<?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.
*
*/

use phpbb\exception\exception_interface;
use phpbb\exception\version_check_exception;

/**
* @ignore
*/
if (!defined('IN_PHPBB'))
{
	exit;
}

class acp_extensions
{
	var $u_action;
	var $tpl_name;
	var $page_title;

	private $config;
	private $template;
	private $user;
	private $log;
	private $request;
	private $phpbb_dispatcher;
	private $ext_manager;
	private $phpbb_container;
	private $php_ini;

	function main($id, $mode)
	{
		// Start the page
		global $config, $user, $template, $request, $phpbb_extension_manager, $phpbb_root_path, $phpbb_log, $phpbb_dispatcher, $phpbb_container;

		$this->config = $config;
		$this->template = $template;
		$this->user = $user;
		$this->request = $request;
		$this->log = $phpbb_log;
		$this->phpbb_dispatcher = $phpbb_dispatcher;
		$this->ext_manager = $phpbb_extension_manager;
		$this->phpbb_container = $phpbb_container;
		$this->php_ini = $this->phpbb_container->get('php_ini');

		$this->user->add_lang(array('install', 'acp/extensions', 'migrator'));

		$this->page_title = 'ACP_EXTENSIONS';

		$action = $this->request->variable('action', 'list');
		$ext_name = $this->request->variable('ext_name', '');

		// What is a safe limit of execution time? Half the max execution time should be safe.
		$safe_time_limit = ($this->php_ini->getNumeric('max_execution_time') / 2);
		$start_time = time();

		// Cancel action
		if ($this->request->is_set_post('cancel'))
		{
			$action = 'list';
			$ext_name = '';
		}

		if (in_array($action, array('enable', 'disable', 'delete_data')) && !check_link_hash($this->request->variable('hash', ''), $action . '.' . $ext_name))
		{
			trigger_error('FORM_INVALID', E_USER_WARNING);
		}

		/**
		* Event to run a specific action on extension
		*
		* @event core.acp_extensions_run_action_before
		* @var	string	action			Action to run; if the event completes execution of the action, should be set to 'none'
		* @var	string	u_action		Url we are at
		* @var	string	ext_name		Extension name from request
		* @var	int		safe_time_limit	Safe limit of execution time
		* @var	int		start_time		Start time
		* @var	string	tpl_name		Template file to load
		* @since 3.1.11-RC1
		* @changed 3.2.1-RC1			Renamed to core.acp_extensions_run_action_before, added tpl_name, added action 'none'
		*/
		$u_action = $this->u_action;
		$tpl_name = '';
		$vars = array('action', 'u_action', 'ext_name', 'safe_time_limit', 'start_time', 'tpl_name');
		extract($this->phpbb_dispatcher->trigger_event('core.acp_extensions_run_action_before', compact($vars)));

		// In case they have been updated by the event
		$this->u_action = $u_action;
		$this->tpl_name = $tpl_name;

		// If they've specified an extension, let's load the metadata manager and validate it.
		if ($ext_name)
		{
			$md_manager = $this->ext_manager->create_extension_metadata_manager($ext_name);

			try
			{
				$md_manager->get_metadata('all');
			}
			catch (exception_interface $e)
			{
				$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));
				trigger_error($message . adm_back_link($this->u_action), E_USER_WARNING);
			}
		}

		// What are we doing?
		switch ($action)
		{
			case 'none':
				// Intentionally empty, used by extensions that execute additional actions in the prior event
				break;

			case 'set_config_version_check_force_unstable':
				$force_unstable = $this->request->variable('force_unstable', false);

				if ($force_unstable)
				{
					$s_hidden_fields = build_hidden_fields(array(
						'force_unstable'	=> $force_unstable,
					));

					confirm_box(false, $this->user->lang('EXTENSION_FORCE_UNSTABLE_CONFIRM'), $s_hidden_fields);
				}
				else
				{
					$this->config->set('extension_force_unstable', false);
					trigger_error($this->user->lang['CONFIG_UPDATED'] . adm_back_link($this->u_action));
				}
				break;

			case 'list':
			default:
				if (confirm_box(true))
				{
					$this->config->set('extension_force_unstable', true);
					trigger_error($this->user->lang['CONFIG_UPDATED'] . adm_back_link($this->u_action));
				}

				$this->list_enabled_exts();
				$this->list_disabled_exts();
				$this->list_available_exts();

