 409,
+                BatteryResult.Status.TOO_SOON, 429, BatteryResult.Status.FAILED, 502);
+        for (var entry : expected.entrySet()) {
+            batteryVerdict = entry.getKey();
+
+            assertEquals(entry.getValue(), post("/api/battery/reserve", "{\"pct\":60}").statusCode());
+            assertEquals(entry.getValue(), post("/api/battery/schedule", "{\"enabled\":false}").statusCode());
+        }
+        batteryVerdict = BatteryResult.Status.FAILED;
+        assertEquals(example("battery-failed"),
+                JSON.readTree(post("/api/battery/schedule", "{\"enabled\":false}").body()));
+    }
+
+    @Test
+    void batteryChangeWithTheGatewayDownIs503() throws Exception {
+        batteryDown = true;
+
+        assertEquals(503, post("/api/battery/reserve", "{\"pct\":60}").statusCode());
+        assertEquals(503, post("/api/battery/schedule", "{\"enabled\":false}").statusCode());
+    }
+
+    @Test
+    void badBatteryRequestsAre400AndSendNothing() throws Exception {
+        for (String body : List.of("", "not json", "[]", "{}", "{\"pct\":\"60\"}", "{\"pct\":60.5}", "{\"pct\":null}",
+                "{\"pct\":60,\"x\":1}")) {
+            assertEquals(400, post("/api/battery/reserve", body).statusCode(), body);
+        }
+        for (String body : List.of("", "not json", "[]", "{\"enabled\":\"yes\"}", "{\"slots\":[{\"slot\":1,\"from\":\"9h\"}]}",
+                "{\"slots\":[{\"slot\":1,\"from\":\"25:00\"}]}", "{\"slots\":[{\"slot\":1,\"socPct\":\"9\"}]}",
+                "{\"slots\":[{\"slot\":1,\"soc\":9}]}", "{\"slots\":[{\"slot\":1,\"gridCharge\":1}]}")) {
+            assertEquals(400, post("/api/battery/schedule", body).statusCode(), body);
+        }
+        assertTrue(batterySent.isEmpty());
+    }
+
+    @Test
+    void batteryWritesAreGuardedLikeEveryWrite() throws Exception {
+        for (String path : List.of("/api/battery/reserve", "/api/battery/schedule")) {
+            assertEquals(415, rawPost(path, "{}", "X-Requested-With", "home-pump").statusCode(), path);
+            assertEquals(403, rawPost(path, "{}", "Content-Type", "application/json").statusCode(), path);
+            assertEquals(403, post(path, "{}", "Origin", "https://evil.example").statusCode(), path);
+            assertEquals(405, get(path).statusCode(), path);
+        }
+        assertEquals(404, post("/api/battery/other", "{}").statusCode());
+        assertTrue(batterySent.isEmpty());
+    }
+
+    private static Forecast exampleForecast() {
+        Map<LocalDate, Forecast.DailyForecast> days = new TreeMap<>();
+        for (int i = 0; i < 5; i++) {
+            days.put(LocalDate.parse("2026-10-19").plusDays(i), new Forecast.DailyForecast(3, 12.0, 4.0, 0.0, 10.0, 7200.0));
+        }
+        days.put(LocalDate.parse("2026-10-24"), new Forecast.DailyForecast(3, 10.9, 3.8, 0.0, 9.0, 7151.0));
+        days.put(LocalDate.parse("2026-10-25"), new Forecast.DailyForecast(51, 13.2, 4.0, 0.3, 4.5, 28314.0));
+        days.put(LocalDate.parse("2026-10-26"), new Forecast.DailyForecast(61, 9.6, 4.1, 8.4, 2.1, 0.0));
+        return new Forecast(10.6, days);
+    }
+
+    /** Twice the forecast radiation of the same days, so the factor is 2 kWh per MJ/m². */
+    private static Map<LocalDate, Double> exampleMeasuredPv() {
+        Map<LocalDate, Double> measured = new HashMap<>();
+        for (int i = 0; i < 5; i++) {
+            measured.put(LocalDate.parse("2026-10-19").plusDays(i), 20.0);
+        }
+        return measured;
+    }
+
+    private static Warning exampleWarning() {
+        return new Warning("Silny wiatr", 2, OffsetDateTime.parse("2026-10-25T08:00:00+01:00"),
+                OffsetDateTime.parse("2026-10-25T18:00:00+01:00"),
+                "Prognozuje się wystąpienie silnego wiatru o średniej prędkości do 45 km/h.");
+    }
+
+    @Test
+    void weatherMatchesExample() throws Exception {
+        assertMatchesExample("/api/weather", "weather");
+    }
+
+    @Test
+    void piSensorMatchesExample()throws Exception {
+        assertMatchesExample("/api/pi-sensor", "pi-sensor");
+    }
+
+    @Test
+    void stalePiSensorMatchesExample() throws Exception {
+        Instant old = Instant.parse("2026-10-23T21:00:00Z");
+        List<DeviceSnapshot> devices = new ArrayList<>(snapshot.devices());
+        Measurement bme = devices.getLast().measurements().get(0);
+        devices.set(devices.size() - 1, new DeviceSnapshot("bme280", true, old, null,
+                List.of(new Measurement(bme.database(), bme.measurement(), bme.fields(), old))));
+        snapshot = new GatewaySnapshot("v1.2.1", devices);
+        assertMatchesExample("/api/pi-sensor", "pi-sensor-stale");
+    }
+
     @Test
     void historyMatchesExample() throws Exception {
         assertMatchesExample("/api/history?series=cwu_temp&range=24h", "history");
     }
 
+    @Test
+    void statsMatchExample() throws Exception {
+        assertMatchesExample("/api/stats?range=7d", "stats");
+    }
+
+    @Test
+    void statsNeedAKnownRange() throws Exception {
+        assertEquals(400, get("/api/stats").statusCode());
+        assertEquals(400, get("/api/stats?range=24h").statusCode());
+        assertEquals(200, get("/api/stats?range=30d").statusCode());
+    }
+
+    @Test
+    void statsAre502WhenInfluxIsDown() throws Exception {
+        historyDown = true;
+
+        assertEquals(502, get("/api/stats?range=7d").statusCode());
+    }
+
     @Test
     void historyRangeDefaultsTo24Hours() throws Exception {
         assertEquals(200, get("/api/history?series=cwu_temp").statusCode());
     }
 
+    @Test
+    void auditMatchesExample() throws Exception {
+        assertMatchesExample("/api/audit?range=7d", "audit");
+    }
+
+    @Test
+    void auditRangeDefaultsAndIsChecked() throws Exception {
+        assertEquals(200, get("/api/audit").statusCode());
+        assertEquals(400, get("/api/audit?range=90d").statusCode());
+    }
+
+    @Test
+    void auditInfluxFailureIs502() throws Exception {
+        auditDown = true;
+
+        assertEquals(502, get("/api/audit?range=7d").statusCode());
+    }
+
     @Test
     void unreachableGatewayIs503WithJsonError() throws Exception {
         gatewayDown = true;
 
-        for (String path : List.of("/api/heat-pump", "/api/energy")) {
+        for (String path : List.of("/api/heat-pump", "/api/energy", "/api/energy/details")) {
             HttpResponse<String> response = get(path);
             assertEquals(503, response.statusCode());
             assertEquals("gateway unreachable", JSON.readTree(response.body()).get("error").asText());
@@ -301,6 +640,78 @@ class ApiServerTest {
         assertEquals(List.of(new Command("cwu_economy", 45, java.time.Duration.ofHours(2), "phone")), sent);
     }
 
+    @Test
+    void restoreMatchesExampleAndAsksForTheUsersSetpoint() throws Exception {
+        HttpResponse<String> response = post("/api/setpoints/cwu_economy/restore", "{}", "Remote-User", "anna");
+
+        assertEquals(200, response.statusCode());
+        assertEquals(example("setpoint-restored"), JSON.readTree(response.body()));
+        assertEquals(List.of("cwu_economy by anna"), restored);
+    }
+
+    @Test
+    void restoreStatusFollowsTheGatewaysVerdict() throws Exception {
+        var expected = Map.of(Outcome.NOT_PENDING, 404, Outcome.CONFLICT, 409, Outcome.TOO_SOON, 429,
+                Outcome.FAILED, 502);
+        for (var entry : expected.entrySet()) {
+            restoreOutcome = entry.getKey();
+
+            assertEquals(entry.getValue(), post("/api/setpoints/cwu_economy/restore", "{}").statusCode());
+        }
+    }
+
+    @Test
+    void restoreWithTheGatewayDownIs503() throws Exception {
+        commandsDown = true;
+
+        assertEquals(503, post("/api/setpoints/cwu_economy/restore", "{}").statusCode());
+    }
+
+    @Test
+    void restoreIsGuardedLikeEveryWrite() throws Exception {
+        String path = "/api/setpoints/cwu_economy/restore";
+        assertEquals(415, rawPost(path, "{}", "X-Requested-With", "home-pump").statusCode());
+        assertEquals(403, rawPost(path, "{}", "Content-Type", "application/json").statusCode());
+        assertEquals(403, post(path, "{}", "Origin", "https://evil.example").statusCode());
+        assertEquals(405, get(path).statusCode());
+        assertTrue(restored.isEmpty());
+    }
+
+    @Test
+    void refreshPassesTheGatewaysAnswerThrough() throws Exception {
+        var response = post("/api/refresh", "{}");
+
+        assertEquals(200, response.statusCode());
+        assertEquals(example("refresh"), JSON.readTree(response.body()));
+        assertEquals(1, refreshes);
+    }
+
+    @Test
+    void refreshIs503WhenTheGatewayCannotBeReached() throws Exception {
+        commandsDown = true;
+
+        assertEquals(503, post("/api/refresh", "{}").statusCode());
+    }
+
+    @Test
+    void refreshIsGuardedLikeEveryWrite() throws Exception {
+        String path = "/api/refresh";
+        assertEquals(415, rawPost(path, "{}", "X-Requested-With", "home-pump").statusCode());
+        assertEquals(403, rawPost(path, "{}", "Content-Type", "application/json").statusCode());
+        assertEquals(403, post(path, "{}", "Origin", "https://evil.example").statusCode());
+        assertEquals(405, get(path).statusCode());
+        assertEquals(0, refreshes);
+    }
+
+    @Test
+    void otherPathsUnderSetpointsAre404() throws Exception {
+        for (String path : List.of("/api/setpoints/", "/api/setpoints/cwu_economy",
+                "/api/setpoints/cwu_economy/restore/x", "/api/setpoints/CWU/restore", "/api/setpoints/a-b/restore")) {
+            assertEquals(404, post(path, "{}").statusCode(), path);
+        }
+        assertTrue(restored.isEmpty());
+    }
+
     @Test
     void rejectedIs422AndMatchesExample() throws Exception {
         verdict = Status.REJECTED;
@@ -343,7 +754,7 @@ class ApiServerTest {
 
     @Test
     void presetResultsMatchExample() throws Exception {
-        HttpResponse<String> response = post("/api/presets/away", "");
+        HttpResponse<String> response = post("/api/presets/away", awayRequest());
 
         assertEquals(200, response.statusCode());
         JsonNode body = JSON.readTree(response.body());
@@ -356,12 +767,66 @@ class ApiServerTest {
     void presetCutShortByALostLinkKeepsTheResultsSoFar() throws Exception {
         answersBeforeDrop = 1;
 
-        HttpResponse<String> response = post("/api/presets/away", "{}");
+        HttpResponse<String> response = post("/api/presets/away", awayRequest());
 
         assertEquals(502, response.statusCode());
         assertEquals(example("setpoints-preset-partial"), JSON.readTree(response.body()));
     }
 
