/*******************************************************

AutoSuggest - a javascript automatic text input completion component
Copyright (C) 2005 Joe Kepley, The Sling & Rock Design Group, Inc.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*******************************************************

Please send any useful modifications or improvements via 
email to joekepley at yahoo (dot) com

*******************************************************/

/********************************************************
 The AutoSuggest class binds to a text input field
 and creates an automatic suggestion dropdown in the style
 of the "IntelliSense" and "AutoComplete" features of some
 desktop apps. 
 Parameters: 
 elem: A DOM element for an INPUT TYPE="text" form field
 suggestions: an array of strings to be used as suggestions
              when someone's typing.

 Example usage: 
 
 Please enter the name of a fruit.
 <input type="text" id="fruit" name="fruit" />
 <script language="Javascript">
 var fruits=new Array("apple","orange","grape","kiwi","cumquat","banana");
 new AutoSuggest(document.getElementById("fruit",fruits));
 </script>

 Requirements: 

 Unfortunately the AutoSuggest class doesn't seem to work 
 well with dynamically-created DIVs. So, somewhere in your 
 HTML, you'll need to add this: 
 <div id="autosuggest"><ul></ul></div>

 Here's a default set of style rules that you'll also want to 
 add to your CSS: 

 .suggestion_list
 {
 background: white;
 border: 1px solid;
 padding: 4px;
 }

 .suggestion_list ul
 {
 padding: 0;
 margin: 0;
 list-style-type: none;
 }

 .suggestion_list a
 {
 text-decoration: none;
 color: navy;
 }

 .suggestion_list .selected
 {
 background: navy;
 color: white;
 }

 .suggestion_list .selected a
 {
 color: white;
 }

 #autosuggest
 {
 display: none;
 }
*********************************************************/
function AutoSuggest(elem, suggestions, combo, collId, homepageUrl)
{

	//The 'me' variable allow you to access the AutoSuggest object
	//from the elem's event handlers defined below.
	var me = this;
	
	var req;
	
	var size;
	
	this.homepageUrl = homepageUrl;
	this.combo  = combo;
	this.collId = collId;

	//A reference to the element we're binding the list to.
	this.elem = elem;

	this.suggestions = suggestions;

	//Arrow to store a subset of eligible suggestions that match the user's input
	this.eligible = new Array();

	//The text input by the user.
	this.inputText = null;

	//A pointer to the index of the highlighted eligible item. -1 means nothing highlighted.
	this.highlighted = -1;
	
	//browser name
    this.b = navigator.appName;

	//A div to use to create the dropdown.
	this.div = document.getElementById("autosuggest");
	
	//if ie put iframe into document
	if ( this.b == "Microsoft Internet Explorer" ) {
       var iframeEl = document.createElement("IFRAME");
       iframeEl.frameBorder = 0;
       iframeEl.src = "javascript:false;";
       iframeEl.style.display = "none";
       iframeEl.style.position = "absolute";
       iframeEl.style.filter = "progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)";
       this.iframe = this.div.parentNode.insertBefore(iframeEl, this.div);
    }
    
	//Do you want to remember what keycode means what? Me neither.
	var TAB = 9;
	var ESC = 27;
	var KEYUP = 38;
	var KEYDN = 40;
	var ENTER = 13;

	//The browsers' own autocomplete feature can be problematic, since it will 
	//be making suggestions from the users' past input.
	//Setting this attribute should turn it off.
	elem.setAttribute("autocomplete","off");
	
	

	//We need to be able to reference the elem by id. If it doesn't have an id, set one.
	if(!elem.id)
	{
		var id = "autosuggest" + idCounter;
		idCounter++;

		elem.id = id;
	}


	/********************************************************
	onkeydown event handler for the input elem.
	Tab key = use the highlighted suggestion, if there is one.
	Esc key = get rid of the autosuggest dropdown
	Up/down arrows = Move the highlight up and down in the suggestions.
	********************************************************/
	elem.onkeydown = function(ev)
	{
		var key = me.getKeyCode(ev);

		switch(key)
		{
			case TAB:
			me.useSuggestion();
			break;
			
			case ENTER:
			me.useSuggestion();
			break;

			case ESC:
			me.hideDiv();
			break;

			case KEYUP:
			if (me.highlighted > 0)
			{
				me.highlighted--;
			}
			me.changeHighlight(key);
			break;

			case KEYDN:
			if (me.highlighted < (me.eligible.length - 1))
			{
				me.highlighted++;
			}
			me.changeHighlight(key);
			break;
		}
	};

