feat: 添加无缝播放，与 auto mix 合并，统一切歌过渡模式

src/components/Setting/config/play.ts

@@ -349,6 +349,11 @@ export const usePlaySettings = (): SettingConfig => {
               get: () => settingStore.useNextPrefetch,
               set: (v) => (settingStore.useNextPrefetch = v),
             }),
+            forceIf: {
+              condition: computed(() => settingStore.useGaplessPlayback),
+              forcedValue: true,
+              forcedDescription: "无缝播放已启用，需要保持预载开启",
+            },
           },
           {
             key: "memoryLastSeek",
@@ -425,50 +430,80 @@ export const usePlaySettings = (): SettingConfig => {
             ],
           },
           {
-            key: "enableAutomix",
-            label: "启用自动混音",
-            type: "switch",
+            key: "songTransitionMode",
+            label: "切歌过渡模式",
+            type: "select",
             tags: [{ text: "Beta", type: "warning" }],
             description: computed(() =>
               settingStore.playbackEngine === "web-audio"
-                ? "是否启用自动混音功能"
-                : "自动混音功能仅在使用 Web Audio 引擎时可用",
+                ? "选择歌曲切换时的过渡方式"
+                : "过渡模式仅在使用 Web Audio 引擎时可用",
             ),
+            options: computed(() => [
+              { label: "关闭", value: "off" },
+              {
+                label: "自动混音 (Auto Mix)",
+                value: "automix",
+                disabled: !isElectron,
+              },
+              {
+                label: "无缝播放 (Gapless)",
+                value: "gapless",
+                disabled: settingStore.audioEngine !== "element",
+              },
+            ]),
             value: computed({
-              get: () => settingStore.enableAutomix,
+              get: () => settingStore.songTransitionMode,
               set: (v) => {
-                if (v) {
+                if (v === "automix") {
                   window.$dialog.warning({
                     title: "启用自动混音 (Beta)",
                     content:
                       "可能出现兼容性问题，该功能在早期测试，遇到问题请反馈issue，不保证可以及时处理。效果可能因为歌曲而异，保守策略。",
                     positiveText: "开启",
                     negativeText: "取消",
                     onPositiveClick: () => {
-                      settingStore.enableAutomix = true;
+                      settingStore.songTransitionMode = "automix";
+                    },
+                  });
+                } else if (v === "gapless") {
+                  window.$dialog.warning({
+                    title: "启用无缝播放 (Beta)",
+                    content:
+                      "无缝播放会预解码下一首歌曲的音频数据，每首歌曲约占用 50-150MB 内存。如果设备内存较小，可能影响性能。该功能目前处于预览状态，有任何问题请提交 Issues。",
+                    positiveText: "开启",
+                    negativeText: "取消",
+                    onPositiveClick: () => {
+                      settingStore.songTransitionMode = "gapless";
                     },
                   });
                 } else {
-                  settingStore.enableAutomix = v;
+                  settingStore.songTransitionMode = v;
                 }
               },
             }),
             disabled: computed(() => settingStore.playbackEngine !== "web-audio"),
-            children: [
-              {
-                key: "automixMaxAnalyzeTime",
-                label: "最大分析时间",
-                type: "input-number",
-                description: "单位秒，越长越精准但更耗时 (建议 60s)",
-                min: 5,
-                max: 300,
-                suffix: "s",
-                value: computed({
-                  get: () => settingStore.automixMaxAnalyzeTime,
-                  set: (v) => (settingStore.automixMaxAnalyzeTime = v),
-                }),
-              },
-            ],
+            condition: () => settingStore.songTransitionMode !== "off",
+            children: computed(() => {
+              if (settingStore.songTransitionMode === "automix") {
+                return [
+                  {
+                    key: "automixMaxAnalyzeTime",
+                    label: "最大分析时间",
+                    type: "input-number" as const,
+                    description: "单位秒，越长越精准但更耗时 (建议 60s)",
+                    min: 5,
+                    max: 300,
+                    suffix: "s",
+                    value: computed({
+                      get: () => settingStore.automixMaxAnalyzeTime,
+                      set: (v: number) => (settingStore.automixMaxAnalyzeTime = v),
+                    }),
+                  },
+                ];
+              }
+              return [];
+            }),
           },
         ],
       },

