/**
 * Ajax.js
 *
 * Collection of Scripts to allow in page communication from browser to (struts) server
 * ie can reload part instead of full page
 *
 * How to use
 * ==========
 * 1) Call retrieveURL from the relevant event on the HTML page (e.g. onclick)
 * 2) Pass the url to contact (e.g. Struts Action) and the name of the HTML form to post
 * 3) When the server responds ...
 *		 - the script loops through the response , looking for <span id="name">newContent</span>
 * 		 - each <span> tag in the *existing* document will be replaced with newContent
 *
 * NOTE: <span id="name"> is case sensitive. Name *must* follow the first quote mark and end in a quote
 *		 Everything after the first '>' mark until </span> is considered content.
 *		 Empty Sections should be in the format <span id="name"></span>
 */

//global variables
  var req;
  var which;
  var g_url;
  var g_sTop;  // to set the position of a scroll div

  /**
   * Get the contents of the URL via an Ajax call
   * url - to get content from (e.g. /struts-ajax/sampleajax.do?ask=COMMAND_NAME_1) 
   * nodeToOverWrite - when callback is made
   * nameOfFormToPost - which form values will be posted up to the server as part 
   *					of the request (can be null)
   */
  function retrieveURL(url,nameOfFormToPost) {
    
    //get the (form based) params to push up as part of the get request
    url=getFormAsString(url,nameOfFormToPost);
    document.body.className = "Wait";
    document.body.style.cursor = 'wait';
        
    //alert(url);
    //Do the Ajax call
    if (window.XMLHttpRequest) { // Non-IE browsers
      req = new XMLHttpRequest();
      req.onreadystatechange = processStateChange;
      try {
      	req.open("GET", url, true); //was get
      	req.setRequestHeader("Content-Type", "text/plain;charset=UTF-8");
      } catch (e) {
        alert("Problem Communicating with Server\n"+e);
        document.body.className = "Normal";
        document.body.style.cursor = 'default';
      }
      req.send(null);
    } else if (window.ActiveXObject) { // IE
      try {
      	req = new ActiveXObject("Msxml2.XMLHTTP");
      } catch (e) {
        try {
      		req = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (e) {
        	alert("Your browser does not support AJAX!");
        	document.body.className = "Normal";
        	document.body.style.cursor = 'default';
        }
      }
      if (req) {
        req.onreadystatechange = processStateChange;
        req.open("GET", url, true);
      	req.setRequestHeader("Content-Type", "text/plain;charset=UTF-8");
        req.send();
      }
    }
    
    g_url=url;
  }
  
 
  function retrieveURL1(url,nameOfFormToPost) {
    
    //get the (form based) params to push up as part of the get request
    url=getFormAsString1(url,nameOfFormToPost);
    //alert(url);
    //Do the Ajax call
    if (window.XMLHttpRequest) { // Non-IE browsers
      req = new XMLHttpRequest();
      req.onreadystatechange = processStateChange;
      try {
      	req.open("GET", url, true); //was get
      } catch (e) {
        alert("Problem Communicating with Server\n"+e);
      }
      req.send(null);
    } else if (window.ActiveXObject) { // IE
      
      req = new ActiveXObject("Microsoft.XMLHTTP");
      if (req) {
        req.onreadystatechange = processStateChange;
        req.open("GET", url, true);
        req.send();
      }
    }
  }

  // to run before the processing
  function preProcess() {
        if (document.getElementById("divFamily1"))
          g_sTop = document.getElementById("divFamily1").scrollTop;
        //alert(g_sTop);
  }
  
  // to run after the processing
  function postProcess() {
        if (document.getElementById("divFamily1") && g_sTop != document.getElementById("divFamily1").scrollTop 
        	&& (g_url.indexOf("processSupportFamily")>=0 || g_url.indexOf("processDriverFamilyList")>=0))
          document.getElementById("divFamily1").scrollTop=g_sTop;
        
        //change to normal cursor after refreshing page
        document.body.className = "Normal";
        document.body.style.cursor = 'default';
  }
  
/*
   * Set as the callback method for when XmlHttpRequest State Changes 
   * used by retrieveUrl
  */
  function processStateChange() {
      
  	  if (req.readyState == 4) { // Complete
      if (req.status == 200) { // OK response
        //alert("Ajax response:"+req.status);
        //alert("Ajax response:"+req.responseText);
        
        preProcess();
        
        //Split the text response into Span elements
        spanElements = splitTextIntoSpan(req.responseText);
        //alert("Ajax response:"+spanElements);
        //Use these span elements to update the page
        replaceExistingWithNewHtml(spanElements);
        
        postProcess();
        
      } else {
        //alert("status:\n " + req.status);
        alert("Problem with server response:\n " + req.statusText);
      }
    }
  }
 
 /**
  * gets the contents of the form as a URL encoded String
  * suitable for appending to a url
  * @param formName to encode
  * @return string with encoded form values , beings with &
  */ 
 function getFormAsString(url,formName){
 	
