12 files changed, 598 insertions, 114 deletions
diff --git a/phpBB/includes/acp/acp_board.php b/phpBB/includes/acp/acp_board.php
index d537885ef1..575d05933f 100644
--- a/phpBB/includes/acp/acp_board.php
+++ b/phpBB/includes/acp/acp_board.php
@@ -57,8 +57,7 @@ class acp_board
 						'board_disable_msg'		=> false,
 						'default_lang'			=> array('lang' => 'DEFAULT_LANGUAGE',		'validate' => 'lang',	'type' => 'select', 'function' => 'language_select', 'params' => array('{CONFIG_VALUE}'), 'explain' => false),
 						'default_dateformat'	=> array('lang' => 'DEFAULT_DATE_FORMAT',	'validate' => 'string',	'type' => 'custom', 'method' => 'dateformat_select', 'explain' => true),
-						'board_timezone'		=> array('lang' => 'SYSTEM_TIMEZONE',		'validate' => 'string',	'type' => 'select', 'function' => 'tz_select', 'params' => array('{CONFIG_VALUE}', 1), 'explain' => true),
-						'board_dst'				=> array('lang' => 'SYSTEM_DST',			'validate' => 'bool',	'type' => 'radio:yes_no', 'explain' => false),
+						'board_timezone'		=> array('lang' => 'SYSTEM_TIMEZONE',		'validate' => 'timezone',	'type' => 'custom', 'method' => 'timezone_select', 'explain' => true),
 						'default_style'			=> array('lang' => 'DEFAULT_STYLE',			'validate' => 'int',	'type' => 'select', 'function' => 'style_select', 'params' => array('{CONFIG_VALUE}', false), 'explain' => false),
 						'override_user_style'	=> array('lang' => 'OVERRIDE_STYLE',		'validate' => 'bool',	'type' => 'radio:yes_no', 'explain' => true),
 
@@ -897,6 +896,18 @@ class acp_board
 			'<br /><br /><input class="button2" type="submit" id="' . $key . '_enable" name="' . $key . '_enable" value="' . $user->lang['ALLOW_QUICK_REPLY_BUTTON'] . '" />';
 	}
 
+	/**
+	* Select guest timezone
+	*/
+	function timezone_select($value, $key)
+	{
+		global $user;
+
+		$timezone_select = phpbb_timezone_select($user, $value, true);
+		$timezone_select['tz_select'];
+
+		return '<select name="config[' . $key . ']" id="' . $key . '">' . $timezone_select['tz_select'] . '</select>';
+	}
 
 	/**
 	* Select default dateformat
@@ -907,10 +918,14 @@ class acp_board
 
 		// Let the format_date function operate with the acp values
 		$old_tz = $user->timezone;
-		$old_dst = $user->dst;
-
-		$user->timezone = $config['board_timezone'] * 3600;
-		$user->dst = $config['board_dst'] * 3600;
+		try
+		{
+			$user->timezone = new DateTimeZone($config['board_timezone']);
+		}
+		catch (Exception $e)
+		{
+			// If the board timezone is invalid, we just use the users timezone.
+		}
 
 		$dateformat_options = '';
 
@@ -930,7 +945,6 @@ class acp_board
 
 		// Reset users date options
 		$user->timezone = $old_tz;
-		$user->dst = $old_dst;
 
 		return "<select name=\"dateoptions\" id=\"dateoptions\" onchange=\"if (this.value == 'custom') { document.getElementById('" . addslashes($key) . "').value = '" . addslashes($value) . "'; } else { document.getElementById('" . addslashes($key) . "').value = this.value; }\">$dateformat_options</select>
 		<input type=\"text\" name=\"config[$key]\" id=\"$key\" value=\"$value\" maxlength=\"30\" />";
diff --git a/phpBB/includes/acp/acp_users.php b/phpBB/includes/acp/acp_users.php
index 1f827d00aa..79c91dd7ee 100644
--- a/phpBB/includes/acp/acp_users.php
+++ b/phpBB/includes/acp/acp_users.php
@@ -1460,9 +1460,8 @@ class acp_users
 				$data = array(
 					'dateformat'		=> utf8_normalize_nfc(request_var('dateformat', $user_row['user_dateformat'], true)),
 					'lang'				=> basename(request_var('lang', $user_row['user_lang'])),
-					'tz'				=> request_var('tz', (float) $user_row['user_timezone']),
+					'tz'				=> request_var('tz', $user_row['user_timezone']),
 					'style'				=> request_var('style', $user_row['user_style']),
-					'dst'				=> request_var('dst', $user_row['user_dst']),
 					'viewemail'			=> request_var('viewemail', $user_row['user_allow_viewemail']),
 					'massemail'			=> request_var('massemail', $user_row['user_allow_massemail']),
 					'hideonline'		=> request_var('hideonline', !$user_row['user_allow_viewonline']),
@@ -1497,7 +1496,7 @@ class acp_users
 					$error = validate_data($data, array(
 						'dateformat'	=> array('string', false, 1, 30),
 						'lang'			=> array('match', false, '#^[a-z_\-]{2,}$#i'),
-						'tz'			=> array('num', false, -14, 14),
+						'tz'			=> array('timezone'),
 
 						'topic_sk'		=> array('string', false, 1, 1),
 						'topic_sd'		=> array('string', false, 1, 1),
@@ -1533,7 +1532,6 @@ class acp_users
 							'user_notify_type'		=> $data['notifymethod'],
 							'user_notify_pm'		=> $data['notifypm'],
 
-							'user_dst'				=> $data['dst'],
 							'user_dateformat'		=> $data['dateformat'],
 							'user_lang'				=> $data['lang'],
 							'user_timezone'			=> $data['tz'],
@@ -1643,6 +1641,7 @@ class acp_users
 					${'s_sort_' . $sort_option . '_dir'} .= '</select>';
 				}
 
