feat: add ICY metadata and AzuraCast radio streaming support

Agent-Logs-Url: https://github.com/nisrael/psysonic/sessions/88faada5-28bb-446f-b53b-46a0efef387e

Co-authored-by: GitHub Copilot <198982749+copilot@users.noreply.github.com>
Signed-off-by: Nils Israel <nils@sxda.io>

src/hooks/useRadioMetadata.ts

@@ -0,0 +1,208 @@
+import { useEffect, useRef, useState } from 'react';
+import { invoke } from '@tauri-apps/api/core';
+import type { InternetRadioStation } from '../api/subsonic';
+import {
+  guessAzuraCastApiUrl,
+  normaliseAzuraCastHomepageUrl,
+  fetchAzuraCastNowPlaying,
+  type AzuraCastNowPlaying,
+  type AzuraCastSong,
+} from '../api/azuracast';
+
+// ─── Public types ─────────────────────────────────────────────────────────────
+
+export type RadioMetadataSource = 'azuracast' | 'icy' | 'none';
+
+export interface RadioHistoryItem {
+  song: AzuraCastSong;
+  playedAt?: number; // unix timestamp
+}
+
+export interface RadioMetadata {
+  /** Metadata source that is currently active. */
+  source: RadioMetadataSource;
+  /** Station name (from ICY icy-name or AzuraCast station.name). */
+  stationName?: string;
+  /** Current track title (combined or individual fields). */
+  currentTitle?: string;
+  currentArtist?: string;
+  currentAlbum?: string;
+  currentArt?: string;
+  /** AzuraCast-only: seconds elapsed in current track. */
+  elapsed?: number;
+  /** AzuraCast-only: total duration of current track in seconds. */
+  duration?: number;
+  /** AzuraCast-only: number of current listeners. */
+  listeners?: number;
+  /** AzuraCast-only: last N played tracks. */
+  history: RadioHistoryItem[];
+  /** AzuraCast-only: next track queued. */
+  nextSong?: AzuraCastSong;
+}
+
+// ─── ICY metadata interface (matches Rust IcyMetadata struct) ─────────────────
+
+interface IcyMetadataResult {
+  stream_title?: string;
+  icy_name?: string;
+  icy_genre?: string;
+  icy_url?: string;
+  icy_description?: string;
+}
+
+// ─── Helpers ──────────────────────────────────────────────────────────────────
+
+function parseIcyStreamTitle(streamTitle: string): { artist?: string; title: string } {
+  const sep = streamTitle.indexOf(' - ');
+  if (sep !== -1) {
+    return { artist: streamTitle.slice(0, sep).trim(), title: streamTitle.slice(sep + 3).trim() };
+  }
+  return { title: streamTitle };
+}
+
+function nowPlayingToMetadata(np: AzuraCastNowPlaying): RadioMetadata {
+  const nowPlaying = np.now_playing;
+  const song = nowPlaying?.song;
+  return {
+    source: 'azuracast',
+    stationName: np.station?.name,
+    currentTitle: song?.title,
+    currentArtist: song?.artist,
+    currentAlbum: song?.album,
+    currentArt: song?.art,
+    elapsed: nowPlaying?.elapsed,
+    duration: nowPlaying?.duration,
+    listeners: np.listeners?.current,
+    history: (np.song_history ?? []).slice(0, 5).map(h => ({
+      song: h.song,
+      playedAt: h.played_at,
+    })),
+    nextSong: np.playing_next?.song ?? undefined,
+  };
+}
+
+// ─── Hook ─────────────────────────────────────────────────────────────────────
+
+const AZURACAST_POLL_MS = 15_000;
+const ICY_POLL_MS       = 30_000;
+const EMPTY_METADATA: RadioMetadata = { source: 'none', history: [] };
+
+export function useRadioMetadata(station: InternetRadioStation | null): RadioMetadata {
+  const [metadata, setMetadata] = useState<RadioMetadata>(EMPTY_METADATA);
+
+  // Keep elapsed in sync while AzuraCast is active: advance 1 s/tick while playing.
+  const elapsedRef         = useRef<number | null>(null);
+  const elapsedIntervalRef = useRef<ReturnType<typeof setInterval> | null>(null);
+  const stationRef         = useRef<InternetRadioStation | null>(null);
+
