module.exports = new Class
({
	Extends: Vn.Object
	,Tag: 'htk-assistant'
	,Properties:
	{
		stepCount:
		{
			type: Number
			,set: function (x)
			{
				this._stepCount = x;
				
				if (x > 0)
					this.setStep (0);
				else
					this.setStep (-1);
			}
			,get: function ()
			{
				return this._stepCount;
			}
		},
		step:
		{
			type: Number
			,set: function (x)
			{
				this.setStep (x);
			}
			,get: function ()
			{
				return this._stepIndex;
			}
		},
		stepFunc:
		{
			type: Function
			,set: function (x)
			{
				this._stepFunc = x;
				this.setStep (this._stepIndex);
			}
			,get: function ()
			{
				return this._stepFunc;
			}
		},
		node:
		{
			type: Object
			,set: function (x)
			{
				x.className = 'htk-assistant';
			}
		},
	}

	,_stepNode: null
	,_stepIndex: -1
	,_stepCount: 0
	,_stepFunc: null

	,setStep: function (stepIndex)
	{
		if (!(stepIndex >= -1 && stepIndex < this.stepCount))
			return;
		
		if (this._stepFunc && stepIndex != -1)
		{
			var stepNode = this._stepFunc (stepIndex);
		
			if (stepNode)
			{
				if (this._stepNode)
					this._stepNode.style.display = 'none';

				this._stepNode = stepNode;
				stepNode.style.display = 'block';

				this._setStepIndex (stepIndex);
			}
			else if (this._stepIndex < stepIndex)
				this.setStep (stepIndex + 1);
			else
				this.setStep (stepIndex - 1);
		}
		else
			this._setStepIndex (stepIndex);
	}
	
	,_setStepIndex: function (stepIndex)
	{
		this._stepIndex = stepIndex;
		this.emit ('step-change', stepIndex);
	}
	
	,movePrevious: function ()
	{
		this.setStep (this._stepIndex - 1);
	}
	
	,moveNext: function ()
	{
		this.setStep (this._stepIndex + 1);
	}
});