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src/automats/healthAutomat.js

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+/**
+ * @file healthAutomat.js
+ * @description Backend latency samples for the settings "Gesundheit" tab
+ * (`GET /api/health/latency`). Not company-scoped; only polls while a view
+ * has called `actions.startPolling()`.
+ */
+
+import { Automat } from 'react-automat';
+import { health as healthApi } from '../api';
+
+const POLL_MS = 60_000;
+
+/**
+ * @typedef {{ timestamp: number, value: number }} LatencyPoint
+ * @typedef {Object} HealthState
+ * @property {'idle'|'loading'|'ready'|'failed'} status
+ * @property {string|null} error
+ * @property {'3h'|'all'} range
+ * @property {LatencyPoint[]} raw Per-minute samples (last 3h)
+ * @property {LatencyPoint[]} avg 30-min rolling 4h average (range=all only)
+ * @property {LatencyPoint[]} max 30-min rolling 4h max (range=all only)
+ */
+
+/** @type {HealthState} */
+const initialState = {
+  status: 'idle',
+  error: null,
+  range: '3h',
+  raw: [],
+  avg: [],
+  max: [],
+};
+
+let healthAutomat;
+let inflight = null;
+let timer = null;
+let pollers = 0;
+
+const actions = {
+  // #region load
+  // MARK: calls GET /api/health/latency from ./api/index.js
+  /**
+   * Loads latency data for the current range. Deduplicates concurrent calls.
+   * @param {boolean} [silent=false] Keep status 'ready' while refreshing
+   */
+  load(silent = false) {
+    if (inflight) return inflight;
+    const { range, status } = healthAutomat.state;
+    if (!silent && status !== 'ready') healthAutomat.setState({ status: 'loading', error: null });
+    inflight = (async () => {
+      try {
+        const data = await healthApi.getLatency(range);
+        // Range may have changed while the request was in flight.
+        if (healthAutomat.state.range !== range) return;
+        healthAutomat.setState({
+          status: 'ready',
+          error: null,
+          raw: data?.raw ?? [],
+          avg: data?.avg ?? [],
+          max: data?.max ?? [],
+        });
+      } catch (err) {
+        healthAutomat.setState({ status: 'failed', error: err?.message ?? String(err) });
+      } finally {
+        inflight = null;
+      }
+    })();
+    return inflight;
+  },
+  // #endregion
+
+  /** Switches between the live 3h view and the long-term view. */
+  setRange(range) {
+    if (range === healthAutomat.state.range) return;
+    healthAutomat.setState({ range, status: 'loading', error: null });
+    void healthAutomat.actions.load();
+  },
+
+  // #region polling
+  /** Starts the once-a-minute refresh (ref-counted). */
+  startPolling() {
+    pollers += 1;
+    if (pollers > 1) return;
+    void actions.load(healthAutomat.state.status === 'ready');
+    timer = setInterval(() => void actions.load(true), POLL_MS);
+  },
+
+  stopPolling() {
+    pollers = Math.max(0, pollers - 1);
+    if (pollers === 0 && timer) {
+      clearInterval(timer);
+      timer = null;
+    }
+  },
+  // #endregion
+};
+
+healthAutomat = new Automat(initialState, actions, { name: 'health' });
+
+export default healthAutomat;