/*
	Dynamic Heading Generator
    By Stewart Rosenberger
    http://www.stewartspeak.com/headings/

	This script searches through a web page for specific or general elements
	and replaces them with dynamically generated images, in conjunction with
	a server-side script.
*/


if(document.createElement && document.getElementsByTagName && !navigator.userAgent.match(/opera\/?6/i))
	com_stewartspeak_replacement();


function com_stewartspeak_replacement()
{

/*  1st parameter specifies the tags containing the text to be replaced
    2nd parameter the name of the text replacement script on the server
    3rd parameter: true if word wrap required; false otherwise */
replaceSelector("h5", "heading_generator.php", true);
var testimageURL = "images/test_image.png" ;

var doNotPrintImages = false;
var printerCSS = "style/replacement-print.css";

var hideFlicker = true;
// Style sheet that hides text headings whilst images are being loaded
var hideFlickerCSS = "style/replacement-screen.css";

/* If the test image hasn't been successfully loaded after one or two seconds
(or however long you see fit), the script will disable the hide headings style sheet, 
and the headings will reappear.
hideFlickerTimeout should be set to the maximum number of milliseconds
(i.e. 1/1000 seconds) that the script will let pass before disabling
the hide headings style sheet. */
var hideFlickerTimeout = 3000;




/* ---------------------------------------------------------------------------
    For basic usage, you should not need to edit anything below this comment.
    If you need to further customize this script's abilities, make sure
	you're familiar with Javascript. And grab a soda or something.
*/

var items;
var imageLoaded = false;
var documentLoaded = false;

function replaceSelector(selector,url,wordwrap)
{
	if(typeof items == "undefined")
		items = new Array();

	items[items.length] = {selector: selector, url: url, wordwrap: wordwrap};
}

if(hideFlicker)
{		
	document.write('<link id="hide-flicker" rel="stylesheet" media="screen" href="' + hideFlickerCSS + '" />');		
	window.flickerCheck = function()
	{
		if(!imageLoaded)
		{
		    // show text headings, only if test image has not been successfully loaded
            setStyleSheetState('hide-flicker',false);
        }
			
	};
	setTimeout('window.flickerCheck();',hideFlickerTimeout)
}

if(doNotPrintImages)
	document.write('<link id="print-text" rel="stylesheet" media="print" href="' + printerCSS + '" />');

var test = new Image();
// Run the function specified in the line below when the image has loaded.  This function calls the replacement function
test.onload = function() { imageLoaded = true; if(documentLoaded) replacement(); };
test.src = testimageURL + "?date=" + (new Date()).getTime();


addLoadHandler(function(){ documentLoaded = true; if(imageLoaded) replacement(); });


function documentLoad()
{
	documentLoaded = true;
	if(imageLoaded)
		replacement();
}

function replacement()
{    
	for(var i=0;i<items.length;i++)
	{
		var elements = getElementsBySelector(items[i].selector);
		if(elements.length > 0) for(var j=0;j<elements.length;j++)
		{
			if(!elements[j])
				continue ;
		
			var text = extractText(elements[j]);
    		while(elements[j].hasChildNodes())
				elements[j].removeChild(elements[j].firstChild);

			var tokens = items[i].wordwrap ? text.split(' ') : [text] ;
			for(var k=0;k<tokens.length;k++)
			{
				var url = items[i].url + "?text="+escape(tokens[k]+' ');
				var image = document.createElement("img");
				// image.className = "replacement";
				image.alt = tokens[k] ;
				image.src = url;
				elements[j].appendChild(image);
			}

			if(doNotPrintImages)
			{
				var span = document.createElement("span");
				span.style.display = 'none';
				span.className = "print-text";
				span.appendChild(document.createTextNode(text));
				elements[j].appendChild(span);
			}
		}
	}

	if(hideFlicker)
		setStyleSheetState('hide-flicker',false);
}

function addLoadHandler(handler)
{
	if(window.addEventListener)
	{
		window.addEventListener("load",handler,false);
	}
	else if(window.attachEvent)
	{
		window.attachEvent("onload",handler);
	}
	else if(window.onload)
	{
		var oldHandler = window.onload;
		window.onload = function piggyback()
		{
			oldHandler();
			handler();
		};
	}
	else
	{
		window.onload = handler;
	}
}

function setStyleSheetState(id,enabled) 
{
	var sheet = document.getElementById(id);
	if(sheet)
		sheet.disabled = (!enabled);
}

function extractText(element)
{
	if(typeof element == "string")
		return element;
	else if(typeof element == "undefined")
		return element;
	else if(element.innerText)
		return element.innerText;