+    @Test
+    void awayPresetSendsTheChosenEndHeldInEachChange() throws Exception {
+        post("/api/presets/away", awayRequest());
+
+        var end = java.time.Instant.parse("2026-11-02T17:00:00Z");
+        assertEquals(List.of(new Command("cwu_comfort", 10, null, end, "phone"),
+                new Command("co_comfort", 15, null, end, "phone")), sent);
+    }
+
+    @Test
+    void awayWithOwnValuesSendsThem() throws Exception {
+        var response = post("/api/presets/away", example("preset-away-values-request").toString());
+
+        assertEquals(200, response.statusCode());
+        var end = java.time.Instant.parse("2026-11-02T17:00:00Z");
+        assertEquals(List.of(new Command("cwu_comfort", 12, null, end, "phone"),
+                new Command("co_comfort", 16, null, end, "phone")), sent);
+    }
+
+    @Test
+    void ownValuesForOtherSetpointsOrOutsideTheLimitsAre400AndSendNothing() throws Exception {
+        String until = "\"until\":\"2026-11-02T18:00:00Z\"";
+        for (String values : List.of("{\"cwu_economy\":6}", "{\"co_comfort\":4}", "{\"co_comfort\":26}",
+                "{\"co_comfort\":null}", "{\"co_comfort\":15.5}", "{\"co_comfort\":\"15\"}", "[]")) {
+            assertEquals(400, post("/api/presets/away", "{" + until + ",\"values\":" + values + "}").statusCode(),
+                    values);
+        }
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void ownValueThatDoesNotLowerAHeldSetpointIs422() throws Exception {
+        var body = "{\"until\":\"2026-11-02T18:00:00Z\",\"values\":{\"co_comfort\":19}}";
+
+        assertEquals(422, post("/api/presets/away", body).statusCode());
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void badOrMissingEndTimesAre400AndSendNothing() throws Exception {
+        for (String body : List.of("", "{}", "{\"until\":null}", "{\"until\":\"tomorrow\"}", "{\"until\":5}",
+                "{\"until\":\"2026-11-02T18:00:00\"}", "not json", "{\"until\":\"2026-11-02T18:00:00Z\",\"x\":1}")) {
+            assertEquals(400, post("/api/presets/away", body).statusCode(), body);
+        }
+        assertEquals(400, post("/api/presets/cwu-now", awayRequest()).statusCode());
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void presetWithoutAnEndStillTakesNoBodyOrAnEmptyObject() throws Exception {
+        assertEquals(200, post("/api/presets/cwu-now", "").statusCode());
+        assertEquals(200, post("/api/presets/cwu-now", "{}").statusCode());
+    }
+
     @Test
     void unknownPresetIs404() throws Exception {
         assertEquals(404, post("/api/presets/nope", "").statusCode());
@@ -372,7 +837,7 @@ class ApiServerTest {
     void presetOutsideLimitsIs422() throws Exception {
         verdict = Status.REJECTED;
 
-        assertEquals(422, post("/api/presets/away", "").statusCode());
+        assertEquals(422, post("/api/presets/away", awayRequest()).statusCode());
     }
 
     @Test
@@ -381,7 +846,7 @@ class ApiServerTest {
 
         assertEquals(503, get("/api/setpoints").statusCode());
         assertEquals(503, post("/api/setpoints", BOOST).statusCode());
-        assertEquals(503, post("/api/presets/away", "").statusCode());
+        assertEquals(503, post("/api/presets/away", awayRequest()).statusCode());
     }
 
     @Test

backend/src/test/java/home/backend/adapters/influx/InfluxAuditRepositoryTest.java

@@ -0,0 +1,105 @@
+package home.backend.adapters.influx;
+
+import com.sun.net.httpserver.HttpServer;
+import home.backend.application.AuditRepository.Row;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class InfluxAuditRepositoryTest {
+
+    private static final Instant FROM = Instant.parse("2026-10-17T12:00:00Z");
+    private static final Instant TO = Instant.parse("2026-10-24T12:00:00Z");
+
+    private HttpServer server;
+    private final List<String> queries = Collections.synchronizedList(new ArrayList<>());
+    private String body;
+
+    @BeforeEach
+    void startServer() throws IOException {
+        server = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        server.createContext("/query", exchange -> {
+            queries.add(URLDecoder.decode(exchange.getRequestURI().getRawQuery(), StandardCharsets.UTF_8));
+            byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
+            exchange.sendResponseHeaders(200, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.close();
+        });
+        server.start();
+    }
+
+    @AfterEach
+    void stopServer() {
+        server.stop(0);
+    }
+
+    @Test
+    void readsHeatPumpRowsFromTheLegacyDatabase() throws IOException {
+        body = fixture("influx-audit-setpoints.json");
+
+        List<Row> rows = repository().heatPump(FROM, TO);
+
+        assertEquals(2, rows.size());
+        assertEquals(new Row(Instant.ofEpochMilli(1761292800000L), "cwu_economy", "restore", "APPLIED", 45.0, 8.0),
+                rows.get(0));
+        assertNull(rows.get(1).oldValue());
+        assertEquals("co_comfort", rows.get(1).target());
+        assertTrue(queries.getFirst().startsWith("db=Dom_Pompa&epoch=ms&q=SELECT * FROM \"setpoint_audit\" "
+                + "WHERE time >= " + FROM.toEpochMilli() + "ms AND time < " + TO.toEpochMilli() + "ms"),
+                queries.getFirst());
+    }
+
+    @Test
+    void readsBatteryRowsByRegisterTag() throws IOException {
+        body = fixture("influx-audit-battery.json");
+
+        List<Row> rows = repository().battery(FROM, TO);
+
+        assertEquals(List.of("reserve", "174"), rows.stream().map(Row::target).toList());
+        assertEquals(60.0, rows.getFirst().newValue());
+        assertTrue(queries.getFirst().startsWith("db=electricity&"), queries.getFirst());
+        assertTrue(queries.getFirst().contains("\"deye_settings_audit\""), queries.getFirst());
+    }
+
+    @Test
+    void noRowsIsAnEmptyList() throws IOException {
+        body = fixture("influx-query-empty.json");
+
+        assertTrue(repository().battery(FROM, TO).isEmpty());
+    }
+
+    @Test
+    void anInfluxErrorIsAnIOException() throws IOException {
+        body = fixture("influx-query-error.json");
+
+        assertThrows(IOException.class, () -> repository().heatPump(FROM, TO));
+    }
+
+    private InfluxAuditRepository repository() {
+        URI base = URI.create("http://127.0.0.1:" + server.getAddress().getPort());
+        return new InfluxAuditRepository(new InfluxSettings(base, Duration.ofSeconds(5)));
+    }
+
+    private static String fixture(String name) throws IOException {
+        return Files.readString(Path.of("src/test/resources/influx", name));
+    }
+}

backend/src/test/java/home/backend/adapters/influx/InfluxHistoryRepositoryTest.java

@@ -1,6 +1,7 @@
 package home.backend.adapters.influx;
 
 import com.sun.net.httpserver.HttpServer;
+import home.backend.domain.HeatPumpSample;
 import home.backend.domain.HistoryView.Point;
 import home.backend.domain.Series;
 import org.junit.jupiter.api.AfterEach;
@@ -208,6 +209,35 @@ class InfluxHistoryRepositoryTest {
                 () -> repository(Duration.ofMillis(200)).history(Series.CWU_TEMP, FROM, TO, 72));
     }
 
+    @Test
+    void readsRawHeatPumpPollsFromTheLegacyDatabase() throws IOException {
+        defaultBody = fixture("influx-query-heat-pump.json");
+
+        List<HeatPumpSample> samples = repository(TIMEOUT).samples(FROM, TO);
+
+        assertEquals("Dom_Pompa", requests.get(0).get("db"));
+        assertEquals("SELECT output_compressor, output_cwu, output_co, output_heater, outdoor_temp, cwu_temp"
+                + " FROM \"heat_pump\" WHERE time >= 1792800000000ms AND time < 1792821600000ms",
+                requests.get(0).get("q"));
+        assertEquals(3, samples.size());
+        assertEquals(new HeatPumpSample(Instant.ofEpochMilli(1792771500000L), 100.0, 100.0, 0.0, 0.0, 8.5, 43.9),
+                samples.get(1));
+        assertEquals(new HeatPumpSample(Instant.ofEpochMilli(1792771800000L), 50.0, 0.0, 100.0, 100.0, null, null),
+                samples.get(2));
+    }
+
+    @Test
+    void noHeatPumpPollsIsAnEmptyList() throws IOException {
+        assertTrue(repository(TIMEOUT).samples(FROM, TO).isEmpty());
+    }
+
+    @Test
+    void heatPumpQueryErrorIsAnIoException() throws IOException {
+        defaultBody = fixture("influx-query-error.json");
+
+        assertThrows(IOException.class, () -> repository(TIMEOUT).samples(FROM, TO));
+    }
+
     @Test
     void rejectsAnEmptyRange() {
         assertThrows(IllegalArgumentException.class,

backend/src/test/java/home/backend/adapters/influx/InfluxPvEnergyTest.java

@@ -0,0 +1,89 @@
+package home.backend.adapters.influx;
+
+import com.sun.net.httpserver.HttpServer;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
+import java.time.Duration;
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class InfluxPvEnergyTest {
+
+    private static final LocalDate FROM = LocalDate.parse("2026-10-19");
+    private static final LocalDate TO = LocalDate.parse("2026-10-24");
+
+    private HttpServer server;
+    private InfluxPvEnergy pv;
+    private final List<String> queries = new ArrayList<>();
+    private int status = 200;
+    /** Day buckets start at Warsaw midnight: 2026-10-19 is 2026-10-18T22:00Z. */
+    private String deye = rows("1792360800000", 22.5, "1792447200000", 8.0);
+    private String fronius = rows("1792360800000", 4400.0, "1792533600000", 100.0);
+
+    @BeforeEach
+    void start() throws IOException {
+        server = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        server.createContext("/query", exchange -> {
+            String query = URLDecoder.decode(exchange.getRequestURI().getRawQuery(), StandardCharsets.UTF_8);
+            queries.add(query);
+            byte[] bytes = (query.contains("\"deye\"") ? deye : fronius).getBytes(StandardCharsets.UTF_8);
+            exchange.sendResponseHeaders(status, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.close();
+        });
+        server.start();
+        var settings = new InfluxSettings(URI.create("http://127.0.0.1:" + server.getAddress().getPort()),
+                Duration.ofSeconds(2));
+        pv = new InfluxPvEnergy(settings);
+    }
+
+    @AfterEach
+    void stop() {
+        server.stop(0);
+    }
+
+    private static String rows(String t1, double v1, String t2, double v2) {
+        return "{\"results\":[{\"statement_id\":0,\"series\":[{\"name\":\"m\",\"columns\":[\"time\",\"max\"],"
+                + "\"values\":[[" + t1 + "," + v1 + "],[" + t2 + "," + v2 + "]]}]}]}";
+    }
+
+    @Test
+    void addsTheDeyeAndFroniusDayCountersPerLocalDay() throws IOException {
+        Map<LocalDate, Double> days = pv.dailyKwh(FROM, TO);
+
+        assertEquals(Map.of(FROM, 22.5 + 4.4), days);
+    }
+
+    @Test
+    void asksForTheDailyMaximumOfEachCounterInWarsawDays() throws IOException {
+        pv.dailyKwh(FROM, TO);
+
+        assertEquals(2, queries.size());
+        String deyeQuery = queries.stream().filter(q -> q.contains("\"deye\"")).findFirst().orElseThrow();
+        assertTrue(deyeQuery.contains("db=electricity"), deyeQuery);
+        assertTrue(deyeQuery.contains("SELECT max(\"pv_today_kwh\") FROM \"deye\" WHERE time >= 1792360800000ms"
+                + " AND time < 1792792800000ms GROUP BY time(1d) fill(none) tz('Europe/Warsaw')"), deyeQuery);
+        assertTrue(queries.stream().anyMatch(q -> q.contains("max(\"energy_day_wh\") FROM \"fronius\"")), queries.toString());
+    }
+
+    @Test
+    void failureIsAnIoError() {
+        status = 500;
+
+        assertThrows(IOException.class, () -> pv.dailyKwh(FROM, TO));
+    }
+}

