/*!
 * http://www.kryogenix.org/code/browser/searchhi/ 
 * This script is by Stuart Langridge licensed under MIT license:
 * http://www.kryogenix.org/code/browser/licence.html
 * Modified by Peter Boere and Adam James.
*/

(function () {

	// Shortcuts
	var win = window,
		doc = document,
		loc = win.location,

		referrer = doc.referrer,

		// Parse referrer hostname from referrer string
		referrerHost = function () {
			var a = doc.createElement( 'a' );
			a.href = referrer;
			return a.hostname;
		}(),

		// By default check for the parameter 'q' as it's a convention
		searchParameter = 'q',

		// List any search engines that do not use the conventional 'q' query parameter;
		// less chance of creating unexpected effects this way ( i.e. 'p' could easily be used as an alias for 'page' or 'product' )
		searchEngines = {
			yahoo: 'p'
		},

		// Helper for iterating arrays, nodelists and objects
		each = function ( obj, callback ) {
			if ( obj+'' === '[object Object]' ) {
				for ( var key in obj ) {
					callback.call( obj, key, obj[ key ] );
				}
			}
			else {
				for ( var i = 0; i < obj.length; i++ ) {
					callback.call( obj, obj[ i ], i );
				}
			}
		},

		// Cache word match regexs for performance gain
		reCache = {},

		highlightWord = function ( node, word ) {
			// Iterate into this nodes childNodes
			if ( node.hasChildNodes ) {
				each( node.childNodes, function ( cn ) {
					highlightWord( cn, word );
				});
			}
			// And do this node itself if it's text and it hasn't already been highlighted
			if ( node.nodeType == 3 && node.parentNode.className != 'searchword' ) {
				var tempNodeVal = node.nodeValue.toLowerCase(),
					tempWordVal = word.toLowerCase(),
					// Setup regex outline
					wordPatt = '\\b' + tempWordVal + '\\b',
					// Get regex from cache or create it ( and cache for re-use )
					wordPatt = reCache[ wordPatt ] = ( reCache[ wordPatt ] || new RegExp( wordPatt ) ),

					match = wordPatt.exec( tempNodeVal );

				if ( match ) {
					var pn = node.parentNode,
						checkn = pn;

					// check if we're inside a "no-search-hilight" zone
					while ( checkn && checkn != doc.body ) { 
						if ( /\bno-search-hilight\b/.test( checkn.className ) ) { 
							return; 
						}
						checkn = checkn.parentNode;
					}

					var nv = node.nodeValue,
						ni = match.index,
						// Create a load of replacement nodes
						before = doc.createTextNode( nv.substr( 0, ni ) ),
						docWordVal = nv.substr( ni, word.length ),
						after = doc.createTextNode( nv.substr( ni + word.length ) ),
						hiwordtext = doc.createTextNode( docWordVal ),
						hiword = doc.createElement( 'span' );
					hiword.className = 'searchword';
					hiword.appendChild( hiwordtext );
					pn.insertBefore( before, node );
					pn.insertBefore( hiword, node );
					pn.insertBefore( after, node );
					pn.removeChild( node );
				}
			}
		},

		searchTermHighlight = function () {
			var tokens = referrer.substr( referrer.indexOf( '?' ) + 1 ).split( '&' );
			each( tokens, function ( token ) {
				var parts = token.split( '=' ),
					param = parts[ 0 ],
					value = parts[ 1 ];
				if ( value && param === searchParameter ) {
					var phrase = unescape( value.replace( /\+/g, ' ' ) ),
						words = phrase.split( /\s+/ );
					// Add the complete phrase to the front of the stack 
					words.unshift( phrase );
					each( words, function ( word ) {
						highlightWord( doc.body, word );
					});
				}
			});
		};

// Apply any non-standard search parameter
each( searchEngines, function ( engine, param ) {
	if ( referrerHost.indexOf( '.' + engine + '.' ) !== -1 ) {
		searchParameter = param;
	}
});

// Proceed only if the referrer string has a query
if ( referrer.indexOf( '?' ) === -1 ) {
	return;
}
else if ( 'jQuery' in win ) {
	jQuery( doc ).ready( searchTermHighlight );
}
else if ( 'addEventListener' in win ) {
	win.addEventListener( 'load', searchTermHighlight, false );
}
else if ( 'attachEvent' in win ) {
	win.attachEvent( 'onload', searchTermHighlight );
}
else {
	win.onload = searchTermHighlight();
}

})();