				$this->template->assign_vars(array(
					'U_VERSIONCHECK_FORCE' 	=> $this->u_action . '&amp;action=list&amp;versioncheck_force=1',
					'FORCE_UNSTABLE'		=> $this->config['extension_force_unstable'],
					'U_ACTION' 				=> $this->u_action,
				));

				$this->tpl_name = 'acp_ext_list';
			break;

			case 'enable_pre':
				try
				{
					$md_manager->validate_enable();
				}
				catch (exception_interface $e)
				{
					$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));
					trigger_error($message . adm_back_link($this->u_action), E_USER_WARNING);
				}

				$extension = $this->ext_manager->get_extension($ext_name);

				$this->check_is_enableable($extension);

				if ($this->ext_manager->is_enabled($ext_name))
				{
					redirect($this->u_action);
				}

				if (confirm_box(true))
				{
					redirect($this->u_action . '&amp;action=enable&amp;ext_name=' . urlencode($ext_name) . '&amp;hash=' . generate_link_hash('enable.' . $ext_name));
				}
				else
				{
					confirm_box(false, $this->user->lang('EXTENSION_ENABLE_CONFIRM', $md_manager->get_metadata('display-name')), build_hidden_fields(array(
						'i'			=> $id,
						'mode'		=> $mode,
						'action'	=> 'enable_pre',
						'ext_name'	=> $ext_name,
					)));
				}
			break;

			case 'enable':
				try
				{
					$md_manager->validate_enable();
				}
				catch (exception_interface $e)
				{
					$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));
					trigger_error($message . adm_back_link($this->u_action), E_USER_WARNING);
				}

				$extension = $this->ext_manager->get_extension($ext_name);

				$this->check_is_enableable($extension);

				try
				{
					while ($this->ext_manager->enable_step($ext_name))
					{
						// Are we approaching the time limit? If so we want to pause the update and continue after refreshing
						if ((time() - $start_time) >= $safe_time_limit)
						{
							meta_refresh(0, $this->u_action . '&amp;action=enable&amp;ext_name=' . urlencode($ext_name) . '&amp;hash=' . generate_link_hash('enable.' . $ext_name));
							trigger_error('EXTENSION_ENABLE_IN_PROGRESS', E_USER_NOTICE);
						}
					}

					// Update custom style for admin area
					$this->template->set_custom_style(array(
						array(
							'name' 		=> 'adm',
							'ext_path' 	=> 'adm/style/',
						),
					), array($phpbb_root_path . 'adm/style'));

					$this->log->add('admin', $this->user->data['user_id'], $this->user->ip, 'LOG_EXT_ENABLE', time(), array($ext_name));
				}
				catch (\phpbb\db\migration\exception $e)
				{
					trigger_error($this->user->lang('MIGRATION_EXCEPTION_ERROR', $e->getLocalisedMessage($this->user)), E_USER_WARNING);
				}

				if ($this->request->is_ajax())
				{
					$actions = $this->output_actions('enabled', [
						'DISABLE'	=> $this->u_action . '&amp;action=disable_pre&amp;ext_name=' . urlencode($ext_name),
					]);

					$data = [
						'EXT_ENABLE_SUCCESS'	=> true,
						'ACTIONS'				=> $actions,
						'REFRESH_DATA'			=> [
							'url'	=> '',
							'time'	=> 0,
						],
					];

					$json_response = new \phpbb\json_response;
					$json_response->send($data);
				}

				trigger_error($this->user->lang('EXTENSION_ENABLE_SUCCESS') . adm_back_link($this->u_action), E_USER_NOTICE);
			break;

			case 'disable_pre':
				if (!$this->ext_manager->is_enabled($ext_name))
				{
					redirect($this->u_action);
				}

				if (confirm_box(true))
				{
					redirect($this->u_action . '&amp;action=disable&amp;ext_name=' . urlencode($ext_name) . '&amp;hash=' . generate_link_hash('disable.' . $ext_name));
				}
				else
				{
					confirm_box(false, $this->user->lang('EXTENSION_DISABLE_CONFIRM', $md_manager->get_metadata('display-name')), build_hidden_fields(array(
						'i'			=> $id,
						'mode'		=> $mode,
						'action'	=> 'disable_pre',
						'ext_name'	=> $ext_name,
					)));
				}
			break;

			case 'disable':
				if (!$this->ext_manager->is_enabled($ext_name))
				{
					redirect($this->u_action);
				}

