class ChatService {
  constructor() {
    this.ws = null
    this.listeners = []
    this.reconnectTimer = null
    this.connected = false
    this.connecting = false
    this.pendingMessages = []
  }

  connect() {
    if (this.ws && this.ws.readyState === WebSocket.OPEN) return
    if (this.connecting) return
    
    this.connecting = true
    var token = localStorage.getItem('token')
    
    if (!token) {
      this.connecting = false
      return
    }
    
    var protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:'
    var host = window.location.host
    var wsUrl = protocol + '//' + host + '/ws/chat?token=' + token
    
    try {
      this.ws = new WebSocket(wsUrl)
    } catch (e) {
      this.connecting = false
      return
    }
    
    var self = this
    
    this.ws.onopen = function() {
      self.connected = true
      self.connecting = false
      clearTimeout(self.reconnectTimer)
      self.pendingMessages.forEach(function(msg) {
        self.ws.send(JSON.stringify(msg))
      })
      self.pendingMessages = []
    }

    this.ws.onmessage = function(event) {
      try {
        var data = JSON.parse(event.data)
        self.listeners.forEach(function(cb) {
          cb(data)
        })
      } catch (e) {}
    }

    this.ws.onclose = function() {
      self.connected = false
      self.connecting = false
      self.reconnectTimer = setTimeout(function() {
        self.connect()
      }, 3000)
    }

    this.ws.onerror = function() {}
  }

  send(data) {
    if (this.ws && this.ws.readyState === WebSocket.CONNECTING) {
      this.pendingMessages.push(data)
      return true
    }
    
    if (this.ws && this.ws.readyState === WebSocket.OPEN) {
      this.ws.send(JSON.stringify(data))
      return true
    }
    
    this.pendingMessages.push(data)
    this.connect()
    return true
  }

  onMessage(callback) {
    var self = this
    this.listeners.push(callback)
    return function() {
      self.listeners = self.listeners.filter(function(cb) {
        return cb !== callback
      })
    }
  }

  disconnect() {
    clearTimeout(this.reconnectTimer)
    if (this.ws) {
      this.ws.close()
      this.ws = null
    }
    this.connected = false
    this.connecting = false
    this.pendingMessages = []
  }
}

var chatService = new ChatService()
export { chatService }