	/********************************************************
	onkeyup handler for the elem
	If the text is of sufficient length, and has been changed, 
	then display a list of eligible suggestions.
	********************************************************/
	elem.onkeyup = function(ev) 
	{
		var key = me.getKeyCode(ev);
		switch(key)
		{
		//The control keys were already handled by onkeydown, so do nothing.
		case TAB:
		case ESC:
		case KEYUP:
		case KEYDN:
			return;
		default:

			if (this.value != me.inputText && this.value.length > 0)
			{
				me.inputText = this.value;
				me.update(this.value);
			}
			else
			{
				me.hideDiv();
			}
		}
	};
	
	/********************************************************
	Update Ajax reponse
	********************************************************/
	 this.update = function(input) {
	    var attid = "-2";
	    if ( this.combo != null) attid = this.combo();
	    var url = me.homepageUrl;
	    url +="/ajax.xml?wid=GetAttributeValues&attId="+attid;
	    url += "&dirids="+this.collId;
	    url += "&input=" + encodeURIComponent(input);
        if (window.XMLHttpRequest) {
          req = new XMLHttpRequest();
        } else if (window.ActiveXObject) {
          req = new ActiveXObject("Microsoft.XMLHTTP");
        }
        req.open("GET", url, true);
        req.onreadystatechange = me.callback;
        req.send("");
     }
	
	/********************************************************
 	 AJAX method called back when AJAX response is ready
	********************************************************/
	 this.callback = function() {
	   
       if (req.readyState == 4) {
          if (req.status == 200) {
              me.hideDiv();
	 	 	  me.parseMessage();
			  me.getEligible();
			  me.createDiv();
			  me.positionDiv();
			  if(size > 0) me.showDiv();
           }
       }
     }
		
	/********************************************************
 	 Parses received ajax xml response
	********************************************************/
     this.parseMessage = function() {

   	     var message = req.responseXML.getElementsByTagName("GetAttributeValues")[0];
	     size = message.getAttribute("size");
	     this.suggestions = new Array(size);
	     var j = 0;
   	     si = 0;
	     for ( var i = 0; i < message.childNodes.length ; i++)
	     {
	       var info = message.childNodes[i];
		   if(info.firstChild != null) {
	          this.suggestions[parseInt(j)] = info.firstChild.nodeValue;
	          j++;
	       }
	      si++;
	     }
	      
	  }


	/********************************************************
	Insert the highlighted suggestion into the input box, and 
	remove the suggestion dropdown.
	********************************************************/
	this.useSuggestion = function()
	{
		if (this.highlighted > -1)
		{
			this.elem.value = this.eligible[parseInt(this.highlighted)];
			this.hideDiv();
			//It's impossible to cancel the Tab key's default behavior. 
			//So this undoes it by moving the focus back to our field right after
			//the event completes.
			//document.getElementById(this.elem.id).focus();
			setTimeout("document.getElementById('" + this.elem.id + "').focus()",0);
			
		}
	};

	/********************************************************
	Display the dropdown. Pretty straightforward.
	********************************************************/
	this.showDiv = function()
	{
		if ( this.b == "Microsoft Internet Explorer" )
		{
		 this.iframe.style.height = this.div.style.height;
		 this.iframe.style.filter = "progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0)";
		 this.iframe.style.display = 'block';
		}
		this.div.style.display = 'block';
	};

	/********************************************************
	Hide the dropdown and clear any highlight.
	********************************************************/
	this.hideDiv = function()
	{
		if ( this.b == "Microsoft Internet Explorer" ) this.iframe.style.display = 'none';
		this.div.style.display = 'none';
		this.highlighted = -1;
	};

