<?php
/**
 * @package     Joomla.Installation
 * @subpackage  Model
 *
 * @copyright   Copyright (C) 2005 - 2017 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

defined('_JEXEC') or die;

use Joomla\Utilities\ArrayHelper;

/**
 * Database configuration model for the Joomla Core Installer.
 *
 * @since  3.1
 */
class InstallationModelDatabase extends JModelBase
{
	/**
	 * The generated user ID.
	 *
	 * @var    integer
	 * @since  3.1
	 */
	protected static $userId = 0;

	/**
	 * Generates the user ID.
	 *
	 * @return  integer  The user ID.
	 *
	 * @since   3.1
	 */
	protected static function generateRandUserId()
	{
		$session    = JFactory::getSession();
		$randUserId = $session->get('randUserId');

		if (empty($randUserId))
		{
			// Create the ID for the root user only once and store in session.
			$randUserId = mt_rand(1, 1000);
			$session->set('randUserId', $randUserId);
		}

		return $randUserId;
	}

	/**
	 * Resets the user ID.
	 *
	 * @return  void
	 *
	 * @since   3.1
	 */
	public static function resetRandUserId()
	{
		self::$userId = 0;

		JFactory::getSession()->set('randUserId', self::$userId);
	}

	/**
	 * Retrieves the default user ID and sets it if necessary.
	 *
	 * @return  integer  The user ID.
	 *
	 * @since   3.1
	 */
	public static function getUserId()
	{
		if (!self::$userId)
		{
			self::$userId = self::generateRandUserId();
		}

		return self::$userId;
	}

	/**
	 * Method to initialise the database.
	 *
	 * @param   array  $options  The options to use for configuration.
	 *
	 * @return  JDatabaseDriver|boolean  Database object on success, boolean false on failure
	 *
	 * @since   3.1
	 */
	public function initialise($options)
	{
		// Get the options as an object for easier handling.
		$options = ArrayHelper::toObject($options);

		// Load the backend language files so that the DB error messages work.
		$lang = JFactory::getLanguage();
		$currentLang = $lang->getTag();

		// Load the selected language
		if (JLanguageHelper::exists($currentLang, JPATH_ADMINISTRATOR))
		{
			$lang->load('joomla', JPATH_ADMINISTRATOR, $currentLang, true);
		}
		// Pre-load en-GB in case the chosen language files do not exist.
		else
		{
			$lang->load('joomla', JPATH_ADMINISTRATOR, 'en-GB', true);
		}

		// Ensure a database type was selected.
		if (empty($options->db_type))
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_INVALID_TYPE'), 'warning');

			return false;
		}

		// Ensure that a hostname and user name were input.
		if (empty($options->db_host) || empty($options->db_user))
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_INVALID_DB_DETAILS'), 'warning');

			return false;
		}

		// Ensure that a database name was input.
		if (empty($options->db_name))
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_EMPTY_NAME'), 'warning');

			return false;
		}

		// Validate database table prefix.
		if (!preg_match('#^[a-zA-Z]+[a-zA-Z0-9_]*$#', $options->db_prefix))
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_PREFIX_MSG'), 'warning');

			return false;
		}

		// Validate length of database table prefix.
		if (strlen($options->db_prefix) > 15)
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_FIX_TOO_LONG'), 'warning');

			return false;
		}

		// Validate length of database name.
		if (strlen($options->db_name) > 64)
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_NAME_TOO_LONG'), 'warning');

			return false;
		}

		// Workaround for UPPERCASE table prefix for postgresql
		if ($options->db_type === 'postgresql' && strtolower($options->db_prefix) !== $options->db_prefix)
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_FIX_LOWERCASE'), 'warning');

			return false;
		}

		$shouldCheckLocalhost = getenv('JOOMLA_INSTALLATION_DISABLE_LOCALHOST_CHECK') !== '1';

		// Per Default allowed DB Hosts
		$localhost = array(
			'localhost',
			'127.0.0.1',
			'::1',
		);

		// Check the security file if the db_host is not localhost / 127.0.0.1 / ::1
		if ($shouldCheckLocalhost && !in_array($options->db_host, $localhost))
		{
			$remoteDbFileTestsPassed = JFactory::getSession()->get('remoteDbFileTestsPassed', false);
			