src/core/audio-player/BaseAudioPlayer.ts

@@ -182,14 +182,20 @@ export abstract class BaseAudioPlayer
     }
 
     const duration = options.fadeIn ? (options.fadeDuration ?? 0.5) : 0;
+    const target = this.volume * this.replayGain;
 
-    // 修复：如果是渐入，强制从 0 开始
+    // 渐入时直接操作 gainNode，绕过 applyFadeTo 避免 cancelScheduledValues 取消刚设置的值
     if (duration > 0 && this.gainNode && this.audioCtx) {
-      this.gainNode.gain.setValueAtTime(0, this.audioCtx.currentTime);
+      const ct = this.audioCtx.currentTime;
+      this.gainNode.gain.cancelScheduledValues(ct);
+      this.gainNode.gain.setValueAtTime(0, ct);
+      const safeStart = ct + 0.02;
+      this.gainNode.gain.setValueAtTime(0, safeStart);
+      this.gainNode.gain.linearRampToValueAtTime(target, safeStart + duration);
+    } else {
+      this.applyFadeTo(target, 0);
     }
 
-    this.applyFadeTo(this.volume * this.replayGain, duration, options.fadeCurve);
-
     try {
       await this.doPlay();
     } catch (e) {
@@ -274,8 +280,8 @@ export abstract class BaseAudioPlayer
    */
   public stop() {
     this.cancelPendingPause();
-    // 捕获可能产生的异步错误
-    Promise.resolve(this.pause({ fadeOut: false })).catch(() => {});
+    // 使用 keepContextRunning 防止挂起共享 AudioContext
+    Promise.resolve(this.pause({ fadeOut: false, keepContextRunning: true })).catch(() => {});
     Promise.resolve(this.doSeek(0)).catch(() => {});
   }
 

src/core/automix/AutomixManager.ts

@@ -3,7 +3,7 @@ import { getSharedAudioContext } from "./SharedAudioContext";
 import { useAudioManager } from "../player/AudioManager";
 import { useSongManager } from "../player/SongManager";
 import { usePlayerController } from "../player/PlayerController";
-import { useDataStore, useMusicStore, useSettingStore, useStatusStore } from "@/stores";
+import { useMusicStore, useSettingStore, useStatusStore } from "@/stores";
 import type {
   AudioAnalysis,
   AutomixPlan,
@@ -1063,37 +1063,7 @@ export class AutomixManager {
   }
 
   public getNextSongForAutomix(): { song: SongType; index: number } | null {
-    const dataStore = useDataStore();
-    const statusStore = useStatusStore();
-    const playerController = usePlayerController();
-
-    if (dataStore.playList.length === 0) return null;
-
-    // 单曲循环模式下，下一首就是当前这首
-    if (statusStore.repeatMode === "one") {
-      const currentSong = dataStore.playList[statusStore.playIndex];
-      if (currentSong) {
-        return { song: currentSong, index: statusStore.playIndex };
-      }
-    }
-
-    if (dataStore.playList.length <= 1) return null;
-
-    let nextIndex = statusStore.playIndex;
-    let attempts = 0;
-    const maxAttempts = dataStore.playList.length;
-
-    while (attempts < maxAttempts) {
-      nextIndex++;
-      if (nextIndex >= dataStore.playList.length) nextIndex = 0;
-
-      const nextSong = dataStore.playList[nextIndex];
-      if (!playerController.shouldSkipSong(nextSong)) {
-        return { song: nextSong, index: nextIndex };
-      }
-      attempts++;
-    }
-    return null;
+    return usePlayerController().getNextSongInfo();
   }
 }