/**
 * 工作流协作 Composable
 * 支持多人实时协作编辑工作流
 */
import { ref, onUnmounted } from 'vue'
import { ElMessage } from 'element-plus'
import { useUserStore } from '@/stores/user'
import api from '@/api'

export interface CollaborationUser {
  user_id: string
  username: string
  joined_at: string
  color: string
}

export interface CollaborationOperation {
  type: string
  user_id: string
  username: string
  data?: any
  timestamp?: string
}

export interface CollaborationMessage {
  type: string
  workflow_id?: string
  current_user?: CollaborationUser
  online_users?: CollaborationUser[]
  user?: CollaborationUser
  user_id?: string
  operation?: CollaborationOperation
  timestamp?: string
}

export function useCollaboration(workflowId: string) {
  const connected = ref<boolean>(false)
  const onlineUsers = ref<CollaborationUser[]>([])
  const currentUser = ref<CollaborationUser | null>(null)
  const ws = ref<WebSocket | null>(null)
  let heartbeatInterval: number | null = null
  let reconnectTimeout: number | null = null
  const reconnectAttempts = ref<number>(0)
  const maxReconnectAttempts = 5
  
  // 操作监听器
  type OperationHandler = (operation: CollaborationOperation) => void
  const operationHandlers = new Set<OperationHandler>()

  // 获取WebSocket URL
  const getWebSocketUrl = () => {
    const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:'
    const hostname = window.location.hostname
    const port = hostname === 'localhost' || hostname === '127.0.0.1' ? '8037' : '8037'
    const userStore = useUserStore()
    const token = userStore.token
    
    if (!token) {
      throw new Error('未登录，无法建立协作连接')
    }
    
    return `${protocol}//${hostname}:${port}/api/v1/collaboration/ws/workflows/${workflowId}?token=${token}`
  }

  // 连接WebSocket
  const connect = () => {
    if (ws.value && ws.value.readyState === WebSocket.OPEN) {
      return // 已经连接
    }

    const wsUrl = getWebSocketUrl()
    console.log('[协作] 连接中:', wsUrl)

    try {
      ws.value = new WebSocket(wsUrl)

      ws.value.onopen = () => {
        console.log('[协作] 连接已建立')
        connected.value = true
        reconnectAttempts.value = 0
        
        // 启动心跳
        startHeartbeat()
      }

      ws.value.onmessage = (event) => {
        try {
          const message: CollaborationMessage = JSON.parse(event.data)
          handleMessage(message)
        } catch (e) {
          console.error('[协作] 解析消息失败:', e)
        }
      }

      ws.value.onerror = (err) => {
        console.error('[协作] 错误:', err)
        connected.value = false
        ElMessage.error('协作连接错误')
      }

      ws.value.onclose = (event) => {
        console.log('[协作] 连接已关闭', event.code, event.reason)
        connected.value = false
        stopHeartbeat()
        
        // 如果不是正常关闭，尝试重连
        if (event.code !== 1000 && reconnectAttempts.value < maxReconnectAttempts) {
          reconnectAttempts.value++
          const delay = Math.min(1000 * Math.pow(2, reconnectAttempts.value), 30000)
          console.log(`[协作] ${delay}ms后尝试重连 (${reconnectAttempts.value}/${maxReconnectAttempts})`)
          
          reconnectTimeout = window.setTimeout(() => {
            connect()
          }, delay)
        }
      }
    } catch (err) {
      console.error('[协作] 连接失败:', err)
      ElMessage.error('协作连接失败')
    }
  }

  // 处理消息
  const handleMessage = (message: CollaborationMessage) => {
    console.log('[协作] 收到消息:', message)

    switch (message.type) {
      case 'collaboration_init':
        // 初始化消息
        if (message.current_user) {
          currentUser.value = message.current_user
        }
        if (message.online_users) {
          onlineUsers.value = message.online_users
        }
        break

      case 'user_joined':
        // 用户加入
        if (message.user) {
          onlineUsers.value.push(message.user)
          ElMessage.info(`${message.user.username} 加入了协作编辑`)
        }
        break

      case 'user_left':
        // 用户离开
        if (message.user_id) {
          onlineUsers.value = onlineUsers.value.filter(u => u.user_id !== message.user_id)
          const user = onlineUsers.value.find(u => u.user_id === message.user_id)
          if (user) {
            ElMessage.info(`${user.username} 离开了协作编辑`)
          }
        }
        break

      case 'operation':
        // 工作流操作
        if (message.operation) {
          // 触发所有注册的操作处理器
          operationHandlers.forEach(handler => {
            try {
              handler(message.operation!)
            } catch (e) {
              console.error('[协作] 操作处理器执行失败:', e)
            }
          })
          console.log('[协作] 收到操作:', message.operation)
        }
        break

      case 'pong':
        // 心跳响应
        break

      case 'error':
        ElMessage.error(message.message || '协作错误')
        break
    }
  }

  // 发送操作
  const sendOperation = (operation: Omit<CollaborationOperation, 'user_id' | 'username' | 'timestamp'>) => {
    if (!ws.value || ws.value.readyState !== WebSocket.OPEN) {
      console.warn('[协作] WebSocket未连接，无法发送操作')
      return
    }

    const fullOperation: CollaborationOperation = {
      ...operation,
      user_id: currentUser.value?.user_id || '',
      username: currentUser.value?.username || '',
      timestamp: new Date().toISOString()
    }

    const message = {
      type: 'operation',
      operation: fullOperation
    }

    try {
      ws.value.send(JSON.stringify(message))
    } catch (e) {
      console.error('[协作] 发送操作失败:', e)
    }
  }

  // 启动心跳
  const startHeartbeat = () => {
    heartbeatInterval = window.setInterval(() => {
      if (ws.value && ws.value.readyState === WebSocket.OPEN) {
        ws.value.send(JSON.stringify({ type: 'ping' }))
      }
    }, 30000) // 每30秒发送一次心跳
  }

  // 停止心跳
  const stopHeartbeat = () => {
    if (heartbeatInterval) {
      clearInterval(heartbeatInterval)
      heartbeatInterval = null
    }
    if (reconnectTimeout) {
      clearTimeout(reconnectTimeout)
      reconnectTimeout = null
    }
  }

  // 断开连接
  const disconnect = () => {
    stopHeartbeat()
    if (ws.value) {
      ws.value.close(1000, '正常关闭')
      ws.value = null
    }
    connected.value = false
    onlineUsers.value = []
    currentUser.value = null
  }

  // 获取在线用户列表
  const fetchOnlineUsers = async () => {
    try {
      const response = await api.get(`/api/v1/collaboration/workflows/${workflowId}/users`)
      if (response.data.online_users) {
        onlineUsers.value = response.data.online_users
      }
    } catch (e) {
      console.error('[协作] 获取在线用户失败:', e)
    }
  }

  // 注册操作监听器
  const onOperation = (handler: OperationHandler) => {
    operationHandlers.add(handler)
    // 返回取消注册函数
    return () => {
      operationHandlers.delete(handler)
    }
  }

  // 取消注册操作监听器
  const offOperation = (handler: OperationHandler) => {
    operationHandlers.delete(handler)
  }

  // 清理
  onUnmounted(() => {
    disconnect()
    operationHandlers.clear()
  })

  return {
    connected,
    onlineUsers,
    currentUser,
    connect,
    disconnect,
    sendOperation,
    fetchOnlineUsers,
    onOperation,
    offOperation
  }
}