const ImType = {
  login: 0,
  keepAlive: 1,
  commonData: 2,
  logout: 3,
  recived: 4,
  responseLogin: 50,
  responseKeepAlive: 51,
  kickout: 54
}

export const ImTypeu = {
  text: 1,
  image: 2,
  file: 3,
  card: 4,
  recall: 5,
  read: 6,
  call: 8,
  group: 9
}

function frame(partial) {
  return {
    bridge: false,
    type: 0,
    dataContent: null,
    from: '-1',
    to: '-1',
    fp: null,
    QoS: false,
    typeu: -1,
    sm: Date.now(),
    ...partial
  }
}

function uuid() {
  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
    const r = (Math.random() * 16) | 0
    const v = c === 'x' ? r : (r & 0x3) | 0x8
    return v.toString(16)
  })
}

class ImClient {
  constructor() {
    this.userId = ''
    this.token = ''
    this.url = ''
    this._closed = true
    this._tries = 0
    this._alive = 0
    this._reconnect = 0
    this._handlers = {}
    this._bound = false
    this._opened = false
    this._ready = false
    this._queue = []
  }

  on(event, fn) {
    this._handlers[event] = fn
  }

  emit(event, payload) {
    const fn = this._handlers[event]
    if (fn) fn(payload)
  }

  connect({ userId, token, url }) {
    this._closed = false
    this.userId = userId
    this.token = token
    this.url = url
    this._open()
  }

  _bindSocket() {
    if (this._bound) return
    this._bound = true
    uni.onSocketOpen(() => {
      this._tries = 0
      this._opened = true
      this._send(frame({
        type: ImType.login,
        from: String(this.userId || ''),
        to: '0',
        dataContent: JSON.stringify({
          loginUserId: String(this.userId || ''),
          loginToken: this.token,
          extra: 'hbuilder-app',
          firstLoginTime: 0
        })
      }))
    })
    uni.onSocketMessage((res) => this._onMessage(res.data))
    uni.onSocketClose(() => {
      this._opened = false
      this._ready = false
      this._clearAlive()
      if (!this._closed) this._schedule()
    })
    uni.onSocketError(() => {
      if (!this._closed) this._schedule()
    })
  }

  _open() {
    this._clear()
    this.emit('status', 'reconnecting')
    this._bindSocket()
    uni.connectSocket({ url: this.url })
  }

  _onMessage(raw) {
    let p
    try {
      p = typeof raw === 'string' ? JSON.parse(raw) : raw
    } catch (_) {
      return
    }
    if (!p || typeof p !== 'object') return
    const type = p.type
    if (type === ImType.responseLogin) {
      let info = {}
      try {
        info = JSON.parse(p.dataContent || '{}')
      } catch (_) {}
      if (info.code === 0) {
        this._ready = true
        this.emit('status', 'connected')
        this._keep()
        this._flush()
      } else {
        this.emit('status', 'offline')
        this.emit('loginFailed', info)
      }
      return
    }
    if (type === ImType.responseKeepAlive) return
    if (type === ImType.kickout) {
      this._closed = true
      this.emit('kick')
      try { uni.closeSocket() } catch (_) {}
      return
    }
    if (type === ImType.recived) {
      this.emit('ack', p.fp || p.dataContent)
      return
    }
    if (type === ImType.commonData) {
      if (p.QoS && p.fp) {
        this._send(frame({
          type: ImType.recived,
          from: this.userId,
          to: '0',
          dataContent: p.fp,
          fp: p.fp
        }))
      }
      let data = {}
      try {
        const dc = p.dataContent
        data = typeof dc === 'string' ? JSON.parse(dc) : (dc || {})
      } catch (_) {
        data = { text: p.dataContent, kind: 'text' }
      }
      this.emit('data', { ...p, data, typeu: p.typeu || ImTypeu.text })
    }
  }

  sendData({ to, typeu, payload, qos = true }) {
    const fp = uuid()
    this._send(frame({
      type: ImType.commonData,
      from: String(this.userId || ''),
      to: String(to || ''),
      typeu,
      QoS: qos,
      fp,
      dataContent: JSON.stringify(payload)
    }))
    return fp
  }

  logout() {
    this._closed = true
    try {
      this._send(frame({ type: ImType.logout, from: this.userId, to: '0' }))
    } catch (_) {}
    try { uni.closeSocket() } catch (_) {}
    this._clear()
  }

  _send(p) {
    const raw = JSON.stringify(p)
    const ctrl = p.type === ImType.login || p.type === ImType.keepAlive || p.type === ImType.logout || p.type === ImType.recived
    if (!this._opened || (!this._ready && !ctrl)) {
      if (!ctrl) this._queue.push(raw)
      return
    }
    try {
      uni.sendSocketMessage({
        data: raw,
        fail: () => {
          if (!ctrl) this._queue.push(raw)
        }
      })
    } catch (_) {
      if (!ctrl) this._queue.push(raw)
    }
  }

  _flush() {
    const pending = this._queue.splice(0, this._queue.length)
    pending.forEach((raw) => {
      try { uni.sendSocketMessage({ data: raw }) } catch (_) {}
    })
  }

  _keep() {
    this._clearAlive()
    this._alive = setInterval(() => {
      this._send(frame({ type: ImType.keepAlive, from: this.userId, to: '0', dataContent: '{}' }))
    }, 5000)
  }

  _schedule() {
    this.emit('status', 'reconnecting')
    const wait = Math.min(15000, 800 * Math.pow(2, this._tries))
    this._tries += 1
    this._reconnect = setTimeout(() => this._open(), wait)
  }

  _clearAlive() {
    if (this._alive) {
      clearInterval(this._alive)
      this._alive = 0
    }
  }

  _clear() {
    this._clearAlive()
    if (this._reconnect) {
      clearTimeout(this._reconnect)
      this._reconnect = 0
    }
  }
}

export const imClient = new ImClient()