<?php
# -- BEGIN LICENSE BLOCK ---------------------------------------
#
# This file is part of Clearbricks.
#
# Copyright (c) 2003-2011 Olivier Meunier & Association Dotclear
# Licensed under the GPL version 2.0 license.
# See LICENSE file or
# http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
#
# -- END LICENSE BLOCK -----------------------------------------

/**
* Date/time utilities
*
* @package Clearbricks
* @subpackage Common
*/
class dt
{
	/**
	* Timestamp formating
	*
	* Returns a date formated like PHP 
	* {@link http://www.php.net/manual/en/function.strftime.php strftime}
	* function.
	* Special cases %a, %A, %b and %B are handled by {@link l10n} library.
	*
	* @param string	$p		Format pattern
	* @param integer	$ts		Timestamp
	* @param string	$tz		Timezone
	* @return	string
	*/
	public static function str($p,$ts=null,$tz=null)
	{
		if ($ts === null) { $ts = time(); }
		
		$hash = '799b4e471dc78154865706469d23d512';
		$p = preg_replace('/(?<!%)%(a|A)/','{{'.$hash.'__$1%w__}}',$p);
		$p = preg_replace('/(?<!%)%(b|B)/','{{'.$hash.'__$1%m__}}',$p);
		
		if ($tz) {
			$T = self::getTZ();
			self::setTZ($tz);
		}
		
		$res = strftime($p,$ts);
		
		if ($tz) {
			self::setTZ($T);
		}
		
		$res = preg_replace_callback('/{{'.$hash.'__(a|A|b|B)([0-9]{1,2})__}}/',array('self','_callback'),$res);
		
		return $res;
	}
	
	/**
	* Date to date
	*
	* Format a literal date to another literal date.
	*
	* @param string	$p		Format pattern
	* @param string	$dt		Date
	* @param string	$tz		Timezone
	* @return	string
	*/
	public static function dt2str($p,$dt,$tz=null)
	{
		return dt::str($p,strtotime($dt),$tz);
	}
	
	/**
	* ISO-8601 formatting
	*
	* Returns a timestamp converted to ISO-8601 format.
	*
	* @param integer	$ts		Timestamp
	* @param string	$tz		Timezone
	* @return	string
	*/
	public static function iso8601($ts,$tz='UTC')
	{
		$o = self::getTimeOffset($tz,$ts);
		$of = sprintf('%02u:%02u',abs($o)/3600,(abs($o)%3600)/60);
		return date('Y-m-d\\TH:i:s',$ts).($o < 0 ? '-' : '+').$of;
	}
	
	/**
	* RFC-822 formatting
	*
	* Returns a timestamp converted to RFC-822 format.
	*
	* @param integer	$ts		Timestamp
	* @param string	$tz		Timezone
	* @return	string
	*/
	public static function rfc822($ts,$tz='UTC')
	{
		# Get offset
		$o = self::getTimeOffset($tz,$ts);
		$of = sprintf('%02u%02u',abs($o)/3600,(abs($o)%3600)/60);
		return strftime('%a, %d %b %Y %H:%M:%S '.($o < 0 ? '-' : '+').$of,$ts);
	}
	
	/**
	* Timezone set
	*
	* Set timezone during script execution.
	*
	* @param	string	$tz		Timezone
	*/
	public static function setTZ($tz)
	{
		if (function_exists('date_default_timezone_set')) {
			date_default_timezone_set($tz);
			return;
		}
		
		if (!ini_get('safe_mode')) {
			putenv('TZ='.$tz);
		}
	}
	
	/**
	* Current timezone
	*
	* Returns current timezone.
	*
	* @return string
	*/
	public static function getTZ()
	{
		if (function_exists('date_default_timezone_get')) {
			return date_default_timezone_get();
		}
		
		return date('T');
	}
	
	/**
	* Time offset
	*
	* Get time offset for a timezone and an optionnal $ts timestamp.
	*
	* @param string	$tz		Timezone
	* @param integer	$ts		Timestamp
	* @return integer
	*/
	public static function getTimeOffset($tz,$ts=false)
	{
		if (!$ts) {
			$ts = time();
		}
		
		$server_tz = self::getTZ();
		$server_offset = date('Z',$ts);
		
		self::setTZ($tz);
		$cur_offset = date('Z',$ts);
		
		self::setTZ($server_tz);
		
		return $cur_offset-$server_offset;
	}
	
	/**
	* UTC conversion
	*
	* Returns any timestamp from current timezone to UTC timestamp.
	*
	* @param integer	$ts		Timestamp
	* @return integer
	*/
	public static function toUTC($ts)
	{
		return $ts + self::getTimeOffset('UTC',$ts);
	}
	
	/**
	* Add timezone
	*
	* Returns a timestamp with its timezone offset.
	*
	* @param string	$tz		Timezone
	* @param integer	$ts		Timestamp
	* @return integer
	*/
	public static function addTimeZone($tz,$ts=false)
	{
		if (!$ts) {
			$ts = time();
		}
		
		return $ts + self::getTimeOffset($tz,$ts);
	}
	
	/**
	* Timzones
	*
	* Returns an array of supported timezones, codes are keys and names are values.
	*
	* @todo Store timzones in a static variable at the first time.
	*
	* @param boolean	$flip	Names are keys and codes are values
	* @param boolean	$groups	Return timezones in arrays of continents
	* @return array
	*/
	public static function getZones($flip=false,$groups=false)
	{
		if (!is_readable($f = dirname(__FILE__).'/tz.dat')) {
			return array();
		}
		
		$tz =  file(dirname(__FILE__).'/tz.dat');
		
		$res = array();
		
		foreach ($tz as $v)
		{
			$v = trim($v);
			if ($v) {
				$res[$v] = str_replace('_',' ',$v);
			}
		}
		
		if ($flip) {
			$res = array_flip($res);
			if ($groups) {
				$tmp = array();
				foreach ($res as $k => $v) {
					$g = explode('/',$k);
					$tmp[$g[0]][$k] = $v;
				}
				$res = $tmp;
			}
		}
		
		return $res;
	}
	
	private static function _callback($args)
	{
		$b = array(1=>'_Jan',2=>'_Feb',3=>'_Mar',4=>'_Apr',5=>'_May',6=>'_Jun',
		7=>'_Jul',8=>'_Aug',9=>'_Sep',10=>'_Oct',11=>'_Nov',12=>'_Dec');
		
		$B = array(1=>'January',2=>'February',3=>'March',4=>'April',
		5=>'May',6=>'June',7=>'July',8=>'August',9=>'September',
		10=>'October',11=>'November',12=>'December');
		
		$a = array(1=>'_Mon',2=>'_Tue',3=>'_Wed',4=>'_Thu',5=>'_Fri',
		6=>'_Sat',0=>'_Sun');
		
		$A = array(1=>'Monday',2=>'Tuesday',3=>'Wednesday',4=>'Thursday',
		5=>'Friday',6=>'Saturday',0=>'Sunday');
		
		return __(${$args[1]}[(integer) $args[2]]);
	}
}
?>