+				$timezone_selects = phpbb_timezone_select($user, $data['tz'], true);
 				$template->assign_vars(array(
 					'S_PREFS'			=> true,
 					'S_JABBER_DISABLED'	=> ($config['jab_enable'] && $user_row['user_jabber'] && @extension_loaded('xml')) ? false : true,
@@ -1656,7 +1655,6 @@ class acp_users
 					'NOTIFY_BOTH'		=> ($data['notifymethod'] == NOTIFY_BOTH) ? true : false,
 					'NOTIFY_PM'			=> $data['notifypm'],
 					'POPUP_PM'			=> $data['popuppm'],
-					'DST'				=> $data['dst'],
 					'BBCODE'			=> $data['bbcode'],
 					'SMILIES'			=> $data['smilies'],
 					'ATTACH_SIG'		=> $data['sig'],
@@ -1683,7 +1681,8 @@ class acp_users
 
 					'S_LANG_OPTIONS'	=> language_select($data['lang']),
 					'S_STYLE_OPTIONS'	=> style_select($data['style']),
-					'S_TZ_OPTIONS'		=> tz_select($data['tz'], true),
+					'S_TZ_OPTIONS'			=> $timezone_selects['tz_select'],
+					'S_TZ_DATE_OPTIONS'		=> $timezone_selects['tz_dates'],
 					)
 				);
 
diff --git a/phpBB/includes/datetime.php b/phpBB/includes/datetime.php
new file mode 100644
index 0000000000..b3462ddf67
--- /dev/null
+++ b/phpBB/includes/datetime.php
@@ -0,0 +1,158 @@
+<?php
+/**
+*
+* @package phpBB3
+* @copyright (c) 2012 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*/
+
+/**
+* phpBB custom extensions to the PHP DateTime class
+* This handles the relative formats phpBB employs
+*/
+class phpbb_datetime extends DateTime
+{
+	/**
+	* String used to wrap the date segment which should be replaced by today/tomorrow/yesterday
+	*/
+	const RELATIVE_WRAPPER = '|';
+
+	/**
+	* @var user User who is the context for this DateTime instance
+	*/
+	protected $user;
+
+	/**
+	* @var array Date formats are preprocessed by phpBB, to save constant recalculation they are cached.
+	*/
+	static protected $format_cache = array();
+
+	/**
+	* Constructs a new instance of phpbb_datetime, expanded to include an argument to inject
+	* the user context and modify the timezone to the users selected timezone if one is not set.
+	*
+	* @param string $time String in a format accepted by strtotime().
+	* @param DateTimeZone $timezone Time zone of the time.
+	* @param user User object for context.
+	*/
+	public function __construct($user, $time = 'now', DateTimeZone $timezone = null)
+	{
+		$this->user	= $user;
+		$timezone	= $timezone ?: $this->user->timezone;
+
+		parent::__construct($time, $timezone);
+	}
+
+	/**
+	* Formats the current date time into the specified format
+	*
+	* @param string $format Optional format to use for output, defaults to users chosen format
+	* @param boolean $force_absolute Force output of a non relative date
+	* @return string Formatted date time
+	*/
+	public function format($format = '', $force_absolute = false)
+	{
+		$format		= $format ? $format : $this->user->date_format;
+		$format		= self::format_cache($format, $this->user);
+		$relative	= ($format['is_short'] && !$force_absolute);
+		$now		= new self($this->user, 'now', $this->user->timezone);
+
+		$timestamp	= $this->getTimestamp();
+		$now_ts		= $now->getTimeStamp();
+
+		$delta		= $now_ts - $timestamp;
+
+		if ($relative)
+		{
+			/*
+			* Check the delta is less than or equal to 1 hour
+			* and the delta not more than a minute in the past
+			* and the delta is either greater than -5 seconds or timestamp
+			* and current time are of the same minute (they must be in the same hour already)
+			* finally check that relative dates are supported by the language pack
+			*/
+			if ($delta <= 3600 && $delta > -60 &&
+			  ($delta >= -5 || (($now_ts / 60) % 60) == (($timestamp / 60) % 60))
+			  && isset($this->user->lang['datetime']['AGO']))
+			{
+				return $this->user->lang(array('datetime', 'AGO'), max(0, (int) floor($delta / 60)));
+			}
+			else
+			{
+				$midnight = clone $now;
+				$midnight->setTime(0, 0, 0);
+
+				$midnight	= $midnight->getTimestamp();
+
+				$day = false;
+
+				if ($timestamp > $midnight + 86400)
+				{
+					$day = 'TOMORROW';
+				}
+				else if ($timestamp > $midnight)
+				{
+					$day = 'TODAY';
+				}
+				else if ($timestamp > $midnight - 86400)
+				{
+					$day = 'YESTERDAY';
+				}
+
+				if ($day !== false)
+				{
+					// Format using the short formatting and finally swap out the relative token placeholder with the correct value
+					return str_replace(self::RELATIVE_WRAPPER . self::RELATIVE_WRAPPER, $this->user->lang['datetime'][$day], strtr(parent::format($format['format_short']), $format['lang']));
+				}
+			}
+		}
+
+		return strtr(parent::format($format['format_long']), $format['lang']);
+	}
+
+	/**
+	* Magic method to convert DateTime object to string
+	*
+	* @return Formatted date time, according to the users default settings.
+	*/
+	public function __toString()
+	{
+		return $this->format();
+	}
+
+	/**
+	* Pre-processes the specified date format
+	*
+	* @param string $format Output format
+	* @param user $user User object to use for localisation
+	* @return array Processed date format
+	*/
+	static protected function format_cache($format, $user)
+	{
+		$lang = $user->lang_name;
+
+		if (!isset(self::$format_cache[$lang]))
+		{
+			self::$format_cache[$lang] = array();
+		}
+
+		if (!isset(self::$format_cache[$lang][$format]))
+		{
+			// Is the user requesting a friendly date format (i.e. 'Today 12:42')?
+			self::$format_cache[$lang][$format] = array(
+				'is_short'		=> strpos($format, self::RELATIVE_WRAPPER) !== false,
+				'format_short'	=> substr($format, 0, strpos($format, self::RELATIVE_WRAPPER)) . self::RELATIVE_WRAPPER . self::RELATIVE_WRAPPER . substr(strrchr($format, self::RELATIVE_WRAPPER), 1),
+				'format_long'	=> str_replace(self::RELATIVE_WRAPPER, '', $format),
+				'lang'			=> $user->lang['datetime'],
+			);
+
+			// Short representation of month in format? Some languages use different terms for the long and short format of May
+			if ((strpos($format, '\M') === false && strpos($format, 'M') !== false) || (strpos($format, '\r') === false && strpos($format, 'r') !== false))
+			{
+				self::$format_cache[$lang][$format]['lang']['May'] = $user->lang['datetime']['May_short'];
+			}
+		}
+
+		return self::$format_cache[$lang][$format];
+	}
+}
diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 633ac3d307..e5b721b1f5 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -1069,32 +1069,209 @@ function style_select($default = '', $all = false)
 }
 
