/**

	ajax.js

	This file contains a collection of JavaScript functions
	used to run queries on the server without loading a complete
	page.

	Part of KMS, (C) 2014 Frederik Keim

  **/


//
//  Global variablees
//
var _readyStateHooks = new Array();


//
//  add a global ready state hook
//
function addReadyStateHook( hook )
{
      if ( !inArray( hook, _readyStateHooks ) )
      {
	    _readyStateHooks[_readyStateHooks.length] = hook;
      }
}

//
//  Remove a global ready state hook
//
function removeReadyStateHook( hook )
{
      arrayRemove( hook, _readyStateHooks );
}


//
//  Create and return a new XML-HTTP request object (browser
//  dependant)
//
function newXMLHttpRequest()
{
      var xmlreq = false;

      if( window.XMLHttpRequest )
      {
	    xmlreq = new XMLHttpRequest();
      }
      else if( window.ActiveXObject )
      {
	    try
	    {
		  xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
	    }
	    catch(e1)
	    {
		  try
		  {
			xmlreq = new ActiveXObject( "Microsoft.XMLHTTP" );
		  }
		  catch(e2)
		  {
			alert( "Fatal error: Your browser does not support XML HTTP requests!" );
		  }
	    }
      }

      return xmlreq;
}


//
//  Returns a function that processes the return value of the XML-HTTP request
//  depending on its HTTP status code
//
function getReadyStateHandler ( req, responseHandler, target, reqAction )
{
      return function()
      {
	    if( req.readyState == 4 )
	    {
		  if( req.status == 200 )
		  {
			// req.responseText contains response in plain text
			// req.responseXml contains XML or parsed DOM tree, RTFM!

			if ( target != null )
			{
			      if ( typeof target == 'string' )
			      {
				  target = document.getElementById(target);
				  target.responseHandler = function( responseText ) { this.innerHTML = responseText; };
			      }
			      target.responseHandler( req.responseText );
			      update( target, reqAction );

			      if ( typeof responseHandler == 'function' )
			      {
				    responseHandler( target );
			      }
			}
			else
			{
			      responseHandler( req.responseText );
			}
		  }
		  else if ( req.status == 401 )
		  {
			window.ignoreMods = true;
			window.location.href = window.baseUrl+"logout.php?sid="+window.sid;
		  }
		  else if( req.status == 403 )
		  {
			// http status 403, do something about that...
		  }
		  else
		  {
			if ( target != null )
			{
			      var errorString = 'Error: HTTP status '+req.status+' in action '+reqAction;
// 			      alert( errorString );
			      update( target, errorString+req.responseText, reqAction );
			}
		  }

	    }
      }
}


//
//  Sends a XML-HTTP request to action.php, sets its response handler
//  function and returns the request object
//
function action( reqAction, target, getParams, postParams, responseHandler )
{
      if ( target === undefined ) target = activeId;

      var async = true;// ( sync == undefined || sync == false ) ? true : false;

      var req = newXMLHttpRequest();
      var handlerFunction = getReadyStateHandler( req, responseHandler, target, reqAction );
      var project = ( window['projectCode'] != undefined ) ? "&project=" + window['projectCode'] : "";
      var projectLang = ( window['projectLang'] != undefined ) ? "&projectlang=" + window['projectLang'] : "";
      var reqUrl = "action.php?action="+reqAction+project+projectLang;
      if ( getParams != undefined ) reqUrl += '&' + getParams;
      if ( postParams == undefined ) var postParams = '';

      req.onreadystatechange = handlerFunction;
      req.open( "POST", reqUrl, true );
      req.setRequestHeader( "Content-Type", "application/x-www-form-urlencoded; charset=utf-8" );
//       req.setRequestHeader( "Content-length", postParams.length );
//       req.setRequestHeader( "Connection", "close" );
      req.send( postParams );

      return req;
}



//
//  Run an action with GET parameters only and with a specified
//  response handler function
//
function raction( name, param, responseHandler )
{
      req = action( name, null, param );
      req.onreadystatechange = function() {
	    if ( req.readyState == 4 && req.status == 200 ) eval( responseHandler+"( req.responseText );" );
      }
}


