Merge pull request #109 from ZHANGTIANYAO1/fix/player-elapsed-reactivity

fix(web): 播放器时间每帧更新、歌词同步 (closes #107)

web/src/App.vue

@@ -118,8 +118,10 @@ let mobileRaf: number | null = null;
 
 function updateMobileProgress() {
   const duration = currentSong.value?.duration ?? 0;
+  // liveElapsed() recomputes each frame; the cached `elapsed` getter would
+  // leave the mobile bar frozen between server pushes (#107).
   mobileProgressPct.value = duration > 0
-    ? Math.min((playerStore.elapsed / duration) * 100, 100)
+    ? Math.min((playerStore.liveElapsed() / duration) * 100, 100)
     : 0;
   mobileRaf = requestAnimationFrame(updateMobileProgress);
 }

web/src/components/Player.vue

@@ -135,8 +135,9 @@ function formatTime(seconds: number): string {
 }
 
 function updateProgress() {
-  // Use store.elapsed which interpolates from server ground truth
-  currentElapsed.value = store.elapsed;
+  // liveElapsed() (an action, not the cached `elapsed` getter) re-interpolates
+  // from the server anchor on every frame so the clock ticks each second (#107).
+  currentElapsed.value = store.liveElapsed();
 
   const duration = currentSong.value?.duration ?? 0;
   progressPercent.value = duration > 0

web/src/stores/elapsed.test.ts

@@ -0,0 +1,44 @@
+import { describe, it, expect, vi, afterEach } from "vitest";
+import { interpolateElapsed, type TimingState } from "./player.js";
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
+function timing(partial: Partial<TimingState>): TimingState {
+  return { serverElapsed: 0, serverSyncTime: 0, wasPlaying: false, ...partial };
+}
+
+describe("interpolateElapsed", () => {
+  it("returns serverElapsed before playback has a sync anchor", () => {
+    expect(interpolateElapsed(timing({ serverElapsed: 12, wasPlaying: false }), false, Infinity)).toBe(12);
+    // wasPlaying but no sync time yet
+    expect(interpolateElapsed(timing({ serverElapsed: 5, wasPlaying: true, serverSyncTime: 0 }), false, Infinity)).toBe(5);
+  });
+
+  it("advances with wall-clock time while playing (regression: must not be frozen)", () => {
+    const spy = vi.spyOn(Date, "now");
+    const t = timing({ serverElapsed: 30, serverSyncTime: 10_000, wasPlaying: true });
+
+    spy.mockReturnValue(10_000);
+    expect(interpolateElapsed(t, false, Infinity)).toBeCloseTo(30, 5);
+
+    spy.mockReturnValue(11_000); // +1s
+    expect(interpolateElapsed(t, false, Infinity)).toBeCloseTo(31, 5);
+
+    spy.mockReturnValue(13_500); // +3.5s — distinct from the 1s reading
+    expect(interpolateElapsed(t, false, Infinity)).toBeCloseTo(33.5, 5);
+  });
+
+  it("freezes at serverElapsed while paused", () => {
+    vi.spyOn(Date, "now").mockReturnValue(99_000);
+    const t = timing({ serverElapsed: 42, serverSyncTime: 10_000, wasPlaying: true });
+    expect(interpolateElapsed(t, true, Infinity)).toBe(42);
+  });
+
+  it("clamps to maxDuration", () => {
+    vi.spyOn(Date, "now").mockReturnValue(1_000_000);
+    const t = timing({ serverElapsed: 100, serverSyncTime: 1_000, wasPlaying: true });
+    expect(interpolateElapsed(t, false, 180)).toBe(180);
+  });
+});

web/src/stores/player.ts

@@ -47,7 +47,7 @@ export interface FavoritePlaylist {
   createdAt: string;
 }
 
-interface TimingState {
+export interface TimingState {
   serverElapsed: number;
   serverSyncTime: number;
   wasPlaying: boolean;
@@ -59,6 +59,33 @@ function defaultTiming(): TimingState {
   return { serverElapsed: 0, serverSyncTime: 0, wasPlaying: false };
 }
 