backend/src/test/java/home/backend/adapters/weather/WeatherClientsTest.java

@@ -0,0 +1,185 @@
+package home.backend.adapters.weather;
+
+import com.sun.net.httpserver.HttpServer;
+import home.backend.domain.Forecast;
+import home.backend.domain.WeatherView.Warning;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.time.Duration;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/** The two clients against a local server that answers with responses recorded from the real services. */
+class WeatherClientsTest {
+
+    private static final WeatherSettings PLACE = WeatherSettings.fromEnvironment(Map.of());
+    private static final Duration TIMEOUT = Duration.ofSeconds(2);
+
+    private HttpServer server;
+    private URI base;
+    private final List<String> requests = new ArrayList<>();
+    private int status = 200;
+    private String body = "";
+
+    @BeforeEach
+    void start() throws IOException {
+        server = HttpServer.create(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0), 0);
+        server.createContext("/", exchange -> {
+            requests.add(exchange.getRequestURI().toString());
+            byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
+            exchange.sendResponseHeaders(status, bytes.length);
+            exchange.getResponseBody().write(bytes);
+            exchange.close();
+        });
+        server.start();
+        base = URI.create("http://127.0.0.1:" + server.getAddress().getPort());
+    }
+
+    @AfterEach
+    void stop() {
+        server.stop(0);
+    }
+
+    private static String fixture(String name) throws IOException {
+        return Files.readString(Path.of("src/test/resources/weather", name));
+    }
+
+    @Test
+    void readsTheOpenMeteoForecastForTheHouse() throws IOException {
+        body = fixture("open-meteo.json");
+
+        Forecast forecast = new OpenMeteoClient(base, PLACE, TIMEOUT).forecast();
+
+        assertEquals(10.6, forecast.temperature());
+        assertEquals(17, forecast.days().size());
+        var today = forecast.days().get(LocalDate.parse("2026-10-24"));
+        assertEquals(3, today.weatherCode());
+        assertEquals(10.9, today.tMax());
+        assertEquals(3.8, today.tMin());
+        assertEquals(6.88, today.radiationMj());
+        assertEquals(7151.32, today.sunshineSeconds());
+        assertEquals(8.4, forecast.days().get(LocalDate.parse("2026-10-26")).precipitationMm());
+        String request = requests.getFirst();
+        for (String part : List.of("latitude=49.684", "longitude=21.77", "timezone=Europe%2FWarsaw",
+                "past_days=14", "shortwave_radiation_sum", "sunshine_duration")) {
+            assertEquals(true, request.contains(part), part + " in " + request);
+        }
+    }
+
+    @Test
+    void aMissingValueInTheForecastIsNull() throws IOException {
+        body = """
+                {"daily":{"time":["2026-10-24"],"weather_code":[null],"temperature_2m_max":[1.5]}}""";
+
+        var day = new OpenMeteoClient(base, PLACE, TIMEOUT).forecast().days().get(LocalDate.parse("2026-10-24"));
+
+        assertNull(day.weatherCode());
+        assertEquals(1.5, day.tMax());
+        assertNull(day.tMin());
+        assertNull(day.radiationMj());
+    }
+
+    @Test
+    void anOpenMeteoFailureIsAnIoError() {
+        body = "{\"error\":true}";
+        status = 500;
+        var client = new OpenMeteoClient(base, PLACE, TIMEOUT);
+        assertThrows(IOException.class, client::forecast);
+
+        status = 200;
+        body = "not json";
+        assertThrows(IOException.class, client::forecast);
+
+        body = "{\"daily\":{}}";
+        assertThrows(IOException.class, client::forecast);
+    }
+
+    @Test
+    void keepsWarningsThatCoverTheCityOrThePowiatAndMapsThem() throws IOException {
+        body = fixture("imgw-warnings.json");
+
+        List<Warning> warnings = new ImgwClient(base, PLACE, TIMEOUT).warnings();
+
+        assertEquals("/api/data/warningsmeteo", requests.getFirst());
+        assertEquals(2, warnings.size());
+        Warning city = warnings.get(0);
+        assertEquals("Silny wiatr", city.event());
+        assertEquals(2, city.level());
+        assertEquals(OffsetDateTime.parse("2026-10-25T08:00:00+01:00"), city.from());
+        assertEquals(OffsetDateTime.parse("2026-10-25T18:00:00+01:00"), city.to());
+        assertEquals("Prognozuje się wystąpienie silnego wiatru o średniej prędkości do 45 km/h, "
+                + "w porywach do 90 km/h, z południa.", city.text());
+        assertEquals(1, warnings.get(1).level());
+    }
+
+    @Test
+    void otherAreasAreIgnoredAndTerytIsConfigurable() throws IOException {
+        body = fixture("imgw-warnings.json");
+        var cityOnly = new WeatherSettings(PLACE.latitude(), PLACE.longitude(), List.of("1862"));
+        var elsewhere = new WeatherSettings(PLACE.latitude(), PLACE.longitude(), List.of("2804"));
+
+        assertEquals(1, new ImgwClient(base, cityOnly, TIMEOUT).warnings().size());
+        assertEquals(1, new ImgwClient(base, elsewhere, TIMEOUT).warnings().size());
+        assertEquals(0, new ImgwClient(base, new WeatherSettings(0, 0, List.of("0000")), TIMEOUT).warnings().size());
+    }
+
+    @Test
+    void aMalformedWarningIsSkippedNotFatal() throws IOException {
+        body = """
+                [{"nazwa_zdarzenia":"Burze","stopien":"x","obowiazuje_od":"2026-10-25 08:00:00",
+                  "obowiazuje_do":"2026-10-25 18:00:00","tresc":"a","teryt":["1862"]},
+                 {"nazwa_zdarzenia":"Burze","stopien":"3","obowiazuje_od":"soon",
+                  "obowiazuje_do":"2026-10-25 18:00:00","tresc":"b","teryt":["1862"]},
+                 {"nazwa_zdarzenia":"Burze","stopien":"3","obowiazuje_od":"2026-10-25 08:00:00",
+                  "obowiazuje_do":"2026-10-25 18:00:00","tresc":"c","teryt":["1862"]}]""";
+
+        List<Warning> warnings = new ImgwClient(base, PLACE, TIMEOUT).warnings();
+
+        assertEquals(1, warnings.size());
+        assertEquals("c", warnings.getFirst().text());
+    }
+
+    @Test
+    void anImgwFailureIsAnIoError() {
+        body = "{}";
+        var client = new ImgwClient(base, PLACE, TIMEOUT);
+        assertThrows(IOException.class, client::warnings);
+
+        status = 503;
+        assertThrows(IOException.class, client::warnings);
+    }
+
+    @Test
+    void settingsDefaultToKrosnoAndRejectNonsense() {
+        assertEquals(49.684, PLACE.latitude());
+        assertEquals(21.770, PLACE.longitude());
+        assertEquals(List.of("1862", "1807"), PLACE.teryt());
+
+        var custom = WeatherSettings.fromEnvironment(
+                Map.of("WEATHER_LAT", "50.1", "WEATHER_LON", "-20", "WEATHER_TERYT", "1465, 1401"));
+        assertEquals(50.1, custom.latitude());
+        assertEquals(-20.0, custom.longitude());
+        assertEquals(List.of("1465", "1401"), custom.teryt());
+
+        assertThrows(IllegalArgumentException.class,
+                () -> WeatherSettings.fromEnvironment(Map.of("WEATHER_LAT", "north")));
+        assertThrows(IllegalArgumentException.class,
+                () -> WeatherSettings.fromEnvironment(Map.of("WEATHER_LON", "200")));
+    }
+}

backend/src/test/java/home/backend/application/AuditServiceTest.java

@@ -0,0 +1,108 @@
+package home.backend.application;
+
+import home.backend.application.AuditRepository.Row;
+import home.backend.domain.AuditEntry;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.ZoneOffset;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class AuditServiceTest {
+
+    private static final Instant NOW = Instant.parse("2026-10-24T12:00:00Z");
+    private static final Clock CLOCK = Clock.fixed(NOW, ZoneOffset.UTC);
+
+    private List<Row> heatPump = List.of();
+    private List<Row> battery = List.of();
+    private final List<Instant> asked = new ArrayList<>();
+
+    private final AuditRepository repository = new AuditRepository() {
+        @Override
+        public List<Row> heatPump(Instant from, Instant to) {
+            asked.add(from);
+            return heatPump;
+        }
+
+        @Override
+        public List<Row> battery(Instant from, Instant to) throws IOException {
+            if (battery == null) {
+                throw new IOException("influx down");
+            }
+            return battery;
+        }
+    };
+    private final AuditService service = new AuditService(repository, CLOCK);
+
+    private static Row row(String time, String target, String by, Double old, Double value) {
+        return new Row(Instant.parse(time), target, by, "APPLIED", old, value);
+    }
+
+    @Test
+    void mergesBothSourcesNewestFirst() throws IOException {
+        heatPump = List.of(row("2026-10-24T08:00:00Z", "cwu_economy", "a", 8.0, 45.0),
+                row("2026-10-22T08:00:00Z", "co_comfort", "a", 19.0, 20.0));
+        battery = List.of(row("2026-10-23T08:00:00Z", "reserve", "b", 50.0, 60.0));
+
+        var entries = service.audit(null).entries();
+
+        assertEquals(List.of("Ciepła woda – oszczędnie", "Rezerwa baterii", "Ogrzewanie – komfort"),
+                entries.stream().map(AuditEntry::what).toList());
+        assertEquals(List.of("heat_pump", "battery", "heat_pump"),
+                entries.stream().map(AuditEntry::source).toList());
+    }
+
+    @Test
+    void namesTheDeyeRegisters() throws IOException {
+        battery = List.of("146", "148", "153", "166", "171", "172", "177", "reserve", "999").stream()
+                .map(register -> row("2026-10-24T08:00:00Z", register, "a", 0.0, 1.0)).toList();
+
+        var entries = service.audit("24h").entries();
+
+        assertEquals(List.of("Harmonogram baterii/0/1", "Przedział 1: start/HHMM", "Przedział 6: start/HHMM",
+                "Przedział 1: poziom/%", "Przedział 6: poziom/%", "Przedział 1: ładowanie z sieci/0/1",
+                "Przedział 6: ładowanie z sieci/0/1", "Rezerwa baterii/%", "Rejestr 999/"),
+                entries.stream().map(e -> e.what() + "/" + e.unit()).toList());
+    }
+
+    @Test
+    void showsARestoreAsAutomaticAndKeepsMissingValuesNull() throws IOException {
+        heatPump = List.of(row("2026-10-24T08:00:00Z", "cwu_economy", "restore", null, 8.4));
+
+        var entry = service.audit("7d").entries().getFirst();
+
+        assertEquals("automatycznie (przywrócenie)", entry.who());
+        assertNull(entry.oldValue());
+        assertEquals(8, entry.newValue());
+        assertEquals("°C", entry.unit());
+    }
+
+    @Test
+    void defaultsToSevenDaysAndAllowsUpToThirty() throws IOException {
+        service.audit(null);
+        service.audit("30d");
+
+        assertEquals(List.of(NOW.minus(Duration.ofDays(7)), NOW.minus(Duration.ofDays(30))), asked);
+    }
+
+    @Test
+    void rejectsAnUnknownRange() {
+        assertThrows(IllegalArgumentException.class, () -> service.audit("90d"));
+        assertThrows(IllegalArgumentException.class, () -> service.audit(""));
+    }
+
+    @Test
+    void failsWhenOneSourceFails() {
+        battery = null;
+
+        assertThrows(IOException.class, () -> service.audit("7d"));
+    }
+}

backend/src/test/java/home/backend/application/LeaseRenewerTest.java

@@ -0,0 +1,92 @@
+package home.backend.application;
+
+import home.backend.domain.Command;
+import home.backend.domain.CommandResult;
+import home.backend.domain.RestoreResult;
+import home.backend.domain.SetpointState;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class LeaseRenewerTest {
+
+    private final AtomicInteger calls = new AtomicInteger();
+    private final CountDownLatch threeCalls = new CountDownLatch(3);
+    private Exception failure;
+
+    private final GatewayCommands gateway = new GatewayCommands() {
+        @Override
+        public CommandResult apply(Command command) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public RestoreResult restore(String setpoint, String requestedBy) {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public SetpointState setpoints() {
+            throw new UnsupportedOperationException();
+        }
+
+        @Override
+        public int renewLeases() throws IOException {
+            calls.incrementAndGet();
+            threeCalls.countDown();
+            if (failure instanceof IOException e) {
+                throw e;
+            }
+            if (failure instanceof RuntimeException e) {
+                throw e;
+            }
+            return 1;
+        }
+    };
+
+    @Test
+    void renewsAtOnceAndThenEveryPeriod() throws Exception {
+        try (var renewer = new LeaseRenewer(gateway)) {
+            renewer.start(Duration.ofMillis(10));
+
+            assertTrue(threeCalls.await(5, TimeUnit.SECONDS));
+        }
+    }
+
+    @Test
+    void aFailedRenewalDoesNotStopTheSchedule() throws Exception {
+        failure = new IOException("tunnel down");
+        try (var renewer = new LeaseRenewer(gateway)) {
+            renewer.start(Duration.ofMillis(10));
+
+            assertTrue(threeCalls.await(5, TimeUnit.SECONDS));
+        }
+    }
+
+    @Test
+    void anUnexpectedErrorDoesNotStopTheScheduleEither() throws Exception {
+        failure = new IllegalStateException("bad answer");
+        try (var renewer = new LeaseRenewer(gateway)) {
+            renewer.start(Duration.ofMillis(10));
+
+            assertTrue(threeCalls.await(5, TimeUnit.SECONDS));
+        }
+    }
+
+    @Test
+    void renewDoesNotThrowOutOfTheScheduler() {
+        failure = new IOException("tunnel down");
+        try (var renewer = new LeaseRenewer(gateway)) {
+            renewer.renew();
+        }
+
+        assertEquals(1, calls.get());
+    }
+}

backend/src/test/java/home/backend/application/ServicesTest.java

@@ -1,5 +1,12 @@
 package home.backend.application;
 