//
//  Returns the content of the file behind URL as plain text
//  (if it is on the same domain or the server has CORS enabled)
//
function remoteFileGet( URL, responseHandler )
{
      var req = newXMLHttpRequest();

      req.onreadystatechange = getReadyStateHandler( req, responseHandler );
      req.open( "GET", URL, true );
      req.setRequestHeader( "Content-Type", "application/x-www-form-urlencoded; charset=utf-8" );
      req.setRequestHeader( "Content-length", 0 );
      req.setRequestHeader( "Connection", "close" );
      req.send();

      return req;
}


//
//  Writes the HTML content of "content" into the DOM element "target",
//  calls the ready state hook functions and the report and system tray
//  update routines
//
function update( target, actionName )
{
      for ( var i = 0; i < _readyStateHooks.length; i++ )
      {
	    eval( _readyStateHooks[i]+"( target );" );
      }

      if ( self.updateReport ) updateReport( actionName );
      if ( self.updateSysTray ) updateSysTray();
}


//
//  Checks if a script file can be accessed on the server and loads
//  if it possible. Otherwise alerts an error.
//
function requireScript( url, responseHandler )
{
      var test = newXMLHttpRequest();
      var done = false;

      test.onreadystatechange = function() {
	    if ( !done && test.status > 0 )
	    {
		  done = true;
		  if ( test.status == 200 ) loadScript( url, responseHandler );
		  else alert( 'Error: no such JavaScript file: ' + url );
	    }
      };

      test.open( "GET", url );
      test.send( null );
}


//
//  Adds a JavaScript file at runtime to the DOM tree
//
function loadScript( url, responseHandler )
{
      if ( responseHandler == undefined ) var responseHandler = '';

      var head = document.getElementsByTagName("head")[0];
      var scriptId = url.replace( /[\/\.:]/g, '' );

      if ( document.getElementById( scriptId ) ) return;

      eval("var oldScript = document.getElementById('"+scriptId+"')");
      if ( oldScript != null )
      {
	    oldScript.parentNode.removeChild( oldScript );
	    delete oldScript;
      }

      var done		= false;

      var script	= document.createElement( 'script' );
      script.src	= url;
      script.type	= "text/javascript";
      script.id		= scriptId;
      script.responseHandler = responseHandler;

      script.onload = script.onreadystatechange = function() {
	    if ( !done && ( !this.readyState || this.readyState === "loaded" || this.readyState === "complete") )
	    {
		  done = true;
		  eval( this.responseHandler );

		  // Handle memory leak in IE
		  script.onload = script.onreadystatechange = null;

		  if ( head && script.parentNode )
		  {
			head.removeChild( script );
		  }
	    }
      };

      head.appendChild( script );

      return script;
}


//
//  Adds a CSS style sheet to the DOM tree at runtim
//
function loadCSS( url, sheetId )
{
      if ( sheetId == undefined ) var sheetId = url.replace( /[\/\.]/g, '' );
      if ( document.getElementById( sheetId ) ) return;

      var sheet = document.createElement( "link" );
      sheet.rel  = "stylesheet";
      sheet.href = url;
      sheet.id   = sheetId;
      document.getElementsByTagName("head")[0].appendChild( sheet );
}


function logout()
{
      var xmlhttp;
      if (window.XMLHttpRequest)
      {
	    xmlhttp = new XMLHttpRequest();
	    xmlhttp.open("GET", baseUrl, true, "logout", "logout");
	    xmlhttp.send("");
	    xmlhttp.onreadystatechange = function() {
		  if (xmlhttp.readyState == 4)
		  {
			location.reload(true);
		  }
	    }
      }
      else if (window.ActiveXObject)
      {
	    xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
	    document.execCommand("ClearAuthenticationCache");
	    location.reload(true);
      }
      return false;
}