 /**
+* Format the timezone offset with hours and minutes
+*
+* @param	int		$tz_offset	Timezone offset in seconds
+* @return	string		Normalized offset string:	-7200 => -02:00
+*													16200 => +04:30
+*/
+function phpbb_format_timezone_offset($tz_offset)
+{
+	$sign = ($tz_offset < 0) ? '-' : '+';
+	$time_offset = abs($tz_offset);
+
+	$offset_seconds	= $time_offset % 3600;
+	$offset_minutes	= $offset_seconds / 60;
+	$offset_hours	= ($time_offset - $offset_seconds) / 3600;
+
+	$offset_string	= sprintf("%s%02d:%02d", $sign, $offset_hours, $offset_minutes);
+	return $offset_string;
+}
+
+/**
+* Compares two time zone labels.
+* Arranges them in increasing order by timezone offset.
+* Places UTC before other timezones in the same offset.
+*/
+function phpbb_tz_select_compare($a, $b)
+{
+	$a_sign = $a[3];
+	$b_sign = $b[3];
+	if ($a_sign != $b_sign)
+	{
+		return $a_sign == '-' ? -1 : 1;
+	}
+
+	$a_offset = substr($a, 4, 5);
+	$b_offset = substr($b, 4, 5);
+	if ($a_offset == $b_offset)
+	{
+		$a_name = substr($a, 12);
+		$b_name = substr($b, 12);
+		if ($a_name == $b_name)
+		{
+			return 0;
+		}
+		else if ($a_name == 'UTC')
+		{
+			return -1;
+		}
+		else if ($b_name == 'UTC')
+		{
+			return 1;
+		}
+		else
+		{
+			return $a_name < $b_name ? -1 : 1;
+		}
+	}
+	else
+	{
+		if ($a_sign == '-')
+		{
+			return $a_offset > $b_offset ? -1 : 1;
+		}
+		else
+		{
+			return $a_offset < $b_offset ? -1 : 1;
+		}
+	}
+}
+
+/**
+* Return list of timezone identifiers
+* We also add the selected timezone if we can create an object with it.
+* DateTimeZone::listIdentifiers seems to not add all identifiers to the list,
+* because some are only kept for backward compatible reasons. If the user has
+* a deprecated value, we add it here, so it can still be kept. Once the user
+* changed his value, there is no way back to deprecated values.
+*
+* @param	string		$selected_timezone		Additional timezone that shall
+*												be added to the list of identiers
+* @return		array		DateTimeZone::listIdentifiers and additional
+*							selected_timezone if it is a valid timezone.
+*/
+function phpbb_get_timezone_identifiers($selected_timezone)
+{
+	$timezones = DateTimeZone::listIdentifiers();
+
+	if (!in_array($selected_timezone, $timezones))
+	{
+		try
+		{
+			// Add valid timezones that are currently selected but not returned
+			// by DateTimeZone::listIdentifiers
+			$validate_timezone = new DateTimeZone($selected_timezone);
+			$timezones[] = $selected_timezone;
+		}
+		catch (Exception $e)
+		{
+		}
+	}
+
+	return $timezones;
+}
+
+/**
 * Pick a timezone
+*
+* @param	string		$default			A timezone to select
+* @param	boolean		$truncate			Shall we truncate the options text
+*
+* @return		string		Returns the options for timezone selector only
+*
+* @deprecated
 */
 function tz_select($default = '', $truncate = false)
 {
 	global $user;
 
-	$tz_select = '';
-	foreach ($user->lang['tz_zones'] as $offset => $zone)
+	$timezone_select = phpbb_timezone_select($user, $default, $truncate);
+	return $timezone_select['tz_select'];
+}
+
+/**
+* Options to pick a timezone and date/time
+*
+* @param	phpbb_user	$user				Object of the current user
+* @param	string		$default			A timezone to select
+* @param	boolean		$truncate			Shall we truncate the options text
+*
+* @return		array		Returns an array, also containing the options for the time selector.
+*/
+function phpbb_timezone_select($user, $default = '', $truncate = false)
+{
+	static $timezones;
+
+	$default_offset = '';
+	if (!isset($timezones))
 	{
-		if ($truncate)
+		$unsorted_timezones = phpbb_get_timezone_identifiers($default);
+
+		$timezones = array();
+		foreach ($unsorted_timezones as $timezone)
 		{
-			$zone_trunc = truncate_string($zone, 50, 255, false, '...');
+			$tz = new DateTimeZone($timezone);
+			$dt = new phpbb_datetime($user, 'now', $tz);
+			$offset = $dt->getOffset();
+			$current_time = $dt->format($user->lang['DATETIME_FORMAT'], true);
+			$offset_string = phpbb_format_timezone_offset($offset);
+			$timezones['GMT' . $offset_string . ' - ' . $timezone] = array(
+				'tz'		=> $timezone,
+				'offest'	=> 'GMT' . $offset_string,
+				'current'	=> $current_time,
+			);
+			if ($timezone === $default)
+			{
+				$default_offset = 'GMT' . $offset_string;
+			}
+		}
+		unset($unsorted_timezones);
+
+		uksort($timezones, 'phpbb_tz_select_compare');
+	}
+
+	$tz_select = $tz_dates = $opt_group = '';
+
+	foreach ($timezones as $timezone)
+	{
+		if ($opt_group != $timezone['offest'])
+		{
+			$tz_select .= ($opt_group) ? '</optgroup>' : '';
+			$tz_select .= '<optgroup label="' . $timezone['offest'] . ' - ' . $timezone['current'] . '">';
+			$opt_group = $timezone['offest'];
+
+			$selected = ($default_offset == $timezone['offest']) ? ' selected="selected"' : '';
+			$tz_dates .= '<option value="' . $timezone['offest'] . ' - ' . $timezone['current'] . '"' . $selected . '>' . $timezone['offest'] . ' - ' . $timezone['current'] . '</option>';
+		}
+
+		if (isset($user->lang['timezones'][$timezone['tz']]))
+		{
+			$title = $label = $user->lang['timezones'][$timezone['tz']];
 		}
 		else
 		{
-			$zone_trunc = $zone;
+			// No label, we'll figure one out
+			$bits = explode('/', str_replace('_', ' ', $timezone['tz']));
+
+			$label = implode(' - ', $bits);
+			$title = $timezone['offest'] . ' - ' . $label;
 		}
 
