// 🚀 真正的流式音频播放器 - 使用Web Audio API解码OGG
// 解决OGG容器格式无法分段播放的问题

export interface AudioPlayerConfig {
  onPlay?: () => void
  onEnded?: () => void
  onError?: (error: Error) => void
}

export class StreamingAudioPlayer {
  private audioChunks: ArrayBuffer[] = []
  private playing = false
  private audioContext: AudioContext | null = null
  private gainNode: GainNode | null = null
  private config: AudioPlayerConfig
  private audioReady = false
  private currentSource: AudioBufferSourceNode | null = null
  private playQueue: AudioBuffer[] = [] // 已解码的音频队列
  private isDecoding = false
  private allChunksReceived = false
  private lastPlayTime = 0 // 上次播放的结束时间
  private startTime = 0 // 开始播放的时间戳
  private lastDecodedDuration = 0 // 上次解码的总时长（用于计算增量）
  private decodedChunksCount = 0 // 已解码的块数
  private hasEnded = false // 防止多次触发 onEnded
  private activeSources = 0 // 正在播放的音频源数量
  
  constructor(config: AudioPlayerConfig = {}) {
    this.config = config
  }

  async init(): Promise<void> {
    console.log('🎵 初始化流式音频播放器（Web Audio API）')
    return Promise.resolve()
  }

  /**
   * 在用户交互时调用此方法，激活AudioContext
   */
  prepareForPlayback() {
    if (this.audioReady && this.audioContext?.state === 'running') {
      console.log('🎯 AudioContext已激活且运行中，跳过重复激活')
      return
    }
    
    console.log('🎯 在用户交互中激活AudioContext（解决Safari自动播放限制）')
    
    try {
      // 如果AudioContext不存在，创建新的
      if (!this.audioContext) {
        const AudioContextClass = window.AudioContext || (window as any).webkitAudioContext
        this.audioContext = new AudioContextClass()
        
        // 创建增益节点（音量放大器）
        this.gainNode = this.audioContext.createGain()
        this.gainNode.gain.value = 4.5 // 4.5倍音量增益
        console.log('🔊 音频增益设置为:', this.gainNode.gain.value, '倍')
        
        // 连接到输出
        this.gainNode.connect(this.audioContext.destination)
      }
      
      // 激活AudioContext（Safari需要用户交互）
      if (this.audioContext.state === 'suspended') {
        this.audioContext.resume().then(() => {
          console.log('✅ AudioContext已恢复，状态:', this.audioContext?.state)
          this.audioReady = true
        })
      } else if (this.audioContext.state === 'running') {
        console.log('✅ AudioContext运行中，状态:', this.audioContext.state)
        this.audioReady = true
      } else {
        console.warn('⚠️ AudioContext状态异常:', this.audioContext.state)
      }
    } catch (error) {
      console.error('❌ AudioContext初始化失败:', error)
    }
  }

  /**
   * 确保AudioContext处于运行状态并验证音量增益
   * 🔑 关键：在每次播放前调用，防止移动端AudioContext被挂起导致无声或音量小
   */
  private async ensureAudioContextReady(): Promise<boolean> {
    if (!this.audioContext || !this.gainNode) {
      console.error('❌ AudioContext或GainNode未初始化')
      return false
    }

    // 检查AudioContext状态
    const currentState = this.audioContext.state
    console.log(`🔍 AudioContext状态检查: ${currentState}`)
    
    if (currentState === 'suspended') {
      console.warn('⚠️ AudioContext被挂起，尝试恢复...')
      try {
        await this.audioContext.resume()
        console.log('✅ AudioContext已恢复:', this.audioContext.state)
      } catch (error) {
        console.error('❌ AudioContext恢复失败:', error)
        return false
      }
    } else if (currentState === 'closed') {
      console.error('❌ AudioContext已关闭，需要重新初始化')
      return false
    }

    // 验证并恢复音量增益
    const currentGain = this.gainNode.gain.value
    const targetGain = 4.5
    
    if (Math.abs(currentGain - targetGain) > 0.1) {
      console.warn(`⚠️ 音量增益异常 (当前: ${currentGain}, 目标: ${targetGain})，正在恢复...`)
      this.gainNode.gain.value = targetGain
      console.log(`✅ 音量增益已恢复为: ${targetGain}倍`)
    } else {
      console.log(`✅ 音量增益正常: ${currentGain}倍`)
    }

    return true
  }

  appendAudioChunk(chunk: ArrayBuffer) {
    const totalChunks = this.audioChunks.length + 1
    console.log(`📦 收集音频块: ${chunk.byteLength} bytes (总计: ${totalChunks} 块)`)
    
    // 收集音频块
    this.audioChunks.push(chunk)
    
    // 🚀 流式解码策略：收到3个块就开始解码并播放
    if (totalChunks === 1) {
      console.log('🎵 AI开始生成语音，等待音频块...')
    } else if (totalChunks === 3 && !this.playing) {
      console.log('⚡ 收到3个音频块，开始流式播放！')
      this.startStreamingPlayback()
    } else if (totalChunks > 3) {
      // 继续解码新块
      this.decodeAndQueue()
    }
  }