				while ($this->ext_manager->disable_step($ext_name))
				{
					// Are we approaching the time limit? If so we want to pause the update and continue after refreshing
					if ((time() - $start_time) >= $safe_time_limit)
					{
						$this->template->assign_var('S_NEXT_STEP', true);

						meta_refresh(0, $this->u_action . '&amp;action=disable&amp;ext_name=' . urlencode($ext_name) . '&amp;hash=' . generate_link_hash('disable.' . $ext_name));
						trigger_error('EXTENSION_DISABLE_IN_PROGRESS', E_USER_NOTICE);
					}
				}
				$this->log->add('admin', $this->user->data['user_id'], $this->user->ip, 'LOG_EXT_DISABLE', time(), array($ext_name));

				if ($this->request->is_ajax())
				{
					$actions = $this->output_actions('disabled', [
						'ENABLE'		=> $this->u_action . '&amp;action=enable_pre&amp;ext_name=' . urlencode($ext_name),
						'DELETE_DATA'	=> $this->u_action . '&amp;action=delete_data_pre&amp;ext_name=' . urlencode($ext_name),
					]);

					$data = [
						'EXT_DISABLE_SUCCESS'	=> true,
						'ACTIONS'				=> $actions,
						'REFRESH_DATA'			=> [
							'url'	=> '',
							'time'	=> 0,
						],
					];

					$json_response = new \phpbb\json_response;
					$json_response->send($data);
				}

				trigger_error($this->user->lang('EXTENSION_DISABLE_SUCCESS') . adm_back_link($this->u_action), E_USER_NOTICE);
			break;

			case 'delete_data_pre':
				if ($this->ext_manager->is_enabled($ext_name))
				{
					redirect($this->u_action);
				}

				if (confirm_box(true))
				{
					redirect($this->u_action . '&amp;action=delete_data&amp;ext_name=' . urlencode($ext_name) . '&amp;hash=' . generate_link_hash('delete_data.' . $ext_name));
				}
				else
				{
					confirm_box(false, $this->user->lang('EXTENSION_DELETE_DATA_CONFIRM', $md_manager->get_metadata('display-name')), build_hidden_fields(array(
						'i'			=> $id,
						'mode'		=> $mode,
						'action'	=> 'delete_data_pre',
						'ext_name'	=> $ext_name,
					)));
				}
			break;

			case 'delete_data':
				if ($this->ext_manager->is_enabled($ext_name))
				{
					redirect($this->u_action);
				}

				try
				{
					while ($this->ext_manager->purge_step($ext_name))
					{
						// Are we approaching the time limit? If so we want to pause the update and continue after refreshing
						if ((time() - $start_time) >= $safe_time_limit)
						{
							$this->template->assign_var('S_NEXT_STEP', true);

							meta_refresh(0, $this->u_action . '&amp;action=delete_data&amp;ext_name=' . urlencode($ext_name) . '&amp;hash=' . generate_link_hash('delete_data.' . $ext_name));
							trigger_error('EXTENSION_DELETE_DATA_IN_PROGRESS', E_USER_NOTICE);
						}
					}
					$this->log->add('admin', $this->user->data['user_id'], $this->user->ip, 'LOG_EXT_PURGE', time(), array($ext_name));
				}
				catch (\phpbb\db\migration\exception $e)
				{
					trigger_error($this->user->lang('MIGRATION_EXCEPTION_ERROR', $e->getLocalisedMessage($this->user)), E_USER_WARNING);
				}

				if ($this->request->is_ajax())
				{
					$actions = $this->output_actions('disabled', [
						'ENABLE'		=> $this->u_action . '&amp;action=enable_pre&amp;ext_name=' . urlencode($ext_name),
					]);

					$data = [
						'EXT_DELETE_DATA_SUCCESS'	=> true,
						'ACTIONS'					=> $actions,
						'REFRESH_DATA'				=> [
							'url'	=> '',
							'time'	=> 0,
						],
					];

					$json_response = new \phpbb\json_response;
					$json_response->send($data);
				}

				trigger_error($this->user->lang('EXTENSION_DELETE_DATA_SUCCESS') . adm_back_link($this->u_action), E_USER_NOTICE);
			break;

			case 'details':
				// Output it to the template
				$meta = $md_manager->get_metadata('all');
				$this->output_metadata_to_template($meta);

				if (isset($meta['extra']['version-check']))
				{
					try
					{
						$updates_available = $this->ext_manager->version_check($md_manager, $this->request->variable('versioncheck_force', false), false, $this->config['extension_force_unstable'] ? 'unstable' : null);

