class Tasks

class Tasks extends InstallTasks {
    
    /**
     * Minimum required MySQLnd version.
     */
    const MYSQLND_MINIMUM_VERSION = '5.0.9';
    
    /**
     * Minimum required libmysqlclient version.
     */
    const LIBMYSQLCLIENT_MINIMUM_VERSION = '5.5.3';
    
    /**
     * The PDO driver name for MySQL and equivalent databases.
     *
     * @var string
     */
    protected $pdoDriver = 'mysql';
    
    /**
     * Constructs a \Drupal\Core\Database\Driver\mysql\Install\Tasks object.
     */
    public function __construct() {
        $this->tasks[] = [
            'arguments' => [],
            'function' => 'ensureInnoDbAvailable',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function name() {
        return t('MySQL, MariaDB, Percona Server, or equivalent');
    }
    
    /**
     * {@inheritdoc}
     */
    public function minimumVersion() {
        // This can not be increased above '5.5.5' without dropping support for all
        // MariaDB versions. MariaDB prefixes its version string with '5.5.5-'. For
        // more information, see
        // https://github.com/MariaDB/server/blob/f6633bf058802ad7da8196d01fd19d75c53f7274/include/mysql_com.h#L42.
        return '5.5.3';
    }
    
    /**
     * {@inheritdoc}
     */
    protected function connect() {
        try {
            // This doesn't actually test the connection.
            Database::setActiveConnection();
            // Now actually do a check.
            try {
                Database::getConnection();
            } catch (\Exception $e) {
                // Detect utf8mb4 incompatibility.
                if ($e->getCode() == Connection::UNSUPPORTED_CHARSET || $e->getCode() == Connection::SQLSTATE_SYNTAX_ERROR && $e->errorInfo[1] == Connection::UNKNOWN_CHARSET) {
                    $this->fail(t('Your MySQL server and PHP MySQL driver must support utf8mb4 character encoding. Make sure to use a database system that supports this (such as MySQL/MariaDB/Percona 5.5.3 and up), and that the utf8mb4 character set is compiled in. See the <a href=":documentation" target="_blank">MySQL documentation</a> for more information.', [
                        ':documentation' => 'https://dev.mysql.com/doc/refman/5.0/en/cannot-initialize-character-set.html',
                    ]));
                    $info = Database::getConnectionInfo();
                    $info_copy = $info;
                    // Set a flag to fall back to utf8. Note: this flag should only be
                    // used here and is for internal use only.
                    $info_copy['default']['_dsn_utf8_fallback'] = TRUE;
                    // In order to change the Database::$databaseInfo array, we need to
                    // remove the active connection, then re-add it with the new info.
                    Database::removeConnection('default');
                    Database::addConnectionInfo('default', 'default', $info_copy['default']);
                    // Connect with the new database info, using the utf8 character set so
                    // that we can run the checkEngineVersion test.
                    Database::getConnection();
                    // Revert to the old settings.
                    Database::removeConnection('default');
                    Database::addConnectionInfo('default', 'default', $info['default']);
                }
                else {
                    // Rethrow the exception.
                    throw $e;
                }
            }
            $this->pass('Drupal can CONNECT to the database ok.');
        } catch (\Exception $e) {
            // Attempt to create the database if it is not found.
            if ($e->getCode() == Connection::DATABASE_NOT_FOUND) {
                // Remove the database string from connection info.
                $connection_info = Database::getConnectionInfo();
                $database = $connection_info['default']['database'];
                unset($connection_info['default']['database']);
                // In order to change the Database::$databaseInfo array, need to remove
                // the active connection, then re-add it with the new info.
                Database::removeConnection('default');
                Database::addConnectionInfo('default', 'default', $connection_info['default']);
                try {
                    // Now, attempt the connection again; if it's successful, attempt to
                    // create the database.
                    Database::getConnection()->createDatabase($database);
                    Database::closeConnection();
                    // Now, restore the database config.
                    Database::removeConnection('default');
                    $connection_info['default']['database'] = $database;
                    Database::addConnectionInfo('default', 'default', $connection_info['default']);
                    // Check the database connection.
                    Database::getConnection();
                    $this->pass('Drupal can CONNECT to the database ok.');
                } catch (DatabaseNotFoundException $e) {
                    // Still no dice; probably a permission issue. Raise the error to the
                    // installer.
                    $this->fail(t('Database %database not found. The server reports the following message when attempting to create the database: %error.', [
                        '%database' => $database,
                        '%error' => $e->getMessage(),
                    ]));
                }
            }
            else {
                // Database connection failed for some other reason than the database
                // not existing.
                $this->fail(t('Failed to connect to your database server. The server reports the following message: %error.<ul><li>Is the database server running?</li><li>Does the database exist or does the database user have sufficient privileges to create the database?</li><li>Have you entered the correct database name?</li><li>Have you entered the correct username and password?</li><li>Have you entered the correct database hostname and port number?</li></ul>', [
                    '%error' => $e->getMessage(),
                ]));
                return FALSE;
            }
        }
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormOptions(array $database) {
        $form = parent::getFormOptions($database);
        if (empty($form['advanced_options']['port']['#default_value'])) {
            $form['advanced_options']['port']['#default_value'] = '3306';
        }
        return $form;
    }
    
    /**
     * Ensure that InnoDB is available.
     */
    public function ensureInnoDbAvailable() {
        $engines = Database::getConnection()->query('SHOW ENGINES')
            ->fetchAllKeyed();
        if (isset($engines['MyISAM']) && $engines['MyISAM'] == 'DEFAULT' && !isset($engines['InnoDB'])) {
            $this->fail(t('The MyISAM storage engine is not supported.'));
        }
    }
    
    /**
     * {@inheritdoc}
     */
    protected function checkEngineVersion() {
        parent::checkEngineVersion();
        // Ensure that the MySQL driver supports utf8mb4 encoding.
        $version = Database::getConnection()->clientVersion();
        if (FALSE !== strpos($version, 'mysqlnd')) {
            // The mysqlnd driver supports utf8mb4 starting at version 5.0.9.
            $version = preg_replace('/^\\D+([\\d.]+).*/', '$1', $version);
            if (version_compare($version, self::MYSQLND_MINIMUM_VERSION, '<')) {
                $this->fail(t("The MySQLnd driver version %version is less than the minimum required version. Upgrade to MySQLnd version %mysqlnd_minimum_version or up, or alternatively switch mysql drivers to libmysqlclient version %libmysqlclient_minimum_version or up.", [
                    '%version' => $version,
                    '%mysqlnd_minimum_version' => self::MYSQLND_MINIMUM_VERSION,
                    '%libmysqlclient_minimum_version' => self::LIBMYSQLCLIENT_MINIMUM_VERSION,
                ]));
            }
        }
        else {
            // The libmysqlclient driver supports utf8mb4 starting at version 5.5.3.
            if (version_compare($version, self::LIBMYSQLCLIENT_MINIMUM_VERSION, '<')) {
                $this->fail(t("The libmysqlclient driver version %version is less than the minimum required version. Upgrade to libmysqlclient version %libmysqlclient_minimum_version or up, or alternatively switch mysql drivers to MySQLnd version %mysqlnd_minimum_version or up.", [
                    '%version' => $version,
                    '%libmysqlclient_minimum_version' => self::LIBMYSQLCLIENT_MINIMUM_VERSION,
                    '%mysqlnd_minimum_version' => self::MYSQLND_MINIMUM_VERSION,
                ]));
            }
        }
    }

}