-		if (is_numeric($offset))
+		if ($truncate)
 		{
-			$selected = ($offset == $default) ? ' selected="selected"' : '';
-			$tz_select .= '<option title="' . $zone . '" value="' . $offset . '"' . $selected . '>' . $zone_trunc . '</option>';
+			$label = truncate_string($label, 50, 255, false, '...');
 		}
+
+		$selected = ($timezone['tz'] === $default) ? ' selected="selected"' : '';
+		$tz_select .= '<option title="' . $title . '" value="' . $timezone['tz'] . '"' . $selected . '>' . $label . '</option>';
 	}
+	$tz_select .= '</optgroup>';
 
-	return $tz_select;
+	return array(
+		'tz_select'		=> $tz_select,
+		'tz_dates'		=> $tz_dates,
+	);
 }
 
 // Functions handling topic/post tracking/marking
@@ -4701,9 +4878,6 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 	$board_url = generate_board_url() . '/';
 	$web_path = (defined('PHPBB_USE_BOARD_URL_PATH') && PHPBB_USE_BOARD_URL_PATH) ? $board_url : $phpbb_root_path;
 
-	// Which timezone?
-	$tz = ($user->data['user_id'] != ANONYMOUS) ? strval(doubleval($user->data['user_timezone'])) : strval(doubleval($config['board_timezone']));
-
 	// Send a proper content-language to the output
 	$user_lang = $user->lang['USER_LANG'];
 	if (strpos($user_lang, '-x-') !== false)
@@ -4726,6 +4900,14 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 		}
 	}
 
+	$dt = new phpbb_datetime($user, 'now', $user->timezone);
+	$timezone_offset = 'GMT' . phpbb_format_timezone_offset($dt->getOffset());
+	$timezone_name = $user->timezone->getName();
+	if (isset($user->lang['timezones'][$timezone_name]))
+	{
+		$timezone_name = $user->lang['timezones'][$timezone_name];
+	}
+
 	// The following assigns all _common_ variables that may be used at any point in a template.
 	$template->assign_vars(array(
 		'SITENAME'						=> $config['sitename'],
@@ -4793,7 +4975,7 @@ function page_header($page_title = '', $display_online_list = true, $item_id = 0
 		'S_CONTENT_FLOW_BEGIN'	=> ($user->lang['DIRECTION'] == 'ltr') ? 'left' : 'right',
 		'S_CONTENT_FLOW_END'	=> ($user->lang['DIRECTION'] == 'ltr') ? 'right' : 'left',
 		'S_CONTENT_ENCODING'	=> 'UTF-8',
-		'S_TIMEZONE'			=> ($user->data['user_dst'] || ($user->data['user_id'] == ANONYMOUS && $config['board_dst'])) ? sprintf($user->lang['ALL_TIMES'], $user->lang['tz'][$tz], $user->lang['tz']['dst']) : sprintf($user->lang['ALL_TIMES'], $user->lang['tz'][$tz], ''),
+		'S_TIMEZONE'			=> sprintf($user->lang['ALL_TIMES'], $timezone_offset, $timezone_name),
 		'S_DISPLAY_ONLINE_LIST'	=> ($l_online_time) ? 1 : 0,
 		'S_DISPLAY_SEARCH'		=> (!$config['load_search']) ? 0 : (isset($auth) ? ($auth->acl_get('u_search') && $auth->acl_getf_global('f_search')) : 1),
 		'S_DISPLAY_PM'			=> ($config['allow_privmsg'] && !empty($user->data['is_registered']) && ($auth->acl_get('u_readpm') || $auth->acl_get('u_sendpm'))) ? true : false,
diff --git a/phpBB/includes/functions_convert.php b/phpBB/includes/functions_convert.php
index e9ec153c50..ac791e0d9b 100644
--- a/phpBB/includes/functions_convert.php
+++ b/phpBB/includes/functions_convert.php
@@ -1884,7 +1884,7 @@ function add_bots()
 			'user_email'			=> '',
 			'user_lang'				=> $config['default_lang'],
 			'user_style'			=> 1,
-			'user_timezone'			=> 0,
+			'user_timezone'			=> 'UTC',
 			'user_allow_massemail'	=> 0,
 		);
 
diff --git a/phpBB/includes/functions_profile_fields.php b/phpBB/includes/functions_profile_fields.php
index 3399334f94..1c15ef897f 100644
--- a/phpBB/includes/functions_profile_fields.php
+++ b/phpBB/includes/functions_profile_fields.php
@@ -554,9 +554,12 @@ class custom_profile
 				else if ($day && $month && $year)
 				{
 					global $user;
-					// Date should display as the same date for every user regardless of timezone, so remove offset
-					// to compensate for the offset added by phpbb_user::format_date()
-					return $user->format_date(gmmktime(0, 0, 0, $month, $day, $year) - ($user->timezone + $user->dst), $user->lang['DATE_FORMAT'], true);
+					// Date should display as the same date for every user regardless of timezone
+
+					return $user->create_datetime()
+						->setDate($year, $month, $day)
+						->setTime(0, 0, 0)
+						->format($user->lang['DATE_FORMAT'], true);
 				}
 
