/**
 *
 * Wechaty: Wechat for ChatBots.
 *
 * Class WechatyEvent
 *
 * Licenst: ISC
 * https://github.com/wechaty/wechaty
 *
 */
/**************************************
 *
 * Events Function Wrapper
 *
 *
 ***************************************/
import Config  import './config'
import Contact import './contact'
import Message import './message'
// import Room    import './room'

import log     import './brolog-env'

const WechatyEvent = {
  list
  , wrap
}

const EVENT_CONFIG = {
  error:          wrapFilehelper
  , friend:       wrapContact
  , heartbeat:    wrapFilehelper
  , login:        wrapFilehelper
  , logout:       null  // NULL
  , message:      wrapMessage
  , 'room-join':  wrapRoom
  , 'room-leave': wrapRoom
  , 'room-topic': wrapRoom
  , scan:         null  // NULL
}

function list() {
  return Object.keys(EVENT_CONFIG)
}

function wrap(event, callback) {
  log.verbose('WechatyEvent', 'wrap(%s, %s)', event, typeof callback)

  // if (!(this instanceof Wechaty)) {
  //   throw new Error('`this` should be Wechaty instance')
  // }
  if (typeof callback !== 'function') {
    throw new Error('`callback` should be function')
  }

  if (!(event in EVENT_CONFIG)) {
    throw new Error('event not support: ' + event)
  }
  const wrapper = EVENT_CONFIG[event]

  /**
   * We assign a empty object to each event callback,
   * to carry the indenpendent scope
   */
  if (wrapper) {
    return wrapper(callback)
  } else {
    return callback
  }
}

function isContact(contact) {
  if (contact.map && contact[0] instanceof Contact) {
    return true
  } else if (contact instanceof Contact) {
    return true
  }
  return false
}

function isRoom(room) {
  /**
   * here not use `instanceof Room` is because circular dependence problem...
   */
  if (!room || !room.constructor
      || room.constructor.name !== 'Room') {
    return fasle
  }
  return true
}

function wrapContact(callback) {
  log.verbose('WechatyEvent', 'wrapContact()')

  return (...argList) => {
    log.silly('WechatyEvent', 'wrapContact() callback')

    if (!isContact(argList[0])) {
      throw new Error('contact not found in argList')
    }

    const contact = argList[0]

    const eventScope = {}
    eventScope.say = (content) => {
      const msg = new Message()
      msg.to(contact)
      msg.content(content)
      return Config.puppetInstance()
                    .send(msg)
    }

    return callback.apply(eventScope, argList)
  }
}

function wrapRoom(callback) {
  log.verbose('WechatyEvent', 'wrapRoom()')

  return (...argList) => {
    log.silly('WechatyEvent', 'wrapRoom() callback')
    let room, contact
    for (let arg of argList) {
      if (!room && isRoom(arg)) {
        room = arg
      } else if (!contact && isContact(arg)) {
        contact = arg
      }
    }

    if (!room || !contact) {
      throw new Error('room or contact not found')
    }

    const eventScope = {}
    eventScope.say = (content, replyTo = null) => {
      if (!replyTo) {
        replyTo = contact
      } else if (!isContact(replyTo)) {
        throw new Error('replyTo is not Contact instance(s)')
      }
      return room.say(content, replyTo)
    }

    return callback.apply(eventScope, argList)
  }
}

function wrapMessage(callback) {
  log.verbose('WechatyEvent', 'wrapMessage()')

  console.log('############### Message type: ')
  console.log(typeof Message)
  return (...argList) => {
    log.silly('WechatyEvent', 'wrapMessage() callback')

    console.log('############### wrapped on message callback')
    // console.log(typeof Message)
    // console.log(argList)
    if (!(argList[0] instanceof Message)) {
      throw new Error('Message instance not found')
    }

    const msg       = argList[0]

    const sender    = msg.from()
    const receiver  = msg.to()
    const room      = msg.room()

    const eventScope = {}
    eventScope.say = (content, replyTo) => {
      log.silly('WechatyEvent', 'wrapMessage() say("%s", "%s")', content, replyTo)

      if (room) {
        return room.say(content, replyTo)
      }

      const msg = new Message()
      msg.to(sender)
      msg.content(content)

      return Config.puppetInstance()
                    .send(msg)
    }

    return callback.apply(eventScope, argList)
  }
}

function wrapFilehelper(callback) {
  log.verbose('WechatyEvent', 'wrapFilehelper()')

  return (...argList) => {
    log.silly('WechatyEvent', 'wrapFilehelper() callback')
    const eventScope = {}
    eventScope.say = (content) =>{
      log.silly('WechatyEvent', 'wrapFilehelper() say(%s)', content)
      const msg = new Message()
      msg.to('filehelper')
      msg.content(content)
      return Config.puppetInstance()
                    .send(msg)
    }

    return callback.apply(eventScope, argList)
  }
}

// module.exports = WechatyEvent.default = WechatyEvent
export default WechatyEvent