/**
* EasyDrag 1.4 - Drag & Drop jQuery Plug-in
*
* Thanks for the community that is helping the improvement
* of this little piece of code.
*
* For usage instructions please visit http://fromvega.com
*/

(function($){

	// to track if the mouse button is pressed
	var isMouseDown    = false;

	// to track the current element being dragged
	var currentElement = null;

	// callback holders
	var dropCallbacks = {};
	var dragCallbacks = {};

	// global position records
	var lastMouseX;
	var lastMouseY;
	var lastElemTop;
	var lastElemLeft;
	
	// track element dragStatus
	var dragStatus = {};	

	// returns the mouse (cursor) current position
	$.getMousePosition = function(e){
		var posx = 0;
		var posy = 0;

		if (!e) var e = window.event;

		if (e.pageX || e.pageY) {
			posx = e.pageX;
			posy = e.pageY;
		}
		else if (e.clientX || e.clientY) {
			posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;
			posy = e.clientY + document.body.scrollTop  + document.documentElement.scrollTop;
		}

		return { 'x': posx, 'y': posy };
	};

	// updates the position of the current element being dragged
	$.updatePosition = function(e) {
		var pos = $.getMousePosition(e);

		var spanX = (pos.x - lastMouseX);
		var spanY = (pos.y - lastMouseY);

		$(currentElement).css("top",  (lastElemTop + spanY));
		$(currentElement).css("left", (lastElemLeft + spanX));
	};

	// when the mouse is moved while the mouse button is pressed
	$(document).mousemove(function(e){
		if(isMouseDown && dragStatus[currentElement.id] == 'on'){
			// update the position and call the registered function
			$.updatePosition(e);
			if(dragCallbacks[currentElement.id] != undefined){
				dragCallbacks[currentElement.id](e, currentElement);
			}

			return false;
		}
	});

	// when the mouse button is released
	$(document).mouseup(function(e){
		if(isMouseDown && dragStatus[currentElement.id] == 'on'){
			isMouseDown = false;
			if(dropCallbacks[currentElement.id] != undefined){
				dropCallbacks[currentElement.id](e, currentElement);
			}

			return false;
		}
	});

	// register the function to be called while an element is being dragged
	$.fn.ondrag = function(callback){
		return this.each(function(){
			dragCallbacks[this.id] = callback;
		});
	};

	// register the function to be called when an element is dropped
	$.fn.ondrop = function(callback){
		return this.each(function(){
			dropCallbacks[this.id] = callback;
		});
	};
	
	// stop the element dragging feature
	$.fn.dragOff = function(){
		return this.each(function(){
			dragStatus[this.id] = 'off';
		});
	};
	
	
	$.fn.dragOn = function(){
		return this.each(function(){
			dragStatus[this.id] = 'on';
		});
	};

	// set an element as draggable - allowBubbling enables/disables event bubbling
	$.fn.easydrag = function(allowBubbling){

		return this.each(function(){

			// if no id is defined assign a unique one
			if(undefined == this.id || !this.id.length) this.id = "easydrag"+(new Date().getTime());

			// set dragStatus 
			dragStatus[this.id] = "on";
			
			// change the mouse pointer
			$(this).css("cursor", "move");

			// when an element receives a mouse press
			$(this).mousedown(function(e){

				// set it as absolute positioned
				$(this).css("position", "absolute");

				// set z-index
				$(this).css("z-index", "10000");

				// update track variables
				isMouseDown    = true;
				currentElement = this;

				// retrieve positioning properties
				var pos    = $.getMousePosition(e);
				lastMouseX = pos.x;
				lastMouseY = pos.y;

				lastElemTop  = this.offsetTop;
				lastElemLeft = this.offsetLeft;

				$.updatePosition(e);

				return allowBubbling ? true : false;
			});
		});
	};

})(jQuery);

jQuery.easing['jswing'] = jQuery.easing['swing'];

