/*  RubberbandSelector version 0.1
 *  (c) 2007 Stanislav Müller
 *
 *  RubberbandSelector is freely distributable under the terms of an MIT-style license.
 *
/*--------------------------------------------------------------------------*/


Number.prototype.between = function(first, second){
	return this >= first && this <= second;
};

var RubberbandSelector = Class.create();
RubberbandSelector.prototype = {
	initialize: function(options){		
		this.lastMouseCoordinates = {
			x: 0,
			y: 0
		};	
		
		var body = this.body = {
			element: $$("body")[0]
		}
				
		Object.extend(this.options, options);
		this.options.selectIn = $$(this.options.selectInSelector)[0];
		this.enable();
		return this;
	},
	
	options: {		
		scrollSensitivity: (window.innerHeight || document.documentElement.clientHeight)/4,
		afterSelectElement: function(element){},
		afterDeselectElement: function(element){},
		beforeSelect: function(event){},
		afterSelect: function(event){},
		elementsSelector: ".selectable",
		selectInSelector: "body"
	},
	
	addSelected: function(element){
		element.className = "selectable selected";
	},
	removeSelected: function(element){
		element.className = "selectable";
	},
	
	selectElements: function(event){
		if(typeof(this.selector) != "undefined"){
			selector_coordinates = this.getCoordinates(this.selector);
			this.selectableCoordinates.each(function(elm){
				
				with(elm){
					if(this.__overlay(elm, selector_coordinates)){
						if(this.addSelection && selected){
							this.removeSelected(element);
							this.options.afterDeselectElement(element);
						}else{
							this.addSelected(element);
							this.options.afterSelectElement(element);
						}
					}else if(this.addSelection && selected){
						this.addSelected(element);
						this.options.afterSelectElement(element);
					}else{
						this.removeSelected(element);
						element.className = element.className.substr()
						this.options.afterDeselectElement(element);
					}
				}				
			}.bind(this));			
		};
	},
	
	__overlay: function(elm, selector_coordinates){
		return (
					(
						(elm.lt.x.between(selector_coordinates.lt.x, selector_coordinates.rt.x)) ||
						(selector_coordinates.lt.x.between(elm.lt.x, elm.rt.x))
					) &&
					(
						(elm.lt.y.between(selector_coordinates.lt.y, selector_coordinates.lb.y)) ||
						(selector_coordinates.lt.y.between(elm.lt.y, elm.lb.y))
					)
			);
	},
	
	enableSelection: function(){
		element = this.body.element;
		with(Prototype.Browser){
			if(Gecko){ 
				element.style.MozUserSelect = "";
			}else if(WebKit){
				element.style.KhtmlUserSelect = "";
			}else if(IE){
				element.unselectable = "off";
				element.onselectstart = function() {
				        return true;
				};
			}else{
				return false;
			}
		}
		return true;
	},
	
	disableSelection: function(){
		http://openjsan.org/doc/j/jc/jcap/Dojo/common/0.4.1/lib/src/html/selection.html
		if(window.getSelection){
			if(Prototype.Browser.WebKit){
				// pulled from WebCore/ecma/kjs_window.cpp, line 2536
				window.getSelection().collapse();
			}else{
				window.getSelection().removeAllRanges();
			}
		}else if(document.selection){
			if(document.selection.empty){
				document.selection.empty();
			}else if(document.selection.clear){
				document.selection.clear();
			}
		}
		
		element = this.body.element;
		with(Prototype.Browser){
			if(Gecko){
				element.style.MozUserSelect = "none";
			}else if(WebKit){
				element.style.KhtmlUserSelect = "none"; 
			}else if(IE){
				element.unselectable = "on";
				element.onselectstart = function() {
				        return false;
				};
			}
		}
	},
	
	startScroll: function(event){
		var mousePosition = this.getCurrentMousePosition(event);
		this.event = {
			pageX: mousePosition.x,
			pageY: mousePosition.y
		};

		this.scrollWindow();
		
		if(this.interval){
			clearInterval(this.interval);
			delete this.interval;
		}
		
		this.interval = setInterval(this.scrollWindow.bind(this, this.event, true), 150);
	},
	
	scrollWindow: function(){
		var event = arguments[0] || this.event;
		Position.prepare();
		
		var windowHeight = window.innerHeight || document.documentElement.clientHeight;
		var pageYOffset = Position.deltaY;
		var pageHeight = document.height || window.height || document.body.scrollHeight;
				
		var pageBottomY = pageYOffset + windowHeight;
		var pageBottomQuarterY = pageBottomY - this.options.scrollSensitivity;

		
		var pageTopY = pageYOffset;
		var pageTopQuarterY = pageTopY + this.options.scrollSensitivity;
				
		if(event.pageY.between(pageTopY, pageTopQuarterY) && 
			(event.pageY <= this.lastMouseCoordinates.y || arguments[1])){
				var step = this.scrollStep(event.pageY, pageTopQuarterY);
				
