TTMusic/entry/src/main/ets/common/service/PlaylistModel.ets

import { VideoItem } from '../../viewmodel/VideoItem';
import { PlayMode } from './PlayerStateModel';
import { LogUtils } from '@ohos/ijkplayer';
import { ArrayUtil, RandomUtil } from '@pura/harmony-utils';

/**
 * 播放列表模型类
 * 管理播放列表和播放导航逻辑
 */
export class PlaylistModel {
  private songs: VideoItem[] = [];
  private currentIndex: number = 0;
  private playedIndices: Set<number> = new Set(); // 用于随机播放的历史记录
  private playHistory: VideoItem[] = []; // 播放历史记录

  constructor(songs: VideoItem[] = [], currentIndex: number = 0) {
    this.songs = [];
    for (const song of songs) {
      this.songs.push(song);
    }
    this.currentIndex = Math.max(0, Math.min(currentIndex, songs.length - 1));
    LogUtils.getInstance().LOGI(`PlaylistModel: Initialized with ${songs.length} songs, index ${this.currentIndex}`);
  }

  /**
   * 获取歌曲列表副本
   */
  getSongs(): VideoItem[] {
    const result: VideoItem[] = [];
    for (const song of this.songs) {
      result.push(song);
    }
    return result;
  }

  /**
   * 获取当前播放索引
   */
  getCurrentIndex(): number {
    return this.currentIndex;
  }

  /**
   * 设置当前播放索引
   */
  setCurrentIndex(index: number): boolean {
    if (index >= 0 && index < this.songs.length) {
      this.currentIndex = index;
      LogUtils.getInstance().LOGI(`PlaylistModel: Current index set to ${index}`);
      return true;
    }
    LogUtils.getInstance().LOGI(`PlaylistModel: Invalid index ${index}, playlist size: ${this.songs.length}`);
    return false;
  }

  /**
   * 获取当前播放的歌曲
   */
  getCurrentSong(): VideoItem | null {
    if (this.isEmpty() || this.currentIndex < 0 || this.currentIndex >= this.songs.length) {
      return null;
    }
    return this.songs[this.currentIndex];
  }

  /**
   * 获取总歌曲数量
   */
  getTotalCount(): number {
    return this.songs.length;
  }

  /**
   * 检查播放列表是否为空
   */
  isEmpty(): boolean {
    return this.songs.length === 0;
  }  
/**
   * 播放列表操作：添加歌曲
   */
  addSong(song: VideoItem, index?: number): void {
    if (index !== undefined && index >= 0 && index <= this.songs.length) {
      this.songs.splice(index, 0, song);
      // 如果插入位置在当前播放位置之前，需要调整当前索引
      if (index <= this.currentIndex) {
        this.currentIndex++;
      }
    } else {
      this.songs.push(song);
    }
    LogUtils.getInstance().LOGI(`PlaylistModel: Song added, total count: ${this.songs.length}`);
  }

  /**
   * 播放列表操作：添加多首歌曲
   */
  addSongs(songs: VideoItem[], index?: number): void {
    if (songs.length === 0) return;
    
    if (index !== undefined && index >= 0 && index <= this.songs.length) {
      for (let i = 0; i < songs.length; i++) {
        this.songs.splice(index + i, 0, songs[i]);
      }
      // 如果插入位置在当前播放位置之前，需要调整当前索引
      if (index <= this.currentIndex) {
        this.currentIndex += songs.length;
      }
    } else {
      for (const song of songs) {
        this.songs.push(song);
      }
    }
    LogUtils.getInstance().LOGI(`PlaylistModel: ${songs.length} songs added, total count: ${this.songs.length}`);
  }

  /**
   * 播放列表操作：移除歌曲
   */
  removeSong(index: number): VideoItem | null {
    if (index < 0 || index >= this.songs.length) {
      LogUtils.getInstance().LOGI(`PlaylistModel: Invalid remove index ${index}`);
      return null;
    }

    const removedSong = this.songs.splice(index, 1)[0];
    
