/* <copyright>
 This file contains proprietary software owned by Motorola Mobility, Inc.<br/>
 No rights, expressed or implied, whatsoever to this software are provided by Motorola Mobility, Inc. hereunder.<br/>
 (c) Copyright 2011 Motorola Mobility, Inc.  All Rights Reserved.
 </copyright> */
/**
	@module montage/ui/composer/swipe-composer
    @requires montage
    @requires montage/ui/composer/composer
*/
var Montage = require("montage").Montage,
    Composer = require("ui/composer/composer").Composer;
/**
 @module montage/ui/composer/swipe-composer
 */
/**
 @class module:montage/ui/composer/swipe-composer.SwipeComposer
 @classdesc Detects a swipe gesture.
 @extends module:montage/ui/composer/composer.Composer
 */
exports.SwipeComposer = Montage.create(Composer, /** @lends module:montage/ui/composer/swipe-composer.SwipeComposer# */ {

/**
    Description TODO
    @function
    @param {Element}
    */
    load: {
        value: function() {
            document.addEventListener("touchstart", this, true);
        }
    },

/**
    Description TODO
    @function
    */
    unload: {
        value: function() {
            document.removeEventListener("touchstart", this, true);
        }
    },

    /**
     TODO
     @private
     */
    _startX: {
        enumerable: false,
        value: 0
    },

    /**
     TODO
     @private
     */
    _startY: {
        enumerable: false,
        value: 0
    },

    /**
     TODO
     @private
     */
    _deltaX: {
        enumerable: false,
        value: 0
    },

    /**
     TODO
     @private
     */
    _deltaY: {
        enumerable: false,
        value: 0
    },

    /**
     TODO
     @private
     */
    _threshold: {
        enumerable: false,
        value: 50
    },

    /**
     TODO
     @private
     */
    _thresholdSwipeAngle: {
        enumerable: false,
        value: 20
    },

    /**
     TODO
     @private
     */
    _startTimestamp: {
        enumerable: false,
        value: 0
    },

    /**
     TODO
     @function
     @param {Event} event The event.
     */
    captureTouchstart: {
        value: function(event) {
            this._reset();
            var touches = event.touches,
                touch = touches[0];
            this._startX = touch.clientX;
            this._startY = touch.clientY;
            this._startTimestamp = event.timeStamp;
            document.addEventListener("touchmove", this, true);
            document.addEventListener("touchend", this, true);
            document.addEventListener("touchcancel", this, true);
        }
    },

    /**
     TODO
     @private
     */
    _reset: {
        enumerable: false,
        value: function() {
            this._startX = 0;
            this._startY = 0;
            this._deltaX = 0;
            this._deltaY = 0;
            this._startSwipeAngle = null;
        }
    },

    /**
     TODO
     @private
     */
    _startSwipeAngle: {
        enumerable: false,
        value: null
    },

    /**
     TODO
     @function
     @param {Event} event The event.
     */
    captureTouchcancel: {
        value: function(event) {
            document.removeEventListener("touchmove", this, true);
            document.removeEventListener("touchend", this, true);
            document.removeEventListener("touchcancel", this, true);
        }
    },

    /**
     TODO
     @function
     @param {Event} event The event.
     */
    captureTouchmove: {
        value: function(event) {
            event.preventDefault();
            var touches = event.changedTouches[0], swipeEvent, direction;

            this._deltaX = touches.clientX - this._startX;
            this._deltaY = touches.clientY - this._startY;

            var dX = this._deltaX,
                dY = this._deltaY,
                threshold = this._threshold,
                swipeAngle = this._findSwipeAngle(dX, dY);

            if (this._startSwipeAngle != null && Math.abs(this._startSwipeAngle - swipeAngle) > this._thresholdSwipeAngle) {
                //Direction changed; Abort touch
                //this.captureTouchcancel();
                this._startSwipeAngle = null;
            }

            if (this._startSwipeAngle == null) {
                this._startSwipeAngle = swipeAngle;
                this._startX = touches.clientX;
                this._startY = touches.clientY;
                this._deltaX = 0;
                this._deltaY = 0;
            }

            if (dX > threshold && dY > threshold) {
                direction = "DIAGONAL";
            } else if (dX > threshold && dY < threshold) {
                if (this._deltaX > 0) {
                    direction = "RIGHT";
                } else {
                    direction = "LEFT";
                }
            } else if (dX < threshold && dY > threshold) {
                if (this._deltaY > 0) {
                    direction = "DOWN";
                } else {
                    direction = "UP";
                }
            }

            if (dX != 0 || dY != 0) {
                swipeEvent = document.createEvent("CustomEvent");
                swipeEvent.initCustomEvent("swipemove", true, false, null);
                swipeEvent.direction = direction;
                swipeEvent.angle = this._startSwipeAngle;
                swipeEvent.velocity = this._findVelocity((event.timeStamp - this._startTimestamp));
                swipeEvent.startX = this._startX;
                swipeEvent.startY = this._startY;
                swipeEvent.dX = this._deltaX;
                swipeEvent.dY = this._deltaY;

                this.dispatchEvent(swipeEvent);
            }
        }
    },

    /**
     TODO
     @private
     */
    _findSwipeAngle: {
        enumerable: false,
        value: function(dX, dY) {
            var swipeAngle = -1 * (Math.atan2(dY, dX) * 180 / 3.14);
            return swipeAngle.toFixed(2);
        }
    },

    /**
     TODO
     @function
     @param {Event} event The event.
     */
    captureTouchend: {
        value: function(event) {

            if (event == null) {
                return;
            }

            var deltaX = Math.abs(this._deltaX),
                deltaY = Math.abs(this._deltaY),
                threshold = this._threshold,
                direction,
                swipeEvent;

            if (deltaX < threshold && deltaY < threshold) {
                this.captureTouchcancel();
                return;
            }

            document.removeEventListener("touchmove", this, true);

            if (deltaX > threshold && deltaY > threshold) {
                direction = "DIAGONAL";
            } else if (deltaX > threshold && deltaY < threshold) {
                if (this._deltaX > 0) {
                    direction = "RIGHT";
                } else {
                    direction = "LEFT";
                }
            } else if (deltaX < threshold && deltaY > threshold) {
                if (this._deltaY > 0) {
                    direction = "DOWN";
                } else {
                    direction = "UP";
                }
            }

            swipeEvent = document.createEvent("CustomEvent");
            swipeEvent.initCustomEvent("swipe", true, false, null);
            swipeEvent.direction = direction;
            swipeEvent.angle = this._startSwipeAngle;
            swipeEvent.velocity = this._findVelocity((event.timeStamp - this._startTimestamp));
            swipeEvent.startX = this._startX;
            swipeEvent.startY = this._startY;
            swipeEvent.dX = this._deltaX;
            swipeEvent.dY = this._deltaY;

            this.dispatchEvent(swipeEvent);
        }
    },

    /**
     TODO
     @private
     */
    _findVelocity: {
        enumerable: false,
        value: function(deltaTime) {
            return (Math.sqrt(/*xSquare*/(this._deltaX * this._deltaX) + /*ySquare*/(this._deltaY * this._deltaY)) / /*deltaTime*/(deltaTime));

        }
    }
});