class DbDumpCommand

class DbDumpCommand extends DbCommandBase {
    
    /**
     * An array of table patterns to exclude completely.
     *
     * This excludes any lingering tables generated during test runs.
     *
     * @var array
     */
    protected $excludeTables = [
        'test[0-9]+',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected function configure() {
        $this->setName('dump-database-d8-mysql')
            ->setDescription('Dump the current database to a generation script')
            ->addOption('schema-only', NULL, InputOption::VALUE_OPTIONAL, 'A comma separated list of tables to only export the schema without data.', 'cache.*,sessions,watchdog')
            ->addOption('insert-count', NULL, InputOption::VALUE_OPTIONAL, ' The number of rows to insert in a single SQL statement.', 1000);
        parent::configure();
    }
    
    /**
     * {@inheritdoc}
     */
    protected function execute(InputInterface $input, OutputInterface $output) : int {
        $connection = $this->getDatabaseConnection($input);
        // If not explicitly set, disable ANSI which will break generated php.
        if ($input->hasParameterOption([
            '--ansi',
        ]) !== TRUE) {
            $output->setDecorated(FALSE);
        }
        $schema_tables = $input->getOption('schema-only');
        $schema_tables = explode(',', $schema_tables);
        $insert_count = (int) $input->getOption('insert-count');
        $output->writeln($this->generateScript($connection, $schema_tables, $insert_count), OutputInterface::OUTPUT_RAW);
        return 0;
    }
    
    /**
     * Generates the database script.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param array $schema_only
     *   Table patterns for which to only dump the schema, no data.
     * @param int $insert_count
     *   The number of rows to insert in a single statement.
     *
     * @return string
     *   The PHP script.
     */
    protected function generateScript(Connection $connection, array $schema_only = [], int $insert_count = 1000) {
        $tables = '';
        $schema_only_patterns = [];
        foreach ($schema_only as $match) {
            $schema_only_patterns[] = '/^' . $match . '$/';
        }
        foreach ($this->getTables($connection) as $table) {
            $schema = $this->getTableSchema($connection, $table);
            // Check for schema only.
            if (empty($schema_only_patterns) || preg_replace($schema_only_patterns, '', $table)) {
                $data = $this->getTableData($connection, $table);
            }
            else {
                $data = [];
            }
            $tables .= $this->getTableScript($table, $schema, $data, $insert_count);
        }
        $script = $this->getTemplate();
        // Substitute in the version.
        $script = str_replace('{{VERSION}}', \Drupal::VERSION, $script);
        // Substitute in the tables.
        $script = str_replace('{{TABLES}}', trim($tables), $script);
        return trim($script);
    }
    
    /**
     * Returns a list of tables, not including those set to be excluded.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     *
     * @return array
     *   An array of table names.
     */
    protected function getTables(Connection $connection) {
        $tables = array_values($connection->schema()
            ->findTables('%'));
        foreach ($tables as $key => $table) {
            // Remove any explicitly excluded tables.
            foreach ($this->excludeTables as $pattern) {
                if (preg_match('/^' . $pattern . '$/', $table)) {
                    unset($tables[$key]);
                }
            }
        }
        // Keep the table names sorted alphabetically.
        asort($tables);
        return $tables;
    }
    
