/*!**********************************************************************************
* Plancake.com                                                                    *
* Open-Source Project by Daniele Occhipinti (owner of plancake.com)               *
* =============================================================================== *
* Software by:                plancake.com team                                   *
* Copyright 2009-2010 by:     Daniele Occhipinti (owner of plancake.com)          *
* Support, News, Updates at:  http://www.plancake.com                             *
***********************************************************************************
* This program is open-source software; you may use it under                      *
* the terms of the provided license as published by Daniele Occhipinti.           *
*                                                                                 *
* This program is distributed in the hope that it is and will be useful, but      *
* WITHOUT ANY WARRANTIES; without even any implied warranty of MERCHANTABILITY    *
* or FITNESS FOR A PARTICULAR PURPOSE.                                            *
*                                                                                 *
* See the "lICENSE" file for details of the Plancake license.                     *
* The latest version can always be found at http://www.plancake.com.              *
**********************************************************************************/

// script by Josh Fraser (http://www.onlineaspect.com)
function calculate_time_zone() {
	var rightNow = new Date();
	var jan1 = new Date(rightNow.getFullYear(), 0, 1, 0, 0, 0, 0);  // jan 1st
	var june1 = new Date(rightNow.getFullYear(), 6, 1, 0, 0, 0, 0); // june 1st
	var temp = jan1.toGMTString();
	var jan2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
	temp = june1.toGMTString();
	var june2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
	var std_time_offset = (jan1 - jan2) / (1000 * 60 * 60);
	var daylight_time_offset = (june1 - june2) / (1000 * 60 * 60);
	var dst;
	if (std_time_offset == daylight_time_offset) {
		dst = "0"; // daylight savings time is NOT observed
	} else {
		// positive is southern, negative is northern hemisphere
		var hemisphere = std_time_offset - daylight_time_offset;
		if (hemisphere >= 0)
			std_time_offset = daylight_time_offset;
		dst = "1"; // daylight savings time is observed
	}
	var i;
	// check just to avoid error messages
	document.getElementById('registration_tz').value = convert(std_time_offset)+","+dst;
}

function convert(value) {
	var hours = parseInt(value);
   	value -= parseInt(value);
	value *= 60;
	var mins = parseInt(value);
   	value -= parseInt(value);
	value *= 60;
	var secs = parseInt(value);
	var display_hours = hours;
	// handle GMT case (00:00)
	if (hours == 0) {
		display_hours = "00";
	} else if (hours > 0) {
		// add a plus sign and perhaps an extra 0
		display_hours = (hours < 10) ? "+0"+hours : "+"+hours;
	} else {
		// add an extra 0 if needed 
		display_hours = (hours > -10) ? "-0"+Math.abs(hours) : hours;
	}
	
	mins = (mins < 10) ? "0"+mins : mins;
	return display_hours+":"+mins;
}

// by Daniele Occhipinti but adapted from above
function isDSTActiveNow()
{
    var rightNow = new Date();
    var jan1 = new Date(rightNow.getFullYear(), 0, 1, 0, 0, 0, 0);  // jan 1st
    var today1 = new Date(rightNow.getFullYear(), rightNow.getMonth(), rightNow.getDate(), 0, 0, 0, 0); // june 1st
    var temp = jan1.toGMTString();
    var jan2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
    temp = today1.toGMTString();
    var today2 = new Date(temp.substring(0, temp.lastIndexOf(" ")-1));
    var std_time_offset = (jan1 - jan2) / (1000 * 60 * 60);
    var daylight_time_offset = (today1 - today2) / (1000 * 60 * 60);
    var dst;
    if (std_time_offset == daylight_time_offset) {
	if (document.getElementById('registration_dst_on')) {
	  document.getElementById('registration_dst_on').value = 0;
	}
	return false;
    } else {
	if (document.getElementById('registration_dst_on')) {
	  document.getElementById('registration_dst_on').value = 1;
	}
	return true;
    }
}