 				return $value;
diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index 9b102b7387..6e658b4ef4 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -197,7 +197,6 @@ function user_add($user_row, $cp_data = false)
 		'user_lastpost_time'	=> 0,
 		'user_lastpage'			=> '',
 		'user_posts'			=> 0,
-		'user_dst'				=> (int) $config['board_dst'],
 		'user_colour'			=> '',
 		'user_occ'				=> '',
 		'user_interests'		=> '',
@@ -677,8 +676,10 @@ function user_ban($mode, $ban, $ban_len, $ban_len_other, $ban_exclude, $ban_reas
 			if (sizeof($ban_other) == 3 && ((int)$ban_other[0] < 9999) &&
 				(strlen($ban_other[0]) == 4) && (strlen($ban_other[1]) == 2) && (strlen($ban_other[2]) == 2))
 			{
-				$time_offset = (isset($user->timezone) && isset($user->dst)) ? (int) $user->timezone + (int) $user->dst : 0;
-				$ban_end = max($current_time, gmmktime(0, 0, 0, (int)$ban_other[1], (int)$ban_other[2], (int)$ban_other[0]) - $time_offset);
+				$ban_end = max($current_time, $user->create_datetime()
+					->setDate((int) $ban_other[0], (int) $ban_other[1], (int) $ban_other[2])
+					->setTime(0, 0, 0)
+					->getTimestamp() + $user->timezone->getOffset(new DateTime('UTC')));
 			}
 			else
 			{
@@ -1247,10 +1248,21 @@ function validate_data($data, $val_ary)
 			$function = array_shift($validate);
 			array_unshift($validate, $data[$var]);
 
-			if ($result = call_user_func_array('validate_' . $function, $validate))
+			if (function_exists('phpbb_validate_' . $function))
 			{
-				// Since errors are checked later for their language file existence, we need to make sure custom errors are not adjusted.
-				$error[] = (empty($user->lang[$result . '_' . strtoupper($var)])) ? $result : $result . '_' . strtoupper($var);
+				if ($result = call_user_func_array('phpbb_validate_' . $function, $validate))
+				{
+					// Since errors are checked later for their language file existence, we need to make sure custom errors are not adjusted.
+					$error[] = (empty($user->lang[$result . '_' . strtoupper($var)])) ? $result : $result . '_' . strtoupper($var);
+				}
+			}
+			else
+			{
+				if ($result = call_user_func_array('validate_' . $function, $validate))
+				{
+					// Since errors are checked later for their language file existence, we need to make sure custom errors are not adjusted.
+					$error[] = (empty($user->lang[$result . '_' . strtoupper($var)])) ? $result : $result . '_' . strtoupper($var);
+				}
 			}
 		}
 	}
@@ -1396,6 +1408,22 @@ function validate_language_iso_name($lang_iso)
 }
 
 /**
+* Validate Timezone Name
+*
+* Tests whether a timezone name is valid
+*
+* @param string $timezone	The timezone string to test
+*
+* @return bool|string		Either false if validation succeeded or
+*							a string which will be used as the error message
+*							(with the variable name appended)
+*/
+function phpbb_validate_timezone($timezone)
+{
+	return (in_array($timezone, phpbb_get_timezone_identifiers($timezone))) ? false : 'TIMEZONE_INVALID';
+}
+
+/**
 * Check to see if the username has been taken, or if it is disallowed.
 * Also checks if it includes the " character, which we don't allow in usernames.
 * Used for registering, changing names, and posting anonymously with a username
diff --git a/phpBB/includes/questionnaire/questionnaire.php b/phpBB/includes/questionnaire/questionnaire.php
index 46a743d7e9..5cb441d536 100644
--- a/phpBB/includes/questionnaire/questionnaire.php
+++ b/phpBB/includes/questionnaire/questionnaire.php
@@ -304,7 +304,6 @@ class phpbb_questionnaire_phpbb_data_provider
 			'avatar_max_width' => true,
 			'avatar_min_height' => true,
 			'avatar_min_width' => true,
-			'board_dst' => true,
 			'board_email_form' => true,
 			'board_hide_emails' => true,
 			'board_timezone' => true,
diff --git a/phpBB/includes/ucp/ucp_prefs.php b/phpBB/includes/ucp/ucp_prefs.php
index 0c9f20f266..2228bc7931 100644
--- a/phpBB/includes/ucp/ucp_prefs.php
+++ b/phpBB/includes/ucp/ucp_prefs.php
@@ -41,9 +41,8 @@ class ucp_prefs
 					'dateformat'	=> request_var('dateformat', $user->data['user_dateformat'], true),
 					'lang'			=> basename(request_var('lang', $user->data['user_lang'])),
 					'style'			=> request_var('style', (int) $user->data['user_style']),
-					'tz'			=> request_var('tz', (float) $user->data['user_timezone']),
+					'tz'			=> request_var('tz', $user->data['user_timezone']),
 
-					'dst'			=> request_var('dst', (bool) $user->data['user_dst']),
 					'viewemail'		=> request_var('viewemail', (bool) $user->data['user_allow_viewemail']),
 					'massemail'		=> request_var('massemail', (bool) $user->data['user_allow_massemail']),
 					'hideonline'	=> request_var('hideonline', (bool) !$user->data['user_allow_viewonline']),
@@ -72,7 +71,7 @@ class ucp_prefs
 					$error = validate_data($data, array(
 						'dateformat'	=> array('string', false, 1, 30),
 						'lang'			=> array('language_iso_name'),
-						'tz'			=> array('num', false, -14, 14),
+						'tz'			=> array('timezone'),
 					));
 
 					if (!check_form_key('ucp_prefs_personal'))
@@ -93,7 +92,6 @@ class ucp_prefs
 							'user_notify_pm'		=> $data['notifypm'],
 							'user_options'			=> $user->data['user_options'],
 
