/* Touches utility
 *
 * Handle template touch events
 *
 */

(function (exports) {
    "use strict";

    /**
     * Touches handle touch events on tablet devices
     * @return {*}
     * @constructor
     */
    var Touches = function () {
        // make it a singleton
        if (exports.touches) {
            return touches;
        }

        /**
         * Touches uses Events to trigger touch events
         */
        Events.call(this, ['touch', 'touchhold', 'swipe']);

        this.UP = 38;
        this.DOWN = 40;
        this.LEFT = 37;
        this.RIGHT = 39;

        this.currentKey = 0;
        this.fingers = 0;
        this.startX = 0;
        this.startY = 0;
        this.curX = 0;
        this.curY = 0;
        this.deltaX = 0;
        this.deltaY = 0;
        this.horzDiff = 0;
        this.vertDiff = 0;
        this.minSwipe = 70;
        this.swipeLength = 0;
        this.swipeAngle = null;
        this.swipeDirection = null;

        /**
         * Reset touch handler variables
         */
        this.reset = function () {
            // reset the variables back to default values
            this.fingers = 0;
            this.startX = 0;
            this.startY = 0;
            this.curX = 0;
            this.curY = 0;
            this.deltaX = 0;
            this.deltaY = 0;
            this.horzDiff = 0;
            this.vertDiff = 0;
            this.swipeLength = 0;
            this.swipeAngle = null;
            this.swipeDirection = null;
        };

        /**
         * Touch Start Handler
         * @param {Event} event touch event
         */
        this.touchStart = function (event) {
            event.preventDefault();

            // get the total number of fingers touching the screen
            this.fingers = event.touches.length;

            //make sure we only have a single finger touch
            if (this.fingers === 1) {
                // get starting coordinates
                this.startX = event.touches[0].pageX;
                this.startY = event.touches[0].pageY;
            } else {
                //don't handle muli-touch gestures
                this.reset();
            }
        }.bind(this);

        /**
         * Touch Move Handler
         * @param {Event} event touch event
         */
        this.touchMove = function (event) {
            event.preventDefault();
            if (event.touches.length == 1) {
                this.curX = event.touches[0].pageX;
                this.curY = event.touches[0].pageY;
            } else {
                this.reset();
            }
        }.bind(this);

        /**
         * Touch End Handler
         * @param {Event} event touch event
         */
        this.touchEnd = function (event) {
            event.preventDefault();
            //Make sure we only have a single finger touch
            if (this.fingers === 1 && this.curX !== 0) {
                //calculate length of swipe
                this.swipeLength = Math.round(Math.sqrt(Math.pow(this.curX - this.startX, 2) + Math.pow(this.curY - this.startY, 2)));

                //if we have met the minimum swipe distance then handle the swipe
                if (this.swipeLength >= this.minSwipe) {
                    this.caluculateAngle();
                    this.getSwipeDirection();
                    this.implimentTouchEvent();
                    this.reset();
                } else {
                    this.handleTap(event);
                }
            } else {
                this.handleTap(event);
            }
        }.bind(this);

        /**
         * Handles single tap as opposed to swipe
         * @param {Event} event
         */
        this.handleTap = function (event) {
            var ele = event.target;
            for (var c = 0; c < ele.classList.length; c++) {
                if (touchObj[ele.classList[c]]) {
                    touchObj[ele.classList[c]](event);
                    break;
                }
            }
        };

        /**
         * Calculate angle of swipe
         */
        this.caluculateAngle = function () {
            var X = this.startX - this.curX;
            var Y = this.curY - this.startY;
            var Z = Math.round(Math.sqrt(Math.pow(X, 2) + Math.pow(Y, 2)));
            var r = Math.atan2(Y, X);
            this.swipeAngle = Math.round(r * 180 / Math.PI);
            if (this.swipeAngle < 0) { this.swipeAngle = 360 - Math.abs(this.swipeAngle); }
        };

        /**
         * If swipe - get the direction
         */
        this.getSwipeDirection = function () {
            if ((this.swipeAngle <= 45) && (this.swipeAngle >= 0)) {
                this.swipeDirection = 'left';
            } else if ((this.swipeAngle <= 360) && (this.swipeAngle >= 315)) {
                this.swipeDirection = 'left';
            } else if ((this.swipeAngle >= 135) && (this.swipeAngle <= 225)) {
                this.swipeDirection = 'right';
            } else if ((this.swipeAngle > 45) && (this.swipeAngle < 135)) {
                this.swipeDirection = 'down';
            } else {
                this.swipeDirection = 'up';
            }
        };

        /**
         * Trigger the correct touch event
         */
        this.implimentTouchEvent = function () {
            if (this.swipeDirection == 'left') {
                this.trigger('swipe', { type: 'swipe', keyCode: this.LEFT });
            } else if (this.swipeDirection == 'right') {
                this.trigger('swipe', { type: 'swipe', keyCode: this.RIGHT });
            } else if (this.swipeDirection == 'up') {
                this.trigger('swipe', { type: 'swipe', keyCode: this.UP });
            } else if (this.swipeDirection == 'down') {
                this.trigger('swipe', { type: 'swipe', keyCode: this.DOWN });
            }
        };

        var touchObj = {};

        this.registerTouchHandler = function (touchEle, touchHandler) {
            touchObj[touchEle] = touchHandler;
        };

        window.addEventListener("touchstart", this.touchStart, false);
        window.addEventListener("touchend", this.touchEnd, false);
        window.addEventListener("touchmove", this.touchMove, false);

    };

    exports.Touches = Touches;
    exports.touches = new Touches();
}(window));