	var text = "";
	var kids = element.childNodes;
	for(var i=0;i<kids.length;i++)
	{
		if(kids[i].nodeType == 1)
		text += extractText(kids[i]);
		else if(kids[i].nodeType == 3)
		text += kids[i].nodeValue;
	}

	return text;
}

/*
	Finds elements on page that match a given CSS selector rule. Some
	complicated rules are not compatible.
	Based on Simon Willison's excellent "getElementsBySelector" function.
	Original code (with comments and description):
		http://simon.incutio.com/archive/2003/03/25/getElementsBySelector
*/
function getElementsBySelector(selector)
{
	var tokens = selector.split(' ');
	var currentContext = new Array(document);
	for(var i=0;i<tokens.length;i++)
	{
		token = tokens[i].replace(/^\s+/,'').replace(/\s+$/,'');
		if(token.indexOf('#') > -1)
		{
			var bits = token.split('#');
			var tagName = bits[0];
			var id = bits[1];
			var element = document.getElementById(id);
			if(tagName && element.nodeName.toLowerCase() != tagName)
				return new Array();
			currentContext = new Array(element);
			continue;
		}

		if(token.indexOf('.') > -1)
		{
			var bits = token.split('.');
			var tagName = bits[0];
			var className = bits[1];
			if(!tagName)
				tagName = '*';

			var found = new Array;
			var foundCount = 0;
			for(var h=0;h<currentContext.length;h++)
			{
				var elements;
				if(tagName == '*')
					elements = currentContext[h].all ? currentContext[h].all : currentContext[h].getElementsByTagName('*');
				else
					elements = currentContext[h].getElementsByTagName(tagName);

				for(var j=0;j<elements.length;j++)
					found[foundCount++] = elements[j];
			}

			currentContext = new Array;
			var currentContextIndex = 0;
			for(var k=0;k<found.length;k++)
			{
				if(found[k].className && found[k].className.match(new RegExp('\\b'+className+'\\b')))
					currentContext[currentContextIndex++] = found[k];
			}

			continue;
	    }

		if(token.match(/^(\w*)\[(\w+)([=~\|\^\$\*]?)=?"?([^\]"]*)"?\]$/))
		{
			var tagName = RegExp.$1;
			var attrName = RegExp.$2;
			var attrOperator = RegExp.$3;
			var attrValue = RegExp.$4;
			if(!tagName)
				tagName = '*';

			var found = new Array;
			var foundCount = 0;
			for(var h=0;h<currentContext.length;h++)
			{
				var elements;
	        	if(tagName == '*')
					elements = currentContext[h].all ? currentContext[h].all : currentContext[h].getElementsByTagName('*');
				else
					elements = currentContext[h].getElementsByTagName(tagName);

				for(var j=0;j<elements.length;j++)
					found[foundCount++] = elements[j];
			}

			currentContext = new Array;
			var currentContextIndex = 0;
			var checkFunction;
			switch(attrOperator)
			{
				case '=':
					checkFunction = function(e) { return (e.getAttribute(attrName) == attrValue); };
					break;
				case '~':
					checkFunction = function(e) { return (e.getAttribute(attrName).match(new RegExp('\\b'+attrValue+'\\b'))); };
					break;
				case '|':
					checkFunction = function(e) { return (e.getAttribute(attrName).match(new RegExp('^'+attrValue+'-?'))); };
					break;
				case '^':
					checkFunction = function(e) { return (e.getAttribute(attrName).indexOf(attrValue) == 0); };
					break;
				case '$':
					checkFunction = function(e) { return (e.getAttribute(attrName).lastIndexOf(attrValue) == e.getAttribute(attrName).length - attrValue.length); };
					break;
				case '*':
					checkFunction = function(e) { return (e.getAttribute(attrName).indexOf(attrValue) > -1); };
					break;
				default :
					checkFunction = function(e) { return e.getAttribute(attrName); };
			}

			currentContext = new Array;
			var currentContextIndex = 0;
			for(var k=0;k<found.length;k++)
			{
				if(checkFunction(found[k]))
					currentContext[currentContextIndex++] = found[k];
			}

			continue;
		}

		tagName = token;
		var found = new Array;
		var foundCount = 0;
		for(var h=0;h<currentContext.length;h++)
		{
			var elements = currentContext[h].getElementsByTagName(tagName);
			for(var j=0;j<elements.length; j++)
				found[foundCount++] = elements[j];
		}

		currentContext = found;
	}

	return currentContext;
}


}