-							'user_dst'				=> $data['dst'],
 							'user_dateformat'		=> $data['dateformat'],
 							'user_lang'				=> $data['lang'],
 							'user_timezone'			=> $data['tz'],
@@ -133,6 +131,7 @@ class ucp_prefs
 				}
 				$dateformat_options .= '>' . $user->lang['CUSTOM_DATEFORMAT'] . '</option>';
 
+				$timezone_selects = phpbb_timezone_select($user, $data['tz'], true);
 				$template->assign_vars(array(
 					'ERROR'				=> (sizeof($error)) ? implode('<br />', $error) : '',
 
@@ -145,7 +144,6 @@ class ucp_prefs
 					'S_HIDE_ONLINE'		=> $data['hideonline'],
 					'S_NOTIFY_PM'		=> $data['notifypm'],
 					'S_POPUP_PM'		=> $data['popuppm'],
-					'S_DST'				=> $data['dst'],
 
 					'DATE_FORMAT'			=> $data['dateformat'],
 					'A_DATE_FORMAT'			=> addslashes($data['dateformat']),
@@ -156,7 +154,8 @@ class ucp_prefs
 
 					'S_LANG_OPTIONS'		=> language_select($data['lang']),
 					'S_STYLE_OPTIONS'		=> ($config['override_user_style']) ? '' : style_select($data['style']),
-					'S_TZ_OPTIONS'			=> tz_select($data['tz'], true),
+					'S_TZ_OPTIONS'			=> $timezone_selects['tz_select'],
+					'S_TZ_DATE_OPTIONS'		=> $timezone_selects['tz_dates'],
 					'S_CAN_HIDE_ONLINE'		=> ($auth->acl_get('u_hideonline')) ? true : false,
 					'S_SELECT_NOTIFY'		=> ($config['jab_enable'] && $user->data['user_jabber'] && @extension_loaded('xml')) ? true : false)
 				);
diff --git a/phpBB/includes/ucp/ucp_register.php b/phpBB/includes/ucp/ucp_register.php
index 5d85029e62..6ce53a79ab 100644
--- a/phpBB/includes/ucp/ucp_register.php
+++ b/phpBB/includes/ucp/ucp_register.php
@@ -100,7 +100,7 @@ class ucp_register
 					'username'			=> utf8_normalize_nfc(request_var('username', '', true)),
 					'email'				=> strtolower(request_var('email', '')),
 					'lang'				=> $user->lang_name,
-					'tz'				=> request_var('tz', (float) $config['board_timezone']),
+					'tz'				=> request_var('tz', $config['board_timezone']),
 				));
 
 			}
@@ -120,7 +120,10 @@ class ucp_register
 			if ($coppa === false && $config['coppa_enable'])
 			{
 				$now = getdate();
-				$coppa_birthday = $user->format_date(mktime($now['hours'] + $user->data['user_dst'], $now['minutes'], $now['seconds'], $now['mon'], $now['mday'] - 1, $now['year'] - 13), $user->lang['DATE_FORMAT']);
+				$coppa_birthday = $user->create_datetime()
+					->setDate($now['year'] - 13, $now['mon'], $now['mday'] - 1)
+					->setTime(0, 0, 0)
+					->format($user->lang['DATE_FORMAT'], true);
 				unset($now);
 
 				$template->assign_vars(array(
@@ -163,7 +166,6 @@ class ucp_register
 			$captcha->init(CONFIRM_REG);
 		}
 
-		$is_dst = $config['board_dst'];
 		$timezone = $config['board_timezone'];
 
 		$data = array(
@@ -172,7 +174,7 @@ class ucp_register
 			'password_confirm'	=> request_var('password_confirm', '', true),
 			'email'				=> strtolower(request_var('email', '')),
 			'lang'				=> basename(request_var('lang', $user->lang_name)),
-			'tz'				=> request_var('tz', (float) $timezone),
+			'tz'				=> request_var('tz', $timezone),
 		);
 
 		// Check and initialize some variables if needed
@@ -189,7 +191,7 @@ class ucp_register
 				'email'				=> array(
 					array('string', false, 6, 60),
 					array('email')),
-				'tz'				=> array('num', false, -14, 14),
+				'tz'				=> array('timezone'),
 				'lang'				=> array('language_iso_name'),
 			));
 
@@ -279,8 +281,7 @@ class ucp_register
 					'user_password'			=> phpbb_hash($data['new_password']),
 					'user_email'			=> $data['email'],
 					'group_id'				=> (int) $group_id,
-					'user_timezone'			=> (float) $data['tz'],
-					'user_dst'				=> $is_dst,
+					'user_timezone'			=> $data['tz'],
 					'user_lang'				=> $data['lang'],
 					'user_type'				=> $user_type,
 					'user_actkey'			=> $user_actkey,
@@ -441,6 +442,7 @@ class ucp_register
 			break;
 		}
 
+		$timezone_selects = phpbb_timezone_select($user, $data['tz'], true);
 		$template->assign_vars(array(
 			'ERROR'				=> (sizeof($error)) ? implode('<br />', $error) : '',
 			'USERNAME'			=> $data['username'],
@@ -453,7 +455,8 @@ class ucp_register
 			'L_PASSWORD_EXPLAIN'		=> $user->lang($config['pass_complex'] . '_EXPLAIN', $user->lang('CHARACTERS', (int) $config['min_pass_chars']), $user->lang('CHARACTERS', (int) $config['max_pass_chars'])),
 
