function ImageSwapper()
{
	//Propriétés privées
	var Images = new Array();
	var ImagesOriginales = new Array();
		
	this.count = count;
	this.preloadImages = preloadImages;
	this.preloadImage = preloadImage;
	this.swapByIndex = swapByIndex;
	this.swapByKey = swapByKey;
	this.restore = restore;
	this.setBaseSrc = setBaseSrc;
	this.imageByIndex = imageByIndex;
	this.imageByKey = imageByKey;
	
	function imageByIndex(iIndex)
	{
		return Images[iIndex][1];
	}
	
	function imageByKey(key)
	{
		var i = 0;
		for (i = 0; i < this.count(); i++)
		{
			if (Images[i][0] == key) 
			{
				return this.imageByIndex(i);
			}
		}
	}
	
	function swapByIndex(oImg, iIndex)
	{
		oImg = validateImage(oImg);

		saveImageOriginale(oImg);
		if (oImg != null)
			oImg.src = Images[iIndex][1].src;
		else
			alert("Une des images passée en paramètre dans swapByIndex ou swapByKey est incorrecte");
	}

	function swapByKey(oImg, key)
	{	
		var i = 0;
		for (i = 0; i < this.count(); i++)
		{
			if (Images[i][0] == key) 
			{
				this.swapByIndex(oImg, i);
				break;	
			}
		}
	}
	
	function preloadImages()
	{
		var i = 0;

		//Il faut passer des array ou des string en paramètre
		//Ex.: preloadImages(Array("i1", "image1.jpg"), Array("i2", "image2.jpg"));
		//Ex.: preloadImages("image1.jpg", "image2.jpg");
		args = preloadImages.arguments;

		for (i = 0 ; i < args.length ; i++)
		{
			if (((args[i] && typeof args[i] == 'object') || typeof args[i] == 'function') && args[i].constructor == Array)
			{
				//true = C'est un Array
				this.preloadImage(args[i][0], args[i][1]);
			}
			else
			{
				//false = Ce n'est pas un array
				//Dans le cas où ce n'est pas un array, la clé devient simplement l'index de l'image
				this.preloadImage(this.count() + 1, args[i]);
			}
		}
	}
	
	function preloadImage(key, imageLink) 
	{ 
		var i = 0, iIndex = Images.length;
		
	  for (i = 0; i < iIndex; i++)
	  {
	  	//Si la clé est déjà présente, on remplace sa valeur
	  	if (Images[i][0] == key)
	  	{
	  		iIndex = i;
	  		break;
	  	}
	  }

		Images[iIndex] = new Array();
		Images[iIndex][0] = key;
		Images[iIndex][1] = new Image;
		Images[iIndex][1].src = imageLink;
		
	}

	function count()
	{
		return Images.length;
	}

	function setBaseSrc(oImg, sSrc)
	{
		var i = 0, iIndex = ImagesOriginales.length;

		oImg = validateImage(oImg);
		
		for (i = 0 ; i < iIndex; i++)
		{
			if (ImagesOriginales[i][0] == oImg.id)
			{
				iIndex = i;
				break;
			}
		}
		
		ImagesOriginales[iIndex] = new Array();
		ImagesOriginales[iIndex][0] = oImg.id;
		ImagesOriginales[iIndex][1] = sSrc;
	}

	function saveImageOriginale(oImg)
	{
		oImg = validateImage(oImg);
		setBaseSrc(oImg, oImg.src);
	}

	function restore(oImg)
	{
		var i = 0, iIndex = ImagesOriginales.length, found = false;

		oImg = validateImage(oImg);
		
		for (i = 0 ; i < iIndex; i++)
		{
			if (ImagesOriginales[i][0] == oImg.id)
			{
				found = true;
				iIndex = i;
				break;
			}
		}

		if (found)
			oImg.src = ImagesOriginales[iIndex][1];
		else
			saveImageOriginale(oImg);			
		
	}

	function validateImage(oImg) 
	{
		if (typeof oImg == "string") 
		{
			var oTmp = document.getElementById(oImg);
			return oTmp;
		}
		else
			return oImg;
	}
}

var imgSwapper = new ImageSwapper();