						$this->template->assign_vars(array(
							'S_UP_TO_DATE' => empty($updates_available),
							'UP_TO_DATE_MSG' => $this->user->lang(empty($updates_available) ? 'UP_TO_DATE' : 'NOT_UP_TO_DATE', $md_manager->get_metadata('display-name')),
						));

						$this->template->assign_block_vars('updates_available', $updates_available);
					}
					catch (exception_interface $e)
					{
						$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));

						$this->template->assign_vars(array(
							'S_VERSIONCHECK_FAIL' => true,
							'VERSIONCHECK_FAIL_REASON' => ($e->getMessage() !== 'VERSIONCHECK_FAIL') ? $message : '',
						));
					}
					$this->template->assign_var('S_VERSIONCHECK', true);
				}
				else
				{
					$this->template->assign_var('S_VERSIONCHECK', false);
				}

				$this->template->assign_vars(array(
					'U_BACK'				=> $this->u_action . '&amp;action=list',
					'U_VERSIONCHECK_FORCE'	=> $this->u_action . '&amp;action=details&amp;versioncheck_force=1&amp;ext_name=' . urlencode($md_manager->get_metadata('name')),
				));

				$this->tpl_name = 'acp_ext_details';
			break;
		}

		/**
		* Event to run after a specific action on extension has completed
		*
		* @event core.acp_extensions_run_action_after
		* @var	string	action			Action that has run
		* @var	string	u_action		Url we are at
		* @var	string	ext_name		Extension name from request
		* @var	int		safe_time_limit	Safe limit of execution time
		* @var	int		start_time		Start time
		* @var	string	tpl_name		Template file to load
		* @since 3.1.11-RC1
		*/
		$u_action = $this->u_action;
		$tpl_name = $this->tpl_name;
		$vars = array('action', 'u_action', 'ext_name', 'safe_time_limit', 'start_time', 'tpl_name');
		extract($this->phpbb_dispatcher->trigger_event('core.acp_extensions_run_action_after', compact($vars)));

		// In case they have been updated by the event
		$this->u_action = $u_action;
		$this->tpl_name = $tpl_name;
	}

	/**
	* Lists all the enabled extensions and dumps to the template
	*
	* @return null
	*/
	public function list_enabled_exts()
	{
		$enabled_extension_meta_data = array();

		foreach ($this->ext_manager->all_enabled() as $name => $location)
		{
			$md_manager = $this->ext_manager->create_extension_metadata_manager($name);

			try
			{
				$meta = $md_manager->get_metadata('all');
				$enabled_extension_meta_data[$name] = array(
					'META_DISPLAY_NAME' => $md_manager->get_metadata('display-name'),
					'META_VERSION' => $meta['version'],
				);

				if (isset($meta['extra']['version-check']))
				{
					try
					{
						$force_update = $this->request->variable('versioncheck_force', false);
						$updates = $this->ext_manager->version_check($md_manager, $force_update, !$force_update);

						$enabled_extension_meta_data[$name]['S_UP_TO_DATE'] = empty($updates);
						$enabled_extension_meta_data[$name]['S_VERSIONCHECK'] = true;
						$enabled_extension_meta_data[$name]['U_VERSIONCHECK_FORCE'] = $this->u_action . '&amp;action=details&amp;versioncheck_force=1&amp;ext_name=' . urlencode($md_manager->get_metadata('name'));
					}
					catch (exception_interface $e)
					{
						// Ignore exceptions due to the version check
					}
				}
				else
				{
					$enabled_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
				}
			}
			catch (exception_interface $e)
			{
				$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));
				$this->template->assign_block_vars('disabled', array(
					'META_DISPLAY_NAME'		=> $this->user->lang('EXTENSION_INVALID_LIST', $name, $message),
					'S_VERSIONCHECK'		=> false,
				));
			}
			catch (\RuntimeException $e)
			{
				$enabled_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
			}
		}

		uasort($enabled_extension_meta_data, array($this, 'sort_extension_meta_data_table'));

		foreach ($enabled_extension_meta_data as $name => $block_vars)
		{
			$block_vars['NAME'] = $name;
			$block_vars['U_DETAILS'] = $this->u_action . '&amp;action=details&amp;ext_name=' . urlencode($name);

			$this->template->assign_block_vars('enabled', $block_vars);

			$this->output_actions('enabled', array(
				'DISABLE'		=> $this->u_action . '&amp;action=disable_pre&amp;ext_name=' . urlencode($name),
			));
		}
	}

