class Connection

class Connection extends DatabaseConnection implements SupportsTemporaryTablesInterface {
    
    /**
     * The name by which to obtain a lock for retrieve the next insert id.
     */
    const POSTGRESQL_NEXTID_LOCK = 1000;
    
    /**
     * Error code for "Unknown database" error.
     */
    const DATABASE_NOT_FOUND = 7;
    
    /**
     * Error code for "Connection failure" errors.
     *
     * Technically this is an internal error code that will only be shown in the
     * PDOException message. It will need to get extracted.
     */
    const CONNECTION_FAILURE = '08006';
    
    /**
     * {@inheritdoc}
     */
    protected $statementWrapperClass = StatementWrapperIterator::class;
    
    /**
     * A map of condition operators to PostgreSQL operators.
     *
     * In PostgreSQL, 'LIKE' is case-sensitive. ILIKE should be used for
     * case-insensitive statements.
     */
    protected static $postgresqlConditionOperatorMap = [
        'LIKE' => [
            'operator' => 'ILIKE',
        ],
        'LIKE BINARY' => [
            'operator' => 'LIKE',
        ],
        'NOT LIKE' => [
            'operator' => 'NOT ILIKE',
        ],
        'REGEXP' => [
            'operator' => '~*',
        ],
        'NOT REGEXP' => [
            'operator' => '!~*',
        ],
    ];
    
    /**
     * {@inheritdoc}
     */
    protected $transactionalDDLSupport = TRUE;
    
    /**
     * {@inheritdoc}
     */
    protected $identifierQuotes = [
        '"',
        '"',
    ];
    
    /**
     * An array of transaction savepoints.
     *
     * The main use for this array is to store information about transaction
     * savepoints opened to to mimic MySql's InnoDB functionality, which provides
     * an inherent savepoint before any query in a transaction.
     *
     * @see ::addSavepoint()
     * @see ::releaseSavepoint()
     * @see ::rollbackSavepoint()
     *
     * @var array<string,Transaction>
     */
    protected array $savepoints = [];
    
    /**
     * Constructs a connection object.
     */
    public function __construct(\PDO $connection, array $connection_options) {
        // Sanitize the schema name here, so we do not have to do it in other
        // functions.
        if (isset($connection_options['schema']) && $connection_options['schema'] !== 'public') {
            $connection_options['schema'] = preg_replace('/[^A-Za-z0-9_]+/', '', $connection_options['schema']);
        }
        // We need to set the connectionOptions before the parent, because setPrefix
        // needs this.
        $this->connectionOptions = $connection_options;
        parent::__construct($connection, $connection_options);
        // Force PostgreSQL to use the UTF-8 character set by default.
        $this->connection
            ->exec("SET NAMES 'UTF8'");
        // Execute PostgreSQL init_commands.
        if (isset($connection_options['init_commands'])) {
            $this->connection
                ->exec(implode('; ', $connection_options['init_commands']));
        }
    }
    
    /**
     * {@inheritdoc}
     */
    protected function setPrefix($prefix) {
        assert(is_string($prefix), 'The \'$prefix\' argument to ' . __METHOD__ . '() must be a string');
        $this->prefix = $prefix;
        // Add the schema name if it is not set to public, otherwise it will use the
        // default schema name.
        $quoted_schema = '';
        if (isset($this->connectionOptions['schema']) && $this->connectionOptions['schema'] !== 'public') {
            $quoted_schema = $this->identifierQuotes[0] . $this->connectionOptions['schema'] . $this->identifierQuotes[1] . '.';
        }
        $this->tablePlaceholderReplacements = [
            $quoted_schema . $this->identifierQuotes[0] . str_replace('.', $this->identifierQuotes[1] . '.' . $this->identifierQuotes[0], $prefix),
            $this->identifierQuotes[1],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public static function open(array &$connection_options = []) {
        // Default to TCP connection on port 5432.
        if (empty($connection_options['port'])) {
            $connection_options['port'] = 5432;
        }
        // PostgreSQL in trust mode doesn't require a password to be supplied.
        if (empty($connection_options['password'])) {
            $connection_options['password'] = NULL;
        }
        else {
            $connection_options['password'] = str_replace('\\', '\\\\', $connection_options['password']);
        }
        $connection_options['database'] = !empty($connection_options['database']) ? $connection_options['database'] : 'template1';
        $dsn = 'pgsql:host=' . $connection_options['host'] . ' dbname=' . $connection_options['database'] . ' port=' . $connection_options['port'];
        // Allow PDO options to be overridden.
        $connection_options += [
            'pdo' => [],
        ];
        $connection_options['pdo'] += [
            \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
            // Prepared statements are most effective for performance when queries
            // are recycled (used several times). However, if they are not re-used,
            // prepared statements become inefficient. Since most of Drupal's
            // prepared queries are not re-used, it should be faster to emulate
            // the preparation than to actually ready statements for re-use. If in
            // doubt, reset to FALSE and measure performance.
\PDO::ATTR_EMULATE_PREPARES => TRUE,
            // Convert numeric values to strings when fetching.
\PDO::ATTR_STRINGIFY_FETCHES => TRUE,
        ];
        try {
            $pdo = new \PDO($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);
        } catch (\PDOException $e) {
            if (static::getSQLState($e) == static::CONNECTION_FAILURE) {
                if (str_contains($e->getMessage(), 'password authentication failed for user')) {
                    throw new DatabaseAccessDeniedException($e->getMessage(), $e->getCode(), $e);
                }
                elseif (str_contains($e->getMessage(), 'database') && str_contains($e->getMessage(), 'does not exist')) {
                    throw new DatabaseNotFoundException($e->getMessage(), $e->getCode(), $e);
                }
            }
            throw $e;
        }
        return $pdo;
    }
    