    // 调整当前播放索引
    if (index < this.currentIndex) {
      this.currentIndex--;
    } else if (index === this.currentIndex) {
      // 如果删除的是当前播放的歌曲，保持索引不变（播放下一首）
      // 但如果删除的是最后一首，需要调整到前一首
      if (this.currentIndex >= this.songs.length && this.songs.length > 0) {
        this.currentIndex = this.songs.length - 1;
      }
    }
    
    LogUtils.getInstance().LOGI(`PlaylistModel: Song removed at index ${index}, total count: ${this.songs.length}`);
    return removedSong;
  }

  /**
   * 播放列表操作：移动歌曲
   */
  moveSong(fromIndex: number, toIndex: number): boolean {
    if (fromIndex < 0 || fromIndex >= this.songs.length || 
        toIndex < 0 || toIndex >= this.songs.length || 
        fromIndex === toIndex) {
      LogUtils.getInstance().LOGI(`PlaylistModel: Invalid move indices from ${fromIndex} to ${toIndex}`);
      return false;
    }

    const song = this.songs.splice(fromIndex, 1)[0];
    this.songs.splice(toIndex, 0, song);
    
    // 调整当前播放索引
    if (fromIndex === this.currentIndex) {
      this.currentIndex = toIndex;
    } else if (fromIndex < this.currentIndex && toIndex >= this.currentIndex) {
      this.currentIndex--;
    } else if (fromIndex > this.currentIndex && toIndex <= this.currentIndex) {
      this.currentIndex++;
    }
    
    LogUtils.getInstance().LOGI(`PlaylistModel: Song moved from ${fromIndex} to ${toIndex}`);
    return true;
  }  /**

   * 播放列表操作：清空播放列表
   */
  clear(): void {
    this.songs = [];
    this.currentIndex = 0;
    this.playedIndices.clear();
    this.playHistory = [];
    LogUtils.getInstance().LOGI('PlaylistModel: Playlist cleared');
  }

  /**
   * 播放列表操作：替换整个播放列表
   */
  replaceSongs(songs: VideoItem[], currentIndex: number = 0): void {
    // 记录调用栈信息以便调试
    const stack = new Error().stack || 'No stack available';
    const caller = stack.split('\n')[2] || 'Unknown caller';
    
    this.songs = [];
    for (const song of songs) {
      this.songs.push(song);
    }
    this.currentIndex = Math.max(0, Math.min(currentIndex, songs.length - 1));
    this.playedIndices.clear();
    this.playHistory = [];
    
    // 添加验证日志，包含调用源信息
    const currentSong = this.getCurrentSong();
    LogUtils.getInstance().LOGI(`PlaylistModel: Playlist replaced with ${songs.length} songs, index ${this.currentIndex}, current song: ${currentSong?.name || 'null'}, caller: ${caller.trim()}`);
    
    // 如果播放列表突然变小，记录更详细的信息
    if (songs.length <= 20) {
      LogUtils.getInstance().LOGI(`PlaylistModel: Small playlist detected (${songs.length} songs), caller stack: ${stack.substring(0, 500)}`);
      LogUtils.getInstance().LOGI(`PlaylistModel: First few songs: ${songs.slice(0, 5).map(s => s.name).join(', ')}`);
    }
    
    // 如果索引无效，记录警告
    if (currentIndex >= 0 && currentIndex < songs.length && this.currentIndex !== currentIndex) {
      LogUtils.getInstance().LOGI(`PlaylistModel: Warning - requested index ${currentIndex} adjusted to ${this.currentIndex}`);
    }
  }

  /**
   * 播放列表操作：随机打乱播放列表
   */
  shuffle(): void {
    if (this.songs.length <= 1) return;
    
    // 保存当前播放的歌曲
    const currentSong = this.getCurrentSong();
    
    // 打乱播放列表
    for (let i = this.songs.length - 1; i > 0; i--) {
      const j = Math.floor(Math.random() * (i + 1));
      const temp = this.songs[i];
      this.songs[i] = this.songs[j];
      this.songs[j] = temp;
    }
    
    // 重新找到当前播放歌曲的位置
    if (currentSong) {
      const newIndex = this.songs.findIndex(song => song.filePath === currentSong.filePath);
      if (newIndex !== -1) {
        this.currentIndex = newIndex;
      }
    }
    
    this.playedIndices.clear();
    LogUtils.getInstance().LOGI('PlaylistModel: Playlist shuffled');
  }