			// When all checks have been passed we don't need to do this here again.
			if ($remoteDbFileTestsPassed === false)
			{
				$generalRemoteDatabaseMessage = JText::sprintf(
					'INSTL_DATABASE_HOST_IS_NOT_LOCALHOST_GENERAL_MESSAGE',
					'https://docs.joomla.org/Special:MyLanguage/J3.x:Secured_procedure_for_installing_Joomla_with_a_remote_database'
				);

				$remoteDbFile = JFactory::getSession()->get('remoteDbFile', false);

				if ($remoteDbFile === false)
				{
					// Add the general message
					JFactory::getApplication()->enqueueMessage($generalRemoteDatabaseMessage, 'warning');

					// This is the file you need to remove if you want to use a remote database
					$remoteDbFile = '_Joomla' . JUserHelper::genRandomPassword(21) . '.txt';
					JFactory::getSession()->set('remoteDbFile', $remoteDbFile);

					// Get the path
					$remoteDbPath = JPATH_INSTALLATION . '/' . $remoteDbFile;

					// When the path is not writable the user needs to create the file manually
					if (!JFile::write($remoteDbPath, ''))
					{
						// Request to create the file manually
						JFactory::getApplication()->enqueueMessage(
							JText::sprintf(
								'INSTL_DATABASE_HOST_IS_NOT_LOCALHOST_CREATE_FILE',
								$remoteDbFile,
								'installation'
							),
							'error'
						);

						JFactory::getSession()->set('remoteDbFileUnwritable', true);

						return false;
					}

					// Save the file name to the session
					JFactory::getSession()->set('remoteDbFileWrittenByJoomla', true);

					// Request to delete that file
					JFactory::getApplication()->enqueueMessage(
						JText::sprintf(
							'INSTL_DATABASE_HOST_IS_NOT_LOCALHOST_DELETE_FILE',
							$remoteDbFile,
							'installation'
						),
						'error'
					);

					return false;
				}

				if (JFactory::getSession()->get('remoteDbFileWrittenByJoomla', false) === true && file_exists(JPATH_INSTALLATION . '/' . $remoteDbFile))
				{
					// Add the general message
					JFactory::getApplication()->enqueueMessage($generalRemoteDatabaseMessage, 'warning');
					
					JFactory::getApplication()->enqueueMessage(
						JText::sprintf(
							'INSTL_DATABASE_HOST_IS_NOT_LOCALHOST_DELETE_FILE',
							$remoteDbFile,
							'installation'
						),
						'error'
					);

					return false;
				}

				if (JFactory::getSession()->get('remoteDbFileUnwritable', false) === true && !file_exists(JPATH_INSTALLATION . '/' . $remoteDbFile))
				{
					// Add the general message
					JFactory::getApplication()->enqueueMessage($generalRemoteDatabaseMessage, 'warning');

					JFactory::getApplication()->enqueueMessage(
						JText::sprintf(
							'INSTL_DATABASE_HOST_IS_NOT_LOCALHOST_CREATE_FILE',
							$remoteDbFile,
							'installation'
						),
						'error'
					);

					return false;
				}

				// All tests for this session passed set it to the session
				JFactory::getSession()->set('remoteDbFileTestsPassed', true);
			}
		}

		// Get a database object.
		try
		{
			return InstallationHelperDatabase::getDbo(
				$options->db_type,
				$options->db_host,
				$options->db_user,
				$options->db_pass,
				$options->db_name,
				$options->db_prefix,
				$options->db_select
			);
		}
		catch (RuntimeException $e)
		{
			JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_COULD_NOT_CONNECT', $e->getMessage()), 'error');

			return false;
		}
	}

	/**
	 * Method to create a new database.
	 *
	 * @param   array  $options  The configuration options
	 *
	 * @return    boolean    True on success.
	 *
	 * @since    3.1
	 */
	public function createDatabase($options)
	{
		// Disable autoselect database before it's created.
		$tmpSelect = true;

		if (isset($options['db_select']))
		{
			$tmpSelect = $options['db_select'];
		}

		$options['db_select'] = false;

		if (!$db = $this->initialise($options))
		{
			return false;
		}

		// Get the options as an object for easier handling.
		$options = ArrayHelper::toObject($options);