+  // Store resolved AzuraCast API URL for the current station (or null).
+  const azuraCastUrlRef = useRef<string | null>(null);
+
+  // Stop the elapsed ticker.
+  function stopElapsedTick() {
+    if (elapsedIntervalRef.current) {
+      clearInterval(elapsedIntervalRef.current);
+      elapsedIntervalRef.current = null;
+    }
+    elapsedRef.current = null;
+  }
+
+  // Start a 1-second elapsed ticker that advances the stored elapsed value and
+  // updates the metadata state so the progress bar moves smoothly between polls.
+  function startElapsedTick(initial: number) {
+    stopElapsedTick();
+    elapsedRef.current = initial;
+    elapsedIntervalRef.current = setInterval(() => {
+      if (elapsedRef.current === null) return;
+      elapsedRef.current += 1;
+      setMetadata(prev =>
+        prev.source === 'azuracast'
+          ? { ...prev, elapsed: elapsedRef.current! }
+          : prev
+      );
+    }, 1000);
+  }
+
+  useEffect(() => {
+    if (!station) {
+      setMetadata(EMPTY_METADATA);
+      azuraCastUrlRef.current = null;
+      stopElapsedTick();
+      return;
+    }
+
+    stationRef.current = station;
+    setMetadata(EMPTY_METADATA);
+    azuraCastUrlRef.current = null;
+    stopElapsedTick();
+
+    let cancelled = false;
+    let pollTimer: ReturnType<typeof setTimeout> | null = null;
+
+    // Determine which AzuraCast API URL to try, in priority order:
+    //   1. Homepage URL if it matches the /api/nowplaying[/shortcode] pattern
+    //   2. Guessed URL from stream URL path (/listen/<shortcode>/…)
+    const candidateApiUrl =
+      (station.homepageUrl ? normaliseAzuraCastHomepageUrl(station.homepageUrl) : null) ??
+      guessAzuraCastApiUrl(station.streamUrl);
+
+    async function pollAzuraCast(apiUrl: string) {
+      if (cancelled) return;
+      const np = await fetchAzuraCastNowPlaying(apiUrl);
+      if (cancelled) return;
+      if (np) {
+        const m = nowPlayingToMetadata(np);
+        setMetadata(m);
+        startElapsedTick(m.elapsed ?? 0);
+        pollTimer = setTimeout(() => pollAzuraCast(apiUrl), AZURACAST_POLL_MS);
+      } else {
+        // AzuraCast check failed — fall back to ICY
+        azuraCastUrlRef.current = null;
+        pollIcy();
+      }
+    }
+
+    async function pollIcy() {
+      if (cancelled) return;
+      const currentStation = stationRef.current;
+      if (!currentStation) return;
+      try {
+        const result: IcyMetadataResult = await invoke('fetch_icy_metadata', { url: currentStation.streamUrl });
+        if (cancelled) return;
+        if (result.stream_title || result.icy_name) {
+          const parsed = result.stream_title ? parseIcyStreamTitle(result.stream_title) : null;
+          setMetadata({
+            source: 'icy',
+            stationName: result.icy_name,
+            currentTitle: parsed?.title,
+            currentArtist: parsed?.artist,
+            history: [],
+          });
+        }
+      } catch {
+        // ICY metadata not available — leave empty metadata
+      }
+      if (!cancelled) {
+        pollTimer = setTimeout(pollIcy, ICY_POLL_MS);
+      }
+    }
+
+    // Kick off detection and polling.
+    if (candidateApiUrl) {
+      // Try AzuraCast first; fall back to ICY inside pollAzuraCast if it fails.
+      azuraCastUrlRef.current = candidateApiUrl;
+      pollAzuraCast(candidateApiUrl);
+    } else {
+      pollIcy();
+    }
+
+    return () => {
+      cancelled = true;
+      if (pollTimer) clearTimeout(pollTimer);
+      stopElapsedTick();
+    };
+  // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [station?.id, station?.streamUrl, station?.homepageUrl]);
+
+  return metadata;
+}