function pc3Accordion( accordionId, parameters ){
	var self = this;
	this.accordion = $(accordionId);
	this.parameters = parameters;
	this.parentWidget = '';
	
	this.init = function(){
		this.tangens = this.parameters.tangens;
		this.degrees = (Math.atan(this.tangens) * 360) / (Math.PI * 2);
		this.activeBox = null;
		this.fixedHeight = false;
		if ( this.parameters.action == "onmouseover" || ( this.parameters.action == "onclick" && this.parameters.fixHeight == 1 ) ) this.fixedHeight = true;

		//gather all boxes
		var firstBoxToOpen = null;
		var maxTitleHeight = 0;
		var maxContentHeight = 0;
		var maxOuterTitleHeight = 0;
		var maxOuterContentHeight = 0;
		
		this.boxes = this.accordion.childElements();
		this.boxes.each( function( box, position ){
			var childs = box.childElements();
			var boxOuterDimension = pc3Widget.getOuterDimension(box, true);
			box.position = position;
			box.boxTitle = childs[0];
			box.boxTitle.box = box;
			if ( !self.firstBoxToOpen ) self.firstBoxToOpen = box.boxTitle;
			var outerDimension = pc3Widget.getOuterDimension(box.boxTitle, true);
			box.titleHeight = outerDimension.height;
			if ( outerDimension.innerHeight > maxTitleHeight ) maxTitleHeight = outerDimension.innerHeight;
			if ( box.titleHeight > maxOuterTitleHeight ) maxOuterTitleHeight = box.titleHeight;
			
			box.boxContent = childs[1];
			outerDimension = pc3Widget.getOuterDimension(box.boxContent, true);
			box.contentHeight = outerDimension.height + boxOuterDimension.offsetsY;
			if ( outerDimension.innerHeight > maxContentHeight ) maxContentHeight = outerDimension.innerHeight;
			if ( box.contentHeight > maxOuterContentHeight ) maxOuterContentHeight = box.contentHeight;
			
			Element.observe(box.boxTitle, (self.parameters.action=='onmouseover'?'mouseover':'click'), function( event ){ self.toggle(this, event)});
		});
		
		var height = parseInt(this.accordion.style.height);
		if ( height > 0 ){
			this.fixedHeight = true;
			maxOuterContentHeight = height - (this.boxes.size() * maxOuterTitleHeight);
			if ( maxOuterContentHeight < 20 ) maxOuterContentHeight = 20;
		}

		//set defaults for boxes
		this.boxes.each( function( box, position ){
			if ( self.fixedHeight ){
				box.titleHeight = maxOuterTitleHeight;
				if ( box.contentHeight > maxOuterContentHeight ) box.boxContent.setStyle({'overflowY':'scroll', 'overflowX':'hidden'});
				box.contentHeight = maxOuterContentHeight;
				box.boxTitle.setStyle({height:maxTitleHeight+'px'});
				box.boxContent.setStyle({height:maxContentHeight+'px'});
			}
			
			box.direction = "";
			box.currentHeight = 0;
			box.displayedHeight = 0;
			box.setStyle({overflow:'hidden', height:box.titleHeight+'px', position:'relative'});
			box.closedClass = box.className;
			box.openedClass = self.parameters.boxes[position];
		});
		
		this.accordion.lastHeight = this.accordion.getHeight();
		
		this.steps = 1;
		this.toggle(this.firstBoxToOpen, '');
		this.steps = (this.parameters.animationDuration * 25) / 1000;
	}
	
	this.toggle = function( boxTitle, event ){
		if ( !this.parentWidget ) this.parentWidget = pc3Widget.getParentWidget(this.accordion);
		if ( event ) event.stop();
		box = boxTitle.box;
		if ( this.activeBox != box ){
			this.toggleStyles(this.activeBox,'closed');
			this.activeBox = box;
			this.toggleStyles(this.activeBox,'opened');
			
			this.activeBoxes = new Array();
			this.boxCounter = 0;
			this.boxes.each( function( box, position ){
				if ( self.activeBox.position == box.position ){
					if ( box.direction == 'close' && box.displayedHeight > 0 ) self.setBoxReverse(box);
					if ( box.displayedHeight < box.contentHeight ) box.direction = 'open';
					else box.direction = '';
				} else {
					if ( box.direction == 'open' && box.displayedHeight < box.contentHeight ) self.setBoxReverse(box);
					if ( box.displayedHeight > 0 ) box.direction = 'close';
					else box.direction = '';
					if ( box.direction ){
						self.activeBoxes[self.boxCounter] = box.position;
						self.boxCounter++;
					}
				}
			});
			
			if ( this.fixedHeight ) this.boxSlideFixed( box );
			else this.boxSlide( box );
		}
	}
	
	this.toggleStyles = function( box, state ){
		if ( !box ) return;
		if ( state == 'opened' ){
			if ( box.openedClass ) box.className = box.openedClass;
		} else {
			if ( box.closedClass ) box.className = box.closedClass;
		}
	}
	
	this.boxSlideFixed = function( box ){
		if ( box != this.activeBox ) return;