+/**
+ * Interpolate the live elapsed seconds from the last server anchor.
+ *
+ * This is a PURE function (its only time source is `Date.now()`), deliberately
+ * kept OUT of the Pinia getter so it can be called fresh every animation frame.
+ * The `elapsed` getter is a Vue `computed` and caches its result until a
+ * REACTIVE dependency changes — but `Date.now()` is not reactive, so a getter
+ * only re-runs on a WebSocket push / server poll (every few seconds). Reading
+ * the getter from a requestAnimationFrame loop therefore returns a frozen value
+ * and the clock appears to jump ~3s at a time (issue #107). Per-frame consumers
+ * must call this helper (via the `liveElapsed` action) instead.
+ */
+export function interpolateElapsed(
+  timing: TimingState,
+  isPaused: boolean,
+  maxDuration: number,
+): number {
+  // No live anchor yet, or paused: report the frozen server position.
+  if (!timing.wasPlaying || timing.serverSyncTime === 0 || isPaused) {
+    return Math.min(timing.serverElapsed, maxDuration);
+  }
+  return Math.min(
+    timing.serverElapsed + (Date.now() - timing.serverSyncTime) / 1000,
+    maxDuration,
+  );
+}
+
 export const usePlayerStore = defineStore('player', {
   state: () => ({
     bots: [] as BotStatus[],
@@ -111,15 +138,19 @@ export const usePlayerStore = defineStore('player', {
       if (!botId) return [];
       return this.queues[botId] ?? [];
     },
-    /** Interpolated elapsed for the active bot */
+    /**
+     * Interpolated elapsed for the active bot. NOTE: as a Pinia getter this is
+     * a Vue `computed` and is CACHED — it only re-runs when a reactive
+     * dependency changes, so it does NOT tick every second on its own. Use it
+     * for one-off reactive reads; per-frame consumers (progress bar, lyrics)
+     * must call the `liveElapsed` action so the clock advances smoothly (#107).
+     */
     elapsed(): number {
       const botId = this.activeBotId ?? this.bots[0]?.id;
       if (!botId || !this.activeBot?.currentSong) return 0;
       const timing = this.timings[botId] ?? defaultTiming();
       const maxDuration = this.activeBot.currentSong.duration || Infinity;
-      if (!timing.wasPlaying || timing.serverSyncTime === 0) return Math.min(timing.serverElapsed, maxDuration);
-      if (this.isPaused) return Math.min(timing.serverElapsed, maxDuration);
-      return Math.min(timing.serverElapsed + (Date.now() - timing.serverSyncTime) / 1000, maxDuration);
+      return interpolateElapsed(timing, this.isPaused, maxDuration);
     },
     /** Sources that are currently logged in. Order: netease before qq. */
     availableSources(): Source[] {
@@ -131,6 +162,21 @@ export const usePlayerStore = defineStore('player', {
   },
 
   actions: {
+    /**
+     * Live elapsed seconds for the active bot, recomputed on every call. Unlike
+     * the `elapsed` getter (a cached computed), this is an action, so it is NOT
+     * memoised — call it from requestAnimationFrame / interval loops so the
+     * progress bar and lyrics advance every frame instead of jumping on each
+     * server push (#107).
+     */
+    liveElapsed(): number {
+      const botId = this.activeBotId ?? this.bots[0]?.id;
+      if (!botId || !this.activeBot?.currentSong) return 0;
+      const timing = this.timings[botId] ?? defaultTiming();
+      const maxDuration = this.activeBot.currentSong.duration || Infinity;
+      return interpolateElapsed(timing, this.isPaused, maxDuration);
+    },
+
     _getTiming(botId: string): TimingState {
       if (!this.timings[botId]) {
         this.timings[botId] = defaultTiming();
@@ -403,9 +449,10 @@ export const usePlayerStore = defineStore('player', {
 
     async pause() {
       if (!this.activeBotId) return;
-      // Freeze elapsed at current interpolated value
+      // Freeze elapsed at the current LIVE interpolated value. Using the cached
+      // `elapsed` getter here could snapshot a value up to a few seconds stale.
       this._setTiming(this.activeBotId, {
-        serverElapsed: this.elapsed,
+        serverElapsed: this.liveElapsed(),
         wasPlaying: false,
       });
       await axios.post(`/api/player/${this.activeBotId}/pause`);

web/src/views/Lyrics.vue

@@ -136,7 +136,9 @@ function scrollToActiveLine(idx: number) {
 
 function syncLyrics() {
   if (!store.isPlaying || lines.value.length === 0) return;
-  const elapsed = store.elapsed;
+  // liveElapsed() (action) is recomputed now; the cached `elapsed` getter only
+  // refreshed on server pushes, leaving highlights ~half a line behind (#107).
+  const elapsed = store.liveElapsed();
   const idx = findActiveLine(elapsed);
   // Only update when the active line actually changes
   if (idx !== activeLine.value && idx >= 0) {