		// Check database version.
		$type = $options->db_type;

		try
		{
			$db_version = $db->getVersion();
		}
		catch (RuntimeException $e)
		{
			/*
			 * We may get here if the database doesn't exist, if so then explain that to users instead of showing the database connector's error
			 * This only supports PostgreSQL and the PDO MySQL drivers presently
			 *
			 * Error Messages:
			 * PDO MySQL: [1049] Unknown database 'database_name'
			 * PostgreSQL: Error connecting to PGSQL database
			 */
			if ($type == 'pdomysql' && strpos($e->getMessage(), '[1049] Unknown database') === 42)
			{
				/*
				 * Now we're really getting insane here; we're going to try building a new JDatabaseDriver instance without the database name
				 * in order to trick the connection into creating the database
				 */
				$altDBoptions = array(
					'driver'   => $options->db_type,
					'host'     => $options->db_host,
					'user'     => $options->db_user,
					'password' => $options->db_pass,
					'prefix'   => $options->db_prefix,
					'select'   => $options->db_select,
				);

				$altDB = JDatabaseDriver::getInstance($altDBoptions);

				// Try to create the database now using the alternate driver
				try
				{
					$this->createDb($altDB, $options, $altDB->hasUTFSupport());
				}
				catch (RuntimeException $e)
				{
					// We did everything we could
					JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_COULD_NOT_CREATE_DATABASE'), 'error');

					return false;
				}

				// If we got here, the database should have been successfully created, now try one more time to get the version
				try
				{
					$db_version = $db->getVersion();
				}
				catch (RuntimeException $e)
				{
					// We did everything we could
					JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_COULD_NOT_CONNECT', $e->getMessage()), 'error');

					return false;
				}
			}
			elseif ($type == 'postgresql' && strpos($e->getMessage(), 'Error connecting to PGSQL database') === 42)
			{
				JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_COULD_NOT_CREATE_DATABASE'), 'error');

				return false;
			}
			// Anything getting into this part of the conditional either doesn't support manually creating the database or isn't that type of error
			else
			{
				JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_COULD_NOT_CONNECT', $e->getMessage()), 'error');

				return false;
			}
		}

		if (!$db->isMinimumVersion())
		{
			JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_INVALID_' . strtoupper($type) . '_VERSION', $db_version), 'error');

			return false;
		}

		if ($db->getServerType() === 'mysql')
		{
			// @internal MySQL versions pre 5.1.6 forbid . / or \ or NULL.
			if (preg_match('#[\\\/\.\0]#', $options->db_name) && (!version_compare($db_version, '5.1.6', '>=')))
			{
				JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_INVALID_NAME', $db_version), 'error');

				return false;
			}
		}

		// @internal Check for spaces in beginning or end of name.
		if (strlen(trim($options->db_name)) <> strlen($options->db_name))
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_NAME_INVALID_SPACES'), 'error');

			return false;
		}

		// @internal Check for asc(00) Null in name.
		if (strpos($options->db_name, chr(00)) !== false)
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_NAME_INVALID_CHAR'), 'error');

			return false;
		}

		// PostgreSQL database older than version 9.0.0 needs to run 'CREATE LANGUAGE' to create function.
		if ($db->getServerType() === 'postgresql' && !version_compare($db_version, '9.0.0', '>='))
		{
			$db->setQuery("select lanpltrusted from pg_language where lanname='plpgsql'");

			try
			{
				$db->execute();
			}
			catch (RuntimeException $e)
			{
				JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_ERROR_POSTGRESQL_QUERY'), 'error');

				return false;
			}

			$column = $db->loadResult();

			if ($column != 't')
			{
				$db->setQuery('CREATE LANGUAGE plpgsql');

				try
				{
					$db->execute();
				}
				catch (RuntimeException $e)
				{
					JFactory::getApplication()->enqueueMessage(JText::_('INSTL_DATABASE_ERROR_POSTGRESQL_QUERY'), 'error');

					return false;
				}
			}
		}

		// Get database's UTF support.
		$utfSupport = $db->hasUTFSupport();

