/**
 * Published on http://www.quirksmode.org/js/detect.html
 * @constructor 
 */
var BrowserDetect = {
	init: function () {
		this.browser = this.searchString(this.dataBrowser) || "An unknown browser";
		this.version = this.searchVersion(navigator.userAgent)
			|| this.searchVersion(navigator.appVersion)
			|| "an unknown version";
		this.OS = this.searchString(this.dataOS) || "an unknown OS";
	},
	searchString: function (data) {
		for (var i=0;i<data.length;i++)	{
			var dataString = data[i].string;
			var dataProp = data[i].prop;
			this.versionSearchString = data[i].versionSearch || data[i].identity;
			if (dataString) {
				if (dataString.indexOf(data[i].subString) != -1)
					return data[i].identity;
			}
			else if (dataProp)
				return data[i].identity;
		}
	},
	searchVersion: function (dataString) {
		var index = dataString.indexOf(this.versionSearchString);
		if (index == -1) return;
		return parseFloat(dataString.substring(index+this.versionSearchString.length+1));
	},
	dataBrowser: [
		{
			string: navigator.userAgent,
			subString: "Chrome",
			identity: "Chrome"
		},
		{ 	string: navigator.userAgent,
			subString: "OmniWeb",
			versionSearch: "OmniWeb/",
			identity: "OmniWeb"
		},
		{
			string: navigator.vendor,
			subString: "Apple",
			identity: "Safari",
			versionSearch: "Version"
		},
		{
			prop: window.opera,
			identity: "Opera"
		},
		{
			string: navigator.vendor,
			subString: "iCab",
			identity: "iCab"
		},
		{
			string: navigator.vendor,
			subString: "KDE",
			identity: "Konqueror"
		},
		{
			string: navigator.userAgent,
			subString: "Firefox",
			identity: "Firefox"
		},
		{
			string: navigator.vendor,
			subString: "Camino",
			identity: "Camino"
		},
		{		// for newer Netscapes (6+)
			string: navigator.userAgent,
			subString: "Netscape",
			identity: "Netscape"
		},
		{
			string: navigator.userAgent,
			subString: "MSIE",
			identity: "Explorer",
			versionSearch: "MSIE"
		},
		{
			string: navigator.userAgent,
			subString: "Gecko",
			identity: "Mozilla",
			versionSearch: "rv"
		},
		{ 		// for older Netscapes (4-)
			string: navigator.userAgent,
			subString: "Mozilla",
			identity: "Netscape",
			versionSearch: "Mozilla"
		}
	],
	dataOS : [
		{
			string: navigator.platform,
			subString: "Win",
			identity: "Windows"
		},
		{
			string: navigator.platform,
			subString: "Mac",
			identity: "Mac"
		},
		{
			   string: navigator.userAgent,
			   subString: "iPhone",
			   identity: "iPhone/iPod"
	    },
		{
			string: navigator.platform,
			subString: "Linux",
			identity: "Linux"
		}
	]

};
BrowserDetect.init();


/**
 * Common Logic
 */
ImagePreview = function() {
  /**
	 * @return {String} Returns object string representation
	 */
	this.toString = function(){
		return "imagePreview";
	};
	
		/**
	 * Stores container id
	 * @private
	 * @type {String}
	 */
	var containerId = 'previewContainer';
	
	/**
	 * Preview offset relative to cursor
	 * @public
	 * @type {Int}
	 */
	this.previewCursorOffsetPx = 10;
	
	/**
	 * Position of the preview image
	 * @public
	 * @type {String} lt - left-top, rb - right-bottom
	 */
	this.position = 'lt';

	/**
	 * Stores reference to container
	 * @private
	 * @type {HTMLElement}
	 */
	var container = null;
	
	/**
	 * Returns a reference to the container
	 * @method getContainer
	 * @return {HTMLElement}
	 */
	this.getContainer = function() {
		if (!container) {
			var my_div = document.createElement('div');
			my_div.setAttribute("id", containerId);
			Element.extend(my_div);
			my_div.setStyle(
				{
					'display': 'none',
					'background': '#FFFFFF',
					'padding': '2px',
					//'border': '1px solid #000000',
					'border': 'none',
					'position': 'absolute',
					'left': '0',
					'top': '0'
				}
			);
			document.body.appendChild(my_div);
			container = $(containerId);
			this.updateContainerDimensions();
		}
		return container;
	};

	/**
	 * Sets a reference to the container
	 * @method setContainer
	 * @param {HTMLElement}
	 */
	this.setContainer = function(_container) {
		container = _container;
	};
};


/**
 * Mouse enters active area
 * @method startPreview
 * @param {Event} event
 * @param {String} imgFileName
 */
ImagePreview.prototype.startPreview = function(event, imgFileName, url) {
	var container = this.getContainer();
	if (container.getStyle('display') == 'none') {
		var previewImgId = 'preview' + imgFileName.replace(/[^0-9A-Za-z]/, '');
		container.update('<img id="' + previewImgId + '" src="' + url + '" alt="loading...">');
		//container.show();
		this.updateContainerDimensions();
		Event.observe(previewImgId, 'load', function(){
			imagePreview.updateContainerDimensions();
			imagePreview.positionizeContainer(event);
			container.show();
		});
	}
	this.positionizeContainer(event);
};