+import home.backend.domain.BatteryChange;
+import home.backend.domain.BatteryResult;
+import home.backend.domain.BatteryView;
+import home.backend.domain.EnergyDetails;
+import home.backend.domain.EnergyDetails.Device;
+import home.backend.domain.EnergyDetails.Group;
+import home.backend.domain.EnergyDetails.Item;
 import home.backend.domain.EnergyView;
 import home.backend.domain.EnergyView.Source;
 import home.backend.domain.GatewaySnapshot;
@@ -9,6 +16,7 @@ import home.backend.domain.HealthView;
 import home.backend.domain.HeatPumpView;
 import home.backend.domain.HeatPumpView.State;
 import home.backend.domain.HistoryView;
+import home.backend.domain.PiSensorView;
 import home.backend.domain.HistoryView.Point;
 import home.backend.domain.Series;
 import org.junit.jupiter.api.Test;
@@ -18,6 +26,7 @@ import java.time.Clock;
 import java.time.Duration;
 import java.time.Instant;
 import java.time.ZoneOffset;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -40,7 +49,7 @@ class ServicesTest {
     }
 
     private static GatewayClient gateway(DeviceSnapshot... devices) {
-        return () -> new GatewaySnapshot(List.of(devices));
+        return () -> new GatewaySnapshot("v1.2.1", List.of(devices));
     }
 
     private static GatewayClient unreachable() {
@@ -166,6 +175,197 @@ class ServicesTest {
         assertThrows(IOException.class, () -> new HeatPumpService(unreachable(), CLOCK).current());
     }
 
+    private static Map<String, Double> settings(double touEnabled) {
+        Map<String, Double> fields = new HashMap<>(Map.of("battery_capacity_ah", 280.0,
+                "tou_enabled", touEnabled, "grid_charge_enabled", 0.0));
+        double[] starts = {100, 500, 900, 1300, 1700, 2100};
+        for (int n = 1; n <= 6; n++) {
+            fields.putAll(Map.of("prog" + n + "_start_hhmm", starts[n - 1], "prog" + n + "_power_w", 8000.0,
+                    "prog" + n + "_soc_pct", 60.0, "prog" + n + "_grid_charge", n == 2 ? 1.0 : 0.0));
+        }
+        return fields;
+    }
+
+    private static BatteryView battery(DeviceSnapshot... devices) throws IOException {
+        return new BatteryService(gateway(devices), new FakeBattery(), CLOCK).current();
+    }
+
+    private static final class FakeBattery implements GatewayBattery {
+        static final List<String> SENT = new java.util.ArrayList<>();
+        final boolean enabled;
+
+        FakeBattery() {
+            this(true);
+        }
+
+        FakeBattery(boolean enabled) {
+            this.enabled = enabled;
+        }
+
+        @Override
+        public BatteryView.Reserve reserve() throws IOException {
+            if (!enabled) {
+                throw new IOException("gateway /battery/reserve answered 404");
+            }
+            return new BatteryView.Reserve(50, 30);
+        }
+
+        @Override
+        public BatteryResult changeSchedule(BatteryChange change, String requestedBy) {
+            SENT.add("schedule by " + requestedBy);
+            return new BatteryResult(BatteryResult.Status.APPLIED, "applied", Map.of());
+        }
+
+        @Override
+        public BatteryResult changeReserve(int pct, String requestedBy) {
+            SENT.add("reserve " + pct + " by " + requestedBy);
+            return new BatteryResult(BatteryResult.Status.APPLIED, "applied", Map.of());
+        }
+    }
+
+    @Test
+    void batteryShowsTheReserveAndIsEditableWhenTheGatewayAcceptsChanges() throws IOException {
+        BatteryView view = battery();
+
+        assertEquals(new BatteryView.Reserve(50, 30), view.reserve());
+        assertTrue(view.editable());
+    }
+
+    @Test
+    void batteryIsNotEditableWithoutGatewayCommandsButStillShowsTheLiveState() throws IOException {
+        BatteryView view = new BatteryService(gateway(device("deye", "home", "deye",
+                Map.of("battery_soc_pct", 80.0))), new FakeBattery(false), CLOCK).current();
+
+        assertNull(view.reserve());
+        assertFalse(view.editable());
+        assertEquals(80.0, view.socPct());
+    }
+
+    @Test
+    void batteryChangesAreHandedToTheGatewayWithTheUser() throws IOException {
+        var service = new BatteryService(gateway(), new FakeBattery(), CLOCK);
+
+        assertEquals(BatteryResult.Status.APPLIED, service.changeReserve(60, "anna").status());
+        assertEquals(BatteryResult.Status.APPLIED,
+                service.changeSchedule(new BatteryChange(true, null), "ola").status());
+        assertEquals(List.of("reserve 60 by anna", "schedule by ola"), FakeBattery.SENT);
+    }
+
+    private static DeviceSnapshot deyeSettings(Map<String, Double> fields, Instant time) {
+        return new DeviceSnapshot("deye-settings", true, time, null,
+                List.of(new Measurement("electricity", "deye_settings", fields, time)));
+    }
+
+    @Test
+    void batteryReadsLiveValuesAndComputesCapacityAtNominalVoltage() throws IOException {
+        BatteryView view = battery(device("deye", "home", "deye", Map.of("battery_soc_pct", 80.0,
+                "battery_power_w", 1500.0, "battery_charge_today_kwh", 2.5)),
+                deyeSettings(settings(0), READ));
+
+        assertFalse(view.stale());
+        assertEquals(80.0, view.socPct());
+        assertEquals(1500.0, view.powerW());
+        assertEquals(2.5, view.today().chargeKwh());
+        assertEquals(14.336, view.capacityKwh(), 1e-9);
+    }
+
+    @Test
+    void batteryScheduleRunsToTheNextStartAndWrapsAroundMidnight() throws IOException {
+        List<BatteryView.Slot> schedule = battery(deyeSettings(settings(1), READ)).schedule();
+
+        assertEquals(6, schedule.size());
+        assertEquals(new BatteryView.Slot("01:00", "05:00", 8000, 60, false), schedule.get(0));
+        assertEquals(new BatteryView.Slot("05:00", "09:00", 8000, 60, true), schedule.get(1));
+        assertEquals(new BatteryView.Slot("21:00", "01:00", 8000, 60, false), schedule.get(5));
+    }
+
+    @Test
+    void batteryScheduleIsEmptyWhenASlotStartIsMissing() throws IOException {
+        Map<String, Double> fields = settings(1);
+        fields.remove("prog3_start_hhmm");
+
+        assertTrue(battery(deyeSettings(fields, READ)).schedule().isEmpty());
+    }
+
+    @Test
+    void batteryModeFollowsTimeOfUse() throws IOException {
+        BatteryView backup = battery(deyeSettings(settings(0), READ));
+        BatteryView scheduled = battery(deyeSettings(settings(1), READ));
+
+        assertFalse(backup.mode().touEnabled());
+        assertEquals("Rezerwa na awarię: bateria nie rozładowuje się na co dzień", backup.mode().description());
+        assertTrue(scheduled.mode().touEnabled());
+        assertEquals("Harmonogram: bateria pracuje według przedziałów", scheduled.mode().description());
+    }
+
+    @Test
+    void batterySettingsAreStaleAfterThirtyMinutesButLiveValuesStayCurrent() throws IOException {
+        var live = device("deye", "home", "deye", Map.of("battery_soc_pct", 80.0));
+
+        BatteryView fresh = battery(live, deyeSettings(settings(0), NOW.minusSeconds(1800)));
+        BatteryView old = battery(live, deyeSettings(settings(0), NOW.minusSeconds(1801)));
+
+        assertFalse(fresh.settingsStale());
+        assertEquals(6, fresh.schedule().size());
+        assertTrue(old.settingsStale());
+        assertEquals(NOW.minusSeconds(1801), old.settingsTime());
+        assertTrue(old.schedule().isEmpty());
+        assertNull(old.mode());
+        assertNull(old.limits());
+        assertNull(old.capacityKwh());
+        assertEquals(80.0, old.socPct());
+    }
+
+    @Test
+    void staleDeyeShowsNoLiveBatteryValues() throws IOException {
+        var old = new Measurement("home", "deye", Map.of("battery_soc_pct", 80.0), NOW.minusSeconds(601));
+
+        BatteryView view = battery(new DeviceSnapshot("deye", true, old.time(), null, List.of(old)),
+                deyeSettings(settings(0), READ));
+
+        assertTrue(view.stale());
+        assertNull(view.socPct());
+        assertNull(view.powerW());
+        assertFalse(view.settingsStale());
+    }
+
+    @Test
+    void batteryWithoutAnyReadingIsStaleTwice() throws IOException {
+        BatteryView view = battery();
+
+        assertTrue(view.stale());
+        assertTrue(view.settingsStale());
+        assertNull(view.time());
+        assertNull(view.settingsTime());
+    }
+
+    private static PiSensorView piSensor(DeviceSnapshot... devices) throws IOException {
+        return new PiSensorService(gateway(devices), CLOCK).current();
+    }
+
+    @Test
+    void piSensorReadsTemperatureHumidityAndPressure() throws IOException {
+        PiSensorView view = piSensor(device("bme280", "measurement", "MEASUREMENT",
+                Map.of("temperature", 20.17, "humidity", 45.82, "pressure", 985.8)));
+
+        assertEquals(READ, view.time());
+        assertFalse(view.stale());
+        assertEquals(20.17, view.temperature());
+        assertEquals(45.82, view.humidity());
+        assertEquals(985.8, view.pressure());
+    }
+
+    @Test
+    void stalePiSensorShowsNoValues() throws IOException {
+        var old = new Measurement("measurement", "MEASUREMENT", Map.of("temperature", 20.0), NOW.minusSeconds(601));
+        PiSensorView view = piSensor(new DeviceSnapshot("bme280", true, old.time(), null, List.of(old)));
+
+        assertTrue(view.stale());
+        assertNull(view.temperature());
+        assertTrue(piSensor().stale());
+        assertNull(piSensor().time());
+    }
+
     private static EnergyView energy(DeviceSnapshot... devices) throws IOException {
         return new EnergyService(gateway(devices), CLOCK).current();
     }
@@ -215,6 +415,80 @@ class ServicesTest {
         assertEquals(List.of(new Source("deye", null, true), new Source("fronius", null, true)), view.sources());
     }
 
+    private static EnergyDetails details(DeviceSnapshot... devices) throws IOException {
+        return new EnergyDetailsService(gateway(devices), CLOCK).current();
+    }
+
+    private static EnergyDetails.Device detailsOf(EnergyDetails details, String id) {
+        return details.devices().stream().filter(d -> d.id().equals(id)).findFirst().orElseThrow();
+    }
+
+    @Test
+    void detailsShowOnlyReportedFieldsAndDropEmptyGroups() throws IOException {
+        EnergyDetails.Device deye = detailsOf(details(device("deye", "home", "deye",
+                Map.of("battery_soc_pct", 80.0, "grid_power_l2_w", 52.0, "pv1_power_w", 10.0))), "deye");
+
+        assertFalse(deye.stale());
+        assertEquals(READ, deye.time());
+        assertEquals(List.of("Bateria", "Sieć", "Panele PV"), deye.groups().stream().map(Group::title).toList());
+        assertEquals(List.of(new Item("Moc L2", 52.0, "W", 0)), deye.groups().get(1).items());
+    }
+
+    @Test
+    void detailsOfAStaleDeviceHaveNoValues() throws IOException {
+        Instant old = NOW.minusSeconds(3600);
+        var stale = new DeviceSnapshot("deye", true, old, null, List.of(new Measurement("home", "deye", DEYE, old)));
+
+        EnergyDetails.Device deye = detailsOf(details(stale), "deye");
+
+        assertTrue(deye.stale());
+        assertEquals(old, deye.time());
+        assertTrue(deye.groups().isEmpty());
+    }
+
+    @Test
+    void detailsListEveryDeviceEvenWhenTheGatewayKnowsNone() throws IOException {
+        EnergyDetails all = details();
+
+        assertEquals(List.of("deye", "fronius", "house-meter"), all.devices().stream().map(Device::id).toList());
+        assertTrue(all.devices().stream().allMatch(d -> d.stale() && d.groups().isEmpty()));
+    }
+
+    @Test
+    void detailsConvertFroniusWhToKwhAndRoundThem() throws IOException {
+        EnergyDetails.Device fronius = detailsOf(details(device("fronius", "home", "fronius",
+                Map.of("energy_day_wh", 4399.99, "energy_total_wh", 2.90713E7))), "fronius");
+
+        assertEquals(List.of(new Item("Dziś", 4.4, "kWh", 1), new Item("Od początku", 29071.0, "kWh", 0)),
+                fronius.groups().get(0).items());
+    }
+
+    @Test
+    void detailsReadTheHouseMeterPerPhase() throws IOException {
+        EnergyDetails.Device meter = detailsOf(details(device("house-meter", "electricity", "PRAD2",
+                Map.of("p1_voltage", 235.69, "p3_voltage", 232.2))), "house-meter");
+
+        assertEquals(List.of(new Item("Napięcie L1", 235.7, "V", 1), new Item("Napięcie L3", 232.2, "V", 1)),
+                meter.groups().get(0).items());
+    }
+
+    @Test
+    void detailsTakeThePhaseEnergyFromItsOwnMeasurement() throws IOException {
+        var meter = new DeviceSnapshot("house-meter", true, READ, null, List.of(
+                new Measurement("electricity", "PRAD2", Map.of("frequency", 50.01), READ),
+                new Measurement("electricity", "house_meter_phases", Map.of("l2_import_energy_active_kwh", 7012.4), READ)));
+
+        Group phases = detailsOf(details(meter), "house-meter").groups().getLast();
+
+        assertEquals("Energia na fazę", phases.title());
+        assertEquals(List.of(new Item("Pobrana L2", 7012.0, "kWh", 0)), phases.items());
+    }
+
+    @Test
+    void detailsFailWhenTheGatewayIsUnreachable() {
+        assertThrows(IOException.class, () -> new EnergyDetailsService(unreachable(), CLOCK).current());
+    }
+
     private static DeviceSnapshot deyeRead(boolean up, Instant time) {
         return new DeviceSnapshot("deye", up, time, null, List.of(new Measurement("home", "deye", DEYE, time)));
     }
@@ -269,7 +543,7 @@ class ServicesTest {
         DeviceSnapshot down = new DeviceSnapshot("deye", false, null, "connect timed out", List.of());
 
