/* AlloyFinger v0.1.15
 * By dntzhang
 * Github: https://github.com/AlloyTeam/AlloyFinger
 */

function getLen(v) {
  return Math.sqrt(v.x * v.x + v.y * v.y)
}

function dot(v1, v2) {
  return v1.x * v2.x + v1.y * v2.y
}

function getAngle(v1, v2) {
  var mr = getLen(v1) * getLen(v2)
  if (mr === 0) return 0
  var r = dot(v1, v2) / mr
  if (r > 1) r = 1
  return Math.acos(r)
}

function cross(v1, v2) {
  return v1.x * v2.y - v2.x * v1.y
}

function getRotateAngle(v1, v2) {
  var angle = getAngle(v1, v2)
  if (cross(v1, v2) > 0) {
    angle *= -1
  }

  return (angle * 180) / Math.PI
}

var HandlerAdmin = function(el) {
  this.handlers = []
  this.el = el
}

HandlerAdmin.prototype.add = function(handler) {
  this.handlers.push(handler)
}

HandlerAdmin.prototype.del = function(handler) {
  if (!handler) this.handlers = []

  for (var i = this.handlers.length; i >= 0; i--) {
    if (this.handlers[i] === handler) {
      this.handlers.splice(i, 1)
    }
  }
}

HandlerAdmin.prototype.dispatch = function() {
  for (var i = 0, len = this.handlers.length; i < len; i++) {
    var handler = this.handlers[i]
    if (typeof handler === 'function') handler.apply(this.el, arguments)
  }
}

function wrapFunc(el, handler) {
  var handlerAdmin = new HandlerAdmin(el)
  handlerAdmin.add(handler)

  return handlerAdmin
}

var AlloyFinger = function(el, option) {
  this.element = typeof el == 'string' ? document.querySelector(el) : el

  this.start = this.start.bind(this)
  this.move = this.move.bind(this)
  this.end = this.end.bind(this)
  this.cancel = this.cancel.bind(this)
  this.element.addEventListener('touchstart', this.start, false)
  this.element.addEventListener('touchmove', this.move, false)
  this.element.addEventListener('touchend', this.end, false)
  this.element.addEventListener('touchcancel', this.cancel, false)

  this.preV = { x: null, y: null }
  this.pinchStartLen = null
  this.zoom = 1
  this.isDoubleTap = false

  var noop = function() {}

  this.rotate = wrapFunc(this.element, option.rotate || noop)
  this.touchStart = wrapFunc(this.element, option.touchStart || noop)
  this.multipointStart = wrapFunc(this.element, option.multipointStart || noop)
  this.multipointEnd = wrapFunc(this.element, option.multipointEnd || noop)
  this.pinch = wrapFunc(this.element, option.pinch || noop)
  this.swipe = wrapFunc(this.element, option.swipe || noop)
  this.tap = wrapFunc(this.element, option.tap || noop)
  this.doubleTap = wrapFunc(this.element, option.doubleTap || noop)
  this.longTap = wrapFunc(this.element, option.longTap || noop)
  this.singleTap = wrapFunc(this.element, option.singleTap || noop)
  this.pressMove = wrapFunc(this.element, option.pressMove || noop)
  this.twoFingerPressMove = wrapFunc(
    this.element,
    option.twoFingerPressMove || noop,
  )
  this.touchMove = wrapFunc(this.element, option.touchMove || noop)
  this.touchEnd = wrapFunc(this.element, option.touchEnd || noop)
  this.touchCancel = wrapFunc(this.element, option.touchCancel || noop)

  this._cancelAllHandler = this.cancelAll.bind(this)

  window.addEventListener('scroll', this._cancelAllHandler)

  this.delta = null
  this.last = null
  this.now = null
  this.tapTimeout = null
  this.singleTapTimeout = null
  this.longTapTimeout = null
  this.swipeTimeout = null
  this.x1 = this.x2 = this.y1 = this.y2 = null
  this.preTapPosition = { x: null, y: null }
}

