//
// Javascript library containing the "svUnits" unit conversion widget
// v1.0 - 8/28/09
//

var debug=0;
var SVUNITS_SID = "2_1";

// these variables can be set by user before calling this library
// but if not, here are the defaults:
if (typeof(svUnits_main_bg) == 'undefined') svUnits_main_bg="white";
if (typeof(svUnits_main_text) == 'undefined') svUnits_main_text="navy";
if (typeof(svUnits_main_border) == 'undefined') svUnits_main_border="1px solid blue";
if (typeof(svUnits_top_bg) == 'undefined') svUnits_top_bg="navy";
if (typeof(svUnits_top_text) == 'undefined') svUnits_top_text="white";
if (typeof(svUnits_top_border) == 'undefined') svUnits_top_border="0px";
if (typeof(svUnits_result_bg) == 'undefined') svUnits_result_bg="navy";
if (typeof(svUnits_result_text) == 'undefined') svUnits_result_text="white";
if (typeof(svUnits_result_border) == 'undefined') svUnits_result_border="0px";
if (typeof(svUnits_unit_bg) == 'undefined') svUnits_unit_bg="#eeeeee";
if (typeof(svUnits_unit_text) == 'undefined') svUnits_unit_text="black";
if (typeof(svUnits_unit_border) == 'undefined') svUnits_unit_border="1px solid gray";

//////////////
//---------- HTML/DOC METHODS
//////////////

// quick wrapper for getElementById:
function _obj(id)
{
	return document.getElementById(id);
}



// write html to the DOM object given by id
// if dbg=1, add a debug button (if global debug=1)
// if op=+, add to current value
function htmlPut(id, html, op, dbg)
{
	var obj = _obj(id);
	if (dbg==null) dbg=0;
	if (op==null) op="";
	if (obj!=null){
		if (debug && dbg==1){
			// automatically insert a debug button
			html += "<input type='button' value='debug' onClick='debugDump(\"" +id+ "\");'>";
		}
		if (op=="+"){
			obj.innerHTML += html;
		} else {
			obj.innerHTML = html;
		}
	}
}


// write debug text to the debug textarea
function debugPut(txt)
{
	debugtxt += "<br/>"+txt;
	if (debug) htmlPut("debug", debugtxt);
}

// called from debug buttons to dump the innerHTML of page sections to debug area
// id = name of an Document object (span) to dump
function debugDump(id)
{
	var obj = _obj(id);
	if (obj==null) return;
	var txt = obj.innerHTML;
	debugtxt = "<textarea cols='60' rows='10'>"+txt+"</textarea>";
	htmlPut("debug", debugtxt);
}

// dummy for now
function showStatus(msg)
{
}

//////////////
//---------- XML METHODS
//////////////

//
// this is called when an XML block is done loading
//
function xmlReturn (){
    if (req.readyState == 4) {    // if req shows "complete"
        if (req.status == 200) {        // if status="OK"
            // ...processing statements go here...
	        showStatus("Ready");	// update status bar
	        //
	        // all responses should have a <method> tag naming a processing function
	        var target_obj = "scvunitz_"+_xdoctag(req.responseXML.documentElement,"target");
	        var contents = _xdoctag(req.responseXML.documentElement,"contents");
	        htmlPut(target_obj, contents);
        } else {
            alert("There was a problem retrieving the XML data:\n" + req.status + "\n" + req.statusText);
	        showStatus(req.statusText);	// update status bar
        }
    }
}


// quick wrapper for XML parsing getElementsByTagName:
// doc is an XMLResponse documentElement
function _xdoctag(doc,id)
{
	var child=doc.getElementsByTagName(id)[0];
	if (child==null){  alert(id+" not found."); return ""; }
	child = child.firstChild;
	return (child==null) ? "" : child.data;
}

//
// this is called to initiate an XML request
// xtype = type of data to get: Script|Node (must be capitalized, since it's used in an URL)
// parameters are in name=value&name=value format
//
function getXML(xtype,params) 
{
	var URL = "http://scvs.com/dev/units/get_"+xtype+".php?"+params;
	URL += "&host="+window.location.host+"&sid="+SVUNITS_SID;
//	alert(URL);
	var waitmsg = "Waiting for XML.";
	debugtxt = "";		// clear debug buffer
    debugPut(URL);	// update status bar
    if (window.XMLHttpRequest) {	    // branch for native XMLHttpRequest object
        req = new XMLHttpRequest();
    } else if (window.ActiveXObject) {	    // branch for IE/Windows ActiveX version
        req = new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        debugPut("No request object.");	// update status bar
        return;
    }
    if (req) {
        req.onreadystatechange = xmlReturn;
        showStatus(waitmsg);	// update status bar
        req.open("GET", URL, true);
        req.send(null);
    }
}