  /**
   * 导航操作：检查是否有下一首
   */
  hasNext(playMode: PlayMode = PlayMode.SEQUENCE): boolean {
    if (this.isEmpty()) return false;
    
    switch (playMode) {
      case PlayMode.SINGLE_REPEAT:
        return true; // 单曲循环总是有下一首（自己）
      case PlayMode.SEQUENCE:
        return this.currentIndex < this.songs.length - 1;
      case PlayMode.NORMAL:
        return this.currentIndex < this.songs.length - 1;
      case PlayMode.RANDOM:
        return this.playedIndices.size < this.songs.length; // 还有未播放的歌曲
      default:
        return false;
    }
  }

  /**
   * 导航操作：检查是否有上一首
   */
  hasPrevious(playMode: PlayMode = PlayMode.SEQUENCE): boolean {
    if (this.isEmpty()) return false;
    
    switch (playMode) {
      case PlayMode.SINGLE_REPEAT:
        return true; // 单曲循环总是有上一首（自己）
      case PlayMode.SEQUENCE:
        return this.currentIndex > 0;
      case PlayMode.NORMAL:
        return this.currentIndex > 0;
      case PlayMode.RANDOM:
        return this.playHistory.length > 1; // 有播放历史记录
      default:
        return false;
    }
  }  
/**
   * 导航操作：获取下一首歌曲
   */
  getNext(playMode: PlayMode = PlayMode.SEQUENCE): VideoItem | null {
    if (this.isEmpty()) return null;
    
    let nextIndex = this.currentIndex;
    
    switch (playMode) {
      case PlayMode.SINGLE_REPEAT:
        // 单曲循环，返回当前歌曲
        break;
      case PlayMode.SEQUENCE:
        // 顺序播放，循环到开头
        nextIndex = (this.currentIndex + 1) % this.songs.length;
        break;
      case PlayMode.NORMAL:
        // 正常播放，不循环
        if (this.currentIndex < this.songs.length - 1) {
          nextIndex = this.currentIndex + 1;
        } else {
          return null; // 已经是最后一首
        }
        break;
      case PlayMode.RANDOM:
        // 随机播放
        nextIndex = this.getRandomNextIndex();
        if (nextIndex === -1) return null;
        break;
    }
    
    return this.songs[nextIndex];
  }

  /**
   * 导航操作：获取上一首歌曲
   */
  getPrevious(playMode: PlayMode = PlayMode.SEQUENCE): VideoItem | null {
    if (this.isEmpty()) return null;
    
    let prevIndex = this.currentIndex;
    
    switch (playMode) {
      case PlayMode.SINGLE_REPEAT:
        // 单曲循环，返回当前歌曲
        break;
      case PlayMode.SEQUENCE:
        // 顺序播放，循环到末尾
        prevIndex = this.currentIndex === 0 ? this.songs.length - 1 : this.currentIndex - 1;
        break;
      case PlayMode.NORMAL:
        // 正常播放，不循环
        if (this.currentIndex > 0) {
          prevIndex = this.currentIndex - 1;
        } else {
          return null; // 已经是第一首
        }
        break;
      case PlayMode.RANDOM:
        // 随机播放，从历史记录获取
        return this.getRandomPrevious();
    }
    
    return this.songs[prevIndex];
  }

  /**
   * 导航操作：移动到下一首
   */
  moveToNext(playMode: PlayMode = PlayMode.SEQUENCE): boolean {
    if (this.isEmpty()) return false;
    
    let nextIndex = this.currentIndex;
    
    // 添加当前歌曲到播放历史（随机模式）
    const currentSong = this.getCurrentSong();
    if (currentSong && playMode === PlayMode.RANDOM) {
      this.addToPlayHistory(currentSong);
      this.playedIndices.add(this.currentIndex);
    }
    