	/**
	* Lists all the disabled extensions and dumps to the template
	*
	* @return null
	*/
	public function list_disabled_exts()
	{
		$disabled_extension_meta_data = array();

		foreach ($this->ext_manager->all_disabled() as $name => $location)
		{
			$md_manager = $this->ext_manager->create_extension_metadata_manager($name);

			try
			{
				$meta = $md_manager->get_metadata('all');
				$disabled_extension_meta_data[$name] = array(
					'META_DISPLAY_NAME' => $md_manager->get_metadata('display-name'),
					'META_VERSION' => $meta['version'],
				);

				if (isset($meta['extra']['version-check']))
				{
					$force_update = $this->request->variable('versioncheck_force', false);
					$updates = $this->ext_manager->version_check($md_manager, $force_update, !$force_update);

					$disabled_extension_meta_data[$name]['S_UP_TO_DATE'] = empty($updates);
					$disabled_extension_meta_data[$name]['S_VERSIONCHECK'] = true;
					$disabled_extension_meta_data[$name]['U_VERSIONCHECK_FORCE'] = $this->u_action . '&amp;action=details&amp;versioncheck_force=1&amp;ext_name=' . urlencode($md_manager->get_metadata('name'));
				}
				else
				{
					$disabled_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
				}
			}
			catch (version_check_exception $e)
			{
				$disabled_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
			}
			catch (exception_interface $e)
			{
				$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));
				$this->template->assign_block_vars('disabled', array(
					'META_DISPLAY_NAME'		=> $this->user->lang('EXTENSION_INVALID_LIST', $name, $message),
					'S_VERSIONCHECK'		=> false,
				));
			}
			catch (\RuntimeException $e)
			{
				$disabled_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
			}
		}

		uasort($disabled_extension_meta_data, array($this, 'sort_extension_meta_data_table'));

		foreach ($disabled_extension_meta_data as $name => $block_vars)
		{
			$block_vars['NAME'] = $name;
			$block_vars['U_DETAILS'] = $this->u_action . '&amp;action=details&amp;ext_name=' . urlencode($name);

			$this->template->assign_block_vars('disabled', $block_vars);

			$this->output_actions('disabled', array(
				'ENABLE'		=> $this->u_action . '&amp;action=enable_pre&amp;ext_name=' . urlencode($name),
				'DELETE_DATA'	=> $this->u_action . '&amp;action=delete_data_pre&amp;ext_name=' . urlencode($name),
			));
		}
	}

	/**
	* Lists all the available extensions and dumps to the template
	*
	* @return null
	*/
	public function list_available_exts()
	{
		$uninstalled = array_diff_key($this->ext_manager->all_available(), $this->ext_manager->all_configured());

		$available_extension_meta_data = array();

		foreach ($uninstalled as $name => $location)
		{
			$md_manager = $this->ext_manager->create_extension_metadata_manager($name);

			try
			{
				$meta = $md_manager->get_metadata('all');
				$available_extension_meta_data[$name] = array(
					'META_DISPLAY_NAME' => $md_manager->get_metadata('display-name'),
					'META_VERSION' => $meta['version'],
				);

				if (isset($meta['extra']['version-check']))
				{
					$force_update = $this->request->variable('versioncheck_force', false);
					$updates = $this->ext_manager->version_check($md_manager, $force_update, !$force_update);

					$available_extension_meta_data[$name]['S_UP_TO_DATE'] = empty($updates);
					$available_extension_meta_data[$name]['S_VERSIONCHECK'] = true;
					$available_extension_meta_data[$name]['U_VERSIONCHECK_FORCE'] = $this->u_action . '&amp;action=details&amp;versioncheck_force=1&amp;ext_name=' . urlencode($md_manager->get_metadata('name'));
				}
				else
				{
					$available_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
				}
			}
			catch (version_check_exception $e)
			{
				$available_extension_meta_data[$name]['S_VERSIONCHECK'] = false;
			}
			catch (exception_interface $e)
			{
				$message = call_user_func_array(array($this->user, 'lang'), array_merge(array($e->getMessage()), $e->get_parameters()));
				$this->template->assign_block_vars('disabled', array(
					'META_DISPLAY_NAME'		=> $this->user->lang('EXTENSION_INVALID_LIST', $name, $message),
					'S_VERSIONCHECK'		=> false,
				));
			}
		}

		uasort($available_extension_meta_data, array($this, 'sort_extension_meta_data_table'));

		foreach ($available_extension_meta_data as $name => $block_vars)
		{
			$block_vars['NAME'] = $name;
			$block_vars['U_DETAILS'] = $this->u_action . '&amp;action=details&amp;ext_name=' . urlencode($name);

