<?php
/**
 * @package     Joomla.Plugin
 * @subpackage  System.stats
 *
 * @copyright   (C) 2015 Open Source Matters, Inc. <https://www.joomla.org>
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

defined('_JEXEC') or die;

// Uncomment the following line to enable debug mode for testing purposes. Note: statistics will be sent on every page load
// define('PLG_SYSTEM_STATS_DEBUG', 1);

/**
 * Statistics system plugin. This sends anonymous data back to the Joomla! Project about the
 * PHP, SQL, Joomla and OS versions
 *
 * @since  3.5
 */
class PlgSystemStats extends JPlugin
{
	/**
	 * Indicates sending statistics is always allowed.
	 *
	 * @var    integer
	 * @since  3.5
	 */
	const MODE_ALLOW_ALWAYS = 1;

	/**
	 * Indicates sending statistics is only allowed one time.
	 *
	 * @var    integer
	 * @since  3.5
	 */
	const MODE_ALLOW_ONCE = 2;

	/**
	 * Indicates sending statistics is never allowed.
	 *
	 * @var    integer
	 * @since  3.5
	 */
	const MODE_ALLOW_NEVER = 3;

	/**
	 * Application object
	 *
	 * @var    JApplicationCms
	 * @since  3.5
	 */
	protected $app;

	/**
	 * Database object
	 *
	 * @var    JDatabaseDriver
	 * @since  3.5
	 */
	protected $db;

	/**
	 * URL to send the statistics.
	 *
	 * @var    string
	 * @since  3.5
	 */
	protected $serverUrl = 'https://developer.joomla.org/stats/submit';

	/**
	 * Unique identifier for this site
	 *
	 * @var    string
	 * @since  3.5
	 */
	protected $uniqueId;

	/**
	 * Listener for the `onAfterInitialise` event
	 *
	 * @return  void
	 *
	 * @since   3.5
	 */
	public function onAfterInitialise()
	{
		if (!$this->app->isClient('administrator') || !$this->isAllowedUser())
		{
			return;
		}

		if (!$this->isDebugEnabled() && !$this->isUpdateRequired())
		{
			return;
		}

		if (JUri::getInstance()->getVar('tmpl') === 'component')
		{
			return;
		}

		// Load plugin language files only when needed (ex: they are not needed in site client).
		$this->loadLanguage();

		JHtml::_('jquery.framework');
		JHtml::_('script', 'plg_system_stats/stats.js', array('version' => 'auto', 'relative' => true));
	}

	/**
	 * User selected to always send data
	 *
	 * @return  void
	 *
	 * @since   3.5
	 *
	 * @throws  Exception         If user is not allowed.
	 * @throws  RuntimeException  If there is an error saving the params or sending the data.
	 */
	public function onAjaxSendAlways()
	{
		if (!$this->isAllowedUser() || !$this->isAjaxRequest())
		{
			throw new Exception(JText::_('JGLOBAL_AUTH_ACCESS_DENIED'), 403);
		}

		$this->params->set('mode', static::MODE_ALLOW_ALWAYS);

		if (!$this->saveParams())
		{
			throw new RuntimeException('Unable to save plugin settings', 500);
		}

		$this->sendStats();

		echo json_encode(array('sent' => 1));
	}

	/**
	 * User selected to never send data.
	 *
	 * @return  void
	 *
	 * @since   3.5
	 *
	 * @throws  Exception         If user is not allowed.
	 * @throws  RuntimeException  If there is an error saving the params.
	 */
	public function onAjaxSendNever()
	{
		if (!$this->isAllowedUser() || !$this->isAjaxRequest())
		{
			throw new Exception(JText::_('JGLOBAL_AUTH_ACCESS_DENIED'), 403);
		}

		$this->params->set('mode', static::MODE_ALLOW_NEVER);

		if (!$this->saveParams())
		{
			throw new RuntimeException('Unable to save plugin settings', 500);
		}

		echo json_encode(array('sent' => 0));
	}

	/**
	 * User selected to send data once.
	 *
	 * @return  void
	 *
	 * @since   3.5
	 *
	 * @throws  Exception         If user is not allowed.
	 * @throws  RuntimeException  If there is an error saving the params or sending the data.
	 */
	public function onAjaxSendOnce()
	{
		if (!$this->isAllowedUser() || !$this->isAjaxRequest())
		{
			throw new Exception(JText::_('JGLOBAL_AUTH_ACCESS_DENIED'), 403);
		}

		$this->params->set('mode', static::MODE_ALLOW_ONCE);

		if (!$this->saveParams())
		{
			throw new RuntimeException('Unable to save plugin settings', 500);
		}

