/**
 * Created by a on 2018/5/3.
 */
(function($){
    var touch = {},
        touchTimeout, tapTimeout, swipeTimeout, longTapTimeout,
        longTapDelay = 300,
        gesture,
        down, up, move,
        eventMap,
        initialized = false

    function swipeDirection(x1, x2, y1, y2) {
        return Math.abs(x1 - x2) >=
        Math.abs(y1 - y2) ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
    }

    function longTap() {
        longTapTimeout = null
        if (touch.last) {
            touch.el.trigger('longTap')
            touch = {}
        }
    }

    function cancelLongTap() {
        if (longTapTimeout) clearTimeout(longTapTimeout)
        longTapTimeout = null
    }

    function cancelAll() {
        if (touchTimeout) clearTimeout(touchTimeout)
        if (tapTimeout) clearTimeout(tapTimeout)
        if (swipeTimeout) clearTimeout(swipeTimeout)
        if (longTapTimeout) clearTimeout(longTapTimeout)
        touchTimeout = tapTimeout = swipeTimeout = longTapTimeout = null
        touch = {}
    }

    function isPrimaryTouch(event){
        return (event.pointerType == 'touch' ||
            event.pointerType == event.MSPOINTER_TYPE_TOUCH)
            && event.isPrimary
    }

    function isPointerEventType(e, type){
        return (e.type == 'pointer'+type ||
        e.type.toLowerCase() == 'mspointer'+type)
    }

    // helper function for tests, so they check for different APIs
    function unregisterTouchEvents(){
        if (!initialized) return
        $(document).off(eventMap.down, down)
            .off(eventMap.up, up)
            .off(eventMap.move, move)
            .off(eventMap.cancel, cancelAll)
        $(window).off('scroll', cancelAll)
        cancelAll()
        initialized = false
    }

    function setup(__eventMap){
        var now, delta, deltaX = 0, deltaY = 0, firstTouch, _isPointerType

        unregisterTouchEvents()

        eventMap = (__eventMap && ('down' in __eventMap)) ? __eventMap :
            ('ontouchstart' in document ?
                { 'down': 'touchstart', 'up': 'touchend',
                    'move': 'touchmove', 'cancel': 'touchcancel' } :
                'onpointerdown' in document ?
                    { 'down': 'pointerdown', 'up': 'pointerup',
                        'move': 'pointermove', 'cancel': 'pointercancel' } :
                    'onmspointerdown' in document ?
                        { 'down': 'MSPointerDown', 'up': 'MSPointerUp',
                            'move': 'MSPointerMove', 'cancel': 'MSPointerCancel' } : false)

        // No API availables for touch events
        if (!eventMap) return

        if ('MSGesture' in window) {
            gesture = new MSGesture()
            gesture.target = document.body

            $(document)
                .bind('MSGestureEnd', function(e){
                    var swipeDirectionFromVelocity =
                        e.velocityX > 1 ? 'Right' : e.velocityX < -1 ? 'Left' : e.velocityY > 1 ? 'Down' : e.velocityY < -1 ? 'Up' : null
                    if (swipeDirectionFromVelocity) {
                        touch.el.trigger('swipe')
                        touch.el.trigger('swipe'+ swipeDirectionFromVelocity)
                    }
                })
        }

        down = function(e){
            if((_isPointerType = isPointerEventType(e, 'down')) &&
                !isPrimaryTouch(e)) return
            firstTouch = _isPointerType ? e :((e.touches) ? e.touches[0]:e.originalEvent.changedTouches[0])
            if (e.touches && e.touches.length === 1 && touch.x2) {
                // Clear out touch movement data if we have it sticking around
                // This can occur if touchcancel doesn't fire due to preventDefault, etc.
                touch.x2 = undefined
                touch.y2 = undefined
            }
            now = Date.now()
            delta = now - (touch.last || now)
            touch.el = jQuery('tagName' in firstTouch.target ?
                firstTouch.target : firstTouch.target.parentNode)
            touchTimeout && clearTimeout(touchTimeout)
            touch.x1 = firstTouch.pageX
            touch.y1 = firstTouch.pageY
            if (delta > 0 && delta <= 250) touch.isDoubleTap = true
            touch.last = now
            longTapTimeout = setTimeout(longTap, longTapDelay)
            // adds the current touch contact for IE gesture recognition
            if (gesture && _isPointerType) gesture.addPointer(e.pointerId)
        }

        move = function(e){
            if((_isPointerType = isPointerEventType(e, 'move')) &&
                !isPrimaryTouch(e)) return
            firstTouch = _isPointerType ? e :((e.touches) ? e.touches[0]:e.originalEvent.changedTouches[0])
            cancelLongTap()
            touch.x2 = firstTouch.pageX
            touch.y2 = firstTouch.pageY

            deltaX += Math.abs(touch.x1 - touch.x2)
            deltaY += Math.abs(touch.y1 - touch.y2)
        }

        up = function(e){
            if((_isPointerType = isPointerEventType(e, 'up')) &&
                !isPrimaryTouch(e)) return
            cancelLongTap()

            // swipe
            if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
                (touch.y2 && Math.abs(touch.y1 - touch.y2) > 30))

                swipeTimeout = setTimeout(function() {
                    if (touch.el){
                        touch.el.trigger('swipe')
                        touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
                    }
                    touch = {}
                }, 0)

            // normal tap
            else if ('last' in touch)
            // don't fire tap when delta position changed by more than 30 pixels,
            // for instance when moving to a point and back to origin
                if (deltaX < 30 && deltaY < 30) {
                    // delay by one tick so we can cancel the 'tap' event if 'scroll' fires
                    // ('tap' fires before 'scroll')
                    tapTimeout = setTimeout(function() {

                        // trigger universal 'tap' with the option to cancelTouch()
                        // (cancelTouch cancels processing of single vs double taps for faster 'tap' response)
                        var event = jQuery.Event('tap')
                        event.cancelTouch = cancelAll
                        // [by paper] fix -> "TypeError: 'undefined' is not an object (evaluating 'touch.el.trigger'), when double tap
                        if (touch.el) touch.el.trigger(event)

                        // trigger double tap immediately
                        if (touch.isDoubleTap) {
                            if (touch.el) touch.el.trigger('doubleTap')
                            touch = {}
                        }

                        // trigger single tap after 250ms of inactivity
                        else {
                            touchTimeout = setTimeout(function(){
                                touchTimeout = null
                                if (touch.el) touch.el.trigger('singleTap')
                                touch = {}
                            }, 250)
                        }
                    }, 0)
                } else {
                    touch = {}
                }
            deltaX = deltaY = 0
        }

        jQuery(document).on(eventMap.up, up)
            .on(eventMap.down, down)
            .on(eventMap.move, move)

        // when the browser window loses focus,
        // for example when a modal dialog is shown,
        // cancel all ongoing events
        jQuery(document).on(eventMap.cancel, cancelAll)

        // scrolling the window indicates intention of the user
        // to scroll, not tap or swipe, so cancel all ongoing events
        jQuery(window).on('scroll', cancelAll)

        initialized = true
    }

    ;['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown',
        'doubleTap', 'tap', 'singleTap', 'longTap'].forEach(function(eventName){
        jQuery.fn[eventName] = function(callback){return this.on(eventName, callback) }
        /*jQuery.fn[eventName] = function(callback){
            return jQuery(document).off(eventName).on(eventName,this,callback)
        }*/
    })

    jQuery.touch = { setup: setup }

    jQuery(document).ready(setup)
})(jQuery)