			$this->template->assign_block_vars('disabled', $block_vars);

			$this->output_actions('disabled', array(
				'ENABLE'		=> $this->u_action . '&amp;action=enable_pre&amp;ext_name=' . urlencode($name),
			));
		}
	}

	/**
	* Output actions to a block
	*
	* @param string $block
	* @param array $actions
	* @return array List of actions to be performed on the extension
	*/
	private function output_actions($block, $actions)
	{
		$vars_ary = array();
		foreach ($actions as $lang => $options)
		{
			$url = $options;
			if (is_array($options))
			{
				$url = $options['url'];
			}

			$vars = array(
				'L_ACTION'			=> $this->user->lang('EXTENSION_' . $lang),
				'L_ACTION_EXPLAIN'	=> (isset($this->user->lang['EXTENSION_' . $lang . '_EXPLAIN'])) ? $this->user->lang('EXTENSION_' . $lang . '_EXPLAIN') : '',
				'U_ACTION'			=> $url,
				'ACTION_AJAX'		=> 'ext_' . strtolower($lang),
			);

			if (isset($options['color']))
			{
				$vars['COLOR'] = $options['color'];
			}

			$this->template->assign_block_vars($block . '.actions', $vars);

			$vars_ary[] = $vars;
		}

		return $vars_ary;
	}

	/**
	* Sort helper for the table containing the metadata about the extensions.
	*/
	protected function sort_extension_meta_data_table($val1, $val2)
	{
		return strnatcasecmp($val1['META_DISPLAY_NAME'], $val2['META_DISPLAY_NAME']);
	}

	/**
	* Outputs extension metadata into the template
	*
	* @param array $metadata Array with all metadata for the extension
	* @return null
	*/
	public function output_metadata_to_template($metadata)
	{
		$this->template->assign_vars(array(
			'META_NAME'			=> $metadata['name'],
			'META_TYPE'			=> $metadata['type'],
			'META_DESCRIPTION'	=> (isset($metadata['description'])) ? $metadata['description'] : '',
			'META_HOMEPAGE'		=> (isset($metadata['homepage'])) ? $metadata['homepage'] : '',
			'META_VERSION'		=> $metadata['version'],
			'META_TIME'			=> (isset($metadata['time'])) ? $metadata['time'] : '',
			'META_LICENSE'		=> $metadata['license'],

			'META_REQUIRE_PHP'		=> (isset($metadata['require']['php'])) ? $metadata['require']['php'] : '',
			'META_REQUIRE_PHP_FAIL'	=> (isset($metadata['require']['php'])) ? false : true,

			'META_REQUIRE_PHPBB'		=> (isset($metadata['extra']['soft-require']['phpbb/phpbb'])) ? $metadata['extra']['soft-require']['phpbb/phpbb'] : '',
			'META_REQUIRE_PHPBB_FAIL'	=> (isset($metadata['extra']['soft-require']['phpbb/phpbb'])) ? false : true,

			'META_DISPLAY_NAME'	=> (isset($metadata['extra']['display-name'])) ? $metadata['extra']['display-name'] : '',
		));

		foreach ($metadata['authors'] as $author)
		{
			$this->template->assign_block_vars('meta_authors', array(
				'AUTHOR_NAME'		=> $author['name'],
				'AUTHOR_EMAIL'		=> (isset($author['email'])) ? $author['email'] : '',
				'AUTHOR_HOMEPAGE'	=> (isset($author['homepage'])) ? $author['homepage'] : '',
				'AUTHOR_ROLE'		=> (isset($author['role'])) ? $author['role'] : '',
			));
		}
	}

	/**
	* Checks whether the extension can be enabled. Triggers error if not.
	* Error message can be set by the extension.
	*
	* @param \phpbb\extension\extension_interface $extension Extension to check
	*/
	protected function check_is_enableable(\phpbb\extension\extension_interface $extension)
	{
		$message = $extension->is_enableable();
		if ($message !== true)
		{
			if (empty($message))
			{
				$message = $this->user->lang('EXTENSION_NOT_ENABLEABLE');
			}
			else if (is_array($message))
			{
				$message = implode('<br>', $message);
			}

			trigger_error($message . adm_back_link($this->u_action), E_USER_WARNING);
		}
	}
}