/**
 * This is the stage scrolling class
 * @author pete goodman - petegoodman.com
*/
var stageScroller = {

	// string : the type of tween to use
	// backEaseIn, backEaseOut, backEaseInOut, elasticEaseIn, elasticEaseOut, elasticEaseInOut, bounceEaseOut, bounceEaseIn, 
	// bounceEaseInOut, regularEaseIn, regularEaseOut, regularEaseInOut, strongEaseIn, strongEaseOut, strongEaseInOut
	tweenType : Tween.elasticEaseInOut, 
	
	// int : the length of time for each tween (in seconds)
	tweenTime : 3,
	
	// boolean : detect whether we are currently scrolling
	currentlyScrolling : false, 
	
	// the setInterval js object for the main scroll (gets cleared and reset)
	scrollInterval : null,
		
	// object : the html stage container element
	stageContainer : null,
	
	// object : the html stage element
	stage : null,
	
	// array : container for all box html elements
	boxes : null,
	
	// int : time between each movement in milliseconds
	tweenTime : 50,
	
	// int : max amount of movement per movement in em
	maxTween : 50,
	
	// ints : the current position of the stage (x=left, y=top)
	stageX : 0,
	stageY : 0,
	
	// ints : the target position for the stage (x=left, y=top)
	targetX : 0,
	targetY : 0,

	// array : links out from the first (links) box to each individual box
	boxlinks : null,
	
	// array : links back from each individual box to the first (links) box
	backlinks : null,
	
	// object : the debugbox created by code
	debugbox : null,
	
	
	/*
	 * initialisation function
	 */
			init: function(tweenType, tweenTime) {

				// condition : change tween type
				if (tweenType != "") {
					this.tweenType = tweenType;
				}
				
				// condition : change tween time
				if (tweenTime != "") {
					this.tweenTime = tweenTime;
				}

				// get the stage container and set initial styles
				this.stageContainer = document.getElementById('stagecontainer');
				this.stageContainer.style.position = "relative";
				this.stageContainer.style.overflow = "visible";
				this.stageContainer.style.overflow = "hidden";
				
				
				// get the stage and set initial styles
				this.stage = document.getElementById('stage');
				this.stage.style.position = "relative";
				this.stage.style.width = "4000px";
				this.stage.style.height = "4000px";
				this.stage.style.right = this.stageX + "px";
				this.stage.style.bottom = this.stageY + "px";
				//this.stage.style.overflow = "hidden";
				
				
				// get all boxes
				this.boxes = LibraryManager.getElementsByClass("box", "stage");
				for (var x = 0; x < this.boxes.length; x++) {
					this.boxes[x].style.position = "absolute";
					this.boxes[x].top = Math.round(Math.cos((2 * Math.PI * x)/this.boxes.length) * 480);
					this.boxes[x].left = Math.round(Math.sin((2 * Math.PI * x)/this.boxes.length) * 480);
					this.boxes[x].style.left = this.boxes[x].left + "px";
					this.boxes[x].style.top = this.boxes[x].top + "px";
					this.boxes[x].style.zIndex = this.boxes.length - x;
				}
				
				//position the first box in the centre
				this.boxes[0].left = this.stageX;
				this.boxes[0].top = this.stageY;
				this.boxes[0].style.left = this.boxes[0].left + "px";
				this.boxes[0].style.top = this.boxes[0].top + "px";
				

				// get the links to each box
				this.boxlinks = this.boxes[0].getElementsByTagName('a');
				for (var i=0; i < this.boxlinks.length; i++) {
					
					// set a value for the current box on the link
					this.boxlinks[i].x = i;
					
					// remove default link behaviour
					this.boxlinks[i].onclick = function() { return false };
					
					// go to the box!
					LibraryManager.addEvent(this.boxlinks[i], 'click', this.goToBox, false);
				};
				
				
				// get all the back links
				this.backlinks = LibraryManager.getElementsByClass('back');
				for (var q=0; q < this.backlinks.length; q++) {