/**
 * Mouse leaves active area
 * @method endPreview
 * @param {Event} event
 */
ImagePreview.prototype.endPreview = function(event) {
	var container = this.getContainer();
	container.hide();
	container.update();
	container.setStyle({'left':'0','top':'0'});
};

/**
 * Shows the image
 */
ImagePreview.prototype.showPic = function(imgFileName, url) {
  var l = $('imageDiv');
  var c = $('imageDivContent');
  if (l != null && c != null) {
    nmLogic.setPageEnabled(false);
    
   	var viewportDim = this.getViewportDimensions();
    l.setStyle({'max-width':(viewportDim.width-20)+'px', 'max-height':(viewportDim.height-20)+'px'});
    l.style.display='block';
    
    var previewImgId = 'preview' + imgFileName.replace(/[^0-9A-Za-z]/, '');
    c.update('<img id="' + previewImgId + '" src="' + url + '" alt="loading...">');
  }
}

/**
 * Shows the image
 */
ImagePreview.prototype.hidePic = function() {
  var l = $('imageDiv');
  if (l != null) {
    nmLogic.setPageEnabled(true);
    l.style.display='none';
  }
}


/**
 * Mouse moves within active area
 * @method movePreview
 * @param {Event} event
 */
ImagePreview.prototype.movePreview = function(event)
{
	this.positionizeContainer(event);
};

/**
 * Updates container's dimensions
 * @method updateContainerDimensions
 * @param {Event} event
 */
ImagePreview.prototype.updateContainerDimensions = function(event)
{
	var container = this.getContainer();
	container.dim = container.getDimensions();
	this.setContainer(container);
	if (event) {
		this.positionizeContainer(event);
	}
};

/**
 * Positionizes container
 * @method positionizeContainer
 * @param {Event} event
 */
ImagePreview.prototype.positionizeContainer = function(event)
{
	var container = this.getContainer();
	var currCursorX = Event.pointerX(event);
	var currCursorY = Event.pointerY(event);
	var viewportDim = this.getViewportDimensions();
	var maxWidth = container.dim.width + this.previewCursorOffsetPx;
	var maxHeight = container.dim.height + this.previewCursorOffsetPx;
	var offsetLeft = 0;
	var offsetTop = 0;
	if (this.position == 'rb') {
		offsetLeft = currCursorX + this.previewCursorOffsetPx;
		offsetTop = currCursorY + this.previewCursorOffsetPx;
		if ((maxWidth + currCursorX - document.body.scrollLeft) > viewportDim.width) {
			if ((currCursorX - maxWidth - document.body.scrollLeft) > 0) {
				offsetLeft = currCursorX - maxWidth;
			} else {
				offsetLeft -= ((currCursorX - document.body.scrollLeft) + maxWidth) - viewportDim.width;
			}
		}
		if ((maxHeight + currCursorY - document.body.scrollTop) > viewportDim.height) {
			if ((currCursorY - maxHeight - document.body.scrollTop) > 0) {
				offsetTop = currCursorY - maxHeight;
			} else {
				offsetTop -= ((currCursorY - document.body.scrollTop) + maxHeight) - viewportDim.height;
			}
		}
	} else if (this.position == 'lt') {
		offsetLeft = currCursorX - maxWidth;
		offsetTop = currCursorY - maxHeight;
		if (maxWidth > currCursorX) {
			offsetLeft = currCursorX + this.previewCursorOffsetPx;
		}
		if (maxHeight > currCursorY) {
			offsetTop = currCursorY + this.previewCursorOffsetPx;
		}
	}
	container.setStyle({'left':offsetLeft+'px', 'top':offsetTop+'px'});
};

/**
 * Resolves current viewport dimensions
 * @method getViewportDimensions
 * @return {Object}
 */
ImagePreview.prototype.getViewportDimensions = function()
{
	var ret = {width:0, height:0};
	ret.width = BrowserDetect.browser == 'Explorer' ?
		// IE Cases
		// Test for IE 5-7 Quirks and IE 4
		(!(document.documentElement.clientWidth) 
		|| (document.documentElement.clientWidth === 0)) ?
		// IE 5-7 Quirks and IE 4 case
		document.body.clientWidth : 
		//IE 6+ Strict Case
		document.documentElement.clientWidth:
		// Gecko and Other DOM compliant case
		window.innerWidth;
	ret.height = BrowserDetect.browser == 'Explorer' ?
		// IE Cases
		// Test for IE 5-7 Quirks and IE 4
		(!(document.documentElement.clientHeight) 
		|| (document.documentElement.clientHeight === 0)) ?
		// IE 5-7 Quirks and IE 4 case
		document.body.clientHeight : 
		//IE 6+ Strict Case
		document.documentElement.clientHeight:
		// Gecko and Other DOM compliant case
		window.innerHeight; 
	return ret;
};



/**
 * Global NetMakler main logic instance
 * @property nmLogic
 * @type Logic
 */
var imagePreview = new ImagePreview();