		// Try to select the database.
		try
		{
			$db->select($options->db_name);
		}
		catch (RuntimeException $e)
		{
			// If the database could not be selected, attempt to create it and then select it.
			if ($this->createDb($db, $options, $utfSupport))
			{
				$db->select($options->db_name);
			}
			else
			{
				JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_ERROR_CREATE', $options->db_name), 'error');

				return false;
			}
		}

		$options = (array) $options;

		// Remove *_errors value.
		foreach ($options as $i => $option)
		{
			if (isset($i['1']) && $i['1'] == '*')
			{
				unset($options[$i]);

				break;
			}
		}

		$options = array_merge(array('db_created' => 1), $options);

		// Restore autoselect value after database creation.
		$options['db_select'] = $tmpSelect;

		JFactory::getSession()->set('setup.options', $options);

		return true;
	}

	/**
	 * Method to process the old database.
	 *
	 * @param   array  $options  The options array.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function handleOldDatabase($options)
	{
		if (!isset($options['db_created']) || !$options['db_created'])
		{
			return $this->createDatabase($options);
		}

		if (!$db = $this->initialise($options))
		{
			return false;
		}

		// Get the options as an object for easier handling.
		$options = ArrayHelper::toObject($options);

		// Set the character set to UTF-8 for pre-existing databases.
		$this->setDatabaseCharset($db, $options->db_name);

		// Should any old database tables be removed or backed up?
		if ($options->db_old == 'remove')
		{
			// Attempt to delete the old database tables.
			if (!$this->deleteDatabase($db, $options->db_prefix))
			{
				// Message queued by method, simply return
				return false;
			}
		}
		else
		{
			// If the database isn't being deleted, back it up.
			if (!$this->backupDatabase($db, $options->db_prefix))
			{
				return false;
			}
		}

		return true;
	}

	/**
	 * Method to create the database tables.
	 *
	 * @param   array  $options  The options array.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function createTables($options)
	{
		if (!isset($options['db_created']) || !$options['db_created'])
		{
			return $this->createDatabase($options);
		}

		if (!$db = $this->initialise($options))
		{
			return false;
		}

		// Get the options as an object for easier handling.
		$options = ArrayHelper::toObject($options);

		// Check database type.
		$type = $options->db_type;

		// Set the character set to UTF-8 for pre-existing databases.
		$this->setDatabaseCharset($db, $options->db_name);

		// Set the appropriate schema script based on UTF-8 support.
		if ($db->getServerType() === 'mysql')
		{
			$schema = 'sql/mysql/joomla.sql';
		}
		elseif ($db->getServerType() === 'mssql')
		{
			$schema = 'sql/sqlazure/joomla.sql';
		}
		else
		{
			$schema = 'sql/' . $type . '/joomla.sql';
		}

		// Check if the schema is a valid file
		if (!is_file($schema))
		{
			JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_ERROR_DB', JText::_('INSTL_DATABASE_NO_SCHEMA')), 'error');

			return false;
		}

		// Attempt to import the database schema.
		if (!$this->populateDatabase($db, $schema))
		{
			return false;
		}

		// Get query object for later database access
		$query = $db->getQuery(true);

		// MySQL only: Attempt to update the table #__utf8_conversion.
		$serverType = $db->getServerType();

		if ($serverType === 'mysql')
		{
			$query->clear()
				->update($db->quoteName('#__utf8_conversion'))
				->set($db->quoteName('converted') . ' = ' . ($db->hasUTF8mb4Support() ? 2 : 1));
			$db->setQuery($query);

			try
			{
				$db->execute();
			}
			catch (RuntimeException $e)
			{
				JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');

				return false;
			}
		}

		// Attempt to update the table #__schema.
		$pathPart = JPATH_ADMINISTRATOR . '/components/com_admin/sql/updates/';

		if ($serverType === 'mysql')
		{
			$pathPart .= 'mysql/';
		}
		elseif ($serverType === 'mssql')
		{
			$pathPart .= 'sqlazure/';
		}
		else
		{
			$pathPart .= $type . '/';
		}

