feat(app): add music queue management with next/prev navigation

Add queue (ShallowRef<Song[]>), currentIndex, playNext, playPrevious,
addToQueue, removeFromQueue to usePlayer. Auto-advance on song end.
Add prev/next buttons and queue count to PlayerBar.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/app/src/components/player/PlayerBar.vue

@@ -36,6 +36,19 @@
 
       <div class="flex flex-col gap-1 flex-1 max-w-xl mx-4">
         <div class="flex items-center gap-2">
+          <!-- Previous button -->
+          <button
+            class="w-8 h-8 rounded-full flex items-center justify-center shrink-0 transition-all hover:scale-105 active:scale-95"
+            :class="hasPrevious
+              ? isDark ? 'text-white/70 hover:text-white/90' : 'text-gray-600 hover:text-gray-800'
+              : isDark ? 'text-white/20' : 'text-gray-300'"
+            :disabled="!hasPrevious"
+            @click="playPrevious"
+          >
+            <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24">
+              <path d="M6 6h2v12H6V6zm3.5 6l8.5 6V6l-8.5 6z" />
+            </svg>
+          </button>
           <button
             class="w-12 h-12 rounded-full flex items-center justify-center glass-button shrink-0 transition-all hover:scale-105 active:scale-95"
             @click="toggle"
@@ -51,6 +64,19 @@
               <path d="M8 5v14l11-7L8 5z" />
             </svg>
           </button>
+          <!-- Next button -->
+          <button
+            class="w-8 h-8 rounded-full flex items-center justify-center shrink-0 transition-all hover:scale-105 active:scale-95"
+            :class="hasNext
+              ? isDark ? 'text-white/70 hover:text-white/90' : 'text-gray-600 hover:text-gray-800'
+              : isDark ? 'text-white/20' : 'text-gray-300'"
+            :disabled="!hasNext"
+            @click="playNext"
+          >
+            <svg class="w-4 h-4" fill="currentColor" viewBox="0 0 24 24">
+              <path d="M6 18l8.5-6L6 6v12zm10-12v12h2V6h-2z" />
+            </svg>
+          </button>
           <span class="text-[10px] font-mono tabular-nums"
                 :class="isDark ? 'text-white/40' : 'text-gray-400'">
             {{ formatTime(currentTime) }}
@@ -73,6 +99,11 @@
         <p v-if="error" class="text-[10px] text-red-400">{{ error }}</p>
       </div>
 
+      <span
+        v-if="queue.length > 1"
+        class="text-[10px] font-mono tabular-nums shrink-0"
+        :class="isDark ? 'text-white/30' : 'text-gray-400'"
+      >{{ queue.length }} songs</span>
       <button
         class="w-9 h-9 rounded-xl flex items-center justify-center path-glass-button path-glass-button-sm shrink-0 transition-all hover:scale-105"
         @click="clear"
@@ -102,9 +133,14 @@ const {
   currentTime,
   duration,
   progress,
+  queue,
+  hasNext,
+  hasPrevious,
   toggle,
   seek,
   clear,
+  playNext,
+  playPrevious,
   setContainer,
 } = usePlayer()
 

packages/app/src/composables/usePlayer.ts

@@ -1,4 +1,4 @@
-import { ref, computed } from 'vue'
+import { ref, shallowRef, computed } from 'vue'
 import type { Song } from '@aiui/core/types/content'
 import Plyr from 'plyr'
 import 'plyr/dist/plyr.css'
@@ -19,6 +19,10 @@ const error = ref<string | null>(null)
 const currentTime = ref(0)
 const duration = ref(0)
 
+// Queue management
+const queue = shallowRef<Song[]>([])
+const currentIndex = ref(-1)
+
 let plyrInstance: Plyr | null = null
 let containerEl: HTMLDivElement | null = null
 
@@ -94,6 +98,10 @@ export function usePlayer() {
     })
     plyrInstance!.on('ended', () => {
       isPlaying.value = false
+      // Auto-advance to next song in queue
+      if (currentIndex.value >= 0 && currentIndex.value < queue.value.length - 1) {
+        playNext()
+      }
     })
     plyrInstance!.on('playing', () => {
       isPlaying.value = true
@@ -155,6 +163,58 @@ export function usePlayer() {
     currentTime.value = time
   }
 
+  function addToQueue(song: Song) {
+    const existing = queue.value.find(s => s.id === song.id)
+    if (!existing) {
+      queue.value = [...queue.value, song]
+    }
+  }
+
+  function playNext() {
+    if (queue.value.length === 0) return
+    const nextIdx = currentIndex.value + 1
+    if (nextIdx < queue.value.length) {
+      currentIndex.value = nextIdx
+      play(queue.value[nextIdx])
+    }
+  }
+
+  function playPrevious() {
+    if (queue.value.length === 0) return
+    const prevIdx = currentIndex.value - 1
+    if (prevIdx >= 0) {
+      currentIndex.value = prevIdx
+      play(queue.value[prevIdx])
+    }
+  }
+
+  function removeFromQueue(index: number) {
+    const newQueue = [...queue.value]
+    newQueue.splice(index, 1)
+    queue.value = newQueue
+    // Adjust currentIndex if needed
+    if (index < currentIndex.value) {
+      currentIndex.value--
+    } else if (index === currentIndex.value) {
+      // Removed the current track — pause
+      currentIndex.value = Math.min(currentIndex.value, newQueue.length - 1)
+    }
+  }
+
+  // Override play to update queue position
+  const originalPlay = play
+  async function playWithQueue(song: Song) {
+    // If not in queue, add it
+    const idx = queue.value.findIndex(s => s.id === song.id)
+    if (idx === -1) {
+      addToQueue(song)
+      currentIndex.value = queue.value.length - 1
+    } else {
+      currentIndex.value = idx
+    }
+    await originalPlay(song)
+  }
+
   function clear() {
     pause()
     destroyPlayer()
@@ -165,6 +225,15 @@ export function usePlayer() {
     error.value = null
   }
 
+  function clearQueue() {
+    clear()
+    queue.value = []
+    currentIndex.value = -1
+  }
+
+  const hasNext = computed(() => currentIndex.value < queue.value.length - 1)
+  const hasPrevious = computed(() => currentIndex.value > 0)
+
   return {
     currentSong,
     playableSource,
@@ -175,11 +244,20 @@ export function usePlayer() {
     duration,
     hasTrack,
     progress,
-    play,
+    queue,
+    currentIndex,
+    hasNext,
+    hasPrevious,
+    play: playWithQueue,
     pause,
     toggle,
     seek,
     clear,
+    clearQueue,
+    addToQueue,
+    playNext,
+    playPrevious,
+    removeFromQueue,
     setContainer,
   }
 }