	/********************************************************
	Modify the HTML in the dropdown to move the highlight.
	********************************************************/
	this.changeHighlight = function()
	{
		var lis = this.div.getElementsByTagName('LI');
		for (i in lis)
		{
			var li = lis[i];

			if (this.highlighted == i)
			{
				li.className = "selected";
			}
			else
			{
				li.className = "";
			}
		}
	};

	/********************************************************
	Position the dropdown div below the input text field.
	********************************************************/
	this.positionDiv = function()
	{
		var el = this.elem;
		var x = 0;
		var y = el.offsetHeight;
	
		//Walk up the DOM and add up all of the offset positions.
		while (el.offsetParent && el.tagName.toUpperCase() != 'BODY')
		{
			x += el.offsetLeft;
			y += el.offsetTop;
			el = el.offsetParent;
		}

		x += el.offsetLeft;
		y += el.offsetTop;

		this.div.style.left = x + 'px';
		this.div.style.top = y + 'px';
	
		if ( this.b == "Microsoft Internet Explorer" ) {
			this.iframe.style.left = x + 'px';
			this.iframe.style.top = y + 'px';
		}
	
	};

	/********************************************************
	Build the HTML for the dropdown div
	********************************************************/
	this.createDiv = function()
	{
		var ul = document.createElement('ul');
	
		//Create an array of LI's for the words.
		for (i in this.eligible)
		{
			var word = this.eligible[i];
	
			var li = document.createElement('li');
			var a = document.createElement('a');
			a.href="javascript:false";
			a.innerHTML = word;
			li.appendChild(a);
	
			if (me.highlighted == i)
			{
				li.className = "selected";
			}
	
			ul.appendChild(li);
		}
	

	    this.div.replaceChild(ul,this.div.childNodes[0]);

	

		/********************************************************
		mouseover handler for the dropdown ul
		move the highlighted suggestion with the mouse
		********************************************************/
		ul.onmouseover = function(ev)
		{
			//Walk up from target until you find the LI.
			var target = me.getEventSource(ev);
			while (target.parentNode && target.tagName.toUpperCase() != 'LI')
			{
				target = target.parentNode;
			}
		
			var lis = me.div.getElementsByTagName('LI');
			
	
			for (i in lis)
			{
				var li = lis[i];
				if(li == target)
				{
					me.highlighted = i;
					break;
				}
			}
			me.changeHighlight();
		};

		/********************************************************
		click handler for the dropdown ul
		insert the clicked suggestion into the input
		********************************************************/
		ul.onclick = function(ev)
		{
			me.useSuggestion();
			me.hideDiv();
			me.cancelEvent(ev);
			return false;
		};

//		if ( this.b == "Microsoft Internet Explorer" ){
//		this.iframe.className="suggestion_list";
//		this.iframe.style.position = 'absolute';
//		}
//	    else {
		this.div.className="suggestion_list";
		this.div.style.position = 'absolute';
//		}

	};

	/********************************************************
	determine which of the suggestions matches the input
	********************************************************/
	this.getEligible = function()
	{
	    this.eligible = this.suggestions;
	};

	/********************************************************
	Helper function to determine the keycode pressed in a 
	browser-independent manner.
	********************************************************/
	this.getKeyCode = function(ev)
	{
		if(ev)			//Moz
		{
			return ev.keyCode;
		}
		if(window.event)	//IE
		{
			return window.event.keyCode;
		}
	};

	/********************************************************
	Helper function to determine the event source element in a 
	browser-independent manner.
	********************************************************/
	this.getEventSource = function(ev)
	{
		if(ev)			//Moz
		{
			return ev.target;
		}
	
		if(window.event)	//IE
		{
			return window.event.srcElement;
		}
	};

	/********************************************************
	Helper function to cancel an event in a 
	browser-independent manner.
	(Returning false helps too).
	********************************************************/
	this.cancelEvent = function(ev)
	{
		if(ev)			//Moz
		{
			ev.preventDefault();
			ev.stopPropagation();
		}
		if(window.event)	//IE
		{
			window.event.returnValue = false;
		}
	}
	
}

//counter to help create unique ID's
var idCounter = 0;