		$files = JFolder::files($pathPart, '\.sql$');

		if (empty($files))
		{
			JFactory::getApplication()->enqueueMessage(JText::_('INSTL_ERROR_INITIALISE_SCHEMA'), 'error');

			return false;
		}

		$version = '';

		foreach ($files as $file)
		{
			if (version_compare($version, JFile::stripExt($file)) < 0)
			{
				$version = JFile::stripExt($file);
			}
		}

		$query->clear()
			->insert($db->quoteName('#__schemas'))
			->columns(
				array(
					$db->quoteName('extension_id'),
					$db->quoteName('version_id')
				)
			)
			->values('700, ' . $db->quote($version));
		$db->setQuery($query);

		try
		{
			$db->execute();
		}
		catch (RuntimeException $e)
		{
			JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');

			return false;
		}

		// Attempt to refresh manifest caches.
		$query->clear()
			->select('*')
			->from('#__extensions');
		$db->setQuery($query);

		$return = true;

		try
		{
			$extensions = $db->loadObjectList();
		}
		catch (RuntimeException $e)
		{
			JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');
			$return = false;
		}

		JFactory::$database = $db;
		$installer = JInstaller::getInstance();

		foreach ($extensions as $extension)
		{
			if (!$installer->refreshManifestCache($extension->extension_id))
			{
				JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_COULD_NOT_REFRESH_MANIFEST_CACHE', $extension->name), 'error');

				return false;
			}
		}

		// Load the localise.sql for translating the data in joomla.sql.
		if ($serverType === 'mysql')
		{
			$dblocalise = 'sql/mysql/localise.sql';
		}
		elseif ($serverType === 'mssql')
		{
			$dblocalise = 'sql/sqlazure/localise.sql';
		}
		else
		{
			$dblocalise = 'sql/' . $type . '/localise.sql';
		}

		if (is_file($dblocalise) && !$this->populateDatabase($db, $dblocalise))
		{
			return false;
		}

		// Handle default backend language setting. This feature is available for localized versions of Joomla.
		$languages = JFactory::getApplication()->getLocaliseAdmin($db);

		if (in_array($options->language, $languages['admin']) || in_array($options->language, $languages['site']))
		{
			// Build the language parameters for the language manager.
			$params = array();

			// Set default administrator/site language to sample data values.
			$params['administrator'] = 'en-GB';
			$params['site']          = 'en-GB';

			if (in_array($options->language, $languages['admin']))
			{
				$params['administrator'] = $options->language;
			}

			if (in_array($options->language, $languages['site']))
			{
				$params['site'] = $options->language;
			}

			$params = json_encode($params);

			// Update the language settings in the language manager.
			$query->clear()
				->update($db->quoteName('#__extensions'))
				->set($db->quoteName('params') . ' = ' . $db->quote($params))
				->where($db->quoteName('element') . ' = ' . $db->quote('com_languages'));
			$db->setQuery($query);

			try
			{
				$db->execute();
			}
			catch (RuntimeException $e)
			{
				JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');

				$return = false;
			}
		}

		return $return;
	}

	/**
	 * Method to install the sample data.
	 *
	 * @param   array  $options  The options array.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function installSampleData($options)
	{
		if (!isset($options['db_created']) || !$options['db_created'])
		{
			return $this->createDatabase($options);
		}

		if (!$db = $this->initialise($options))
		{
			return false;
		}

		// Get the options as an object for easier handling.
		$options = ArrayHelper::toObject($options);
		$options->sample_file = "sample_data.sql";

		// Build the path to the sample data file.
		$type = $options->db_type;

		if ($db->getServerType() === 'mysql')
		{
			$type = 'mysql';
		}
		elseif ($db->getServerType() === 'mssql')
		{
			$type = 'sqlazure';
		}

		$data = JPATH_INSTALLATION . '/sql/' . $type . '/' . $options->sample_file;

		// Attempt to import the database schema if one is chosen.
		if ($options->sample_file != '')
		{
			if (!file_exists($data))
			{
				JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_FILE_DOES_NOT_EXIST', $data), 'error');

				return false;
			}
			elseif (!$this->populateDatabase($db, $data))
			{
				return false;
			}

