Kinetic.TextToTextColumn = function(config){
	Kinetic.Group.call(this, config);
	this.data = config.data;
	
	this.initExercise();
	this.createExercise();
	this.eventHandlers();
}
	
Kinetic.TextToTextColumn.prototype = {
	createExercise: function(){
		// columns
		var dropItemData = this.data.dropItems;
		
		this.dropItems = new Array();
		
		for (var i = 0; i < dropItemData.length; i++){
			this.dropItems[i] = new Kinetic.TextToTextColumnDropItem({
				'data': dropItemData[i],
				'x': dropItemData[i].x,
				'y': dropItemData[i].y
			});
			
			this.add(this.dropItems[i]);
		}
		
		// drag item group
		this.itemGroup = new Kinetic.Group({
			'x': this.data.dragItemPositionArea.x,
			'y': this.data.dragItemPositionArea.y
		});
		this.add(this.itemGroup);
		
		// drag items
		var itemData = shuffleArray(this.data.dragItems);
		
		this.items = new Array();
		
		var xPos = 0;
		var yPos = 0;
		var rowHeight = 0;
		
		for (var i = 0; i < itemData.length; i++){
			this.items[i] = new Kinetic.DragItem({
				'data': itemData[i],
				'x': xPos,
				'draggable': true
			});
			this.itemGroup.add(this.items[i]);
			
			if ((xPos + this.items[i].getWidth()) > this.data.dragItemPositionArea.width){
				xPos = 0;
				yPos += rowHeight + 5;
				rowHeight = 0;
			}
			
			if (this.items[i].getHeight() > rowHeight){
				rowHeight = this.items[i].getHeight();
			}
			
			this.items[i].setX(xPos);
			this.items[i].setY(yPos);
			
			xPos += this.items[i].getWidth() + 5;
		}
	},
	
	eventHandlers: function(){
		var thisObject = this;
		
		for (var i = 0; i < this.items.length; i++){
			this.items[i].on('dragstart', function(evt){
				thisObject.dragStart(this, evt);
			});
			
			this.items[i].on('dragend', function(evt){
				thisObject.dragEnd(this, evt);
			});
		}
	},
	
	dragStart: function(thisObject, evt){
		thisObject.moveToTop();
		
		if (thisObject.dropItem != undefined){
			thisObject.dropItem.removeItem(thisObject);
			thisObject.dropItem = null;
		}
	},
	
	dragEnd: function(thisObject, evt){
		var myCenterX = thisObject.getX() + this.itemGroup.getX() + (thisObject.getWidth() / 2);
		var myCenterY = thisObject.getY() + this.itemGroup.getY() + (thisObject.getHeight() / 2);
		
		// check drop items 
		var hit = false;
		
		for (var i = 0; i < this.dropItems.length; i++){
			var minX = this.dropItems[i].getX();
			var minY = this.dropItems[i].getY();
			var maxX = minX + this.dropItems[i].getWidth();
			var maxY = minY + this.dropItems[i].getHeight();
			
			if (myCenterX > minX && myCenterX < maxX && myCenterY > minY && myCenterY < maxY){
				thisObject.dropItem = this.dropItems[i];
				
				this.dropItems[i].addItem(thisObject);
				
				hit = true;
				
				break;
			}
		}
		
		if (!hit){
			var oriX = thisObject.oriX;
			var oriY = thisObject.oriY;
			var tween = new Kinetic.Tween({
				'node': thisObject,
				'x': oriX,
				'y': oriY,
				'duration': 0.2,
				'easing': Kinetic.Easings.EaseInOut
			});
			tween.play();
		}
	},
	
	checkAnswer: function(){
		this.attempts -= 1;
		
		if (this.attempts == 0){
			this.blockExercise();
		}
		
		this.correct = true;
		
		var targetId = null;
		var dropItemId = null;
		
		var toMove = new Array();
		
		for (var i = 0; i < this.items.length; i++){
			targetId = this.items[i].data.target;
			
			dropItemId = null;
			if (this.items[i].dropItem != undefined){
				dropItemId = this.items[i].dropItem.data.id;
			}
			
			if (targetId == dropItemId){
				this.items[i].setCorrect();
			} else {
				this.correct = false;
				
				this.items[i].setWrong();
				
				// remove from wrong position
				if (dropItemId != null){
					for (var j = 0; j < this.dropItems.length; j++){
						if (this.dropItems[j].data.id == dropItemId){
							this.dropItems[j].removeItem(this.items[i]);
						}
					}
				}
				
				// move to the right position (delayed)
				for (var j = 0; j < this.dropItems.length; j++){
					if (this.dropItems[j].data.id == targetId){
						toMove.push(new Array(this.dropItems[j], this.items[i]));
					}
				}
			}
		}
		
		
		window.setTimeout(function(){
			for (var i = 0; i < toMove.length; i++){
				toMove[i][0].addItem(toMove[i][1]);
			}
		}, 500);
		
		
		this.draw();
		
		this.showFeedback(this.correct, this.attempts);
	}
}

Kinetic.Util.extend(Kinetic.TextToTextColumn, Kinetic.ExerciseType);