  /**
   * 开始流式播放
   */
  private async startStreamingPlayback() {
    if (!this.audioContext || !this.gainNode) {
      console.error('❌ AudioContext未初始化')
      return
    }

    // 🔑 关键：每次播放前都检查并恢复AudioContext状态
    const isReady = await this.ensureAudioContextReady()
    if (!isReady) {
      console.error('❌ AudioContext未就绪，无法开始播放')
      this.config.onError?.(new Error('音频环境未就绪'))
      return
    }

    this.playing = true
    this.startTime = this.audioContext.currentTime
    this.lastPlayTime = this.startTime
    
    // 触发onPlay回调
    this.config.onPlay?.()
    
    // 开始解码并排队播放
    await this.decodeAndQueue()
  }

  /**
   * 解码音频块并加入播放队列
   * 🔑 关键：每次都解码所有已收到的块（OGG需要完整上下文），但只播放新增部分
   */
  private async decodeAndQueue() {
    if (this.isDecoding || !this.audioContext) {
      return
    }

    // 检查是否有新块需要解码
    if (this.audioChunks.length === this.decodedChunksCount) {
      console.log('⏭️ 没有新的音频块，跳过解码')
      return
    }

    this.isDecoding = true

    try {
      // ⭐ 关键：合并所有已收到的块（包括之前的），保证OGG编码上下文完整
      const totalLength = this.audioChunks.reduce((sum, chunk) => sum + chunk.byteLength, 0)
      const combined = new Uint8Array(totalLength)
      let offset = 0
      
      for (const chunk of this.audioChunks) {
        combined.set(new Uint8Array(chunk), offset)
        offset += chunk.byteLength
      }
      
      console.log(`🔄 累积解码: ${totalLength} bytes (${this.audioChunks.length} 块, 新增 ${this.audioChunks.length - this.decodedChunksCount} 块)`)
      
      // 使用Web Audio API解码完整的OGG数据
      const fullAudioBuffer = await this.audioContext.decodeAudioData(combined.buffer.slice(0))
      
      console.log(`✅ 解码成功: ${fullAudioBuffer.duration.toFixed(2)}秒 (总时长), 新增: ${(fullAudioBuffer.duration - this.lastDecodedDuration).toFixed(2)}秒`)
      
      // 只播放新增的部分
      this.playIncrementalAudio(fullAudioBuffer, this.lastDecodedDuration)
      
      // 更新已解码的信息
      this.lastDecodedDuration = fullAudioBuffer.duration
      this.decodedChunksCount = this.audioChunks.length
      
    } catch (error) {
      console.error('❌ 音频解码失败:', error)
      
      // 如果是部分数据解码失败，等待更多数据
      if (!this.allChunksReceived) {
        console.log('⏳ 等待更多音频数据...')
      } else {
        this.config.onError?.(new Error('音频解码失败'))
      }
    } finally {
      this.isDecoding = false
      
      // 🔑 关键修复：解码完成后，检查是否还有新的音频块需要解码
      // 这样可以处理在解码过程中新到达的音频块
      if (this.audioChunks.length > this.decodedChunksCount) {
        console.log(`🔄 检测到 ${this.audioChunks.length - this.decodedChunksCount} 个未解码的块，继续解码...`)
        // 使用 setTimeout 避免递归调用栈过深
        setTimeout(() => this.decodeAndQueue(), 0)
      }
    }
  }

  /**
   * 播放增量音频（只播放新增的部分）
   * @param fullBuffer 完整的音频缓冲（包含之前的+新增的）
   * @param offsetTime 从哪个时间点开始播放（跳过已播放的部分）
   */
  private playIncrementalAudio(fullBuffer: AudioBuffer, offsetTime: number) {
    if (!this.audioContext || !this.gainNode) {
      console.error('❌ AudioContext未初始化')
      return
    }

    // 计算新增音频的时长
    const newDuration = fullBuffer.duration - offsetTime
    
    if (newDuration <= 0) {
      console.log('⏭️ 没有新的音频需要播放')
      return
    }

    // 🔑 关键：确保AudioContext处于运行状态（同步检查）
    if (this.audioContext.state === 'suspended') {
      console.warn('⚠️ AudioContext被挂起，尝试快速恢复...')
      this.audioContext.resume().then(() => {
        console.log('✅ AudioContext已快速恢复')
      }).catch((error) => {
        console.error('❌ AudioContext恢复失败:', error)
      })
    }

    // 验证音量增益（同步）
    const currentGain = this.gainNode.gain.value
    if (currentGain < 4.0) {
      console.warn(`⚠️ 播放前检测到音量过低 (${currentGain})，恢复至4.5`)
      this.gainNode.gain.value = 4.5
    }

    // 创建音频源节点
    const source = this.audioContext.createBufferSource()
    source.buffer = fullBuffer
    
    // 连接到增益节点
    source.connect(this.gainNode)
    
    // 计算播放时间（紧接着上一段）
    const playTime = Math.max(this.lastPlayTime, this.audioContext.currentTime)
    