jQuery.extend( jQuery.easing,
{
	def: 'easeOutQuad',
	swing: function (x, t, b, c, d) {
		//alert(jQuery.easing.default);
		return jQuery.easing[jQuery.easing.def](x, t, b, c, d);
	},
	easeInQuad: function (x, t, b, c, d) {
		return c*(t/=d)*t + b;
	},
	easeOutQuad: function (x, t, b, c, d) {
		return -c *(t/=d)*(t-2) + b;
	},
	easeInOutQuad: function (x, t, b, c, d) {
		if ((t/=d/2) < 1) return c/2*t*t + b;
		return -c/2 * ((--t)*(t-2) - 1) + b;
	},
	easeInCubic: function (x, t, b, c, d) {
		return c*(t/=d)*t*t + b;
	},
	easeOutCubic: function (x, t, b, c, d) {
		return c*((t=t/d-1)*t*t + 1) + b;
	},
	easeInOutCubic: function (x, t, b, c, d) {
		if ((t/=d/2) < 1) return c/2*t*t*t + b;
		return c/2*((t-=2)*t*t + 2) + b;
	},
	easeInQuart: function (x, t, b, c, d) {
		return c*(t/=d)*t*t*t + b;
	},
	easeOutQuart: function (x, t, b, c, d) {
		return -c * ((t=t/d-1)*t*t*t - 1) + b;
	},
	easeInOutQuart: function (x, t, b, c, d) {
		if ((t/=d/2) < 1) return c/2*t*t*t*t + b;
		return -c/2 * ((t-=2)*t*t*t - 2) + b;
	},
	easeInQuint: function (x, t, b, c, d) {
		return c*(t/=d)*t*t*t*t + b;
	},
	easeOutQuint: function (x, t, b, c, d) {
		return c*((t=t/d-1)*t*t*t*t + 1) + b;
	},
	easeInOutQuint: function (x, t, b, c, d) {
		if ((t/=d/2) < 1) return c/2*t*t*t*t*t + b;
		return c/2*((t-=2)*t*t*t*t + 2) + b;
	},
	easeInSine: function (x, t, b, c, d) {
		return -c * Math.cos(t/d * (Math.PI/2)) + c + b;
	},
	easeOutSine: function (x, t, b, c, d) {
		return c * Math.sin(t/d * (Math.PI/2)) + b;
	},
	easeInOutSine: function (x, t, b, c, d) {
		return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
	},
	easeInExpo: function (x, t, b, c, d) {
		return (t==0) ? b : c * Math.pow(2, 10 * (t/d - 1)) + b;
	},
	easeOutExpo: function (x, t, b, c, d) {
		return (t==d) ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;
	},
	easeInOutExpo: function (x, t, b, c, d) {
		if (t==0) return b;
		if (t==d) return b+c;
		if ((t/=d/2) < 1) return c/2 * Math.pow(2, 10 * (t - 1)) + b;
		return c/2 * (-Math.pow(2, -10 * --t) + 2) + b;
	},
	easeInCirc: function (x, t, b, c, d) {
		return -c * (Math.sqrt(1 - (t/=d)*t) - 1) + b;
	},
	easeOutCirc: function (x, t, b, c, d) {
		return c * Math.sqrt(1 - (t=t/d-1)*t) + b;
	},
	easeInOutCirc: function (x, t, b, c, d) {
		if ((t/=d/2) < 1) return -c/2 * (Math.sqrt(1 - t*t) - 1) + b;
		return c/2 * (Math.sqrt(1 - (t-=2)*t) + 1) + b;
	},
	easeInElastic: function (x, t, b, c, d) {
		var s=1.70158;var p=0;var a=c;
		if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
		if (a < Math.abs(c)) { a=c; var s=p/4; }
		else var s = p/(2*Math.PI) * Math.asin (c/a);
		return -(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
	},
	easeOutElastic: function (x, t, b, c, d) {
		var s=1.70158;var p=0;var a=c;
		if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
		if (a < Math.abs(c)) { a=c; var s=p/4; }
		else var s = p/(2*Math.PI) * Math.asin (c/a);
		return a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b;
	},
	easeInOutElastic: function (x, t, b, c, d) {
		var s=1.70158;var p=0;var a=c;
		if (t==0) return b;  if ((t/=d/2)==2) return b+c;  if (!p) p=d*(.3*1.5);
		if (a < Math.abs(c)) { a=c; var s=p/4; }
		else var s = p/(2*Math.PI) * Math.asin (c/a);
		if (t < 1) return -.5*(a*Math.pow(2,10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )) + b;
		return a*Math.pow(2,-10*(t-=1)) * Math.sin( (t*d-s)*(2*Math.PI)/p )*.5 + c + b;
	},
	easeInBack: function (x, t, b, c, d, s) {
		if (s == undefined) s = 1.70158;
		return c*(t/=d)*t*((s+1)*t - s) + b;
	},
	easeOutBack: function (x, t, b, c, d, s) {
		if (s == undefined) s = 1.70158;
		return c*((t=t/d-1)*t*((s+1)*t + s) + 1) + b;
	},
	easeInOutBack: function (x, t, b, c, d, s) {
		if (s == undefined) s = 1.70158; 
		if ((t/=d/2) < 1) return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b;
		return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b;
	},
	easeInBounce: function (x, t, b, c, d) {
		return c - jQuery.easing.easeOutBounce (x, d-t, 0, c, d) + b;
	},
	easeOutBounce: function (x, t, b, c, d) {
		if ((t/=d) < (1/2.75)) {
			return c*(7.5625*t*t) + b;
		} else if (t < (2/2.75)) {
			return c*(7.5625*(t-=(1.5/2.75))*t + .75) + b;
		} else if (t < (2.5/2.75)) {
			return c*(7.5625*(t-=(2.25/2.75))*t + .9375) + b;
		} else {
			return c*(7.5625*(t-=(2.625/2.75))*t + .984375) + b;
		}
	},
	easeInOutBounce: function (x, t, b, c, d) {
		if (t < d/2) return jQuery.easing.easeInBounce (x, t*2, 0, c, d) * .5 + b;
		return jQuery.easing.easeOutBounce (x, t*2-d, 0, c, d) * .5 + c*.5 + b;
	}
});