         HealthView view = new HealthService(gateway(device("heat-pump", "Dom_Pompa", "heat_pump", Map.of()),
-                down), CLOCK).current();
+                down), CLOCK, "v1.3.0").current();
 
         assertTrue(view.gatewayReachable());
         assertEquals(NOW, view.time());
@@ -279,12 +553,22 @@ class ServicesTest {
         assertEquals(READ, view.devices().get(0).lastSuccess());
     }
 
+    @Test
+    void healthReportsBothVersions() {
+        HealthView view = new HealthService(gateway(), CLOCK, "v1.3.0").current();
+
+        assertEquals("v1.3.0", view.backendVersion());
+        assertEquals("v1.2.1", view.gatewayVersion());
+    }
+
     @Test
     void healthWithUnreachableGatewayHasNoDevices() {
-        HealthView view = new HealthService(unreachable(), CLOCK).current();
+        HealthView view = new HealthService(unreachable(), CLOCK, "v1.3.0").current();
 
         assertFalse(view.gatewayReachable());
         assertTrue(view.devices().isEmpty());
+        assertEquals("v1.3.0", view.backendVersion());
+        assertNull(view.gatewayVersion());
     }
 
     /** Remembers the request and answers with one point. */

backend/src/test/java/home/backend/application/SetpointServiceTest.java

@@ -3,6 +3,8 @@ package home.backend.application;
 import home.backend.adapters.config.PresetFile;
 import home.backend.domain.Command;
 import home.backend.domain.CommandResult;
+import home.backend.domain.RestoreResult;
+import home.backend.domain.RestoreResult.Outcome;
 import home.backend.domain.CommandResult.Status;
 import home.backend.domain.Preset;
 import home.backend.domain.Preset.Change;
@@ -16,8 +18,10 @@ import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
 import java.time.Duration;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -25,6 +29,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class SetpointServiceTest {
 
+    private static final Instant RETURN = Instant.parse("2026-11-02T17:00:00Z");
     private static final SetpointState STATE = new SetpointState(List.of(
             new Setpoint("co_comfort", 4132, 5, 25, 1, 19),
             new Setpoint("cwu_economy", 4143, 5, 48, 1, 8),
@@ -33,6 +38,7 @@ class SetpointServiceTest {
     private final List<Command> sent = new ArrayList<>();
     /** What the gateway does on the next calls to apply, in order: a Status, or an IOException; then APPLIED. */
     private final List<Object> script = new ArrayList<>();
+    private final List<String> restored = new ArrayList<>();
     private boolean down;
     private final GatewayCommands gateway = new GatewayCommands() {
         @Override
@@ -48,6 +54,15 @@ class SetpointServiceTest {
             return new CommandResult((Status) next, command.setpoint(), null);
         }
 
+        @Override
+        public RestoreResult restore(String setpoint, String requestedBy) throws IOException {
+            if (down) {
+                throw new IOException("tunnel down");
+            }
+            restored.add(setpoint + " by " + requestedBy);
+            return new RestoreResult(Outcome.RESTORED, "restored");
+        }
+
         @Override
         public SetpointState setpoints() throws IOException {
             if (down) {
@@ -55,10 +70,29 @@ class SetpointServiceTest {
             }
             return STATE;
         }
+
+        @Override
+        public int renewLeases() {
+            return 0;
+        }
     };
     private final List<Preset> presets = PresetFile.load(null);
     private final SetpointService service = new SetpointService(gateway, presets);
 
+    @Test
+    void restoreAsksTheGatewayInTheUsersName() throws Exception {
+        assertEquals(Outcome.RESTORED, service.restore("cwu_economy", "anna").outcome());
+
+        assertEquals(List.of("cwu_economy by anna"), restored);
+    }
+
+    @Test
+    void restoreWithTheGatewayDownIsAnIoError() {
+        down = true;
+
+        assertThrows(IOException.class, () -> service.restore("cwu_economy", "anna"));
+    }
+
     @Test
     void viewJoinsGatewayStateAndPresets() throws Exception {
         var view = service.current();
@@ -93,33 +127,93 @@ class SetpointServiceTest {
 
     @Test
     void boostPresetSendsOneTimedCommand() throws Exception {
-        var result = service.applyPreset("cwu-now", "anna").orElseThrow();
+        var result = service.applyPreset("cwu-now", null, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.APPLIED, result.status());
         assertEquals(List.of(new Command("cwu_economy", 45, Duration.ofHours(2), "anna")), sent);
     }
 
     @Test
-    void awayPresetSendsBothChangesUntilChanged() throws Exception {
-        var result = service.applyPreset("away", "anna").orElseThrow();
+    void awayPresetSendsBothChangesHeldUntilTheChosenTime() throws Exception {
+        var result = service.applyPreset("away", RETURN, Map.of(), "anna").orElseThrow();
 
         assertEquals(2, result.results().size());
-        assertEquals(List.of(new Command("cwu_comfort", 10, null, "anna"), new Command("co_comfort", 15, null, "anna")),
-                sent);
+        assertEquals(List.of(new Command("cwu_comfort", 10, null, RETURN, "anna"),
+                new Command("co_comfort", 15, null, RETURN, "anna")), sent);
+    }
+
+    @Test
+    void ownValuesReplaceTheDefaultsAndTheRestKeepThem() throws Exception {
+        service.applyPreset("away", RETURN, Map.of("co_comfort", 16), "anna");
+
+        assertEquals(List.of(new Command("cwu_comfort", 10, null, RETURN, "anna"),
+                new Command("co_comfort", 16, null, RETURN, "anna")), sent);
+    }
+
+    @Test
+    void ownValuesAreAllowedForAnOrdinaryPresetToo() throws Exception {
+        service.applyPreset("cwu-now", null, Map.of("cwu_economy", 40), "anna");
+
+        assertEquals(List.of(new Command("cwu_economy", 40, Duration.ofHours(2), "anna")), sent);
+    }
+
+    @Test
+    void aValueForASetpointOutsideThePresetIsRefusedBeforeAnythingIsSent() {
+        assertThrows(IllegalArgumentException.class,
+                () -> service.applyPreset("away", RETURN, Map.of("cwu_economy", 6), "anna"));
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void aValueOutsideTheGatewayLimitsIsRefusedBeforeAnythingIsSent() {
+        for (int value : List.of(4, 26, 0)) {
+            assertThrows(IllegalArgumentException.class,
+                    () -> service.applyPreset("away", RETURN, Map.of("co_comfort", value), "anna"));
+        }
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void aHeldValueThatDoesNotLowerTheCurrentOneWritesNothing() throws Exception {
+        var result = service.applyPreset("away", RETURN, Map.of("co_comfort", 19), "anna").orElseThrow();
+
+        assertEquals(PresetResult.Status.REJECTED, result.status());
+        assertEquals(List.of(ChangeStatus.NOT_ATTEMPTED, ChangeStatus.REJECTED), statuses(result));
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void aHeldPresetNeedsAnEndTimeAndOthersRefuseOne() {
+        assertThrows(IllegalArgumentException.class, () -> service.applyPreset("away", null, Map.of(), "anna"));
+        assertThrows(IllegalArgumentException.class, () -> service.applyPreset("cwu-now", RETURN, Map.of(), "anna"));
+        assertTrue(sent.isEmpty());
+    }
+
+    @Test
+    void aHeldPresetThatWouldNotLowerAnySetpointWritesNothing() throws Exception {
+        var cold = new Preset("cold", "Zimno", "chosen", List.of(new Change("cwu_comfort", 10, null),
+                new Change("co_comfort", 19, null)));
+
+        var result = new SetpointService(gateway, List.of(cold)).applyPreset("cold", RETURN, Map.of(), "anna").orElseThrow();
+
+        assertEquals(PresetResult.Status.REJECTED, result.status());
+        assertEquals(List.of(ChangeStatus.NOT_ATTEMPTED, ChangeStatus.REJECTED), statuses(result));
+        assertTrue(result.results().getLast().message().contains("not below the current 19"));
+        assertTrue(sent.isEmpty());
     }
 
     @Test
     void unknownPresetIsEmpty() throws Exception {
-        assertTrue(service.applyPreset("nope", "anna").isEmpty());
+        assertTrue(service.applyPreset("nope", null, Map.of(), "anna").isEmpty());
         assertTrue(sent.isEmpty());
     }
 
     @Test
     void presetOutsideGatewayLimitsWritesNothing() throws Exception {
-        var tooHot = new Preset("hot", "Za gorąco", List.of(new Change("co_comfort", 15, null),
+        var tooHot = new Preset("hot", "Za gorąco", null, List.of(new Change("co_comfort", 15, null),
                 new Change("cwu_economy", 60, 2.0)));
 
-        var result = new SetpointService(gateway, List.of(tooHot)).applyPreset("hot", "anna").orElseThrow();
+        var result = new SetpointService(gateway, List.of(tooHot)).applyPreset("hot", null, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.REJECTED, result.status());
         assertEquals(List.of(ChangeStatus.NOT_ATTEMPTED, ChangeStatus.REJECTED), statuses(result));
@@ -129,9 +223,9 @@ class SetpointServiceTest {
 
     @Test
     void presetWithUnknownSetpointWritesNothing() throws Exception {
-        var odd = new Preset("odd", "Dziwny", List.of(new Change("garage_heater", 1, null)));
+        var odd = new Preset("odd", "Dziwny", null, List.of(new Change("garage_heater", 1, null)));
 
-        var result = new SetpointService(gateway, List.of(odd)).applyPreset("odd", "anna").orElseThrow();
+        var result = new SetpointService(gateway, List.of(odd)).applyPreset("odd", null, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.REJECTED, result.status());
         assertTrue(sent.isEmpty());
@@ -145,7 +239,7 @@ class SetpointServiceTest {
     void presetReportsEveryChangeAndStopsAfterTheFirstThatIsNotApplied() throws Exception {
         script.add(Status.FAILED);
 
-        var result = service.applyPreset("away", "anna").orElseThrow();
+        var result = service.applyPreset("away", RETURN, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.FAILED, result.status());
         assertEquals(List.of(ChangeStatus.FAILED, ChangeStatus.NOT_ATTEMPTED), statuses(result));
@@ -156,7 +250,7 @@ class SetpointServiceTest {
     void secondChangeRejectedLeavesThePresetPartial() throws Exception {
         script.addAll(List.of(Status.APPLIED, Status.REJECTED));
 
-        var result = service.applyPreset("away", "anna").orElseThrow();
+        var result = service.applyPreset("away", RETURN, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.PARTIAL, result.status());
         assertEquals(List.of(ChangeStatus.APPLIED, ChangeStatus.REJECTED), statuses(result));
@@ -166,7 +260,7 @@ class SetpointServiceTest {
     void firstChangeRejectedByTheGatewayIsRejectedAsAWhole() throws Exception {
         script.add(Status.REJECTED);
 
-        var result = service.applyPreset("away", "anna").orElseThrow();
+        var result = service.applyPreset("away", RETURN, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.REJECTED, result.status());
         assertEquals(List.of(ChangeStatus.REJECTED, ChangeStatus.NOT_ATTEMPTED), statuses(result));
@@ -176,7 +270,7 @@ class SetpointServiceTest {
     void lostAnswerOnTheSecondChangeKeepsTheFirstResult() throws Exception {
         script.addAll(List.of(Status.APPLIED, new IOException("tunnel dropped")));
 
-        var result = service.applyPreset("away", "anna").orElseThrow();
+        var result = service.applyPreset("away", RETURN, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.PARTIAL, result.status());
         assertEquals(List.of(ChangeStatus.APPLIED, ChangeStatus.UNKNOWN), statuses(result));
@@ -186,7 +280,7 @@ class SetpointServiceTest {
     void lostAnswerOnTheFirstChangeIsFailedNotUnreachable() throws Exception {
         script.add(new IOException("tunnel dropped"));
 
