/**
 * 语音通话组合式函数
 * 
 * 功能：
 * - 整合 WebRTC 管理和信令服务
 * - 管理通话状态
 * - 处理语音转文字
 */
import { ref, computed, onUnmounted } from 'vue'
import { ElMessage } from 'element-plus'
import { WebRTCManager, createWebRTCManager, type ConnectionState } from '@/utils/webrtc'
import request from '@/api/request'

export type VoiceCallState = 'idle' | 'requesting' | 'ringing' | 'connecting' | 'connected' | 'ended'

export interface UseVoiceCallOptions {
  roomCode: string
  onTranscript?: (text: string, isFinal: boolean) => void
  onRemoteTranscript?: (text: string) => void
}

export function useVoiceCall(options: UseVoiceCallOptions) {
  const { roomCode, onTranscript, onRemoteTranscript } = options

  // ==================== 状态 ====================
  const callState = ref<VoiceCallState>('idle')
  const connectionState = ref<ConnectionState>('idle')
  const isMuted = ref(false)
  const isRemoteMuted = ref(false)
  const localAudioLevel = ref(0)
  const remoteAudioLevel = ref(0)
  const callDuration = ref(0)
  const errorMessage = ref<string | null>(null)

  // 语音识别相关
  const isTranscribing = ref(false)
  const currentTranscript = ref('')

  // 内部状态
  let webrtcManager: WebRTCManager | null = null
  let recognition: any = null // SpeechRecognition
  let callTimer: number | null = null
  let audioLevelTimer: number | null = null

  // ==================== 计算属性 ====================
  const isCallActive = computed(() => 
    ['requesting', 'ringing', 'connecting', 'connected'].includes(callState.value)
  )

  const canStartCall = computed(() => callState.value === 'idle')
  const canEndCall = computed(() => isCallActive.value)

  // ==================== 信令 API ====================
  
  async function sendSignal(signalType: string, payload: any) {
    try {
      await request.post(`/api/v1/practice/rooms/${roomCode}/signal`, {
        signal_type: signalType,
        payload
      })
    } catch (error) {
      console.error('[VoiceCall] 发送信令失败:', error)
      throw error
    }
  }

  // ==================== 通话控制 ====================

  /**
   * 发起语音通话
   */
  async function startCall() {
    if (!canStartCall.value) {
      console.warn('[VoiceCall] 无法发起通话，当前状态:', callState.value)
      return
    }

    try {
      callState.value = 'requesting'
      errorMessage.value = null

      // 创建 WebRTC 管理器
      webrtcManager = createWebRTCManager({
        onConnectionStateChange: handleConnectionStateChange,
        onIceCandidate: handleIceCandidate,
        onRemoteStream: handleRemoteStream,
        onError: handleError
      })

      // 创建 Offer
      const offer = await webrtcManager.createOffer()

      // 发送开始信令
      await sendSignal('voice_start', {})

      // 发送 Offer
      await sendSignal('voice_offer', {
        type: offer.type,
        sdp: offer.sdp
      })

      callState.value = 'ringing'
      ElMessage.info('正在呼叫对方...')

    } catch (error: any) {
      console.error('[VoiceCall] 发起通话失败:', error)
      errorMessage.value = error.message || '发起通话失败'
      callState.value = 'idle'
      webrtcManager?.close()
      webrtcManager = null
      ElMessage.error(errorMessage.value)
    }
  }

  /**
   * 接听语音通话
   */
  async function answerCall(offer: RTCSessionDescriptionInit) {
    try {
      callState.value = 'connecting'
      errorMessage.value = null

      // 创建 WebRTC 管理器
      webrtcManager = createWebRTCManager({
        onConnectionStateChange: handleConnectionStateChange,
        onIceCandidate: handleIceCandidate,
        onRemoteStream: handleRemoteStream,
        onError: handleError
      })

      // 处理 Offer 并创建 Answer
      const answer = await webrtcManager.handleOffer(offer)