AlloyFinger.prototype = {
  start: function(evt) {
    if (!evt.touches) return
    this.now = Date.now()
    this.x1 = evt.touches[0].pageX
    this.y1 = evt.touches[0].pageY
    this.delta = this.now - (this.last || this.now)
    this.touchStart.dispatch(evt, this.element)
    if (this.preTapPosition.x !== null) {
      this.isDoubleTap =
        this.delta > 0 &&
        this.delta <= 250 &&
        Math.abs(this.preTapPosition.x - this.x1) < 30 &&
        Math.abs(this.preTapPosition.y - this.y1) < 30
      if (this.isDoubleTap) clearTimeout(this.singleTapTimeout)
    }
    this.preTapPosition.x = this.x1
    this.preTapPosition.y = this.y1
    this.last = this.now
    var preV = this.preV,
      len = evt.touches.length
    if (len > 1) {
      this._cancelLongTap()
      this._cancelSingleTap()
      var v = {
        x: evt.touches[1].pageX - this.x1,
        y: evt.touches[1].pageY - this.y1,
      }
      preV.x = v.x
      preV.y = v.y
      this.pinchStartLen = getLen(preV)
      this.multipointStart.dispatch(evt, this.element)
    }
    this._preventTap = false
    this.longTapTimeout = setTimeout(
      function() {
        this.longTap.dispatch(evt, this.element)
        this._preventTap = true
      }.bind(this),
      750,
    )
  },
  move: function(evt) {
    if (!evt.touches) return
    var preV = this.preV,
      len = evt.touches.length,
      currentX = evt.touches[0].pageX,
      currentY = evt.touches[0].pageY
    this.isDoubleTap = false
    if (len > 1) {
      var sCurrentX = evt.touches[1].pageX,
        sCurrentY = evt.touches[1].pageY
      var v = {
        x: evt.touches[1].pageX - currentX,
        y: evt.touches[1].pageY - currentY,
      }

      if (preV.x !== null) {
        if (this.pinchStartLen > 0) {
          evt.zoom = getLen(v) / this.pinchStartLen
          this.pinch.dispatch(evt, this.element)
        }

        evt.angle = getRotateAngle(v, preV)
        this.rotate.dispatch(evt, this.element)
      }
      preV.x = v.x
      preV.y = v.y

      if (this.x2 !== null && this.sx2 !== null) {
        evt.deltaX = (currentX - this.x2 + sCurrentX - this.sx2) / 2
        evt.deltaY = (currentY - this.y2 + sCurrentY - this.sy2) / 2
      } else {
        evt.deltaX = 0
        evt.deltaY = 0
      }
      this.twoFingerPressMove.dispatch(evt, this.element)

      this.sx2 = sCurrentX
      this.sy2 = sCurrentY
    } else {
      if (this.x2 !== null) {
        evt.deltaX = currentX - this.x2
        evt.deltaY = currentY - this.y2

        //move事件中添加对当前触摸点到初始触摸点的判断，
        //如果曾经大于过某个距离(比如10),就认为是移动到某个地方又移回来，应该不再触发tap事件才对。
        var movedX = Math.abs(this.x1 - this.x2),
          movedY = Math.abs(this.y1 - this.y2)

        if (movedX > 10 || movedY > 10) {
          this._preventTap = true
        }
      } else {
        evt.deltaX = 0
        evt.deltaY = 0
      }

      this.pressMove.dispatch(evt, this.element)
    }

    this.touchMove.dispatch(evt, this.element)

    this._cancelLongTap()
    this.x2 = currentX
    this.y2 = currentY

    if (len > 1) {
      evt.preventDefault()
    }
  },
  end: function(evt) {
    if (!evt.changedTouches) return
    this._cancelLongTap()
    var self = this
    if (evt.touches.length < 2) {
      this.multipointEnd.dispatch(evt, this.element)
      this.sx2 = this.sy2 = null
    }

