<?php

namespace Drupal\Core\Database;

use Composer\Autoload\ClassLoader;
use Drupal\Core\Database\Event\StatementEvent;
use Drupal\Core\Extension\DatabaseDriverList;
use Drupal\Core\Cache\NullBackend;

/**
 * Primary front-controller for the database system.
 *
 * This class is un-extendable. It acts to encapsulate all control and
 * shepherding of database connections into a single location without the use of
 * globals.
 *
 * @final
 */
abstract class Database {

  /**
   * A nested array of active connections, keyed by database name and target.
   *
   * @var array
   */
  protected static $connections = [];

  /**
   * A processed copy of the database connection information from settings.php.
   *
   * @var array
   */
  protected static $databaseInfo = [];

  /**
   * A list of key/target credentials to simply ignore.
   *
   * @var array
   */
  protected static $ignoreTargets = [];

  /**
   * The key of the currently active database connection.
   *
   * @var string
   */
  protected static $activeKey = 'default';

  /**
   * An array of active query log objects.
   *
   * @var array
   * Every connection has one and only one logger object for all targets and
   * logging keys.
   *
   * @code
   *   [
   *     '$db_key' => DatabaseLog object.
   *   ]
   * @endcode
   */
  protected static $logs = [];

  /**
   * Starts logging a given logging key on the specified connection.
   *
   * @param string $logging_key
   *   The logging key to log.
   * @param string $key
   *   The database connection key for which we want to log.
   *
   * @return \Drupal\Core\Database\Log
   *   The query log object. Note that the log object does support richer
   *   methods than the few exposed through the Database class, so in some
   *   cases it may be desirable to access it directly.
   *
   * @see \Drupal\Core\Database\Log
   */
  final public static function startLog($logging_key, $key = 'default') {
    if (empty(self::$logs[$key])) {
      self::$logs[$key] = new Log($key);

      // Every target already active for this connection key needs to have the
      // logging object associated with it.
      if (!empty(self::$connections[$key])) {
        foreach (self::$connections[$key] as $connection) {
          $connection->enableEvents(StatementEvent::all());
          $connection->setLogger(self::$logs[$key]);
        }
      }
    }

    self::$logs[$key]->start($logging_key);
    return self::$logs[$key];
  }

  /**
   * Retrieves the queries logged on for given logging key.
   *
   * This method also ends logging for the specified key. To get the query log
   * to date without ending the logger request the logging object by starting
   * it again (which does nothing to an open log key) and call methods on it as
   * desired.
   *
   * @param string $logging_key
   *   The logging key to log.
   * @param string $key
   *   The database connection key for which we want to log.
   *
   * @return array
   *   The query log for the specified logging key and connection.
   *
   * @see \Drupal\Core\Database\Log
   */
  final public static function getLog($logging_key, $key = 'default') {
    if (empty(self::$logs[$key])) {
      return [];
    }
    $queries = self::$logs[$key]->get($logging_key);
    self::$logs[$key]->end($logging_key);
    return $queries;
  }

  /**
   * Gets the connection object for the specified database key and target.
   *
   * @param string $target
   *   The database target name.
   * @param string $key
   *   The database connection key. Defaults to NULL which means the active key.
   *
   * @return \Drupal\Core\Database\Connection
   *   The corresponding connection object.
   */
  final public static function getConnection($target = 'default', $key = NULL) {
    if (!isset($key)) {
      // By default, we want the active connection, set in setActiveConnection.
      $key = self::$activeKey;
    }
    // If the requested target does not exist, or if it is ignored, we fall back
    // to the default target. The target is typically either "default" or
    // "replica", indicating to use a replica SQL server if one is available. If
    // it's not available, then the default/primary server is the correct server
    // to use.
    if (!empty(self::$ignoreTargets[$key][$target]) || !isset(self::$databaseInfo[$key][$target])) {
      $target = 'default';
    }

    if (!isset(self::$connections[$key][$target])) {
      // If necessary, a new connection is opened.
      self::$connections[$key][$target] = self::openConnection($key, $target);
    }
    return self::$connections[$key][$target];
  }

  /**
   * Determines if there is an active connection.
   *
   * Note that this method will return FALSE if no connection has been
   * established yet, even if one could be.
   *
   * @return bool
   *   TRUE if there is at least one database connection established, FALSE
   *   otherwise.
   */
  final public static function isActiveConnection() {
    return !empty(self::$activeKey) && !empty(self::$connections) && !empty(self::$connections[self::$activeKey]);
  }

  /**
   * Sets the active connection to the specified key.
   *
   * @return string|null
   *   The previous database connection key.
   */
  final public static function setActiveConnection($key = 'default') {
    if (!empty(self::$databaseInfo[$key])) {
      $old_key = self::$activeKey;
      self::$activeKey = $key;
      return $old_key;
    }
  }