					// set a value for the current box on the link
					this.backlinks[q].x = q;
					
					// remove default link behaviour
					this.backlinks[q].onclick = function() { return false };					
					
					// go to the box!
					LibraryManager.addEvent(this.backlinks[q], 'click', this.goFromBox, false);
				};
				
				
				// start debug
				this.debug('debug initialised');
				
			},
			
			
	/*
	 * function to select a random number - for the box positioning
	 */
			random: function(min, max) {
				return Math.floor(Math.random() * (max - min + 1) + min);
			},
			
	
	/*
	 * function to initiate a scroll to a specific box from the centre
	 */		
			goToBox: function() {
				
				// if no scroll is currently going on
				if (!stageScroller.currentlyScrolling) {

					// get the box in question
					var box = stageScroller.boxes[this.x + 1];

					// start the scroll to the box's location
					stageScroller.scrollStage(box.left, box.top);

					// debug
					stageScroller.debug('scrolling to box ' + (this.x+1) + ', x:' + box.left + ', y:' + box.top);
				}
			},

			
	/*
	 * function to initiate a scroll from a specific box back to centre
	 */		
			goFromBox: function() {
				
				// if no scroll is currently going on
				if (!stageScroller.currentlyScrolling) {
				
					// get the home box
					var homebox = stageScroller.boxes[0];

					// start the scroll to the home box
					stageScroller.scrollStage(homebox.left, homebox.top);

					// debug
					stageScroller.debug('heading back from box ' + (this.x+1));
				}
			},
			
			
	/*
	 * function to start the scrolling of the stage from it's current position to point (x,y)
	 */
			scrollStage: function(x, y) {
				
				// set the currently scrolling
				stageScroller.currentlyScrolling = true;

				// set the target location
				stageScroller.targetX = x;
				stageScroller.targetY = y;

				// start the scroll!
				t1 = new Tween(stageScroller.stage.style,'right',stageScroller.tweenType,stageScroller.stageX,stageScroller.targetX,stageScroller.tweenTime,'px');
				t2 = new Tween(stageScroller.stage.style,'bottom',stageScroller.tweenType,stageScroller.stageY,stageScroller.targetY,stageScroller.tweenTime,'px');

				t1.onMotionFinished = function() {
					stageScroller.currentlyScrolling = false;
					stageScroller.stageX = stageScroller.targetX;
					stageScroller.stageY = stageScroller.targetY;
					this.onMotionFinished = undefined;
				};
				t1.start();
				t2.start();

				//debug
				//stageScroller.debug('targetX = ' + stageScroller.targetX + ", stageX = " + stageScroller.stageX);
			},
			
	/*
	 * function to create a debugbox and add message
	 */		
			debug: function(newmessage) {
				
				// if debugbox doesn't exist, create it
				if (stageScroller.debugbox == null) {
				
					//get the body element
					var body = document.getElementsByTagName("body")[0];

					//create the new html element
					stageScroller.debugbox = document.createElement('div');
					stageScroller.debugbox.id = "debugbox";
					stageScroller.debugbox.style.width = "100%";
					stageScroller.debugbox.style.position = "absolute";
					stageScroller.debugbox.style.top = "2em";
					stageScroller.debugbox.style.right = "2em";
					stageScroller.debugbox.style.width = "20em";
					stageScroller.debugbox.style.height = "50em";
					stageScroller.debugbox.style.overflow = "auto";
					stageScroller.debugbox.style.border = "1px solid #f90";
					stageScroller.debugbox.style.padding = "1em";
					stageScroller.debugbox.style.zindex = "9999";
				
					//add the new html element to the document
					//body.appendChild(stageScroller.debugbox);
				
				}
				
				// add message to debugbox
				var message = document.createElement('p');
				var messagetxt = document.createTextNode("> " + newmessage);
				message.appendChild(messagetxt);
				//stageScroller.debugbox.appendChild(message);
				
			}
}