				if(event.pageY - this.options.scrollSensitivity > 0){
					window.scrollTo(false, pageYOffset - step);
					this.event.pageY = event.pageY - step;
				}else{
					window.scrollTo(false, 0);
				}
		}else if(event.pageY.between(pageBottomQuarterY, pageBottomY) && 
			(event.pageY >= this.lastMouseCoordinates.y || arguments[1])){
				var step = this.scrollStep(pageBottomQuarterY, event.pageY);
				
				if(pageBottomY + step < pageHeight){
					window.scrollTo(false, pageBottomY + step - windowHeight);
					this.event.pageY = event.pageY + step;
				}else{
					window.scrollTo(false, (pageHeight - windowHeight) + this.options.scrollSensitivity);
				}
		}
	
		arguments[1] ? this.mousemove(event, true) : "";
		
		this.lastMouseCoordinates = {
			x: event.pageX,
			y: event.pageY
		};
	},
	
	scrollStep: function(upperPoint, pointer){
		return pointer - upperPoint;
	},
	
	getCurrentMousePosition: function(event, interval){
		var pointerX = Event.pointerX(event);
		var pointerY = Event.pointerY(event);
		
		return {
			x: pointerX,
			y: pointerY
		}
	},
	
	getStye: function(event, isMoving){
		
		var mousePosition = isMoving ? {
			x: Event.pointerX(event),
			y: Event.pointerY(event)
		} : this.getCurrentMousePosition(event);
		
		var L, 
				T, 
				W, 
				H, 
				pointerX = mousePosition.x, 
				pointerY = mousePosition.y;
		
		
		W	= 	(pointerX - this.startCoordinates.x) + "px";
		H	= 	(pointerY - this.startCoordinates.y) + "px";
		T	=		this.startCoordinates.y+"px";
		L	= 	this.startCoordinates.x+"px";
		
		if(this.startCoordinates.x - pointerX > 0){
			W = this.startCoordinates.x - pointerX + "px";
			L = (pointerX) + "px";
		}
		
		if(this.startCoordinates.y - pointerY > 0){
			H = this.startCoordinates.y - pointerY + "px";
			T = (pointerY) + "px";
		}
		
		return {
			top: 			T,
			left: 		L,
			width: 		W,
			height: 	H
		};
	},
	
	getCoordinates: function(elm){
		var position = Position.positionedOffset(elm);
		var dimensions = elm.getDimensions();
		
		return {
			lb : { x: position[0], y: position[1] + dimensions.height },
			lt : { x: position[0], y: position[1] },
			rt : { x: position[0] + dimensions.width, y: position[1]},
			rb : { x: position[0] + dimensions.width, y: position[1] + dimensions.height},
			element: elm,
			selected: /selected/.test(elm.className)
		};
	},
	
	
	findSelectablesCoordinates: function(){
		this.selectableCoordinates = [];
		$$(this.options.elementsSelector).each(function(selectable){
			this.selectableCoordinates.push(this.getCoordinates(selectable));
		}.bind(this));
		return this.selectableCoordinates;
	},
	
	createSelector: function(){
		var selector = $("rubberbandSelector");
		if(!selector){
			var selector = document.createElement("div");
			selector.id = "rubberbandSelector";
			this.body.element.appendChild(selector);
		}
		this.selector = $(selector);		
		Position.absolutize(this.selector);
		this.selector.setOpacity(0.5);
		return this.selector;
		
	},
	
	setStartMousePosition: function(event){
		var mousePosition = this.getCurrentMousePosition(event);
		this.startCoordinates = {
			x: mousePosition.x,
			y: mousePosition.y
		}
		return this.startCoordinates;
	},
	
	getAllSelectedElements: function(){
		var selectedElements = [];
		this.findSelectablesCoordinates().each(function(element){			
				if(element.selected){
					selectedElements.push(element.element);
				}
		});		
		return selectedElements;
	},
	
	// EVENTS	
	
	mousedown: function(event) {
		this.options.beforeSelect(event);		
		this.disableSelection();
		
		this.setStartMousePosition(event);
		this.findSelectablesCoordinates();
		this.createSelector();	
		
		this.keyevents(event);
		this.move(event);
		Event.stop(event);
		
				
		Event.observe(document, 'mousemove', this.move);
	},
	
	mousemove: function(event, isScolling){
		if(!this.selector){ return this.mouseup(event); }
		
		this.selector.setStyle(this.getStye(event, isScolling));
		if(!isScolling) this.startScroll(event);
		this.selectElements(event);
	},
	
	mouseup: function(event){
		try{
			this.selector.remove();
			delete this.selector;
			clearInterval(this.interval);
			delete this.interval;
		}catch(e){}
		
		this.enableSelection();
		this.keyevents(event);
		Event.stopObserving(document, 'mousemove', this.move);
		this.options.afterSelect(event);
	},
	
	keyevents: function(event){
		this.addSelection = event.shiftKey ? true : false;
	},
		
	enable: function(){
		this.down = this.mousedown.bindAsEventListener(this);
		this.move = this.mousemove.bindAsEventListener(this);
		this.up = this.mouseup.bindAsEventListener(this);
		
		Event.observe(this.options.selectIn, 'mousedown', this.down);
		Event.observe(document, 'mouseup', this.up);
	},
	
	disable: function(){
		Event.stopObserving(this.options.selectIn, 'mousedown', this.down);
	}
};