    /**
     * {@inheritdoc}
     */
    public function query($query, array $args = [], $options = []) {
        $options += $this->defaultOptions();
        // The PDO PostgreSQL driver has a bug which doesn't type cast booleans
        // correctly when parameters are bound using associative arrays.
        // @see http://bugs.php.net/bug.php?id=48383
        foreach ($args as &$value) {
            if (is_bool($value)) {
                $value = (int) $value;
            }
        }
        // We need to wrap queries with a savepoint if:
        // - Currently in a transaction.
        // - A 'mimic_implicit_commit' does not exist already.
        // - The query is not a savepoint query.
        $wrap_with_savepoint = $this->inTransaction() && !$this->transactionManager()
            ->has('mimic_implicit_commit') && !(is_string($query) && (stripos($query, 'ROLLBACK TO SAVEPOINT ') === 0 || stripos($query, 'RELEASE SAVEPOINT ') === 0 || stripos($query, 'SAVEPOINT ') === 0));
        if ($wrap_with_savepoint) {
            // Create a savepoint so we can rollback a failed query. This is so we can
            // mimic MySQL and SQLite transactions which don't fail if a single query
            // fails. This is important for tables that are created on demand. For
            // example, \Drupal\Core\Cache\DatabaseBackend.
            $this->addSavepoint();
            try {
                $return = parent::query($query, $args, $options);
                $this->releaseSavepoint();
            } catch (\Exception $e) {
                $this->rollbackSavepoint();
                throw $e;
            }
        }
        else {
            $return = parent::query($query, $args, $options);
        }
        return $return;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareStatement(string $query, array $options, bool $allow_row_count = FALSE) : StatementInterface {
        // mapConditionOperator converts some operations (LIKE, REGEXP, etc.) to
        // PostgreSQL equivalents (ILIKE, ~*, etc.). However PostgreSQL doesn't
        // automatically cast the fields to the right type for these operators,
        // so we need to alter the query and add the type-cast.
        $query = preg_replace('/ ([^ ]+) +(I*LIKE|NOT +I*LIKE|~\\*|!~\\*) /i', ' ${1}::text ${2} ', $query);
        return parent::prepareStatement($query, $options, $allow_row_count);
    }
    public function queryRange($query, $from, $count, array $args = [], array $options = []) {
        return $this->query($query . ' LIMIT ' . (int) $count . ' OFFSET ' . (int) $from, $args, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function queryTemporary($query, array $args = [], array $options = []) {
        $tablename = 'db_temporary_' . uniqid();
        $this->query('CREATE TEMPORARY TABLE {' . $tablename . '} AS ' . $query, $args, $options);
        return $tablename;
    }
    public function driver() {
        return 'pgsql';
    }
    public function databaseType() {
        return 'pgsql';
    }
    