 	//Setup the return String
 	returnString ="";
 	
  	//Get the form values
 	if (document.forms[formName] != null) {
 	formElements=document.forms[formName].elements;
 	
 	//loop through the array , building up the url
 	//in the form /strutsaction.do&name=value
 	for ( var i=formElements.length-1; i>=0; --i ){
 		//we escape (encode) each value
 		if(formElements[i].type != "button" && formElements[i].type != "submit" && formElements[i].type != "checkbox"){	
 		  returnString=returnString+"&"+escape(formElements[i].name)+"="+escape(formElements[i].value); 
 		}else if(formElements[i].type == "checkbox"){
 	    returnString=returnString+"&"+escape(formElements[i].name)+"="+escape(formElements[i].checked);
 	  }
 	}}
 	
 	if(url.indexOf("?")<0 && returnString!=""){
 		returnString="?"+returnString.substring(1);
 	}
 	//return the values
 	/*if(returnString.indexOf("%28")>-1)
 	  returnString=replaceAll(returnString,"%28","(");
 	if(returnString.indexOf("%29")>-1)
 	  returnString=replaceAll(returnString,"%29",")");
 	alert(returnString);
 	*/
 	return (url+returnString); 
 }
 
 function getFormAsString1(url,formName){
 	
 	//Setup the return String
 	returnString ="";
 	
  	//Get the form values
 	formElements=document.forms[formName].elements;
 	
 	//loop through the array , building up the url
 	//in the form /strutsaction.do&name=value
 	
 	for ( var i=formElements.length-1; i>=0; --i ){
 		//we escape (encode) each value
 		//alert(formElements[i].type);
 		if(formElements[i].type != "button" && formElements[i].type != "submit" && formElements[i].type != "hidden" && formElements[i].type != "checkbox"){	
 		  returnString=returnString+"&"+escape(formElements[i].name)+"="+escape(formElements[i].value); 
 		}else if(formElements[i].type == "checkbox" && formElements[i].checked){
 	    returnString=returnString+"&"+escape(formElements[i].name)+"="+escape(formElements[i].value);
 	  }
 	}
 	
 	if(url.indexOf("?")<0){
 		returnString="?"+returnString.substring(1);
 	}
 	//return the values
 	/*if(returnString.indexOf("%28")>-1)
 	  returnString=replaceAll(returnString,"%28","(");
 	if(returnString.indexOf("%29")>-1)
 	  returnString=replaceAll(returnString,"%29",")");
 	alert(returnString);
 	*/
 	return (url+returnString); 
 }
 
 function replaceAll( str, from, to ) {
    var idx = str.indexOf( from );


    while ( idx > -1 ) {
        str = str.replace( from, to ); 
        idx = str.indexOf( from );
    }

    return str;
}
 
 
 /**
 * Splits the text into <span> elements
 * @param the text to be parsed
 * @return array of <span> elements - this array can contain nulls
 */
 function splitTextIntoSpan(textToSplit){
   
  	//Split the document
 	returnElements=textToSplit.split("</span>")
 	//alert("returnElements length "+returnElements.length);
 	//Process each of the elements 	
 	for ( var i=returnElements.length-1; i>=0; --i ){
 		
 		//Remove everything before the 1st span
 		spanPos = returnElements[i].indexOf("<span");		
 		
 		//if we find a match , take out everything before the span
 		if(spanPos>0){
 			subString=returnElements[i].substring(spanPos);
 			returnElements[i]=subString;
 		  //alert("span element"+subString);
 		} 
 	}
 	
 	return returnElements;
 }
 
 /*
  * Replace html elements in the existing (ie viewable document)
  * with new elements (from the ajax requested document)
  * WHERE they have the same name AND are <span> elements
  * @param newTextElements (output of splitTextIntoSpan)
  *					in the format <span id=name>texttoupdate
  */
 function replaceExistingWithNewHtml(newTextElements){
 	//loop through newTextElements
 	for ( var i=newTextElements.length-1; i>=0; --i ){
  
 		//check that this begins with <span
 		if(newTextElements[i].indexOf("<span")>-1){
 			
 			//get the name - between the 1st and 2nd quote mark
 			var startNamePos=newTextElements[i].indexOf('"')+1;
 			var endNamePos=newTextElements[i].indexOf('"',startNamePos);
 			var name=newTextElements[i].substring(startNamePos,endNamePos);
 			
 			//get the content - everything after the first > mark
 			startContentPos=newTextElements[i].indexOf('>')+1;
 			var htmlcontent=newTextElements[i].substring(startContentPos);
 			//alert("htmlcontent "+htmlcontent);
 			//Now update the existing Document with this element
 			
	 			//check that this element exists in the document
	 			if(document.getElementById(name)){
	 			
	 				//alert("Replacing Element:"+name);
	 				document.getElementById(name).innerHTML = htmlcontent;
	 			} else {
	 				//alert("Element:"+name+"not found in existing document");
	 			}
 		}
 	}
 }