    // 增加活跃音频源计数
    this.activeSources++
    console.log(`🎵 播放增量音频: ${newDuration.toFixed(2)}秒 (跳过前${offsetTime.toFixed(2)}秒), 延迟: ${((playTime - this.audioContext.currentTime) * 1000).toFixed(0)}ms, 活跃源: ${this.activeSources}`)
    
    // 设置结束回调
    source.onended = () => {
      // 减少活跃音频源计数
      this.activeSources--
      console.log(`🎵 音频段播放完成 (剩余活跃源: ${this.activeSources})`)
      
      // 检查是否还有未解码的数据
      const hasNewChunks = this.audioChunks.length > this.decodedChunksCount
      
      if (hasNewChunks) {
        console.log(`🔄 继续解码新的 ${this.audioChunks.length - this.decodedChunksCount} 个块`)
        this.decodeAndQueue()
      } else if (this.allChunksReceived && this.activeSources === 0 && !this.hasEnded) {
        // ⭐ 关键：所有块已接收 + 所有音频源都播放完成 + 未触发过结束
        console.log('✅ 所有音频播放完成 - 触发 onEnded 回调')
        this.playing = false
        this.hasEnded = true // 标记已结束，防止重复触发
        this.config.onEnded?.()
      } else if (this.hasEnded) {
        console.log('⏭️ 已触发过 onEnded，跳过重复调用')
      } else if (this.activeSources > 0) {
        console.log(`⏳ 还有 ${this.activeSources} 个音频源在播放...`)
      } else {
        console.log('⏳ 等待更多音频块...')
      }
    }
    
    // ⭐ 关键：使用offset参数跳过已播放的部分，只播放新增部分
    // start(when, offset, duration)
    source.start(playTime, offsetTime, newDuration)
    this.currentSource = source
    
    // 更新下次播放时间
    this.lastPlayTime = playTime + newDuration
  }

  async play() {
    console.log(`🎵 play()被调用 (ai_response_end) - 音频块数: ${this.audioChunks.length}, 播放状态: ${this.playing ? '播放中' : '空闲'}`)
    
    // 🔑 关键：每次播放前都检查并恢复AudioContext状态
    if (this.audioContext && this.gainNode) {
      const isReady = await this.ensureAudioContextReady()
      if (!isReady) {
        console.error('❌ AudioContext未就绪，播放可能失败')
      }
    }
    
    // 标记所有音频块已接收完毕
    this.allChunksReceived = true
    
    // 如果还没开始播放，立即开始
    if (!this.playing && this.audioChunks.length > 0) {
      console.log('⚡ 开始播放所有音频')
      await this.startStreamingPlayback()
    } else if (this.playing && this.audioChunks.length > 0) {
      // 已经在播放，解码剩余的块
      console.log('🔄 继续解码剩余音频块')
      await this.decodeAndQueue()
    } else if (!this.playing && this.audioChunks.length === 0) {
      console.log('⚠️ 没有音频数据可播放')
    }
  }

  pause() {
    if (this.currentSource) {
      this.currentSource.stop()
      this.currentSource = null
    }
    this.playing = false
  }

  stop() {
    console.log('🛑 停止播放')
    
    if (this.currentSource) {
      try {
        this.currentSource.stop()
      } catch (e) {
        // 忽略已经停止的错误
      }
      this.currentSource = null
    }
    
    this.playing = false
    // 注意：不重置 activeSources，让 onended 自然触发递减
  }

  clear() {
    const chunksCount = this.audioChunks.length
    console.log(`🧹 清理播放器状态 - 丢弃 ${chunksCount} 个音频块`)
    
    this.stop()
    this.audioChunks = []
    this.playQueue = []
    this.allChunksReceived = false
    this.lastPlayTime = 0
    this.startTime = 0
    this.lastDecodedDuration = 0
    this.decodedChunksCount = 0
    this.hasEnded = false // 重置结束标志
    this.activeSources = 0 // 重置活跃音频源计数
  }

  destroy() {
    this.stop()
    this.audioChunks = []
    this.playQueue = []
    
    if (this.audioContext) {
      this.audioContext.close().catch((err) => {
        console.warn('AudioContext关闭失败:', err)
      })
      this.audioContext = null
    }
    
    this.gainNode = null
    this.audioReady = false
  }

  isPlaying(): boolean {
    return this.playing
  }

  getCurrentTime(): number {
    if (!this.audioContext || !this.playing) {
      return 0
    }
    return this.audioContext.currentTime - this.startTime
  }

  getBufferedProgress(): number {
    return this.audioChunks.length
  }

  /**
   * 设置音量增益倍数
   */
  setGain(gain: number) {
    if (this.gainNode) {
      const clampedGain = Math.max(0.5, Math.min(5.0, gain))
      this.gainNode.gain.value = clampedGain
      console.log('🔊 音量增益已调整为:', clampedGain, '倍')
    } else {
      console.warn('⚠️ GainNode未初始化，无法调整增益')
    }
  }

  getGain(): number {
    return this.gainNode?.gain.value || 1.0
  }
}