-        var result = service.applyPreset("away", "anna").orElseThrow();
+        var result = service.applyPreset("away", RETURN, Map.of(), "anna").orElseThrow();
 
         assertEquals(PresetResult.Status.FAILED, result.status());
         assertEquals(List.of(ChangeStatus.UNKNOWN, ChangeStatus.NOT_ATTEMPTED), statuses(result));
@@ -198,7 +292,7 @@ class SetpointServiceTest {
 
         assertThrows(IOException.class, service::current);
         assertThrows(IOException.class, () -> service.apply("cwu_economy", 45, null, "anna"));
-        assertThrows(IOException.class, () -> service.applyPreset("away", "anna"));
+        assertThrows(IOException.class, () -> service.applyPreset("away", RETURN, Map.of(), "anna"));
         assertTrue(sent.isEmpty());
     }
 }

backend/src/test/java/home/backend/application/StatsServiceTest.java

@@ -0,0 +1,214 @@
+package home.backend.application;
+
+import home.backend.domain.HeatPumpSample;
+import home.backend.domain.StatsView;
+import home.backend.domain.StatsView.Day;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.ZoneOffset;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class StatsServiceTest {
+
+    /** Monday 2026-10-26 11:00 in Warsaw; the week before it holds the change to winter time. */
+    private static final Instant NOW = Instant.parse("2026-10-26T10:00:00Z");
+
+    private Instant askedFrom;
+    private Instant askedTo;
+
+    private StatsView stats(String range, Instant now, HeatPumpSample... samples) throws IOException {
+        HeatPumpSamples repository = (from, to) -> {
+            askedFrom = from;
+            askedTo = to;
+            return List.of(samples);
+        };
+        return new StatsService(repository, Clock.fixed(now, ZoneOffset.UTC)).stats(range);
+    }
+
+    private static HeatPumpSample compressor(String time, double stage) {
+        return new HeatPumpSample(Instant.parse(time), stage, 0.0, 0.0, 0.0, null, null);
+    }
+
+    private static Day day(StatsView view, String date) {
+        return view.days().stream().filter(d -> d.date().equals(LocalDate.parse(date))).findFirst().orElseThrow();
+    }
+
+    @Test
+    void asksForWholeLocalDaysUpToNow() throws IOException {
+        stats("7d", NOW);
+
+        assertEquals(Instant.parse("2026-10-19T22:00:00Z"), askedFrom);
+        assertEquals(NOW, askedTo);
+    }
+
+    @Test
+    void listsOneDayPerLocalDateOldestFirst() throws IOException {
+        StatsView view = stats("30d", NOW);
+
+        assertEquals(30, view.days().size());
+        assertEquals(LocalDate.parse("2026-09-27"), view.days().getFirst().date());
+        assertEquals(LocalDate.parse("2026-10-26"), view.days().getLast().date());
+    }
+
+    @Test
+    void noDataGivesEmptyDaysAndZeroTotals() throws IOException {
+        StatsView view = stats("7d", NOW);
+
+        assertEquals(7, view.days().size());
+        for (Day d : view.days()) {
+            assertNull(d.compressorHours());
+            assertNull(d.compressorStarts());
+            assertNull(d.avgOutdoorTemp());
+        }
+        assertEquals(0.0, view.totals().compressorHours());
+        assertEquals(0, view.totals().compressorStarts());
+        assertNull(view.totals().avgOutdoorTemp());
+        assertNull(view.totals().minCwuTemp());
+    }
+
+    @Test
+    void aGapIsCappedAtTenMinutesPerPoll() throws IOException {
+        StatsView view = stats("7d", NOW,
+                compressor("2026-10-23T10:00:00Z", 100),
+                compressor("2026-10-23T10:05:00Z", 100),
+                compressor("2026-10-23T11:00:00Z", 0));
+
+        assertEquals(0.25, day(view, "2026-10-23").compressorHours());
+    }
+
+    @Test
+    void theLastPollHoldsUntilNowAtMostTenMinutes() throws IOException {
+        StatsView recent = stats("7d", NOW, compressor("2026-10-26T09:58:00Z", 50));
+        StatsView old = stats("7d", NOW, compressor("2026-10-26T08:00:00Z", 50));
+
+        assertEquals(0.03, day(recent, "2026-10-26").compressorHours());
+        assertEquals(0.17, day(old, "2026-10-26").compressorHours());
+    }
+
+    @Test
+    void countsOnlyTransitionsFromOffToOn() throws IOException {
+        StatsView view = stats("7d", NOW,
+                compressor("2026-10-23T10:00:00Z", 100),
+                compressor("2026-10-23T10:05:00Z", 100),
+                compressor("2026-10-23T10:10:00Z", 0),
+                compressor("2026-10-23T10:15:00Z", 0),
+                compressor("2026-10-23T10:20:00Z", 50),
+                compressor("2026-10-23T10:25:00Z", 100),
+                compressor("2026-10-23T10:30:00Z", 0),
+                compressor("2026-10-23T10:35:00Z", 100));
+
+        assertEquals(2, day(view, "2026-10-23").compressorStarts());
+        assertEquals(2, view.totals().compressorStarts());
+    }
+
+    @Test
+    void aStartAtMidnightBelongsToTheNewDay() throws IOException {
+        StatsView view = stats("7d", NOW,
+                compressor("2026-10-24T21:55:00Z", 0),
+                compressor("2026-10-24T22:00:00Z", 100));
+
+        assertEquals(0, day(view, "2026-10-24").compressorStarts());
+        assertEquals(1, day(view, "2026-10-25").compressorStarts());
+    }
+
+    @Test
+    void splitsAStretchAtLocalMidnightInSummerTime() throws IOException {
+        StatsView view = stats("7d", NOW,
+                compressor("2026-10-24T21:58:00Z", 100),
+                compressor("2026-10-24T22:03:00Z", 0));
+
+        assertEquals(0.03, day(view, "2026-10-24").compressorHours());
+        assertEquals(0.05, day(view, "2026-10-25").compressorHours());
+    }
+
+    @Test
+    void splitsAStretchAtLocalMidnightInWinterTime() throws IOException {
+        StatsView view = stats("7d", NOW,
+                compressor("2026-10-25T22:58:00Z", 100),
+                compressor("2026-10-25T23:03:00Z", 0));
+
+        assertEquals(0.03, day(view, "2026-10-25").compressorHours());
+        assertEquals(0.05, day(view, "2026-10-26").compressorHours());
+    }
+
+    @Test
+    void theDayOfTheClockChangeLastsTwentyFiveHours() throws IOException {
+        List<HeatPumpSample> samples = new ArrayList<>();
+        Instant at = Instant.parse("2026-10-24T22:00:00Z");
+        while (at.isBefore(Instant.parse("2026-10-25T23:00:00Z"))) {
+            samples.add(compressor(at.toString(), 100));
+            at = at.plusSeconds(300);
+        }
+
+        StatsView view = stats("7d", NOW, samples.toArray(HeatPumpSample[]::new));
+
+        assertEquals(25.0, day(view, "2026-10-25").compressorHours());
+        assertNull(day(view, "2026-10-26").compressorHours());
+    }
+
+    @Test
+    void sumsEachOutputSeparately() throws IOException {
+        StatsView view = stats("7d", NOW,
+                new HeatPumpSample(Instant.parse("2026-10-23T10:00:00Z"), 100.0, 100.0, 0.0, 0.0, 10.0, 40.0),
+                new HeatPumpSample(Instant.parse("2026-10-23T10:05:00Z"), 100.0, 0.0, 100.0, 100.0, 12.0, 38.0),
+                new HeatPumpSample(Instant.parse("2026-10-23T10:10:00Z"), 0.0, 0.0, 0.0, 0.0, null, null));
+
+        Day d = day(view, "2026-10-23");
+        assertEquals(0.17, d.compressorHours());
+        assertEquals(0.08, d.cwuHours());
+        assertEquals(0.08, d.coHours());
+        assertEquals(0.08, d.heaterHours());
+        assertEquals(11.0, d.avgOutdoorTemp());
+        assertEquals(38.0, d.minCwuTemp());
+        assertEquals(40.0, d.maxCwuTemp());
+    }
+
+    @Test
+    void totalsCoverTheWholeRangeWithTheTemperatureOfAllPolls() throws IOException {
+        StatsView view = stats("7d", NOW,
+                new HeatPumpSample(Instant.parse("2026-10-22T10:00:00Z"), 100.0, 0.0, 0.0, 0.0, 10.0, 30.0),
+                new HeatPumpSample(Instant.parse("2026-10-22T10:05:00Z"), 0.0, 0.0, 0.0, 0.0, 10.0, 31.0),
+                new HeatPumpSample(Instant.parse("2026-10-23T10:00:00Z"), 100.0, 0.0, 0.0, 100.0, 4.0, 45.0),
+                new HeatPumpSample(Instant.parse("2026-10-23T10:05:00Z"), 0.0, 0.0, 0.0, 0.0, 4.0, 44.0));
+
+        assertEquals(0.17, view.totals().compressorHours());
+        assertEquals(0.08, view.totals().heaterHours());
+        assertEquals(7.0, view.totals().avgOutdoorTemp());
+        assertEquals(30.0, view.totals().minCwuTemp());
+        assertEquals(45.0, view.totals().maxCwuTemp());
+    }
+
+    @Test
+    void aMissingFieldCountsAsOffAndUnknownStateIsNoStart() throws IOException {
+        StatsView view = stats("7d", NOW,
+                new HeatPumpSample(Instant.parse("2026-10-23T10:00:00Z"), null, null, null, null, null, null),
+                compressor("2026-10-23T10:05:00Z", 100));
+
+        assertEquals(0, day(view, "2026-10-23").compressorStarts());
+        assertNull(day(view, "2026-10-23").avgOutdoorTemp());
+    }
+
+    @Test
+    void rejectsAnUnknownRange() {
+        assertThrows(IllegalArgumentException.class, () -> stats("24h", NOW));
+        assertThrows(IllegalArgumentException.class, () -> stats(null, NOW));
+    }
+
+    @Test
+    void propagatesRepositoryFailure() {
+        StatsService service = new StatsService((from, to) -> {
+            throw new IOException("influx down");
+        }, Clock.fixed(NOW, ZoneOffset.UTC));
+
+        assertThrows(IOException.class, () -> service.stats("7d"));
+    }
+}