    /**
     * Returns a schema array for a given table.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $table
     *   The table name.
     *
     * @return array
     *   A schema array (as defined by hook_schema()).
     *
     * @todo This implementation is hard-coded for MySQL.
     */
    protected function getTableSchema(Connection $connection, $table) {
        // Check this is MySQL.
        if ($connection->databaseType() !== 'mysql') {
            throw new \RuntimeException('This script can only be used with MySQL database backends.');
        }
        $query = $connection->query("SHOW FULL COLUMNS FROM {" . $table . "}");
        $definition = [];
        while (($row = $query->fetchAssoc()) !== FALSE) {
            $name = $row['Field'];
            // Parse out the field type and meta information.
            preg_match('@([a-z]+)(?:\\((\\d+)(?:,(\\d+))?\\))?\\s*(unsigned)?@', $row['Type'], $matches);
            $type = $this->fieldTypeMap($connection, $matches[1]);
            if ($row['Extra'] === 'auto_increment') {
                // If this is an auto increment, then the type is 'serial'.
                $type = 'serial';
            }
            $definition['fields'][$name] = [
                'type' => $type,
                'not null' => $row['Null'] === 'NO',
            ];
            if ($size = $this->fieldSizeMap($connection, $matches[1])) {
                $definition['fields'][$name]['size'] = $size;
            }
            if (isset($matches[2]) && $type === 'numeric') {
                // Add precision and scale.
                $definition['fields'][$name]['precision'] = $matches[2];
                $definition['fields'][$name]['scale'] = $matches[3];
            }
            elseif ($type === 'time') {
                // @todo Core doesn't support these, but copied from `migrate-db.sh` for now.
                // Convert to varchar.
                $definition['fields'][$name]['type'] = 'varchar';
                $definition['fields'][$name]['length'] = '100';
            }
            elseif ($type === 'datetime') {
                // Adjust for other database types.
                $definition['fields'][$name]['mysql_type'] = 'datetime';
                $definition['fields'][$name]['pgsql_type'] = 'timestamp without time zone';
                $definition['fields'][$name]['sqlite_type'] = 'varchar';
                $definition['fields'][$name]['sqlsrv_type'] = 'smalldatetime';
            }
            elseif (!isset($definition['fields'][$name]['size'])) {
                // Try use the provided length, if it doesn't exist default to 100. It's
                // not great but good enough for our dumps at this point.
                $definition['fields'][$name]['length'] = $matches[2] ?? 100;
            }
            if (isset($row['Default'])) {
                $definition['fields'][$name]['default'] = $row['Default'];
            }
            if (isset($matches[4])) {
                $definition['fields'][$name]['unsigned'] = TRUE;
            }
            // Check for the 'varchar_ascii' type that should be 'binary'.
            if (isset($row['Collation']) && $row['Collation'] == 'ascii_bin') {
                $definition['fields'][$name]['type'] = 'varchar_ascii';
                $definition['fields'][$name]['binary'] = TRUE;
            }
            // Check for the non-binary 'varchar_ascii'.
            if (isset($row['Collation']) && $row['Collation'] == 'ascii_general_ci') {
                $definition['fields'][$name]['type'] = 'varchar_ascii';
            }
            // Check for the 'utf8_bin' collation.
            if (isset($row['Collation']) && $row['Collation'] == 'utf8_bin') {
                $definition['fields'][$name]['binary'] = TRUE;
            }
        }
        // Set primary key, unique keys, and indexes.
        $this->getTableIndexes($connection, $table, $definition);
        // Set table collation.
        $this->getTableCollation($connection, $table, $definition);
        return $definition;
    }
    
    /**
     * Adds primary key, unique keys, and index information to the schema.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $table
     *   The table to find indexes for.
     * @param array &$definition
     *   The schema definition to modify.
     */
    protected function getTableIndexes(Connection $connection, $table, &$definition) {
        // Note, this query doesn't support ordering, so that is worked around
        // below by keying the array on Seq_in_index.
        $query = $connection->query("SHOW INDEX FROM {" . $table . "}");
        while (($row = $query->fetchAssoc()) !== FALSE) {
            $index_name = $row['Key_name'];
            $column = $row['Column_name'];
            // Key the arrays by the index sequence for proper ordering (start at 0).
            $order = $row['Seq_in_index'] - 1;
            // If specified, add length to the index.
            if ($row['Sub_part']) {
                $column = [
                    $column,
                    $row['Sub_part'],
                ];
            }
            if ($index_name === 'PRIMARY') {
                $definition['primary key'][$order] = $column;
            }
            elseif ($row['Non_unique'] == 0) {
                $definition['unique keys'][$index_name][$order] = $column;
            }
            else {
                $definition['indexes'][$index_name][$order] = $column;
            }
        }
    }
    
    /**
     * Set the table collation.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $table
     *   The table to find indexes for.
     * @param array &$definition
     *   The schema definition to modify.
     */
    protected function getTableCollation(Connection $connection, $table, &$definition) {
        // Remove identifier quotes from the table name. See
        // \Drupal\mysql\Driver\Database\mysql\Connection::$identifierQuotes.
        $table = trim($connection->prefixTables('{' . $table . '}'), '"');
        $query = $connection->query("SHOW TABLE STATUS WHERE NAME = :table_name", [
            ':table_name' => $table,
        ]);
        $data = $query->fetchAssoc();
        // Map the collation to a character set. For example, 'utf8mb4_general_ci'
        // (MySQL 5) or 'utf8mb4_0900_ai_ci' (MySQL 8) will be mapped to 'utf8mb4'.
        [
            $charset,
        ] = explode('_', $data['Collation'], 2);
        // Set `mysql_character_set`. This will be ignored by other backends.
        $definition['mysql_character_set'] = $charset;
    }
    
    /**
     * Gets all data from a given table.
     *
     * If a table is set to be schema only, and empty array is returned.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $table
     *   The table to query.
     *
     * @return array
     *   The data from the table as an array.
     */
    protected function getTableData(Connection $connection, $table) {
        $order = $this->getFieldOrder($connection, $table);
        $query = $connection->query("SELECT * FROM {" . $table . "} " . $order);
        $results = [];
        while (($row = $query->fetchAssoc()) !== FALSE) {
            $results[] = $row;
        }
        return $results;
    }
    
