/*
 * FCKeditor - The text editor for internet
 * Copyright (C) 2003-2005 Frederico Caldeira Knabben
 * 
 * Licensed under the terms of the GNU Lesser General Public License:
 * 		http://www.opensource.org/licenses/lgpl-license.php
 * 
 * For further information visit:
 * 		http://www.fckeditor.net/
 * 
 * "Support Open Source software. What about a donation today?"
 * 
 * File Name: fckscriptloader.js
 * 	Defines the FCKScriptLoader object that is used to dynamically load
 * 	scripts in the editor.
 * 
 * File Authors:
 * 		Frederico Caldeira Knabben (fredck@fckeditor.net)
 */

// This object is used to download scripts and css files sequentialy.
// A file download is not started until the previous file was not completelly
// downloaded.
var FCKScriptLoader = new Object() ;
FCKScriptLoader.IsLoading = false ;
FCKScriptLoader.Queue = new Array() ;

// Adds a script or css to the queue.
FCKScriptLoader.AddScript = function( scriptPath )
{
	FCKScriptLoader.Queue[ FCKScriptLoader.Queue.length ] = scriptPath ;
	
	if ( !this.IsLoading )
		this.CheckQueue() ;
}

// Checks the queue to see if there is something to load.
// This function should not be called by code. It's a internal function
// that's called recursively.
FCKScriptLoader.CheckQueue = function() 
{
	// Check if the queue is not empty.
	if ( this.Queue.length > 0 )
	{
		this.IsLoading = true ;
		
		// Get the first item in the queue
		var sScriptPath = this.Queue[0] ;
		
		// Removes the first item from the queue
		var oTempArray = new Array() ;
		for ( i = 1 ; i < this.Queue.length ; i++ )
			oTempArray[ i - 1 ] = this.Queue[ i ] ;
		this.Queue = oTempArray ;
		
		this.LoadFile( sScriptPath ) ;
	}
	else
	{
		this.IsLoading = false ;
		
		// Call the "OnEmpty" event.
		if ( this.OnEmpty ) 
			this.OnEmpty() ;
	}
}

FCKScriptLoader.LoadFile = function( filePath ) 
{
	//window.status = ( 'Loading ' + filePath + '...' ) ;

	// Dynamically load the file (it can be a CSS or a JS)
	var e ;
	
	// If it is a CSS
	if ( filePath.lastIndexOf( '.css' ) > 0 )
	{
		e = document.createElement( 'LINK' ) ;
		e.rel	= 'stylesheet' ;
		e.type	= 'text/css' ;
	}
	// It it is a JS
	else
	{
		e = document.createElement( "script" ) ;
			e.type	= "text/javascript" ;
	}
	
	// Add the new object to the HEAD.
	document.getElementsByTagName("head")[0].appendChild( e ) ; 

	// Start downloading it.
	if ( e.tagName == 'LINK' )
	{
		// IE must wait for the file to be downloaded.
		if ( FCKBrowserInfo.IsIE )
			e.onload = FCKScriptLoader_OnLoad ;
		// Gecko doens't fire any event when the CSS is loaded, so we 
		// can't wait for it.
		else
			FCKScriptLoader.CheckQueue() ;
			
		e.href = filePath ;
	}
	else
	{
		// Gecko fires the "onload" event and IE fires "onreadystatechange"
		e.onload = e.onreadystatechange = FCKScriptLoader_OnLoad ;
		e.src = filePath ;
	}
}

function FCKScriptLoader_OnLoad()
{
	// Gecko doesn't have a "readyState" property
	if ( this.tagName == 'LINK' || !this.readyState || this.readyState == 'loaded' )
		// Load the next script available in the queue
		FCKScriptLoader.CheckQueue() ;
}