backend/src/test/java/home/backend/application/WeatherServiceTest.java

@@ -0,0 +1,274 @@
+package home.backend.application;
+
+import home.backend.domain.Forecast;
+import home.backend.domain.Forecast.DailyForecast;
+import home.backend.domain.WeatherView;
+import home.backend.domain.WeatherView.Warning;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.time.Clock;
+import java.time.Duration;
+import java.time.Instant;
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class WeatherServiceTest {
+
+    private static final Instant START = Instant.parse("2026-10-24T10:00:00Z");
+    private static final LocalDate TODAY = LocalDate.parse("2026-10-24");
+
+    private Instant now = START;
+    private final Clock clock = new Clock() {
+        @Override
+        public ZoneId getZone() {
+            return ZoneOffset.UTC;
+        }
+
+        @Override
+        public Clock withZone(ZoneId zone) {
+            return Clock.fixed(now, zone);
+        }
+
+        @Override
+        public Instant instant() {
+            return now;
+        }
+    };
+
+    private final AtomicInteger forecastCalls = new AtomicInteger();
+    private final AtomicInteger warningCalls = new AtomicInteger();
+    private boolean forecastDown;
+    private boolean warningsDown;
+    private boolean influxDown;
+    private int measuredDays = 5;
+    private LocalDate today = TODAY;
+    private List<Warning> warned = List.of(warning(START.plus(Duration.ofHours(8))));
+
+    private final WeatherService service = new WeatherService(
+            () -> {
+                forecastCalls.incrementAndGet();
+                if (forecastDown) {
+                    throw new IOException("open-meteo down");
+                }
+                return forecast();
+            },
+            () -> {
+                warningCalls.incrementAndGet();
+                if (warningsDown) {
+                    throw new IOException("imgw down");
+                }
+                return warned;
+            },
+            (from, to) -> {
+                if (influxDown) {
+                    throw new IOException("influx down");
+                }
+                assertEquals(today.minusDays(14), from);
+                assertEquals(today, to);
+                Map<LocalDate, Double> measured = new HashMap<>();
+                for (int i = 1; i <= measuredDays; i++) {
+                    measured.put(today.minusDays(i), 15.0);
+                }
+                return measured;
+            },
+            clock);
+
+    private Forecast forecast() {
+        Map<LocalDate, DailyForecast> days = new TreeMap<>();
+        for (int i = 1; i <= 14; i++) {
+            days.put(today.minusDays(i), new DailyForecast(3, 10.0, 2.0, 0.0, 5.0, 3600.0));
+        }
+        days.put(today, new DailyForecast(0, 12.34, 3.0, 0.0, 6.0, 5400.0));
+        days.put(today.plusDays(1), new DailyForecast(63, 9.0, 4.0, 5.5, null, null));
+        days.put(today.plusDays(2), new DailyForecast(null, null, null, null, 1.0, 0.0));
+        return new Forecast(8.5, days);
+    }
+
+    private static Warning warning(Instant until) {
+        return new Warning("Burza", 2, OffsetDateTime.ofInstant(START, ZoneOffset.UTC),
+                OffsetDateTime.ofInstant(until, ZoneOffset.UTC), "text");
+    }
+
+    @Test
+    void shapesThreeDaysAndEstimatesPvFromTheFactor() throws IOException {
+        WeatherView view = service.current();
+
+        assertEquals(START, view.time());
+        assertEquals(8.5, view.now().temperature());
+        assertEquals(3.0, view.pvFactor(), 1e-9);
+        assertEquals(TODAY, view.today().date());
+        assertEquals("Bezchmurnie", view.today().description());
+        assertEquals(12.34, view.today().tMax());
+        assertEquals(1.5, view.today().sunshineHours());
+        assertEquals(18.0, view.today().pvForecastKwh());
+        assertEquals(TODAY.plusDays(2), view.dayAfter().date());
+        assertEquals("Deszcz", view.tomorrow().description());
+        assertEquals(5.5, view.tomorrow().precipitationMm());
+        assertNull(view.tomorrow().pvForecastKwh());
+        assertEquals(3.0, view.dayAfter().pvForecastKwh());
+        assertEquals("Brak danych", view.dayAfter().description());
+        assertFalse(view.stale());
+    }
+
+    @Test
+    void usesTheWarsawDateNearMidnight() throws IOException {
+        now = Instant.parse("2026-10-23T22:30:00Z");
+
+        assertEquals(TODAY, service.current().today().date());
+    }
+
+    @Test
+    void aForecastFetchedBeforeLocalMidnightIsNotUsedAfterIt() throws IOException {
+        now = Instant.parse("2026-10-24T21:50:00Z");
+        service.current();
+
+        now = Instant.parse("2026-10-24T22:05:00Z");
+        today = TODAY.plusDays(1);
+        WeatherView view = service.current();
+
+        assertEquals(2, forecastCalls.get());
+        assertEquals(today, view.today().date());
+        assertEquals(today.plusDays(2), view.dayAfter().date());
+    }
+
+    @Test
+    void aFailedRefreshServesTheOlderWarningsWithoutAskingAgainFor60Seconds() throws IOException {
+        service.current();
+        warningsDown = true;
+        now = START.plus(Duration.ofMinutes(11));
+        service.current();
+        assertEquals(2, warningCalls.get());
+
+        now = now.plusSeconds(59);
+        assertTrue(service.current().stale());
+        assertEquals(2, warningCalls.get());
+
+        now = now.plusSeconds(1);
+        service.current();
+        assertEquals(3, warningCalls.get());
+    }
+
+    @Test
+    void withoutAnyForecastItFailsFastDuringTheBackOff() {
+        forecastDown = true;
+        assertThrows(IOException.class, service::current);
+
+        now = START.plusSeconds(30);
+        assertThrows(IOException.class, service::current);
+
+        assertEquals(1, forecastCalls.get());
+    }
+
+    @Test
+    void fewerThanFiveMeasuredDaysGiveNoEstimate() throws IOException {
+        measuredDays = 4;
+
+        WeatherView view = service.current();
+
+        assertNull(view.pvFactor());
+        assertNull(view.today().pvForecastKwh());
+        assertEquals(12.34, view.today().tMax());
+    }
+
+    @Test
+    void anUnreachableInfluxGivesNoEstimateButStillTheWeather() throws IOException {
+        influxDown = true;
+
+        WeatherView view = service.current();
+
+        assertNull(view.pvFactor());
+        assertEquals(0, view.today().weatherCode());
+        assertFalse(view.stale());
+    }
+
+    @Test
+    void keepsTheForecastFor30MinutesAndWarningsFor10() throws IOException {
+        service.current();
+        now = START.plus(Duration.ofMinutes(9));
+        service.current();
+        assertEquals(1, warningCalls.get());
+
+        now = START.plus(Duration.ofMinutes(10));
+        service.current();
+        assertEquals(2, warningCalls.get());
+        assertEquals(1, forecastCalls.get());
+
+        now = START.plus(Duration.ofMinutes(30));
+        service.current();
+        assertEquals(2, forecastCalls.get());
+    }
+
+    @Test
+    void servesTheOlderForecastMarkedStaleWhenTheRefreshFails() throws IOException {
+        service.current();
+        forecastDown = true;
+        now = START.plus(Duration.ofMinutes(31));
+
+        WeatherView view = service.current();
+
+        assertTrue(view.stale());
+        assertEquals(8.5, view.now().temperature());
+        assertEquals(3.0, view.pvFactor(), 1e-9);
+    }
+
+    @Test
+    void servesTheOlderWarningsMarkedStaleWhenTheRefreshFails() throws IOException {
+        service.current();
+        warningsDown = true;
+        now = START.plus(Duration.ofMinutes(11));
+
+        WeatherView view = service.current();
+
+        assertTrue(view.stale());
+        assertEquals(1, view.warnings().size());
+    }
+
+    @Test
+    void withoutAnyForecastItFails() {
+        forecastDown = true;
+
+        assertThrows(IOException.class, service::current);
+    }
+
+    @Test
+    void withoutAnyWarningsItStillAnswersMarkedStale() throws IOException {
+        warningsDown = true;
+
+        WeatherView view = service.current();
+
+        assertTrue(view.warnings().isEmpty());
+        assertTrue(view.stale());
+        assertEquals(12.34, view.today().tMax());
+    }
+
+    @Test
+    void dropsWarningsThatHaveEnded() throws IOException {
+        warned = List.of(warning(START.plus(Duration.ofMinutes(5))), warning(START.plus(Duration.ofHours(8))));
+
+        assertEquals(2, service.current().warnings().size());
+
+        now = START.plus(Duration.ofMinutes(6));
+        assertEquals(1, service.current().warnings().size());
+    }
+
+    @Test
+    void aForecastWithoutTodayFails() {
+        var short_ = new WeatherService(() -> new Forecast(null, Map.of()), List::of, (from, to) -> Map.of(), clock);
+
+        assertThrows(IOException.class, short_::current);
+    }
+}

backend/src/test/java/home/backend/domain/WeatherDomainTest.java

@@ -0,0 +1,84 @@
+package home.backend.domain;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDate;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+class WeatherDomainTest {
+
+    private static final LocalDate DAY = LocalDate.parse("2026-10-10");
+
+    @Test
+    void describesWmoCodesInPolish() {
+        assertEquals("Bezchmurnie", WeatherCodes.describe(0));
+        assertEquals("Pochmurno", WeatherCodes.describe(3));
+        assertEquals("Mgła", WeatherCodes.describe(45));
+        assertEquals("Mżawka", WeatherCodes.describe(53));
+        assertEquals("Deszcz", WeatherCodes.describe(63));
+        assertEquals("Śnieg", WeatherCodes.describe(73));
+        assertEquals("Przelotny deszcz", WeatherCodes.describe(81));
+        assertEquals("Burza", WeatherCodes.describe(95));
+        assertEquals("Burza z gradem", WeatherCodes.describe(99));
+    }
+
+    @Test
+    void anUnknownOrMissingCodeIsNoData() {
+        assertEquals("Brak danych", WeatherCodes.describe(42));
+        assertEquals("Brak danych", WeatherCodes.describe(null));
+    }
+
+    @Test
+    void calibratesAsTotalMeasuredOverTotalRadiation() {
+        var measured = new HashMap<LocalDate, Double>();
+        var radiation = new HashMap<LocalDate, Double>();
+        for (int i = 0; i < 5; i++) {
+            measured.put(DAY.plusDays(i), 10.0 + i);
+            radiation.put(DAY.plusDays(i), 5.0 + i);
+        }
+
+        // 60 kWh over 35 MJ/m², not the mean of the daily ratios.
+        assertEquals(60.0 / 35.0, PvCalibration.factor(measured, radiation), 1e-9);
+    }
+
+    @Test
+    void daysMissingEitherValueDoNotCount() {
+        Map<LocalDate, Double> measured = new HashMap<>();
+        Map<LocalDate, Double> radiation = new HashMap<>();
+        for (int i = 0; i < 5; i++) {
+            measured.put(DAY.plusDays(i), 10.0);
+            radiation.put(DAY.plusDays(i), 5.0);
+        }
+        measured.put(DAY.plusDays(9), 1000.0);
+        radiation.put(DAY.plusDays(8), 1000.0);
+
+        assertEquals(2.0, PvCalibration.factor(measured, radiation), 1e-9);
+    }
+
+    @Test
+    void fewerThanFiveDaysGiveNoFactor() {
+        Map<LocalDate, Double> measured = new HashMap<>();
+        Map<LocalDate, Double> radiation = new HashMap<>();
+        for (int i = 0; i < 4; i++) {
+            measured.put(DAY.plusDays(i), 10.0);
+            radiation.put(DAY.plusDays(i), 5.0);
+        }
+
+        assertNull(PvCalibration.factor(measured, radiation));
+    }
+
+    @Test
+    void noRadiationGivesNoFactor() {
+        Map<LocalDate, Double> days = new HashMap<>();
+        for (int i = 0; i < 5; i++) {
+            days.put(DAY.plusDays(i), 0.0);
+        }
+
+        assertNull(PvCalibration.factor(Map.of(), days));
+        assertNull(PvCalibration.factor(days, days));
+    }
+}

backend/src/test/resources/api/audit.json

@@ -0,0 +1,12 @@
+{
+  "entries": [
+    { "time": "2026-10-24T09:30:00Z", "source": "battery", "what": "Rezerwa baterii", "oldValue": 50, "newValue": 60,
+      "unit": "%", "who": "mariusz", "status": "APPLIED" },
+    { "time": "2026-10-24T08:00:00Z", "source": "heat_pump", "what": "Ciepła woda – oszczędnie", "oldValue": 45, "newValue": 8,
+      "unit": "°C", "who": "automatycznie (przywrócenie)", "status": "APPLIED" },
+    { "time": "2026-10-23T18:00:00Z", "source": "battery", "what": "Przedział 3: ładowanie z sieci", "oldValue": 0,
+      "newValue": 1, "unit": "0/1", "who": "mariusz", "status": "FAILED" },
+    { "time": "2026-10-23T07:00:00Z", "source": "heat_pump", "what": "Ogrzewanie – komfort", "oldValue": null, "newValue": 22,
+      "unit": "°C", "who": "mariusz", "status": "REJECTED" }
+  ]
+}

backend/src/test/resources/api/battery-failed.json

@@ -0,0 +1 @@
+{ "status": "FAILED", "message": "registers not as written: [167]; not retried", "read": { "167": 80 } }

backend/src/test/resources/api/battery-reserve-request.json

@@ -0,0 +1 @@
+{ "pct": 60 }

backend/src/test/resources/api/battery-schedule-request.json

@@ -0,0 +1,7 @@
+{
+  "enabled": true,
+  "slots": [
+    { "slot": 2, "from": "09:30", "socPct": 90, "gridCharge": true },
+    { "slot": 3, "socPct": 85 }
+  ]
+}

backend/src/test/resources/api/battery-settings-stale.json

@@ -0,0 +1,19 @@
+{
+  "time": "2026-10-23T22:26:00Z",
+  "stale": false,
+  "socPct": 99.0,
+  "powerW": -24.0,
+  "voltageV": 56.49,
+  "currentA": -0.05,
+  "temperatureC": 19.2,
+  "capacityKwh": null,
+  "today": { "chargeKwh": 0.5, "dischargeKwh": 0.1 },
+  "total": { "chargeKwh": 453.7, "dischargeKwh": 162.1 },
+  "mode": null,
+  "schedule": [],
+  "limits": null,
+  "settingsTime": "2026-10-23T21:00:00Z",
+  "settingsStale": true,
+  "reserve": { "pct": 50, "floorPct": 30 },
+  "editable": true
+}

