<?php
/**
*
* This file is part of the phpBB Forum Software package.
*
* @copyright (c) phpBB Limited <https://www.phpbb.com>
* @license GNU General Public License, version 2 (GPL-2.0)
*
* For full copyright and license information, please see
* the docs/CREDITS.txt file.
*
*/

namespace phpbb\db\migration\data\v310;

class timezone extends \phpbb\db\migration\migration
{
	public function effectively_installed()
	{
		return !$this->db_tools->sql_column_exists($this->table_prefix . 'users', 'user_dst');
	}

	static public function depends_on()
	{
		return array('\phpbb\db\migration\data\v30x\release_3_0_11');
	}

	public function update_schema()
	{
		return array(
			'change_columns'	=> array(
				$this->table_prefix . 'users'			=> array(
					'user_timezone'		=> array('VCHAR:100', ''),
				),
			),
		);
	}

	public function update_data()
	{
		return array(
			array('custom', array(array($this, 'update_timezones'))),
		);
	}

	public function update_timezones($start)
	{
		$start = (int) $start;
		$limit = 500;
		$converted = 0;

		$update_blocks = array();

		$sql = 'SELECT user_id, user_timezone, user_dst
			FROM ' . $this->table_prefix . 'users
			ORDER BY user_id ASC';
		$result = $this->db->sql_query_limit($sql, $limit, $start);
		while ($row = $this->db->sql_fetchrow($result))
		{
			$converted++;

			// In case this is somehow run twice on a row.
			// Otherwise it would just end up as UTC on the second run
			if (is_numeric($row['user_timezone']))
			{
				$update_blocks[$row['user_timezone'] . ':' . $row['user_dst']][] = (int) $row['user_id'];
			}
		}
		$this->db->sql_freeresult($result);

		// Update blocks of users who share the same timezone/dst
		foreach ($update_blocks as $timezone => $user_ids)
		{
			$timezone = explode(':', $timezone);
			$converted_timezone = $this->convert_phpbb30_timezone($timezone[0], $timezone[1]);

			$sql = 'UPDATE ' . $this->table_prefix . "users
				SET user_timezone = '" . $this->db->sql_escape($converted_timezone) . "'
				WHERE " . $this->db->sql_in_set('user_id', $user_ids);
			$this->sql_query($sql);
		}

		if ($converted == $limit)
		{
			// There are still more to convert
			return $start + $limit;
		}

		// Update board default timezone
		$sql = 'UPDATE ' . $this->table_prefix . "config
			SET config_value = '" . $this->convert_phpbb30_timezone($this->config['board_timezone'], $this->config['board_dst']) . "'
			WHERE config_name = 'board_timezone'";
		$this->sql_query($sql);
	}

	/**
	* 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	$dst		int		Users daylight saving time
	*	@return		string		Users new php Timezone which is used since 3.1
	*/
	public function convert_phpbb30_timezone($timezone, $dst)
	{
		$offset = (float) $timezone + (int) $dst;

		switch ($timezone)
		{
			case '-12':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 12] Baker Island Time'
			case '-11':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 11] Niue Time, Samoa Standard Time'
			case '-10':
				return 'Etc/GMT+' . abs($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+' . abs($offset);	//'[UTC - 9] Alaska Standard Time, Gambier Island Time'
			case '-8':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 8] Pacific Standard Time'
			case '-7':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 7] Mountain Standard Time'
			case '-6':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 6] Central Standard Time'
			case '-5':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 5] Eastern Standard Time'
			case '-4.5':
				return 'America/Caracas';			//'[UTC - 4:30] Venezuelan Standard Time'
			case '-4':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 4] Atlantic Standard Time'
			case '-3.5':
				return 'America/St_Johns';			//'[UTC - 3:30] Newfoundland Standard Time'
			case '-3':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 3] Amazon Standard Time, Central Greenland Time'
			case '-2':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 2] Fernando de Noronha Time, South Georgia &amp; the South Sandwich Islands Time'
			case '-1':
				return 'Etc/GMT+' . abs($offset);	//'[UTC - 1] Azores Standard Time, Cape Verde Time, Eastern Greenland Time'
			case '0':
				return (!$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';
		}
	}
}