		var step = box.contentHeight / this.steps;
		if ( step < 0.5 ) step = 0.51;
		box.currentHeight = Math.round(box.currentHeight + step);
		var displayedHeight = this.getDisplayHeight(box, box.direction);
		var totalMove = displayedHeight - box.displayedHeight;
		if ( displayedHeight >= box.contentHeight || totalMove <= 0 ){
			box.currentHeight = box.contentHeight;
			box.displayedHeight = box.currentHeight;
			totalMove = 10000;
			box.direction = '';
		} else {
			box.displayedHeight = displayedHeight;
		}
		box.setStyle({height:(box.titleHeight + box.displayedHeight)+'px'});
		var totalMoveHeight = 0;
		var remainingTotalMove = totalMove;

		var numberOfActiveBoxes = this.activeBoxes.length;
		for(var i = 0; i < numberOfActiveBoxes; i++) totalMoveHeight = totalMoveHeight + this.boxes[this.activeBoxes[i]].displayedHeight;
		
		var removeBoxes = new Array();
		var removeBoxesCounter = 0;
		
		
		for(var i = 0; i < numberOfActiveBoxes; i++){
			if ( box != this.activeBox ) continue;
			
			var currentBox = this.boxes[this.activeBoxes[i]];
			if ( i == (numberOfActiveBoxes - 1) ){
				currentBox.displayedHeight = currentBox.displayedHeight - remainingTotalMove;
			} else {
				move = Math.round((totalMove * currentBox.displayedHeight) / totalMoveHeight);
				if ( move > remainingTotalMove ) move = remainingTotalMove;
				remainingTotalMove = remainingTotalMove - move;
				currentBox.displayedHeight = currentBox.displayedHeight - move;
			}
			if ( currentBox.displayedHeight <= 0 ){
				currentBox.displayedHeight = 0;
				currentBox.currentHeight = 0;
				currentBox.direction = '';
				removeBoxes[removeBoxesCounter] = i;
				removeBoxesCounter++;
			} else {
				currentBox.currentHeight = this.getCurrentHeight(currentBox);
			}
			currentBox.setStyle({height:(currentBox.titleHeight + currentBox.displayedHeight)+'px'});

		}
		for(var i = 0; i < removeBoxes.length; i++) this.activeBoxes.splice((removeBoxes[i]-i),1);

		if ( this.activeBoxes.length > 0 || box.contentHeight != box.displayedHeight ) setTimeout(function() { self.boxSlideFixed( box ); },40);

	}


	this.boxSlide = function( box ){
		if ( box != this.activeBox ) return;
		
		var allBoxesMoved = true;
		this.boxes.each( function( box, position ){
			if ( !box.direction ) return;
			
			var step = box.contentHeight / self.steps;
			if ( step < 0.5 ) step = 0.51;
			if ( self.activeBox.position == box.position ){
				box.currentHeight = Math.round(box.currentHeight + step);
				if ( box.currentHeight >= box.contentHeight ){
					box.currentHeight = box.contentHeight;
					box.displayedHeight = box.currentHeight;
					box.direction = '';
				} else {
					box.displayedHeight = self.getDisplayHeight(box, box.direction);
					allBoxesMoved = false;
				}
			} else {
				box.currentHeight = Math.round(box.currentHeight - step);
				if ( box.currentHeight <= 0 ){
					box.currentHeight = 0;
					box.displayedHeight = box.currentHeight;
					box.direction = '';
				} else {
					box.displayedHeight = self.getDisplayHeight(box, box.direction);
					allBoxesMoved = false;
				}
			}
			box.setStyle({height:(box.titleHeight + box.displayedHeight)+'px'});
		});
		if ( this.accordion.lastHeight != this.accordion.getHeight() ){
			this.parentWidget.update();
			this.accordion.lastHeight = this.accordion.getHeight();
		}
		if ( !allBoxesMoved ) setTimeout(function() { self.boxSlide( box ); },40);
	}
	
	this.setBoxReverse = function( box ){
		degrees = (Math.atan(this.tangens - (this.getFactor( box, box.direction ) * this.tangens)) * 360) / (Math.PI * 2);
		if ( box.direction == "open" ) box.currentHeight = Math.round((box.contentHeight * degrees) / this.degrees);
		else box.currentHeight = box.contentHeight - Math.round((box.contentHeight * degrees) / this.degrees);
	}

	this.getFactor = function( box, direction ){
		if ( direction == "open" ) pastDegrees = this.degrees - ((box.currentHeight * this.degrees) / box.contentHeight);
		else pastDegrees = (box.currentHeight * this.degrees) / box.contentHeight;
		if ( pastDegrees > this.degrees ) pastDegrees = this.degrees;
		if ( pastDegrees < 0 ) pastDegrees = 0;
		return Math.tan((pastDegrees * (Math.PI * 2)) / 360) / this.tangens;
	}

	this.getDisplayHeight = function( box, direction ){
		if ( direction == "open" ) return box.contentHeight - Math.round(box.contentHeight * this.getFactor( box, box.direction ));
		else return Math.round(box.contentHeight * this.getFactor( box, box.direction ));
	}

	this.getCurrentHeight = function( box ){
		degrees = (box.displayedHeight * this.degrees) / box.contentHeight;
		tangens = (degrees * this.tangens) / this.degrees;
		return Math.round((((Math.atan(tangens) * 360) / (Math.PI * 2)) * box.contentHeight) / this.degrees);
	}
	
	this.init();
}