			$this->postInstallSampleData($db, $options->sample_file);
		}

		return true;
	}

	/**
	 * Sample data tables and data post install process.
	 *
	 * @param   JDatabaseDriver  $db              Database connector object $db*.
	 * @param   string           $sampleFileName  The sample dats filename.
	 *
	 * @return  void
	 *
	 * @since   3.1
	 */
	protected function postInstallSampleData($db, $sampleFileName = '')
	{
		// Update the sample data user ids.
		$this->updateUserIds($db);

		// If not joomla sample data for testing, update the sample data dates.
		if ($sampleFileName !== 'sample_testing.sql')
		{
			$this->updateDates($db);
		}
	}

	/**
	 * Method to install the cms data.
	 *
	 * @param   array  $options  The options array.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.6.1
	 */
	public function installCmsData($options)
	{
		// Attempt to create the database tables.
		if (!$this->createTables($options))
		{
			return false;
		}

		if (!$db = $this->initialise($options))
		{
			return false;
		}

		// Run Cms data post install to update user ids.
		return $this->postInstallCmsData($db);
	}

	/**
	 * Cms tables and data post install process.
	 *
	 * @param   JDatabaseDriver  $db  Database connector object $db*.
	 *
	 * @return  void
	 *
	 * @since   3.6.1
	 */
	protected function postInstallCmsData($db)
	{
		// Update the cms data user ids.
		$this->updateUserIds($db);

		// Update the cms data dates.
		$this->updateDates($db);
	}

	/**
	 * Method to update the user id of sql data content to the new rand user id.
	 *
	 * @param   JDatabaseDriver  $db  Database connector object $db*.
	 *
	 * @return  void
	 *
	 * @since   3.6.1
	 */
	protected function updateUserIds($db)
	{
		// Create the ID for the root user.
		$userId = self::getUserId();

		// Update all core tables created_by fields of the tables with the random user id.
		$updatesArray = array(
			'#__banners'         => array('created_by', 'modified_by'),
			'#__categories'      => array('created_user_id', 'modified_user_id'),
			'#__contact_details' => array('created_by', 'modified_by'),
			'#__content'         => array('created_by', 'modified_by'),
			'#__fields'          => array('created_user_id', 'modified_by'),
			'#__finder_filters'  => array('created_by', 'modified_by'),
			'#__newsfeeds'       => array('created_by', 'modified_by'),
			'#__tags'            => array('created_user_id', 'modified_user_id'),
			'#__ucm_content'     => array('core_created_user_id', 'core_modified_user_id'),
			'#__ucm_history'     => array('editor_user_id'),
			'#__user_notes'      => array('created_user_id', 'modified_user_id'),
		);

		foreach ($updatesArray as $table => $fields)
		{
			foreach ($fields as $field)
			{
				$query = $db->getQuery(true)
					->update($db->quoteName($table))
					->set($db->quoteName($field) . ' = ' . $db->quote($userId))
					->where($db->quoteName($field) . ' != 0')
					->where($db->quoteName($field) . ' IS NOT NULL');

				$db->setQuery($query);

				try
				{
					$db->execute();
				}
				catch (RuntimeException $e)
				{
					JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');
				}
			}
		}
	}

	/**
	 * Method to update the dates of sql data content to the current date.
	 *
	 * @param   JDatabaseDriver  $db  Database connector object $db*.
	 *
	 * @return  void
	 *
	 * @since   3.7.0
	 */
	protected function updateDates($db)
	{
		// Get the current date.
		$currentDate = JFactory::getDate()->toSql();
		$nullDate    = $db->getNullDate();