    /**
     * Overrides \Drupal\Core\Database\Connection::createDatabase().
     *
     * @param string $database
     *   The name of the database to create.
     *
     * @throws \Drupal\Core\Database\DatabaseNotFoundException
     */
    public function createDatabase($database) {
        // Escape the database name.
        $database = Database::getConnection()->escapeDatabase($database);
        $db_created = FALSE;
        // Try to determine the proper locales for character classification and
        // collation. If we could determine locales other than 'en_US', try creating
        // the database with these first.
        $ctype = setlocale(LC_CTYPE, 0);
        $collate = setlocale(LC_COLLATE, 0);
        if ($ctype && $collate) {
            try {
                $this->connection
                    ->exec("CREATE DATABASE {$database} WITH TEMPLATE template0 ENCODING='UTF8' LC_CTYPE='{$ctype}.UTF-8' LC_COLLATE='{$collate}.UTF-8'");
                $db_created = TRUE;
            } catch (\Exception $e) {
                // It might be that the server is remote and does not support the
                // locale and collation of the webserver, so we will try again.
            }
        }
        // Otherwise fall back to creating the database using the 'en_US' locales.
        if (!$db_created) {
            try {
                $this->connection
                    ->exec("CREATE DATABASE {$database} WITH TEMPLATE template0 ENCODING='UTF8' LC_CTYPE='en_US.UTF-8' LC_COLLATE='en_US.UTF-8'");
            } catch (\Exception $e) {
                // If the database can't be created with the 'en_US' locale either,
                // we're finally throwing an exception.
                throw new DatabaseNotFoundException($e->getMessage());
            }
        }
    }
    public function mapConditionOperator($operator) {
        return static::$postgresqlConditionOperatorMap[$operator] ?? NULL;
    }
    
    /**
     * Creates the appropriate sequence name for a given table and serial field.
     *
     * This method should only be called by the driver's code.
     *
     * @param string $table
     *   The table name to use for the sequence.
     * @param string $field
     *   The field name to use for the sequence.
     *
     * @return string
     *   A table prefix-parsed string for the sequence name.
     *
     * @internal
     */
    public function makeSequenceName($table, $field) {
        $sequence_name = $this->prefixTables('{' . $table . '}_' . $field . '_seq');
        // Remove identifier quotes as we are constructing a new name from a
        // prefixed and quoted table name.
        return str_replace($this->identifierQuotes, '', $sequence_name);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFullQualifiedTableName($table) {
        $options = $this->getConnectionOptions();
        $schema = $options['schema'] ?? 'public';
        // The fully qualified table name in PostgreSQL is in the form of
        // <database>.<schema>.<table>.
        return $options['database'] . '.' . $schema . '.' . $this->getPrefix() . $table;
    }
    
    /**
     * Add a new savepoint with a unique name.
     *
     * The main use for this method is to mimic InnoDB functionality, which
     * provides an inherent savepoint before any query in a transaction.
     *
     * @param $savepoint_name
     *   A string representing the savepoint name. By default,
     *   "mimic_implicit_commit" is used.
     */
    public function addSavepoint($savepoint_name = 'mimic_implicit_commit') {
        if ($this->inTransaction()) {
            $this->savepoints[$savepoint_name] = $this->startTransaction($savepoint_name);
        }
    }
    
    /**
     * Release a savepoint by name.
     *
     * @param $savepoint_name
     *   A string representing the savepoint name. By default,
     *   "mimic_implicit_commit" is used.
     */
    public function releaseSavepoint($savepoint_name = 'mimic_implicit_commit') {
        if ($this->inTransaction() && $this->transactionManager()
            ->has($savepoint_name)) {
            unset($this->savepoints[$savepoint_name]);
        }
    }
    
    /**
     * Rollback a savepoint by name if it exists.
     *
     * @param $savepoint_name
     *   A string representing the savepoint name. By default,
     *   "mimic_implicit_commit" is used.
     */
    public function rollbackSavepoint($savepoint_name = 'mimic_implicit_commit') {
        if ($this->inTransaction() && $this->transactionManager()
            ->has($savepoint_name)) {
            $this->savepoints[$savepoint_name]
                ->rollBack();
            unset($this->savepoints[$savepoint_name]);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function hasJson() : bool {
        try {
            return (bool) $this->query('SELECT JSON_TYPEOF(\'1\')');
        } catch (\Exception $e) {
            return FALSE;
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function exceptionHandler() {
        return new ExceptionHandler();
    }
    
    /**
     * {@inheritdoc}
     */
    public function select($table, $alias = NULL, array $options = []) {
        return new Select($this, $table, $alias, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function insert($table, array $options = []) {
        return new Insert($this, $table, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function upsert($table, array $options = []) {
        return new Upsert($this, $table, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function update($table, array $options = []) {
        return new Update($this, $table, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function delete($table, array $options = []) {
        return new Delete($this, $table, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function truncate($table, array $options = []) {
        return new Truncate($this, $table, $options);
    }
    
    /**
     * {@inheritdoc}
     */
    public function schema() {
        if (empty($this->schema)) {
            $this->schema = new Schema($this);
        }
        return $this->schema;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function driverTransactionManager() : TransactionManagerInterface {
        return new TransactionManager($this);
    }

}