		$this->sendStats();

		echo json_encode(array('sent' => 1));
	}

	/**
	 * Send the stats to the server.
	 * On first load | on demand mode it will show a message asking users to select mode.
	 *
	 * @return  void
	 *
	 * @since   3.5
	 *
	 * @throws  Exception         If user is not allowed.
	 * @throws  RuntimeException  If there is an error saving the params or sending the data.
	 */
	public function onAjaxSendStats()
	{
		if (!$this->isAllowedUser() || !$this->isAjaxRequest())
		{
			throw new Exception(JText::_('JGLOBAL_AUTH_ACCESS_DENIED'), 403);
		}

		// User has not selected the mode. Show message.
		if ((int) $this->params->get('mode') !== static::MODE_ALLOW_ALWAYS)
		{
			$data = array(
				'sent' => 0,
				'html' => $this->getRenderer('message')->render($this->getLayoutData())
			);

			echo json_encode($data);

			return;
		}

		if (!$this->saveParams())
		{
			throw new RuntimeException('Unable to save plugin settings', 500);
		}

		$this->sendStats();

		echo json_encode(array('sent' => 1));
	}

	/**
	 * Get the data through events
	 *
	 * @param   string  $context  Context where this will be called from
	 *
	 * @return  array
	 *
	 * @since   3.5
	 */
	public function onGetStatsData($context)
	{
		return $this->getStatsData();
	}

	/**
	 * Debug a layout of this plugin
	 *
	 * @param   string  $layoutId  Layout identifier
	 * @param   array   $data      Optional data for the layout
	 *
	 * @return  string
	 *
	 * @since   3.5
	 */
	public function debug($layoutId, $data = array())
	{
		$data = array_merge($this->getLayoutData(), $data);

		return $this->getRenderer($layoutId)->debug($data);
	}

	/**
	 * Get the data for the layout
	 *
	 * @return  array
	 *
	 * @since   3.5
	 */
	protected function getLayoutData()
	{
		return array(
			'plugin'       => $this,
			'pluginParams' => $this->params,
			'statsData'    => $this->getStatsData()
		);
	}

	/**
	 * Get the layout paths
	 *
	 * @return  array
	 *
	 * @since   3.5
	 */
	protected function getLayoutPaths()
	{
		$template = JFactory::getApplication()->getTemplate();

		return array(
			JPATH_ADMINISTRATOR . '/templates/' . $template . '/html/layouts/plugins/' . $this->_type . '/' . $this->_name,
			__DIR__ . '/layouts',
		);
	}

	/**
	 * Get the plugin renderer
	 *
	 * @param   string  $layoutId  Layout identifier
	 *
	 * @return  JLayout
	 *
	 * @since   3.5
	 */
	protected function getRenderer($layoutId = 'default')
	{
		$renderer = new JLayoutFile($layoutId);

		$renderer->setIncludePaths($this->getLayoutPaths());

		return $renderer;
	}

	/**
	 * Get the data that will be sent to the stats server.
	 *
	 * @return  array
	 *
	 * @since   3.5
	 */
	private function getStatsData()
	{
		$data = array(
			'unique_id'   => $this->getUniqueId(),
			'php_version' => PHP_VERSION,
			'db_type'     => $this->db->name,
			'db_version'  => $this->db->getVersion(),
			'cms_version' => JVERSION,
			'server_os'   => php_uname('s') . ' ' . php_uname('r')
		);

		// Check if we have a MariaDB version string and extract the proper version from it
		if (preg_match('/^(?:5\.5\.5-)?(mariadb-)?(?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)/i', $data['db_version'], $versionParts))
		{
			$data['db_version'] = $versionParts['major'] . '.' . $versionParts['minor'] . '.' . $versionParts['patch'];
		}

		return $data;
	}

	/**
	 * Get the unique id. Generates one if none is set.
	 *
	 * @return  integer
	 *
	 * @since   3.5
	 */
	private function getUniqueId()
	{
		if (null === $this->uniqueId)
		{
			$this->uniqueId = $this->params->get('unique_id', hash('sha1', JUserHelper::genRandomPassword(28) . time()));
		}

		return $this->uniqueId;
	}

	/**
	 * Check if current user is allowed to send the data
	 *
	 * @return  boolean
	 *
	 * @since   3.5
	 */
	private function isAllowedUser()
	{
		return JFactory::getUser()->authorise('core.admin');
	}

	/**
	 * Check if the debug is enabled
	 *
	 * @return  boolean
	 *
	 * @since   3.5
	 */
	private function isDebugEnabled()
	{
		return defined('PLG_SYSTEM_STATS_DEBUG');
	}