    // 直接计算下一个索引，而不依赖getNext方法
    switch (playMode) {
      case PlayMode.SINGLE_REPEAT:
        // 单曲循环，索引不变
        LogUtils.getInstance().LOGI(`PlaylistModel: Single repeat mode, staying at index ${this.currentIndex}`);
        return true;
      case PlayMode.SEQUENCE:
        // 顺序播放，循环到开头
        nextIndex = (this.currentIndex + 1) % this.songs.length;
        break;
      case PlayMode.NORMAL:
        // 正常播放，不循环
        if (this.currentIndex < this.songs.length - 1) {
          nextIndex = this.currentIndex + 1;
        } else {
          LogUtils.getInstance().LOGI('PlaylistModel: Already at last song in normal mode');
          return false; // 已经是最后一首
        }
        break;
      case PlayMode.RANDOM:
        // 随机播放
        nextIndex = this.getRandomNextIndex();
        if (nextIndex === -1) {
          LogUtils.getInstance().LOGI('PlaylistModel: No available random song');
          return false;
        }
        break;
      default:
        return false;
    }
    
    // 更新索引
    if (nextIndex >= 0 && nextIndex < this.songs.length) {
      const oldIndex = this.currentIndex;
      this.currentIndex = nextIndex;
      LogUtils.getInstance().LOGI(`PlaylistModel: Moved to next song from index ${oldIndex} to ${this.currentIndex}`);
      return true;
    }
    
    return false;
  } 
 /**
   * 导航操作：移动到上一首
   */
  moveToPrevious(playMode: PlayMode = PlayMode.SEQUENCE): boolean {
    const prevSong = this.getPrevious(playMode);
    if (!prevSong) return false;
    
    // 更新索引
    const prevIndex = this.songs.findIndex(song => song.filePath === prevSong.filePath);
    if (prevIndex !== -1) {
      this.currentIndex = prevIndex;
      
      // 随机播放模式下，从历史记录中移除
      if (playMode === PlayMode.RANDOM && this.playHistory.length > 0) {
        this.playHistory.pop(); // 移除最后一个（当前播放的）
      }
      
      LogUtils.getInstance().LOGI(`PlaylistModel: Moved to previous song at index ${this.currentIndex}`);
      return true;
    }
    
    return false;
  }

  /**
   * 根据文件路径查找歌曲索引
   */
  findSongIndex(filePath: string): number {
    return this.songs.findIndex(song => song.filePath === filePath);
  }

  /**
   * 播放指定索引的歌曲
   */
  playSongAtIndex(index: number): boolean {
    if (index >= 0 && index < this.songs.length) {
      this.currentIndex = index;
      LogUtils.getInstance().LOGI(`PlaylistModel: Playing song at index ${index}`);
      return true;
    }
    LogUtils.getInstance().LOGI(`PlaylistModel: Invalid play index ${index}`);
    return false;
  }

  /**
   * 获取随机播放的下一个索引
   */
  private getRandomNextIndex(): number {
    const unplayedIndices: number[] = [];
    for (let i = 0; i < this.songs.length; i++) {
      if (!this.playedIndices.has(i)) {
        unplayedIndices.push(i);
      }
    }
    
    if (unplayedIndices.length === 0) {
      // 所有歌曲都播放过了，重置并重新开始
      this.playedIndices.clear();
      this.playHistory = [];
      for (let i = 0; i < this.songs.length; i++) {
        if (i !== this.currentIndex) {
          unplayedIndices.push(i);
        }
      }
    }
    
    if (unplayedIndices.length === 0) return -1;
    
    const randomIndex = Math.floor(Math.random() * unplayedIndices.length);
    return unplayedIndices[randomIndex];
  }

  /**
   * 获取随机播放模式下的上一首
   */
  private getRandomPrevious(): VideoItem | null {
    if (this.playHistory.length >= 2) {
      // 返回历史记录的第二首（第一首是当前播放的）
      return this.playHistory[this.playHistory.length - 2];
    }
    return null;
  }

  /**
   * 添加到播放历史记录
   */
  private addToPlayHistory(song: VideoItem): void {
    this.playHistory.push(song);
    // 限制历史记录长度，避免内存占用过多
    if (this.playHistory.length > 50) {
      this.playHistory.shift();
    }
  }

  /**
   * 获取播放历史记录
   */
  getPlayHistory(): VideoItem[] {
    const result: VideoItem[] = [];
    for (const item of this.playHistory) {
      result.push(item);
    }
    return result;
  }
}