      // 发送 Answer
      await sendSignal('voice_answer', {
        type: answer.type,
        sdp: answer.sdp
      })

      ElMessage.success('已接听通话')

    } catch (error: any) {
      console.error('[VoiceCall] 接听通话失败:', error)
      errorMessage.value = error.message || '接听通话失败'
      callState.value = 'idle'
      webrtcManager?.close()
      webrtcManager = null
      ElMessage.error(errorMessage.value)
    }
  }

  /**
   * 拒绝来电
   */
  async function rejectCall() {
    try {
      await sendSignal('voice_end', { reason: 'rejected' })
      callState.value = 'idle'
    } catch (error) {
      console.error('[VoiceCall] 拒绝通话失败:', error)
    }
  }

  /**
   * 结束通话
   */
  async function endCall() {
    try {
      await sendSignal('voice_end', { reason: 'ended' })
    } catch (error) {
      console.error('[VoiceCall] 发送结束信令失败:', error)
    }

    cleanup()
    callState.value = 'ended'

    // 延迟恢复到 idle 状态
    setTimeout(() => {
      callState.value = 'idle'
    }, 1000)
  }

  /**
   * 切换静音
   */
  function toggleMute() {
    if (webrtcManager) {
      isMuted.value = !isMuted.value
      webrtcManager.setMuted(isMuted.value)
    }
  }

  // ==================== 信令处理 ====================

  /**
   * 处理接收到的信令消息
   */
  async function handleSignal(signalType: string, payload: any, fromUserId: number) {
    console.log('[VoiceCall] 收到信令:', signalType)

    switch (signalType) {
      case 'voice_start':
        // 收到通话请求
        if (callState.value === 'idle') {
          callState.value = 'ringing'
          ElMessage.info('收到语音通话请求')
        }
        break

      case 'voice_offer':
        // 收到 Offer，自动接听
        if (callState.value === 'ringing' || callState.value === 'idle') {
          await answerCall({
            type: payload.type,
            sdp: payload.sdp
          })
        }
        break

      case 'voice_answer':
        // 收到 Answer
        if (webrtcManager && callState.value === 'ringing') {
          await webrtcManager.handleAnswer({
            type: payload.type,
            sdp: payload.sdp
          })
        }
        break

      case 'ice_candidate':
        // 收到 ICE 候选
        if (webrtcManager && payload.candidate) {
          await webrtcManager.addIceCandidate(payload)
        }
        break

      case 'voice_end':
        // 对方结束通话
        cleanup()
        callState.value = 'ended'
        ElMessage.info('通话已结束')
        setTimeout(() => {
          callState.value = 'idle'
        }, 1000)
        break
    }
  }

  // ==================== WebRTC 回调 ====================

  function handleConnectionStateChange(state: ConnectionState) {
    connectionState.value = state
    
    if (state === 'connected') {
      callState.value = 'connected'
      startCallTimer()
      startAudioLevelMonitor()
      startSpeechRecognition()
      ElMessage.success('语音通话已连接')
    } else if (state === 'failed' || state === 'disconnected') {
      if (callState.value === 'connected') {
        ElMessage.warning('通话连接断开')
      }
    }
  }

  async function handleIceCandidate(candidate: RTCIceCandidate) {
    try {
      await sendSignal('ice_candidate', candidate.toJSON())
    } catch (error) {
      console.error('[VoiceCall] 发送 ICE 候选失败:', error)
    }
  }

  function handleRemoteStream(stream: MediaStream) {
    console.log('[VoiceCall] 收到远程音频流')
    
    // 播放远程音频
    const audio = new Audio()
    audio.srcObject = stream
    audio.play().catch(e => console.error('[VoiceCall] 播放远程音频失败:', e))
  }

  function handleError(error: Error) {
    console.error('[VoiceCall] WebRTC 错误:', error)
    errorMessage.value = error.message
  }

