class Tasks

class Tasks extends InstallTasks {
    
    /**
     * Minimum required PostgreSQL version.
     *
     * The contrib extension pg_trgm is supposed to be installed.
     *
     * @see https://www.postgresql.org/docs/10/pgtrgm.html
     */
    const PGSQL_MINIMUM_VERSION = '10';
    
    /**
     * {@inheritdoc}
     */
    protected $pdoDriver = 'pgsql';
    
    /**
     * Constructs a \Drupal\pgsql\Driver\Database\pgsql\Install\Tasks object.
     */
    public function __construct() {
        $this->tasks[] = [
            'function' => 'checkEncoding',
            'arguments' => [],
        ];
        $this->tasks[] = [
            'function' => 'checkBinaryOutput',
            'arguments' => [],
        ];
        $this->tasks[] = [
            'function' => 'checkStandardConformingStrings',
            'arguments' => [],
        ];
        $this->tasks[] = [
            'function' => 'initializeDatabase',
            'arguments' => [],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function name() {
        return t('PostgreSQL');
    }
    
    /**
     * {@inheritdoc}
     */
    public function minimumVersion() {
        return static::PGSQL_MINIMUM_VERSION;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function connect() {
        try {
            // This doesn't actually test the connection.
            Database::setActiveConnection();
            // Now actually do a check.
            Database::getConnection();
            $this->pass('Drupal can CONNECT to the database ok.');
        } catch (\Exception $e) {
            // Attempt to create the database if it is not found.
            if ($e instanceof DatabaseNotFoundException) {
                // 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 a non-existent
                // database.
                $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, and 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;
    }
    
    /**
     * Check encoding is UTF8.
     */
    protected function checkEncoding() {
        try {
            if (Database::getConnection()->query('SHOW server_encoding')
                ->fetchField() == 'UTF8') {
                $this->pass(t('Database is encoded in UTF-8'));
            }
            else {
                $this->fail(t('The %driver database must use %encoding encoding to work with Drupal. Recreate the database with %encoding encoding. See <a href="INSTALL.pgsql.txt">INSTALL.pgsql.txt</a> for more details.', [
                    '%encoding' => 'UTF8',
                    '%driver' => $this->name(),
                ]));
            }
        } catch (\Exception $e) {
            $this->fail(t('Drupal could not determine the encoding of the database was set to UTF-8'));
        }
    }
    
    /**
     * Check Binary Output.
     *
     * Unserializing does not work on Postgresql 9 when bytea_output is 'hex'.
     */
    public function checkBinaryOutput() {
        $database_connection = Database::getConnection();
        if (!$this->checkBinaryOutputSuccess()) {
            // First try to alter the database. If it fails, raise an error telling
            // the user to do it themselves.
            $connection_options = $database_connection->getConnectionOptions();
            // It is safe to include the database name directly here, because this
            // code is only called when a connection to the database is already
            // established, thus the database name is guaranteed to be a correct
            // value.
            $query = "ALTER DATABASE \"{$connection_options['database']}\" SET bytea_output = 'escape';";
            try {
                $database_connection->query($query);
            } catch (\Exception $e) {
                // Ignore possible errors when the user doesn't have the necessary
                // privileges to ALTER the database.
            }
            // Close the database connection so that the configuration parameter
            // is applied to the current connection.
            Database::closeConnection();
            // Recheck, if it fails, finally just rely on the end user to do the
            // right thing.
            if (!$this->checkBinaryOutputSuccess()) {
                $replacements = [
                    '%setting' => 'bytea_output',
                    '%current_value' => 'hex',
                    '%needed_value' => 'escape',
                    '@query' => $query,
                ];
                $this->fail(t("The %setting setting is currently set to '%current_value', but needs to be '%needed_value'. Change this by running the following query: <code>@query</code>", $replacements));
            }
        }
    }
    
    /**
     * Verify that a binary data roundtrip returns the original string.
     */
    protected function checkBinaryOutputSuccess() {
        $bytea_output = Database::getConnection()->query("SHOW bytea_output")
            ->fetchField();
        return $bytea_output == 'escape';
    }
    