	/**
	 * Check if last_run + interval > now
	 *
	 * @return  boolean
	 *
	 * @since   3.5
	 */
	private function isUpdateRequired()
	{
		$last     = (int) $this->params->get('lastrun', 0);
		$interval = (int) $this->params->get('interval', 12);
		$mode     = (int) $this->params->get('mode', 0);

		if ($mode === static::MODE_ALLOW_NEVER)
		{
			return false;
		}

		// Never updated or debug enabled
		if (!$last || $this->isDebugEnabled())
		{
			return true;
		}

		return (abs(time() - $last) > $interval * 3600);
	}

	/**
	 * Check valid AJAX request
	 *
	 * @return  boolean
	 *
	 * @since   3.5
	 */
	private function isAjaxRequest()
	{
		return strtolower($this->app->input->server->get('HTTP_X_REQUESTED_WITH', '')) === 'xmlhttprequest';
	}

	/**
	 * Render a layout of this plugin
	 *
	 * @param   string  $layoutId  Layout identifier
	 * @param   array   $data      Optional data for the layout
	 *
	 * @return  string
	 *
	 * @since   3.5
	 */
	public function render($layoutId, $data = array())
	{
		$data = array_merge($this->getLayoutData(), $data);

		return $this->getRenderer($layoutId)->render($data);
	}

	/**
	 * Save the plugin parameters
	 *
	 * @return  boolean
	 *
	 * @since   3.5
	 */
	private function saveParams()
	{
		// Update params
		$this->params->set('lastrun', time());
		$this->params->set('unique_id', $this->getUniqueId());
		$interval = (int) $this->params->get('interval', 12);
		$this->params->set('interval', $interval ?: 12);

		$query = $this->db->getQuery(true)
				->update($this->db->quoteName('#__extensions'))
				->set($this->db->quoteName('params') . ' = ' . $this->db->quote($this->params->toString('JSON')))
				->where($this->db->quoteName('type') . ' = ' . $this->db->quote('plugin'))
				->where($this->db->quoteName('folder') . ' = ' . $this->db->quote('system'))
				->where($this->db->quoteName('element') . ' = ' . $this->db->quote('stats'));

		try
		{
			// Lock the tables to prevent multiple plugin executions causing a race condition
			$this->db->lockTable('#__extensions');
		}
		catch (Exception $e)
		{
			// If we can't lock the tables it's too risky to continue execution
			return false;
		}

		try
		{
			// Update the plugin parameters
			$result = $this->db->setQuery($query)->execute();

			$this->clearCacheGroups(array('com_plugins'), array(0, 1));
		}
		catch (Exception $exc)
		{
			// If we failed to execute
			$this->db->unlockTables();
			$result = false;
		}

		try
		{
			// Unlock the tables after writing
			$this->db->unlockTables();
		}
		catch (Exception $e)
		{
			// If we can't lock the tables assume we have somehow failed
			$result = false;
		}

		return $result;
	}

	/**
	 * Send the stats to the stats server
	 *
	 * @return  boolean
	 *
	 * @since   3.5
	 *
	 * @throws  RuntimeException  If there is an error sending the data.
	 */
	private function sendStats()
	{
		try
		{
			// Don't let the request take longer than 2 seconds to avoid page timeout issues
			$response = JHttpFactory::getHttp()->post($this->serverUrl, $this->getStatsData(), null, 2);
		}
		catch (UnexpectedValueException $e)
		{
			// There was an error sending stats. Should we do anything?
			throw new RuntimeException('Could not send site statistics to remote server: ' . $e->getMessage(), 500);
		}
		catch (RuntimeException $e)
		{
			// There was an error connecting to the server or in the post request
			throw new RuntimeException('Could not connect to statistics server: ' . $e->getMessage(), 500);
		}
		catch (Exception $e)
		{
			// An unexpected error in processing; don't let this failure kill the site
			throw new RuntimeException('Unexpected error connecting to statistics server: ' . $e->getMessage(), 500);
		}

		if ($response->code !== 200)
		{
			$data = json_decode($response->body);

			throw new RuntimeException('Could not send site statistics to remote server: ' . $data->message, $response->code);
		}

		return true;
	}

	/**
	 * Clears cache groups. We use it to clear the plugins cache after we update the last run timestamp.
	 *
	 * @param   array  $clearGroups   The cache groups to clean
	 * @param   array  $cacheClients  The cache clients (site, admin) to clean
	 *
	 * @return  void
	 *
	 * @since   3.5
	 */
	private function clearCacheGroups(array $clearGroups, array $cacheClients = array(0, 1))
	{
		foreach ($clearGroups as $group)
		{
			foreach ($cacheClients as $client_id)
			{
				try
				{
					$options = array(
						'defaultgroup' => $group,
						'cachebase'    => $client_id ? JPATH_ADMINISTRATOR . '/cache' : $this->app->get('cache_path', JPATH_SITE . '/cache')
					);

					$cache = JCache::getInstance('callback', $options);
					$cache->clean();
				}
				catch (Exception $e)
				{
					// Ignore it
				}
			}
		}
	}
}