// a category has been selected, call to get the units section:
function getUnits(){
	var cat = document.scvunitz_cat_form.category.value;
	getXML("units","fmt=xhtml&cat="+cat);
}


// a category has been selected, call to get the units section:
function getFinal(){
	var _amt = document.scvunitz_core_form.amount.value;
	var _to = document.scvunitz_core_form.to_unit.value;
	var _from = document.scvunitz_core_form.from_unit.value;
	var cat = document.scvunitz_core_form.category.value;
	getXML("convert","fmt=xhtml&cat="+cat+"&amt="+_amt+"&to="+_to+"&from="+_from);
}

var scvUnits_cat_list = "<b>Category:</b> <select name='category' onChange='getUnits();'>"
	+"<option value=''>Choose a Category::</option>"
	+"<option value='acceleration'>acceleration</option>"
	+"<option value='angle'>angle</option>"
	+"<option value='area'>area</option>"
	+"<option value='charge'>charge</option>"
	+"<option value='current'>current</option>"
	+"<option value='length'>distance</option>"
	+"<option value='energy'>energy</option>"
	+"<option value='fluid volume'>fluid volume</option>"
	+"<option value='force'>force</option>"
	+"<option value='length'>length</option>"
	+"<option value='magnetic field'>magnetic field</option>"
	+"<option value='mass'>mass</option>"
	+"<option value='power'>power</option>"
	+"<option value='pressure'>pressure</option>"
	+"<option value='speed'>speed</option>"
	+"<option value='time'>time</option>"
	+"<option value='speed'>velocity</option>"
	+"<option value='volume'>volume</option>"
	+"<option value='mass'>weight</option>"
	+"</select>"
	+"";
// write all our style stuff here:
document.write("<style>.svUnits_maintable{font-family: Arial,Helvetica,Sans-Serif;font-size: 11px;background-color:"+svUnits_main_bg+"; color:"+svUnits_main_text+";border: "+svUnits_main_border+";}"
	+ ".svUnits_header{background-color:"+svUnits_top_bg+"; font-size: 14px;height: 24px;text-align: center;color:"+svUnits_top_text+";border: "+svUnits_top_border+";}"
	+ ".svUnits_units{background-color:"+svUnits_unit_bg+"; font-size: 12px; text-align: left; color:"+svUnits_unit_text+";border: "+svUnits_unit_border+";}"
	+ ".svUnits_result{background-color: "+svUnits_result_bg+"; font-size: 14px;text-align: center;color: "+svUnits_result_text+";border: "+svUnits_result_border+";}</style>");

var svUnits_about = "<a style='font-size:10px;' target='new' href='http://scvs.com/svUnits.php'>About <b>svUnits</b></a>\n";
var svUnits_head = "<td class='svUnits_header'><b>svUnits</b> ... a unit conversion widget</td>\n";
var svUnits_catform = "<form name='scvunitz_cat_form'>\n"
	+ "<div id='scvunitz_cat' width='298' height='40'>"+scvUnits_cat_list+"</div>\n"
	+ "</form>\n";
var svUnits_core = "<form name='scvunitz_core_form' method='post'>\n"
	+ "<div id='scvunitz_core' width='298' height='150'>"
	+ "Choose a category from the list above."
	+ "</div>\n"
	+ "</form>\n";

// write all our startup HTML here:
var svUnits_full = "<tr>\n"
	+ svUnits_head
	+ "</tr><tr>"
	+ "<td valign='top' align='center'>\n"
	+ svUnits_catform
	+ "<hr/>\n"
	+ svUnits_core
	+ "</td>\n</tr>\n"
	+ "<tr><td class='svUnits_result'>\n"
	+ "<div id='scvunitz_result' width='298' height='150'></div>\n"
	+ "<hr/>"+svUnits_about
	+ "</td></tr>\n";
document.write("<div id='scvunitz_main' width='302' height='262'>\n"
	+ "<table width='300' height='260' border='0' class='svUnits_maintable'>\n"
	+ svUnits_full
	+ "</table>\n</div>\n");



// begin by retrieving the category list:
//getXML("categories","fmt=xhtml");