    /**
     * Ensures standard_conforming_strings setting is 'on'.
     *
     * When standard_conforming_strings setting is 'on' string literals ('...')
     * treat backslashes literally, as specified in the SQL standard. This allows
     * Drupal to convert between bytea, text and varchar columns.
     */
    public function checkStandardConformingStrings() {
        $database_connection = Database::getConnection();
        if (!$this->checkStandardConformingStringsSuccess()) {
            // First try to alter the database. If it fails, raise an error telling
            // the user to do it themselves.
            $connection_options = $database_connection->getConnectionOptions();
            // It is safe to include the database name directly here, because this
            // code is only called when a connection to the database is already
            // established, thus the database name is guaranteed to be a correct
            // value.
            $query = "ALTER DATABASE \"" . $connection_options['database'] . "\" SET standard_conforming_strings = 'on';";
            try {
                $database_connection->query($query);
            } catch (\Exception $e) {
                // Ignore possible errors when the user doesn't have the necessary
                // privileges to ALTER the database.
            }
            // Close the database connection so that the configuration parameter
            // is applied to the current connection.
            Database::closeConnection();
            // Recheck, if it fails, finally just rely on the end user to do the
            // right thing.
            if (!$this->checkStandardConformingStringsSuccess()) {
                $replacements = [
                    '%setting' => 'standard_conforming_strings',
                    '%current_value' => 'off',
                    '%needed_value' => 'on',
                    '@query' => $query,
                ];
                $this->fail(t("The %setting setting is currently set to '%current_value', but needs to be '%needed_value'. Change this by running the following query: <code>@query</code>", $replacements));
            }
        }
    }
    
    /**
     * Verifies the standard_conforming_strings setting.
     */
    protected function checkStandardConformingStringsSuccess() {
        $standard_conforming_strings = Database::getConnection()->query("SHOW standard_conforming_strings")
            ->fetchField();
        return $standard_conforming_strings == 'on';
    }
    
    /**
     * Make PostgreSQL Drupal friendly.
     */
    public function initializeDatabase() {
        // We create some functions using global names instead of prefixing them
        // like we do with table names. This is so that we don't double up if more
        // than one instance of Drupal is running on a single database. We therefore
        // avoid trying to create them again in that case.
        // At the same time checking for the existence of the function fixes
        // concurrency issues, when both try to update at the same time.
        try {
            $connection = Database::getConnection();
            // When testing, two installs might try to run the CREATE FUNCTION queries
            // at the same time. Do not let that happen.
            $connection->query('SELECT pg_advisory_lock(1)');
            // Don't use {} around pg_proc table.
            if (!$connection->query("SELECT COUNT(*) FROM pg_proc WHERE proname = 'rand'")
                ->fetchField()) {
                $connection->query('CREATE OR REPLACE FUNCTION "rand"() RETURNS float AS
          \'SELECT random();\'
          LANGUAGE \'sql\'', [], [
                    'allow_delimiter_in_query' => TRUE,
                ]);
            }
            if (!$connection->query("SELECT COUNT(*) FROM pg_proc WHERE proname = 'substring_index'")
                ->fetchField()) {
                $connection->query('CREATE OR REPLACE FUNCTION "substring_index"(text, text, integer) RETURNS text AS
          \'SELECT array_to_string((string_to_array($1, $2)) [1:$3], $2);\'
          LANGUAGE \'sql\'', [], [
                    'allow_delimiter_in_query' => TRUE,
                    'allow_square_brackets' => TRUE,
                ]);
            }
            $connection->query('SELECT pg_advisory_unlock(1)');
            $this->pass(t('PostgreSQL has initialized itself.'));
        } catch (\Exception $e) {
            $this->fail(t('Drupal could not be correctly setup with the existing database due to the following error: @error.', [
                '@error' => $e->getMessage(),
            ]));
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormOptions(array $database) {
        $form = parent::getFormOptions($database);
        if (empty($form['advanced_options']['port']['#default_value'])) {
            $form['advanced_options']['port']['#default_value'] = '5432';
        }
        return $form;
    }

}