/* Commonly used functions */
/* krudd - emlab, UoW - 18/2/05 */

/* Useful info */
var isMacIE5 = /MSIE 5[\S\s]+Mac/i.test( navigator.userAgent );
var isIE = /MSIE/i.test( navigator.userAgent );
var isOpera = /OPERA/i.test( navigator.userAgent );
var isSafari = /SAFARI/i.test( navigator.userAgent );

/* Strip spaces, etc from string to make it suitable for useing as an id, etc */
function stripNonAlphaNumericChars( str )
{
	return str.replace( /[^a-z0-9]+/gi, '' );
}

/* Remove multiple spaces and trim whitespace from both ends */
function compact( str )
{
	return str.replace( /\s+/, ' ' ).replace( /^\s*|\s*$/g, '' );
}

/* hide/show content. */
function hideElement( elem )
{
	if ( elem && elem.style.display != 'none' )
		elem.style.display = 'none';
}

function showElement( elem )
{
	if ( elem && elem.style.display == 'none' )
		elem.style.display = '';
}

/* Part of an accessible way of "hiding" content. */
function concealElement( elem )
{
	if ( elem && elem.className.indexOf( 'concealed' ) < 0 )
		elem.className = compact( elem.className + ' concealed' );
}

function unconcealElement( elem )
{
	if ( elem && elem.className.indexOf( 'concealed' ) > -1 )
		elem.className = compact( elem.className.replace( /\bconcealed\b/, ' ' ) );
}

/* Base cookie functions */
function setCookie( name, value, hours )
{
	var expire = '';
	if( hours !== null ) {
		expire = new Date(); expire.setTime( expire.getTime() + ( hours * 36e5 ) );
		expire = '; expires=' + expire.toGMTString();
	}
	document.cookie = name + '=' + escape( value ) + expire + '; path=/'; 
}

function getCookie( name )
{
	var cv = ( new RegExp( name + '=([^;]+)' ) ).exec( document.cookie );
	return ( cv !== null ) ? unescape( cv[ 1 ] ) : null;
}

function killCookie( name )
{
	document.cookie = name + '=; expires=Wed, 13-Apr-1977 00:00:00 GMT; path=/';
}

/* Persistant flags - for 'foldingdefs.js' and 'tabbeddivs.js' */
function storeFlagState( flagSetName, flagName, state )
{
	var flagSet = getCookie( flagSetName );
	if ( flagSet == null ) flagSet = '';
	var curState = flagSet.indexOf( flagName ) != -1;
	if ( state != curState ) {
		if ( state == true )
			flagSet += flagName + '+';
		else
			flagSet = flagSet.replace( flagName + '+', '' );

		setCookie( flagSetName, flagSet, 1 );
	}
}

function getFlagState( flagSetName, flagName )
{
	var flagSet = getCookie( flagSetName );
	return flagSet ? flagSet.indexOf( flagName ) != -1 : null;
}

/* Make a 5 character "flag" from a string for use with store/getFlagState functions */
function makeFlagID( text )
{
	function charAtT( str, t ) { return str.charAt( Math.floor( ( str.length - 1 ) * t ) ) }; 
	return charAtT(text,0) + charAtT(text,0.25) + charAtT(text,0.5) + charAtT(text,0.75) + charAtT(text,1.0);
}

/* Add function to the list of "onload" fired functions */
function addLoadEvent( newOnLoad )
{
	var oldOnLoad = window.onload;
	if ( typeof( window.onload ) != 'function' )
		window.onload = newOnLoad;
	else
		window.onload = function() { oldOnLoad(); newOnLoad(); }
}

/* Create a link node (DOM methods) */
function createLink( url, text )
{
	var linkNode = document.createElement( 'A' );
	linkNode.href = url;
	if ( text && text.length > 0 )
		linkNode.appendChild( document.createTextNode( text ) );
	return linkNode;
}

/* Create a generic DOM node, with optional text node content */
function createDOMNode( tag, text )
{
	var node = document.createElement( tag );
	if ( text && text.length > 0 )
		node.appendChild( document.createTextNode( text ) );
	return node;
}

/* Add a style */
function addStyle( rule )
{
	if ( isIE && !isOpera && !isMacIE5 ) {
		var elem = document.createStyleSheet().cssText = rule;
	}
	else {
		var elem = document.createElement( 'LINK' );
		elem.rel = 'stylesheet';
		elem.type = 'text/css';
		elem.href = 'data:text/css,' + escape( rule );
		document.getElementsByTagName( 'HEAD' )[ 0 ].appendChild( elem );
	}
}

/* Switch header image on main pages */
function switchHeaderImage()
{
	if ( document.body.className.indexOf( 'mainPage' ) != -1 ) {
		var pageHeading = document.getElementById( 'pageHeading' );
		if ( pageHeading )
			pageHeading.className = "pageHeading" + Math.round( Math.random() * 13 );
	}
}

function changeWidth(theElement)
{
	if(isIE)
	{
		theElement.className = 'expandBox';
	}
}
function changeWidthBack(theElement)
{
	if(isIE)
	{
		theElement.className = 'normalBox';
	}
}

function checkForMacIE()
{
	if( isMacIE5 )
	{
		alert('Internet Explorer for Macintosh is not supported on this site please use FireFox or Safari');
	}
}

addLoadEvent( switchHeaderImage );