 			'S_LANG_OPTIONS'	=> language_select($data['lang']),
-			'S_TZ_OPTIONS'		=> tz_select($data['tz']),
+			'S_TZ_OPTIONS'			=> $timezone_selects['tz_select'],
+			'S_TZ_DATE_OPTIONS'		=> $timezone_selects['tz_dates'],
 			'S_CONFIRM_REFRESH'	=> ($config['enable_confirm'] && $config['confirm_refresh']) ? true : false,
 			'S_REGISTRATION'	=> true,
 			'S_COPPA'			=> $coppa,
diff --git a/phpBB/includes/update_helpers.php b/phpBB/includes/update_helpers.php
new file mode 100644
index 0000000000..8e8e9670b0
--- /dev/null
+++ b/phpBB/includes/update_helpers.php
@@ -0,0 +1,112 @@
+<?php
+/**
+*
+* @package phpBB3
+* @copyright (c) 2012 phpBB Group
+* @license http://opensource.org/licenses/gpl-2.0.php GNU General Public License v2
+*/
+
+/**
+* phpBB Update Helpers
+*/
+class phpbb_update_helpers
+{
+	/**
+	* Determine the new timezone for a given phpBB 3.0 timezone and
+	* "Daylight Saving Time" option
+	*
+	*	@param	$timezone	float	Users timezone in 3.0
+	*	@param	$dst		int		Users daylight saving time
+	*	@return		string		Users new php Timezone which is used since 3.1
+	*/
+	function convert_phpbb30_timezone($timezone, $dst)
+	{
+		$offset = $timezone + $dst;
+
+		switch ($timezone)
+		{
+			case '-12':
+				return 'Etc/GMT' . $offset;		//'[UTC - 12] Baker Island Time'
+			case '-11':
+				return 'Etc/GMT' . $offset;		//'[UTC - 11] Niue Time, Samoa Standard Time'
+			case '-10':
+				return 'Etc/GMT' . $offset;		//'[UTC - 10] Hawaii-Aleutian Standard Time, Cook Island Time'
+			case '-9.5':
+				return 'Pacific/Marquesas';		//'[UTC - 9:30] Marquesas Islands Time'
+			case '-9':
+				return 'Etc/GMT' . $offset;		//'[UTC - 9] Alaska Standard Time, Gambier Island Time'
+			case '-8':
+				return 'Etc/GMT' . $offset;		//'[UTC - 8] Pacific Standard Time'
+			case '-7':
+				return 'Etc/GMT' . $offset;		//'[UTC - 7] Mountain Standard Time'
+			case '-6':
+				return 'Etc/GMT' . $offset;		//'[UTC - 6] Central Standard Time'
+			case '-5':
+				return 'Etc/GMT' . $offset;		//'[UTC - 5] Eastern Standard Time'
+			case '-4.5':
+				return 'America/Caracas';		//'[UTC - 4:30] Venezuelan Standard Time'
+			case '-4':
+				return 'Etc/GMT' . $offset;		//'[UTC - 4] Atlantic Standard Time'
+			case '-3.5':
+				return 'America/St_Johns';		//'[UTC - 3:30] Newfoundland Standard Time'
+			case '-3':
+				return 'Etc/GMT' . $offset;		//'[UTC - 3] Amazon Standard Time, Central Greenland Time'
+			case '-2':
+				return 'Etc/GMT' . $offset;		//'[UTC - 2] Fernando de Noronha Time, South Georgia &amp; the South Sandwich Islands Time'
+			case '-1':
+				return 'Etc/GMT' . $offset;		//'[UTC - 1] Azores Standard Time, Cape Verde Time, Eastern Greenland Time'
+			case '0':
+				return (!$dst) ? 'UTC' : 'Etc/GMT+1';		//'[UTC] Western European Time, Greenwich Mean Time'
+			case '1':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 1] Central European Time, West African Time'
+			case '2':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 2] Eastern European Time, Central African Time'
+			case '3':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 3] Moscow Standard Time, Eastern African Time'
+			case '3.5':
+				return 'Asia/Tehran';			//'[UTC + 3:30] Iran Standard Time'
+			case '4':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 4] Gulf Standard Time, Samara Standard Time'
+			case '4.5':
+				return 'Asia/Kabul';			//'[UTC + 4:30] Afghanistan Time'
+			case '5':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 5] Pakistan Standard Time, Yekaterinburg Standard Time'
+			case '5.5':
+				return 'Asia/Kolkata';			//'[UTC + 5:30] Indian Standard Time, Sri Lanka Time'
+			case '5.75':
+				return 'Asia/Kathmandu';		//'[UTC + 5:45] Nepal Time'
+			case '6':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 6] Bangladesh Time, Bhutan Time, Novosibirsk Standard Time'
+			case '6.5':
+				return 'Indian/Cocos';			//'[UTC + 6:30] Cocos Islands Time, Myanmar Time'
+			case '7':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 7] Indochina Time, Krasnoyarsk Standard Time'
+			case '8':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 8] Chinese Standard Time, Australian Western Standard Time, Irkutsk Standard Time'
+			case '8.75':
+				return 'Australia/Eucla';		//'[UTC + 8:45] Southeastern Western Australia Standard Time'
+			case '9':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 9] Japan Standard Time, Korea Standard Time, Chita Standard Time'
+			case '9.5':
+				return 'Australia/ACT';			//'[UTC + 9:30] Australian Central Standard Time'
+			case '10':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 10] Australian Eastern Standard Time, Vladivostok Standard Time'
+			case '10.5':
+				return 'Australia/Lord_Howe';	//'[UTC + 10:30] Lord Howe Standard Time'
+			case '11':
+				return 'Etc/GMT+' . $offset;	//'[UTC + 11] Solomon Island Time, Magadan Standard Time'
+			case '11.5':
+				return 'Pacific/Norfolk';		//'[UTC + 11:30] Norfolk Island Time'
+			case '12':
+				return 'Etc/GMT+12';			//'[UTC + 12] New Zealand Time, Fiji Time, Kamchatka Standard Time'
+			case '12.75':
+				return 'Pacific/Chatham';		//'[UTC + 12:45] Chatham Islands Time'
+			case '13':
+				return 'Pacific/Tongatapu';		//'[UTC + 13] Tonga Time, Phoenix Islands Time'
+			case '14':
+				return 'Pacific/Kiritimati';	//'[UTC + 14] Line Island Time'
+			default:
+				return 'UTC';
+		}
+	}
+}
diff --git a/phpBB/includes/user.php b/phpBB/includes/user.php
index cf9e6b9994..fcbfaaddfa 100644
--- a/phpBB/includes/user.php
+++ b/phpBB/includes/user.php
@@ -29,8 +29,11 @@ class phpbb_user extends phpbb_session
 	var $help = array();
 	var $style = array();
 	var $date_format;
-	var $timezone;
-	var $dst;
+
+	/**
+	* DateTimeZone object holding the timezone of the user
+	*/
+	public $timezone;
 
 	var $lang_name = false;
 	var $lang_id = false;
@@ -79,15 +82,13 @@ class phpbb_user extends phpbb_session
 			$this->lang_name = (file_exists($this->lang_path . $this->data['user_lang'] . "/common.$phpEx")) ? $this->data['user_lang'] : basename($config['default_lang']);
 