    //swipe
    if (
      (this.x2 && Math.abs(this.x1 - this.x2) > 30) ||
      (this.y2 && Math.abs(this.y1 - this.y2) > 30)
    ) {
      evt.direction = this._swipeDirection(this.x1, this.x2, this.y1, this.y2)
      this.swipeTimeout = setTimeout(function() {
        self.swipe.dispatch(evt, self.element)
      }, 0)
    } else {
      this.tapTimeout = setTimeout(function() {
        if (!self._preventTap) {
          self.tap.dispatch(evt, self.element)
        }
        // trigger double tap immediately
        if (self.isDoubleTap) {
          self.doubleTap.dispatch(evt, self.element)
          self.isDoubleTap = false
        }
      }, 0)

      if (!self.isDoubleTap) {
        self.singleTapTimeout = setTimeout(function() {
          self.singleTap.dispatch(evt, self.element)
        }, 250)
      }
    }

    this.touchEnd.dispatch(evt, this.element)

    this.preV.x = 0
    this.preV.y = 0
    this.zoom = 1
    this.pinchStartLen = null
    this.x1 = this.x2 = this.y1 = this.y2 = null
  },
  cancelAll: function() {
    this._preventTap = true
    clearTimeout(this.singleTapTimeout)
    clearTimeout(this.tapTimeout)
    clearTimeout(this.longTapTimeout)
    clearTimeout(this.swipeTimeout)
  },
  cancel: function(evt) {
    this.cancelAll()
    this.touchCancel.dispatch(evt, this.element)
  },
  _cancelLongTap: function() {
    clearTimeout(this.longTapTimeout)
  },
  _cancelSingleTap: function() {
    clearTimeout(this.singleTapTimeout)
  },
  _swipeDirection: function(x1, x2, y1, y2) {
    return Math.abs(x1 - x2) >= Math.abs(y1 - y2)
      ? x1 - x2 > 0
        ? 'Left'
        : 'Right'
      : y1 - y2 > 0
      ? 'Up'
      : 'Down'
  },

  on: function(evt, handler) {
    if (this[evt]) {
      this[evt].add(handler)
    }
  },

  off: function(evt, handler) {
    if (this[evt]) {
      this[evt].del(handler)
    }
  },

  destroy: function() {
    if (this.singleTapTimeout) clearTimeout(this.singleTapTimeout)
    if (this.tapTimeout) clearTimeout(this.tapTimeout)
    if (this.longTapTimeout) clearTimeout(this.longTapTimeout)
    if (this.swipeTimeout) clearTimeout(this.swipeTimeout)

    this.element.removeEventListener('touchstart', this.start)
    this.element.removeEventListener('touchmove', this.move)
    this.element.removeEventListener('touchend', this.end)
    this.element.removeEventListener('touchcancel', this.cancel)

    this.rotate.del()
    this.touchStart.del()
    this.multipointStart.del()
    this.multipointEnd.del()
    this.pinch.del()
    this.swipe.del()
    this.tap.del()
    this.doubleTap.del()
    this.longTap.del()
    this.singleTap.del()
    this.pressMove.del()
    this.twoFingerPressMove.del()
    this.touchMove.del()
    this.touchEnd.del()
    this.touchCancel.del()

    this.preV = this.pinchStartLen = this.zoom = this.isDoubleTap = this.delta = this.last = this.now = this.tapTimeout = this.singleTapTimeout = this.longTapTimeout = this.swipeTimeout = this.x1 = this.x2 = this.y1 = this.y2 = this.preTapPosition = this.rotate = this.touchStart = this.multipointStart = this.multipointEnd = this.pinch = this.swipe = this.tap = this.doubleTap = this.longTap = this.singleTap = this.pressMove = this.touchMove = this.touchEnd = this.touchCancel = this.twoFingerPressMove = null

    window.removeEventListener('scroll', this._cancelAllHandler)
    return null
  },
}

export default AlloyFinger