  // ==================== 语音识别 ====================

  function startSpeechRecognition() {
    // 检查浏览器支持
    const SpeechRecognition = (window as any).SpeechRecognition || (window as any).webkitSpeechRecognition
    
    if (!SpeechRecognition) {
      console.warn('[VoiceCall] 浏览器不支持语音识别')
      return
    }

    recognition = new SpeechRecognition()
    recognition.continuous = true
    recognition.interimResults = true
    recognition.lang = 'zh-CN'

    recognition.onstart = () => {
      isTranscribing.value = true
      console.log('[VoiceCall] 语音识别已启动')
    }

    recognition.onresult = (event: any) => {
      let interimTranscript = ''
      let finalTranscript = ''

      for (let i = event.resultIndex; i < event.results.length; i++) {
        const transcript = event.results[i][0].transcript
        if (event.results[i].isFinal) {
          finalTranscript += transcript
        } else {
          interimTranscript += transcript
        }
      }

      currentTranscript.value = interimTranscript || finalTranscript
      
      if (finalTranscript) {
        onTranscript?.(finalTranscript, true)
      } else if (interimTranscript) {
        onTranscript?.(interimTranscript, false)
      }
    }

    recognition.onerror = (event: any) => {
      console.error('[VoiceCall] 语音识别错误:', event.error)
      if (event.error !== 'no-speech') {
        isTranscribing.value = false
      }
    }

    recognition.onend = () => {
      // 如果通话还在进行，重新启动识别
      if (callState.value === 'connected' && !isMuted.value) {
        recognition.start()
      } else {
        isTranscribing.value = false
      }
    }

    try {
      recognition.start()
    } catch (error) {
      console.error('[VoiceCall] 启动语音识别失败:', error)
    }
  }

  function stopSpeechRecognition() {
    if (recognition) {
      recognition.stop()
      recognition = null
    }
    isTranscribing.value = false
  }

  // ==================== 辅助功能 ====================

  function startCallTimer() {
    callDuration.value = 0
    callTimer = window.setInterval(() => {
      callDuration.value++
    }, 1000)
  }

  function stopCallTimer() {
    if (callTimer) {
      clearInterval(callTimer)
      callTimer = null
    }
  }

  function startAudioLevelMonitor() {
    audioLevelTimer = window.setInterval(async () => {
      if (webrtcManager) {
        const localStream = webrtcManager.getLocalStream()
        const remoteStream = webrtcManager.getRemoteStream()

        if (localStream) {
          localAudioLevel.value = await webrtcManager.getAudioLevel(localStream)
        }
        if (remoteStream) {
          remoteAudioLevel.value = await webrtcManager.getAudioLevel(remoteStream)
        }
      }
    }, 100)
  }

  function stopAudioLevelMonitor() {
    if (audioLevelTimer) {
      clearInterval(audioLevelTimer)
      audioLevelTimer = null
    }
  }

  function formatDuration(seconds: number): string {
    const mins = Math.floor(seconds / 60)
    const secs = seconds % 60
    return `${mins.toString().padStart(2, '0')}:${secs.toString().padStart(2, '0')}`
  }

  // ==================== 清理 ====================

  function cleanup() {
    stopCallTimer()
    stopAudioLevelMonitor()
    stopSpeechRecognition()
    
    webrtcManager?.close()
    webrtcManager = null

    isMuted.value = false
    isRemoteMuted.value = false
    localAudioLevel.value = 0
    remoteAudioLevel.value = 0
    currentTranscript.value = ''
  }

  // 组件卸载时清理
  onUnmounted(() => {
    if (isCallActive.value) {
      endCall()
    }
    cleanup()
  })

  // ==================== 返回 ====================

  return {
    // 状态
    callState,
    connectionState,
    isMuted,
    isRemoteMuted,
    localAudioLevel,
    remoteAudioLevel,
    callDuration,
    errorMessage,
    isTranscribing,
    currentTranscript,

    // 计算属性
    isCallActive,
    canStartCall,
    canEndCall,

    // 方法
    startCall,
    answerCall,
    rejectCall,
    endCall,
    toggleMute,
    handleSignal,
    formatDuration
  }
}