 			$this->date_format = $this->data['user_dateformat'];
-			$this->timezone = $this->data['user_timezone'] * 3600;
-			$this->dst = $this->data['user_dst'] * 3600;
+			$user_timezone = $this->data['user_timezone'];
 		}
 		else
 		{
 			$this->lang_name = basename($config['default_lang']);
 			$this->date_format = $config['default_dateformat'];
-			$this->timezone = $config['board_timezone'] * 3600;
-			$this->dst = $config['board_dst'] * 3600;
+			$user_timezone = $config['board_timezone'];
 
 			/**
 			* If a guest user is surfing, we try to guess his/her language first by obtaining the browser language
@@ -126,6 +127,16 @@ class phpbb_user extends phpbb_session
 			*/
 		}
 
+		try
+		{
+			$this->timezone = new DateTimeZone($user_timezone);
+		}
+		catch (Exception $e)
+		{
+			// If the timezone the user has selected is invalid, we fall back to UTC.
+			$this->timezone = new DateTimeZone('UTC');
+		}
+
 		// We include common language file here to not load it every time a custom language file is included
 		$lang = &$this->lang;
 
@@ -612,70 +623,46 @@ class phpbb_user extends phpbb_session
 	*/
 	function format_date($gmepoch, $format = false, $forcedate = false)
 	{
-		static $midnight;
-		static $date_cache;
-
-		$format = (!$format) ? $this->date_format : $format;
-		$now = time();
-		$delta = $now - $gmepoch;
-
-		if (!isset($date_cache[$format]))
-		{
-			// Is the user requesting a friendly date format (i.e. 'Today 12:42')?
-			$date_cache[$format] = array(
-				'is_short'      => strpos($format, '|'),
-				'format_short'  => substr($format, 0, strpos($format, '|')) . '||' . substr(strrchr($format, '|'), 1),
-				'format_long'   => str_replace('|', '', $format),
-				'lang'          => $this->lang['datetime'],
-			);
-
-			// Short representation of month in format? Some languages use different terms for the long and short format of May
-			if ((strpos($format, '\M') === false && strpos($format, 'M') !== false) || (strpos($format, '\r') === false && strpos($format, 'r') !== false))
-			{
-				$date_cache[$format]['lang']['May'] = $this->lang['datetime']['May_short'];
-			}
-		}
+		static $utc;
 
-		// Zone offset
-		$zone_offset = $this->timezone + $this->dst;
-
-		// Show date < 1 hour ago as 'xx min ago' but not greater than 60 seconds in the future
-		// A small tolerence is given for times in the future but in the same minute are displayed as '< than a minute ago'
-		if ($delta < 3600 && $delta > -60 && ($delta >= -5 || (($now / 60) % 60) == (($gmepoch / 60) % 60)) && $date_cache[$format]['is_short'] !== false && !$forcedate && isset($this->lang['datetime']['AGO']))
+		if (!isset($utc))
 		{
-			return $this->lang(array('datetime', 'AGO'), max(0, (int) floor($delta / 60)));
+			$utc = new DateTimeZone('UTC');
 		}
 
-		if (!$midnight)
-		{
-			list($d, $m, $y) = explode(' ', gmdate('j n Y', time() + $zone_offset));
-			$midnight = gmmktime(0, 0, 0, $m, $d, $y) - $zone_offset;
-		}
-
-		if ($date_cache[$format]['is_short'] !== false && !$forcedate && !($gmepoch < $midnight - 86400 || $gmepoch > $midnight + 172800))
-		{
-			$day = false;
+		$time = new phpbb_datetime($this, "@$gmepoch", $utc);
+		$time->setTimezone($this->timezone);
 
-			if ($gmepoch > $midnight + 86400)
-			{
-				$day = 'TOMORROW';
-			}
-			else if ($gmepoch > $midnight)
-			{
-				$day = 'TODAY';
-			}
-			else if ($gmepoch > $midnight - 86400)
-			{
-				$day = 'YESTERDAY';
-			}
+		return $time->format($format, $forcedate);
+	}
 
-			if ($day !== false)
-			{
-				return str_replace('||', $this->lang['datetime'][$day], strtr(@gmdate($date_cache[$format]['format_short'], $gmepoch + $zone_offset), $date_cache[$format]['lang']));
-			}
-		}
+	/**
+	* Create a phpbb_datetime object in the context of the current user
+	*
+	* @since 3.1
+	* @param string $time String in a format accepted by strtotime().
+	* @param DateTimeZone $timezone Time zone of the time.
+	* @return phpbb_datetime Date time object linked to the current users locale
+	*/
+	public function create_datetime($time = 'now', DateTimeZone $timezone = null)
+	{
+		$timezone = $timezone ?: $this->timezone;
+		return new phpbb_datetime($this, $time, $timezone);
+	}
 
-		return strtr(@gmdate($date_cache[$format]['format_long'], $gmepoch + $zone_offset), $date_cache[$format]['lang']);
+	/**
+	* Get the UNIX timestamp for a datetime in the users timezone, so we can store it in the database.
+	*
+	* @param	string			$format		Format of the entered date/time
+	* @param	string			$time		Date/time with the timezone applied
+	* @param	DateTimeZone	$timezone	Timezone of the date/time, falls back to timezone of current user
+	* @return	int			Returns the unix timestamp
+	*/
+	public function get_timestamp_from_format($format, $time, DateTimeZone $timezone = null)
+	{
+		$timezone = $timezone ?: $this->timezone;
+		$date = DateTime::createFromFormat($format, $time, $timezone);
+		return ($date !== false) ? $date->format('U') : false;
 	}
 
 	/**