		// Update all core tables date fields of the tables with the current date.
		$updatesArray = array(
			'#__banners'             => array('publish_up', 'publish_down', 'reset', 'created', 'modified'),
			'#__banner_tracks'       => array('track_date'),
			'#__categories'          => array('created_time', 'modified_time'),
			'#__contact_details'     => array('publish_up', 'publish_down', 'created', 'modified'),
			'#__content'             => array('publish_up', 'publish_down', 'created', 'modified'),
			'#__contentitem_tag_map' => array('tag_date'),
			'#__fields'              => array('created_time', 'modified_time'),
			'#__finder_filters'      => array('created', 'modified'),
			'#__finder_links'        => array('indexdate', 'publish_start_date', 'publish_end_date', 'start_date', 'end_date'),
			'#__messages'            => array('date_time'),
			'#__modules'             => array('publish_up', 'publish_down'),
			'#__newsfeeds'           => array('publish_up', 'publish_down', 'created', 'modified'),
			'#__redirect_links'      => array('created_date', 'modified_date'),
			'#__tags'                => array('publish_up', 'publish_down', 'created_time', 'modified_time'),
			'#__ucm_content'         => array('core_created_time', 'core_modified_time', 'core_publish_up', 'core_publish_down'),
			'#__ucm_history'         => array('save_date'),
			'#__users'               => array('registerDate', 'lastvisitDate', 'lastResetTime'),
			'#__user_notes'          => array('publish_up', 'publish_down', 'created_time', 'modified_time'),
		);

		foreach ($updatesArray as $table => $fields)
		{
			foreach ($fields as $field)
			{
				$query = $db->getQuery(true)
					->update($db->quoteName($table))
					->set($db->quoteName($field) . ' = ' . $db->quote($currentDate))
					->where($db->quoteName($field) . ' != ' . $db->quote($nullDate));

				$db->setQuery($query);

				try
				{
					$db->execute();
				}
				catch (RuntimeException $e)
				{
					JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');
				}
			}
		}
	}

	/**
	 * Method to backup all tables in a database with a given prefix.
	 *
	 * @param   JDatabaseDriver  $db      JDatabaseDriver object.
	 * @param   string           $prefix  Database table prefix.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since    3.1
	 */
	public function backupDatabase($db, $prefix)
	{
		$return = true;
		$backup = 'bak_' . $prefix;

		// Get the tables in the database.
		$tables = $db->getTableList();

		if ($tables)
		{
			foreach ($tables as $table)
			{
				// If the table uses the given prefix, back it up.
				if (strpos($table, $prefix) === 0)
				{
					// Backup table name.
					$backupTable = str_replace($prefix, $backup, $table);

					// Drop the backup table.
					try
					{
						$db->dropTable($backupTable, true);
					}
					catch (RuntimeException $e)
					{
						JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_ERROR_BACKINGUP', $e->getMessage()), 'error');

						$return = false;
					}

					// Rename the current table to the backup table.
					try
					{
						$db->renameTable($table, $backupTable, $backup, $prefix);
					}
					catch (RuntimeException $e)
					{
						JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_ERROR_BACKINGUP', $e->getMessage()), 'error');

						$return = false;
					}
				}
			}
		}

		return $return;
	}

	/**
	 * Method to create a new database.
	 *
	 * @param   JDatabaseDriver  $db       JDatabase object.
	 * @param   JObject          $options  JObject coming from "initialise" function to pass user
	 *                                     and database name to database driver.
	 * @param   boolean          $utf      True if the database supports the UTF-8 character set.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function createDb($db, $options, $utf)
	{
		// Build the create database query.
		try
		{
			// Run the create database query.
			$db->createDatabase($options, $utf);
		}
		catch (RuntimeException $e)
		{
			// If an error occurred return false.
			return false;
		}

		return true;
	}

	/**
	 * Method to delete all tables in a database with a given prefix.
	 *
	 * @param   JDatabaseDriver  $db      JDatabaseDriver object.
	 * @param   string           $prefix  Database table prefix.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function deleteDatabase($db, $prefix)
	{
		$return = true;

		// Get the tables in the database.
		$tables = $db->getTableList();

		if ($tables)
		{
			foreach ($tables as $table)
			{
				// If the table uses the given prefix, drop it.
				if (strpos($table, $prefix) === 0)
				{
					// Drop the table.
					try
					{
						$db->dropTable($table);
					}
					catch (RuntimeException $e)
					{
						JFactory::getApplication()->enqueueMessage(JText::sprintf('INSTL_DATABASE_ERROR_DELETE', $e->getMessage()), 'error');

						$return = false;
					}
				}
			}
		}

		return $return;
	}

	/**
	 * Method to import a database schema from a file.
	 *
	 * @param   JDatabaseDriver  $db      JDatabase object.
	 * @param   string           $schema  Path to the schema file.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function populateDatabase($db, $schema)
	{
		$return = true;