    /**
     * Given a database field type, return a Drupal type.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $type
     *   The MySQL field type.
     *
     * @return string
     *   The Drupal schema field type. If there is no mapping, the original field
     *   type is returned.
     */
    protected function fieldTypeMap(Connection $connection, $type) {
        // Convert everything to lowercase.
        $map = array_map('strtolower', $connection->schema()
            ->getFieldTypeMap());
        $map = array_flip($map);
        // The MySql map contains type:size. Remove the size part.
        return isset($map[$type]) ? explode(':', $map[$type])[0] : $type;
    }
    
    /**
     * Given a database field type, return a Drupal size.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $type
     *   The MySQL field type.
     *
     * @return string|null
     *   The Drupal schema field size.
     */
    protected function fieldSizeMap(Connection $connection, $type) {
        // Convert everything to lowercase.
        $map = array_map('strtolower', $connection->schema()
            ->getFieldTypeMap());
        $map = array_flip($map);
        // Do nothing if the field type is not defined.
        if (!isset($map[$type])) {
            return NULL;
        }
        $schema_type = explode(':', $map[$type])[0];
        // Only specify size on these types.
        if (in_array($schema_type, [
            'blob',
            'float',
            'int',
            'text',
        ])) {
            // The MySql map contains type:size. Remove the type part.
            return explode(':', $map[$type])[1];
        }
    }
    
    /**
     * Gets field ordering for a given table.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection to use.
     * @param string $table
     *   The table name.
     *
     * @return string
     *   The order string to append to the query.
     */
    protected function getFieldOrder(Connection $connection, $table) {
        // @todo this is MySQL only since there are no Database API functions for
        // table column data.
        // @todo this code is duplicated in `core/scripts/migrate-db.sh`.
        $connection_info = $connection->getConnectionOptions();
        // Order by primary keys.
        $order = '';
        $query = "SELECT `COLUMN_NAME` FROM `information_schema`.`COLUMNS`\n    WHERE (`TABLE_SCHEMA` = '" . $connection_info['database'] . "')\n    AND (`TABLE_NAME` = '{" . $table . "}') AND (`COLUMN_KEY` = 'PRI')\n    ORDER BY COLUMN_NAME";
        $results = $connection->query($query);
        while (($row = $results->fetchAssoc()) !== FALSE) {
            $order .= $row['COLUMN_NAME'] . ', ';
        }
        if (!empty($order)) {
            $order = ' ORDER BY ' . rtrim($order, ', ');
        }
        return $order;
    }
    
    /**
     * The script template.
     *
     * @return string
     *   The template for the generated PHP script.
     */
    protected function getTemplate() {
        // The template contains an instruction for the file to be ignored by PHPCS.
        // This is because the files can be huge and coding standards are
        // irrelevant.
        $script = <<<'END_OF_SCRIPT'
<?php
// phpcs:ignoreFile
/**
 * @file
 * A database agnostic dump for testing purposes.
 *
 * This file was generated by the Drupal {{VERSION}} db-tools.php script.
 */

use Drupal\Core\Database\Database;

$connection = Database::getConnection();
// Ensure any tables with a serial column with a value of 0 are created as
// expected.
if ($connection->databaseType() === 'mysql') {
  $sql_mode = $connection->query("SELECT @@sql_mode;")->fetchField();
  $connection->query("SET sql_mode = '$sql_mode,NO_AUTO_VALUE_ON_ZERO'");
}

{{TABLES}}

// Reset the SQL mode.
if ($connection->databaseType() === 'mysql') {
  $connection->query("SET sql_mode = '$sql_mode'");
}
END_OF_SCRIPT;
        return $script;
    }
    
    /**
     * The part of the script for each table.
     *
     * @param string $table
     *   Table name.
     * @param array $schema
     *   Drupal schema definition.
     * @param array $data
     *   Data for the table.
     * @param int $insert_count
     *   The number of rows to insert in a single statement.
     *
     * @return string
     *   The table create statement, and if there is data, the insert command.
     */
    protected function getTableScript($table, array $schema, array $data, int $insert_count = 1000) {
        $output = '';
        $output .= "\$connection->schema()->createTable('" . $table . "', " . Variable::export($schema) . ");\n\n";
        if (!empty($data)) {
            $data_chunks = array_chunk($data, $insert_count);
            foreach ($data_chunks as $data_chunk) {
                $insert = '';
                foreach ($data_chunk as $record) {
                    $insert .= "->values(" . Variable::export($record) . ")\n";
                }
                $fields = Variable::export(array_keys($schema['fields']));
                $output .= <<<EOT
\$connection->insert('{<span class="php-variable">$table</span>}')
->fields({<span class="php-variable">$fields</span>})
{<span class="php-variable">$insert</span>}->execute();

EOT;
            }
        }
        return $output;
    }

}