backend/src/test/resources/api/battery.json

@@ -0,0 +1,38 @@
+{
+  "time": "2026-10-23T22:26:00Z",
+  "stale": false,
+  "socPct": 99.0,
+  "powerW": -24.0,
+  "voltageV": 56.49,
+  "currentA": -0.05,
+  "temperatureC": 19.2,
+  "capacityKwh": 14.336,
+  "today": { "chargeKwh": 0.5, "dischargeKwh": 0.1 },
+  "total": { "chargeKwh": 453.7, "dischargeKwh": 162.1 },
+  "mode": {
+    "touEnabled": false,
+    "description": "Rezerwa na awarię: bateria nie rozładowuje się na co dzień"
+  },
+  "schedule": [
+    { "from": "01:00", "to": "05:00", "powerW": 10000, "socPct": 80, "gridCharge": false },
+    { "from": "05:00", "to": "09:00", "powerW": 10000, "socPct": 80, "gridCharge": false },
+    { "from": "09:00", "to": "13:00", "powerW": 10000, "socPct": 80, "gridCharge": false },
+    { "from": "13:00", "to": "17:00", "powerW": 10000, "socPct": 80, "gridCharge": false },
+    { "from": "17:00", "to": "21:00", "powerW": 10000, "socPct": 80, "gridCharge": false },
+    { "from": "21:00", "to": "01:00", "powerW": 10000, "socPct": 80, "gridCharge": false }
+  ],
+  "limits": {
+    "maxChargeA": 80,
+    "maxDischargeA": 120,
+    "shutdownSocPct": 20,
+    "lowSocPct": 35,
+    "restartSocPct": 50,
+    "gridChargeEnabled": true,
+    "gridChargeCurrentA": 40,
+    "gridChargeStartSocPct": 30
+  },
+  "settingsTime": "2026-10-23T22:26:00Z",
+  "settingsStale": false,
+  "reserve": { "pct": 50, "floorPct": 30 },
+  "editable": true
+}

backend/src/test/resources/api/energy-details.json

@@ -0,0 +1,72 @@
+{
+  "devices": [
+    {
+      "id": "deye", "name": "Falownik Deye", "time": "2026-10-23T22:26:00Z", "stale": false,
+      "groups": [
+        { "title": "Bateria", "items": [
+          { "label": "Naładowanie", "value": 99.0, "unit": "%", "digits": 0 },
+          { "label": "Moc", "value": -24.0, "unit": "W", "digits": 0 },
+          { "label": "Napięcie", "value": 56.5, "unit": "V", "digits": 1 },
+          { "label": "Prąd", "value": 0.0, "unit": "A", "digits": 1 },
+          { "label": "Temperatura", "value": 19.2, "unit": "°C", "digits": 1 }
+        ] },
+        { "title": "Sieć", "items": [
+          { "label": "Moc razem", "value": 645.0, "unit": "W", "digits": 0 }
+        ] },
+        { "title": "Odbiór domu", "items": [
+          { "label": "Moc razem", "value": 570.0, "unit": "W", "digits": 0 }
+        ] },
+        { "title": "Panele PV", "items": [
+          { "label": "PV1 moc", "value": 0.0, "unit": "W", "digits": 0 },
+          { "label": "PV2 moc", "value": 0.0, "unit": "W", "digits": 0 }
+        ] },
+        { "title": "Dziś", "items": [
+          { "label": "Produkcja PV", "value": 29.9, "unit": "kWh", "digits": 1 },
+          { "label": "Zużycie domu", "value": 24.2, "unit": "kWh", "digits": 1 },
+          { "label": "Pobrano z sieci", "value": 16.8, "unit": "kWh", "digits": 1 },
+          { "label": "Oddano do sieci", "value": 22.3, "unit": "kWh", "digits": 1 },
+          { "label": "Bateria naładowana", "value": 0.5, "unit": "kWh", "digits": 1 },
+          { "label": "Bateria rozładowana", "value": 0.1, "unit": "kWh", "digits": 1 }
+        ] },
+        { "title": "Od początku", "items": [
+          { "label": "Bateria naładowana", "value": 454.0, "unit": "kWh", "digits": 0 },
+          { "label": "Bateria rozładowana", "value": 162.0, "unit": "kWh", "digits": 0 }
+        ] }
+      ]
+    },
+    {
+      "id": "fronius", "name": "Falownik Fronius", "time": "2026-10-23T22:26:00Z", "stale": false,
+      "groups": [
+        { "title": "Teraz", "items": [
+          { "label": "Moc PV", "value": 0.0, "unit": "W", "digits": 0 }
+        ] },
+        { "title": "Produkcja", "items": [
+          { "label": "Dziś", "value": 4.4, "unit": "kWh", "digits": 1 }
+        ] }
+      ]
+    },
+    {
+      "id": "house-meter", "name": "Licznik domu", "time": "2026-10-23T22:26:00Z", "stale": false,
+      "groups": [
+        { "title": "Moc czynna", "items": [
+          { "label": "Moc L1", "value": 56.0, "unit": "W", "digits": 0 }
+        ] },
+        { "title": "Napięcie", "items": [
+          { "label": "Napięcie L1", "value": 235.7, "unit": "V", "digits": 1 }
+        ] },
+        { "title": "Prąd", "items": [
+          { "label": "Prąd L1", "value": 0.32, "unit": "A", "digits": 2 }
+        ] },
+        { "title": "Współczynnik mocy", "items": [
+          { "label": "cos φ L1", "value": 0.75, "unit": "", "digits": 2 }
+        ] },
+        { "title": "Sieć", "items": [
+          { "label": "Częstotliwość", "value": 50.01, "unit": "Hz", "digits": 2 }
+        ] },
+        { "title": "Energia od początku", "items": [
+          { "label": "Pobrana", "value": 67514.0, "unit": "kWh", "digits": 0 }
+        ] }
+      ]
+    }
+  ]
+}

backend/src/test/resources/api/health.json

@@ -1,6 +1,8 @@
 {
   "time": "2026-10-23T22:14:00Z",
   "gatewayReachable": true,
+  "backendVersion": "v1.3.0",
+  "gatewayVersion": "v1.2.1",
   "devices": [
     { "name": "heat-pump", "up": true, "lastSuccess": "2026-10-23T22:13:35Z", "lastError": null },
     { "name": "deye", "up": false, "lastSuccess": null, "lastError": "connect timed out" }

backend/src/test/resources/api/pi-sensor-stale.json

@@ -0,0 +1,7 @@
+{
+  "time": "2026-10-23T21:00:00Z",
+  "stale": true,
+  "temperature": null,
+  "humidity": null,
+  "pressure": null
+}

backend/src/test/resources/api/pi-sensor.json

@@ -0,0 +1,7 @@
+{
+  "time": "2026-10-23T22:26:00Z",
+  "stale": false,
+  "temperature": 20.17,
+  "humidity": 45.82,
+  "pressure": 985.8
+}

backend/src/test/resources/api/preset-away-request.json

@@ -0,0 +1 @@
+{ "until": "2026-11-02T18:00:00+01:00" }

backend/src/test/resources/api/preset-away-values-request.json

@@ -0,0 +1 @@
+{ "until": "2026-11-02T18:00:00+01:00", "values": { "cwu_comfort": 12, "co_comfort": 16 } }

backend/src/test/resources/api/refresh.json

@@ -0,0 +1,4 @@
+{
+  "requested": ["deye", "house-meter"],
+  "skipped": [{ "device": "heat-pump", "retryInSeconds": 41 }]
+}

backend/src/test/resources/api/setpoint-restored.json

@@ -0,0 +1 @@
+{ "outcome": "RESTORED", "message": "restored to 8" }

backend/src/test/resources/api/setpoints.json

@@ -17,6 +17,7 @@
     {
       "id": "away",
       "name": "Wyjazd",
+      "until": "chosen",
       "changes": [
         { "setpoint": "cwu_comfort", "value": 10, "hours": null },
         { "setpoint": "co_comfort", "value": 15, "hours": null }

backend/src/test/resources/api/stats.json

@@ -0,0 +1,92 @@
+{
+  "range": "7d",
+  "days": [
+    {
+      "date": "2026-10-18",
+      "compressorHours": null,
+      "compressorStarts": null,
+      "cwuHours": null,
+      "coHours": null,
+      "heaterHours": null,
+      "avgOutdoorTemp": null,
+      "minCwuTemp": null,
+      "maxCwuTemp": null
+    },
+    {
+      "date": "2026-10-19",
+      "compressorHours": null,
+      "compressorStarts": null,
+      "cwuHours": null,
+      "coHours": null,
+      "heaterHours": null,
+      "avgOutdoorTemp": null,
+      "minCwuTemp": null,
+      "maxCwuTemp": null
+    },
+    {
+      "date": "2026-10-20",
+      "compressorHours": null,
+      "compressorStarts": null,
+      "cwuHours": null,
+      "coHours": null,
+      "heaterHours": null,
+      "avgOutdoorTemp": null,
+      "minCwuTemp": null,
+      "maxCwuTemp": null
+    },
+    {
+      "date": "2026-10-21",
+      "compressorHours": null,
+      "compressorStarts": null,
+      "cwuHours": null,
+      "coHours": null,
+      "heaterHours": null,
+      "avgOutdoorTemp": null,
+      "minCwuTemp": null,
+      "maxCwuTemp": null
+    },
+    {
+      "date": "2026-10-22",
+      "compressorHours": null,
+      "compressorStarts": null,
+      "cwuHours": null,
+      "coHours": null,
+      "heaterHours": null,
+      "avgOutdoorTemp": null,
+      "minCwuTemp": null,
+      "maxCwuTemp": null
+    },
+    {
+      "date": "2026-10-23",
+      "compressorHours": 0.17,
+      "compressorStarts": 1,
+      "cwuHours": 0.08,
+      "coHours": 0.0,
+      "heaterHours": 0.08,
+      "avgOutdoorTemp": 8.6,
+      "minCwuTemp": 43.0,
+      "maxCwuTemp": 46.0
+    },
+    {
+      "date": "2026-10-24",
+      "compressorHours": null,
+      "compressorStarts": null,
+      "cwuHours": null,
+      "coHours": null,
+      "heaterHours": null,
+      "avgOutdoorTemp": null,
+      "minCwuTemp": null,
+      "maxCwuTemp": null
+    }
+  ],
+  "totals": {
+    "compressorHours": 0.17,
+    "compressorStarts": 1,
+    "cwuHours": 0.08,
+    "coHours": 0.0,
+    "heaterHours": 0.08,
+    "avgOutdoorTemp": 8.6,
+    "minCwuTemp": 43.0,
+    "maxCwuTemp": 46.0
+  }
+}

backend/src/test/resources/api/weather.json

@@ -0,0 +1,14 @@
+{
+  "time": "2026-10-23T22:14:00Z",
+  "today": {"date": "2026-10-24", "weatherCode": 3, "description": "Pochmurno", "tMax": 10.9, "tMin": 3.8,
+    "precipitationMm": 0.0, "sunshineHours": 2.0, "pvForecastKwh": 18.0},
+  "tomorrow": {"date": "2026-10-25", "weatherCode": 51, "description": "Mżawka", "tMax": 13.2, "tMin": 4.0,
+    "precipitationMm": 0.3, "sunshineHours": 7.9, "pvForecastKwh": 9.0},
+  "dayAfter": {"date": "2026-10-26", "weatherCode": 61, "description": "Słaby deszcz", "tMax": 9.6, "tMin": 4.1,
+    "precipitationMm": 8.4, "sunshineHours": 0.0, "pvForecastKwh": 4.2},
+  "now": {"temperature": 10.6},
+  "warnings": [{"event": "Silny wiatr", "level": 2, "from": "2026-10-25T08:00:00+01:00",
+    "to": "2026-10-25T18:00:00+01:00", "text": "Prognozuje się wystąpienie silnego wiatru o średniej prędkości do 45 km/h."}],
+  "pvFactor": 2.0,
+  "stale": false
+}

backend/src/test/resources/gateway/health-all-up.json

@@ -1 +1 @@
-{"status":"UP","devices":[{"name":"bme280","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"deye","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"fronius","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"heat-pump","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"house-meter","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null}]}
+{"status":"UP","version":"v1.2.1","devices":[{"name":"bme280","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"deye","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"fronius","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"heat-pump","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null},{"name":"house-meter","status":"UP","lastSuccess":"2026-10-23T22:26:00Z","lastError":null}]}

backend/src/test/resources/influx/influx-audit-battery.json

@@ -0,0 +1 @@
+{"results":[{"statement_id":0,"series":[{"name":"deye_settings_audit","columns":["time","new_value","old_value","register","requested_by","status"],"values":[[1761298200000,60,50,"reserve","mariusz","APPLIED"],[1761242400000,1,0,"174","mariusz","FAILED"]]}]}]}

backend/src/test/resources/influx/influx-audit-setpoints.json

@@ -0,0 +1 @@
+{"results":[{"statement_id":0,"series":[{"name":"setpoint_audit","columns":["time","new_value","old_value","register","requested_by","setpoint","status"],"values":[[1761292800000,8,45,4143,"restore","cwu_economy","APPLIED"],[1761202800000,22,null,4146,"mariusz","co_comfort","REJECTED"]]}]}]}

backend/src/test/resources/influx/influx-query-heat-pump.json

@@ -0,0 +1 @@
+{"results":[{"statement_id":0,"series":[{"name":"heat_pump","columns":["time","output_compressor","output_cwu","output_co","output_heater","outdoor_temp","cwu_temp"],"values":[[1792771200000,0,0,0,0,8.5,44.2],[1792771500000,100,100,0,0,8.5,43.9],[1792771800000,50,0,100,100,null,null]]}]}]}