		// Get the contents of the schema file.
		if (!($buffer = file_get_contents($schema)))
		{
			JFactory::getApplication()->enqueueMessage($db->getErrorMsg(), 'error');

			return false;
		}

		// Get an array of queries from the schema and process them.
		$queries = $this->splitQueries($buffer);

		foreach ($queries as $query)
		{
			// Trim any whitespace.
			$query = trim($query);

			// If the query isn't empty and is not a MySQL or PostgreSQL comment, execute it.
			if (!empty($query) && ($query{0} != '#') && ($query{0} != '-'))
			{
				/**
				 * If we don't have UTF-8 Multibyte support we'll have to convert queries to plain UTF-8
				 *
				 * Note: the JDatabaseDriver::convertUtf8mb4QueryToUtf8 performs the conversion ONLY when
				 * necessary, so there's no need to check the conditions in JInstaller.
				 */
				$query = $db->convertUtf8mb4QueryToUtf8($query);

				/**
				 * This is a query which was supposed to convert tables to utf8mb4 charset but the server doesn't
				 * support utf8mb4. Therefore we don't have to run it, it has no effect and it's a mere waste of time.
				 */
				if (!$db->hasUTF8mb4Support() && stripos($query, 'CONVERT TO CHARACTER SET utf8 ') !== false)
				{
					continue;
				}

				// Execute the query.
				$db->setQuery($query);

				try
				{
					$db->execute();
				}
				catch (RuntimeException $e)
				{
					JFactory::getApplication()->enqueueMessage($e->getMessage(), 'error');

					$return = false;
				}
			}
		}

		return $return;
	}

	/**
	 * Method to set the database character set to UTF-8.
	 *
	 * @param   JDatabaseDriver  $db    JDatabaseDriver object.
	 * @param   string           $name  Name of the database to process.
	 *
	 * @return  boolean  True on success.
	 *
	 * @since   3.1
	 */
	public function setDatabaseCharset($db, $name)
	{
		// Run the create database query.
		$db->setQuery($db->getAlterDbCharacterSet($name));

		try
		{
			$db->execute();
		}
		catch (RuntimeException $e)
		{
			return false;
		}

		return true;
	}

	/**
	 * Method to split up queries from a schema file into an array.
	 *
	 * @param   string  $query  SQL schema.
	 *
	 * @return  array  Queries to perform.
	 *
	 * @since   3.1
	 */
	protected function splitQueries($query)
	{
		$buffer    = array();
		$queries   = array();
		$in_string = false;

		// Trim any whitespace.
		$query = trim($query);

		// Remove comment lines.
		$query = preg_replace("/\n\#[^\n]*/", '', "\n" . $query);

		// Remove PostgreSQL comment lines.
		$query = preg_replace("/\n\--[^\n]*/", '', "\n" . $query);

		// Find function.
		$funct = explode('CREATE OR REPLACE FUNCTION', $query);

		// Save sql before function and parse it.
		$query = $funct[0];

		// Parse the schema file to break up queries.
		for ($i = 0; $i < strlen($query) - 1; $i++)
		{
			if (!$in_string && $query[$i] === ';')
			{
				$queries[] = substr($query, 0, $i);
				$query     = substr($query, $i + 1);
				$i         = 0;
			}

			if ($in_string && $query[$i] == $in_string && $buffer[1] !== '\\')
			{
				$in_string = false;
			}
			elseif (!$in_string && ($query[$i] === '"' || $query[$i] === "'") && (!isset($buffer[0]) || $buffer[0] !== '\\'))
			{
				$in_string = $query[$i];
			}

			if (isset ($buffer[1]))
			{
				$buffer[0] = $buffer[1];
			}

			$buffer[1] = $query[$i];
		}

		// If the is anything left over, add it to the queries.
		if (!empty($query))
		{
			$queries[] = $query;
		}

		// Add function part as is.
		for ($f = 1, $fMax = count($funct); $f < $fMax; $f++)
		{
			$queries[] = 'CREATE OR REPLACE FUNCTION ' . $funct[$f];
		}

		return $queries;
	}
}
