//=========================//
//						   //
// Live Search Javascript  //
//						   //
//=========================//

//$Id:livesearch.js 711 2009-06-10 14:31:55Z jamescollier $

//Global variables.
var httprequest; //Request object.
var link_number; //Hyperlink number that is appearing as being 'hovered' over.
var arrows_active; //True if updown arrows have been used to navigate live search items, false if not.

//Function: showLiveSearchResult()
//Called 'onKeyUp' when an entry is made in the live search box.
//Takes a variable and submits it to live_search_results.php as a get parameter.
function showLiveSearchResult(str,event)
{
	//Variables
	var live_search_results_page_url="live_search_results.php"; //Url of results page.
	live_search_results_page_url=live_search_results_page_url+"?p_live_search_input="+str;	//Add string to be found; the user's entry.
	live_search_results_page_url=live_search_results_page_url+"&sid="+Math.random(); //Add random number to stop caching. Shouldn't be a problem for our update frequency, though.

	//Handle event variable, and place code of key struck into key_code.
	if (!event) event = window.event;
	var key_code=event.keyCode? event.keyCode : event.charCode

	if (key_code == 40 || key_code == 38 || key_code == 13){
	 	 processMenuNavigation(key_code) //If 40 (Down Arrow), 38 (Up Arrow) or 13 (Return Key) are struck pass to processMenuNavigation().
	 }else{
	 	//If any other key if struck, handle it.

		link_number = 0; //Set link number to 0, so that up/down arrows start from the top.
		arrows_active = false; //Set to false so that return key will submit the form, as no entries are highlightem.

		//If string is 2 characters or under ignore so as to return too many results.
		if (str.length<=2)
			{
				document.getElementById("liveSearchDiv").style.display="none";
			  	return;
		  	}

		httprequest=GetXmlHttpObject() //Intiate request object.
		httprequest.open("GET",live_search_results_page_url,true);  //Open request using url string.
		httprequest.send(null);  //Send request.
		httprequest.onreadystatechange=stateChanged; //When state changes execute stateChanged function.

	}
}

//Function: stateChanged()
//Called by showLiveSearchResult() when ready state changes, ie results page is 'fetched'.
//The response text (the results) are placed into the live search div.
//Returns html.
function stateChanged()
{
	//If document is ready.
	if (httprequest.readyState==4)
	{
		var response = httprequest.responseText.split('\n').join(''); //Remove newline.
		if(response !== "") //Check if there's been a response (Any results found).
		{
			document.getElementById("liveSearchDiv").innerHTML=httprequest.responseText; //Insert response text.
			document.getElementById("liveSearchDiv").style.display="block"; //Make div viewable.
		}
	}
}

//Function GetXmlHttpObject()
//Create request object to be used to load live_search_results.php.
//Returns a new http request.
function GetXmlHttpObject()
{
	if (window.XMLHttpRequest)
	{
	  	// code for IE7+, Firefox, Chrome, Opera, Safari
	  	return new XMLHttpRequest();
	}
	if (window.ActiveXObject)
	{
		// code for IE6, IE5
		return new ActiveXObject("Microsoft.XMLHTTP");
	}
	return null;
}

//Function processMenuNavigation()
//Called by showLiveSearchResult() when up, down or enter is struck.
//Recieves a keycode (a code that represents a keyboard press) and uses it to navigate the live search results appropriately.
function processMenuNavigation(key_code)
{
	switch(key_code)
	{
		case 38: //Arrow Up
		    link_number -= 1; //When down arrow is pressed select previous url.

		    //If we are are the first url...
		    if(link_number == 0)
		    {
			   	var link_number_previous = link_number + 1; //Set previous to be last in the list.
		      	document.getElementById("liveSearchTextField").value = "" ; //Empty the search text field.
		      	arrows_active = true; //Set to true to that search box cannot be submitted.
		 	}else{
		 		//Set to true to that search box cannot be submitted
				arrows_active = true;
				//Previous is higher url, further up the url list.
		 	  	var link_number_previous = link_number + 1;
	 			//Set search text field to contain highlighted value (like google suggest).
		 	  	document.getElementById("liveSearchTextField").value = document.getElementById("livesearch_hyperlink_id_"+link_number).innerHTML.replace("&nbsp;&nbsp;","") ;
		 	 	//Set url to appear as though being hovered over.
		 	 	document.getElementById("livesearch_hyperlink_id_"+link_number).className="liveSearchLinkHover";
		 	 	document.getElementById("livesearch_hyperlink_id_"+link_number).style.color="#fff";
		 	}

			//Set url to appear as though not being hovered over.
		    document.getElementById("livesearch_hyperlink_id_"+link_number_previous).className="liveSearchLink";
		    document.getElementById("livesearch_hyperlink_id_"+link_number_previous).style.color='';
		    break;

	    case 40: //Arrow down

		    link_number ++; //When down arrow is pressed, increment url to be highlighted.
		    var link_number_previous = link_number - 1; //Url to be un-highlighted, previous highlighted url.

			//If there are no more urls in list, keep last url highlighted.
		    if(document.getElementById("livesearch_hyperlink_id_"+link_number) == null){
		      	link_number = link_number - 1;
		      	link_number_previous = link_number_previous + 1;
		    }

		    //Set arrows active to true, to precent return key submitting form.
			arrows_active = true;
		    //Set search text field to contain highlighted value (like google suggest).
		    document.getElementById("liveSearchTextField").value = document.getElementById("livesearch_hyperlink_id_"+link_number).innerHTML.replace("&nbsp;&nbsp;","") ;

		    //Set next url to appear as if hovered.
		    document.getElementById("livesearch_hyperlink_id_"+link_number).className="liveSearchLinkHover";
		    document.getElementById("livesearch_hyperlink_id_"+link_number).style.color="#fff";
		    //Set previous url to appear as if not hovered.
		    document.getElementById("livesearch_hyperlink_id_"+link_number_previous).className="liveSearchLink";
			document.getElementById("livesearch_hyperlink_id_"+link_number_previous).style.color='';
			break;

	    case 13: //Return key

		    var url = document.getElementById("livesearch_hyperlink_id_"+link_number).href; //Get highlighted url.
		    window.location = url; //Redirect to highlighted url.
	    	break;

	   }
}

//Function checkLiveSearchSubmission()
//Called to return true or false when 'find' (submit) is pressed on the live search form.
//Checks if enter should submit the form, or should follow highlighted link.
function checkLiveSearchSubmission(){

	if(arrows_active == true){
		//If any items have been highlighted via arrow keys, form cannot be submitted via return key.
		return false;

	}else{
		//Else, no highlited and search box can be submitted like a normal form.
		return true;
	}

}

//Function: resetHighlightedLinks()
//Called when a user hovers a live search link.
//Resets live search dropdown box items highlighted by the use of the arrow keys.
function resetHighlightedLinks()
{

	document.getElementById("livesearch_hyperlink_id_"+link_number).style.color='';
	link_number = 0; //Set global variable to '0', so that next time the user wants to use arrow keys it starts from the top.
	var reset_link_number = 1;

	//Cycles through links and set CSS class, untill 'null', meaning there are no more.
	while(document.getElementById("livesearch_hyperlink_id_"+reset_link_number) != null){
		document.getElementById("livesearch_hyperlink_id_"+reset_link_number).className="liveSearchLink";
		reset_link_number ++;
	}
}