  /**
   * Process the configuration file for database information.
   *
   * @param array $info
   *   The database connection information, as defined in settings.php. The
   *   structure of this array depends on the database driver it is connecting
   *   to.
   */
  final public static function parseConnectionInfo(array $info) {
    // If there is no "driver" property, then we assume it's an array of
    // possible connections for this target. Pick one at random. That allows
    // us to have, for example, multiple replica servers.
    if (empty($info['driver'])) {
      $info = $info[mt_rand(0, count($info) - 1)];
    }

    // Prefix information, default to an empty prefix.
    $info['prefix'] = $info['prefix'] ?? '';

    // Backwards compatibility layer for Drupal 8 style database connection
    // arrays. Those have the wrong 'namespace' key set, or not set at all
    // for core supported database drivers.
    if (empty($info['namespace']) || str_starts_with($info['namespace'], 'Drupal\\Core\\Database\\Driver\\')) {
      switch (strtolower($info['driver'])) {
        case 'mysql':
          $info['namespace'] = 'Drupal\\mysql\\Driver\\Database\\mysql';
          break;

        case 'pgsql':
          $info['namespace'] = 'Drupal\\pgsql\\Driver\\Database\\pgsql';
          break;

        case 'sqlite':
          $info['namespace'] = 'Drupal\\sqlite\\Driver\\Database\\sqlite';
          break;
      }
    }
    // Backwards compatibility layer for Drupal 8 style database connection
    // arrays. Those do not have the 'autoload' key set for core database
    // drivers.
    if (empty($info['autoload'])) {
      switch (trim($info['namespace'], '\\')) {
        case "Drupal\\mysql\\Driver\\Database\\mysql":
          $info['autoload'] = "core/modules/mysql/src/Driver/Database/mysql/";
          break;

        case "Drupal\\pgsql\\Driver\\Database\\pgsql":
          $info['autoload'] = "core/modules/pgsql/src/Driver/Database/pgsql/";
          break;

        case "Drupal\\sqlite\\Driver\\Database\\sqlite":
          $info['autoload'] = "core/modules/sqlite/src/Driver/Database/sqlite/";
          break;
      }
    }

    return $info;
  }

  /**
   * Adds database connection information for a given key/target.
   *
   * This method allows to add new connections at runtime.
   *
   * Under normal circumstances the preferred way to specify database
   * credentials is via settings.php. However, this method allows them to be
   * added at arbitrary times, such as during unit tests, when connecting to
   * admin-defined third party databases, etc. Use
   * \Drupal\Core\Database\Database::setActiveConnection to select the
   * connection to use.
   *
   * If the given key/target pair already exists, this method will be ignored.
   *
   * @param string $key
   *   The database key.
   * @param string $target
   *   The database target name.
   * @param array $info
   *   The database connection information, as defined in settings.php. The
   *   structure of this array depends on the database driver it is connecting
   *   to.
   * @param \Composer\Autoload\ClassLoader $class_loader
   *   The class loader. Used for adding the database driver to the autoloader
   *   if $info['autoload'] is set.
   * @param string $app_root
   *   The app root.
   *
   * @see \Drupal\Core\Database\Database::setActiveConnection
   */
  final public static function addConnectionInfo($key, $target, array $info, $class_loader = NULL, $app_root = NULL) {
    if (empty(self::$databaseInfo[$key][$target])) {
      $info = self::parseConnectionInfo($info);
      self::$databaseInfo[$key][$target] = $info;

      // If the database driver is provided by a module, then its code may need
      // to be instantiated prior to when the module's root namespace is added
      // to the autoloader, because that happens during service container
      // initialization but the container definition is likely in the database.
      // Therefore, allow the connection info to specify an autoload directory
      // for the driver.
      if (isset($info['autoload']) && $class_loader && $app_root) {
        $class_loader->addPsr4($info['namespace'] . '\\', $app_root . '/' . $info['autoload']);

        // When the database driver is extending from other database drivers,
        // then add autoload directory for the parent database driver modules
        // as well.
        if (!empty($info['dependencies'])) {
          assert(is_array($info['dependencies']));
          foreach ($info['dependencies'] as $dependency) {
            if (isset($dependency['namespace']) && isset($dependency['autoload'])) {
              $class_loader->addPsr4($dependency['namespace'] . '\\', $app_root . '/' . $dependency['autoload']);
            }
          }
        }
      }
    }
  }

  /**
   * Gets information on the specified database connection.
   *
   * @param string $key
   *   (optional) The connection key for which to return information.
   *
   * @return array|null
   *   An associative array of database information. Defaults to an empty array.
   */
  final public static function getConnectionInfo($key = 'default') {
    if (!empty(self::$databaseInfo[$key])) {
      return self::$databaseInfo[$key];
    }
  }

  /**
   * Gets connection information for all available databases.
   *
   * @return array
   *   An associative array of database information for all available database,
   *   keyed by the database name. Defaults to an empty array.
   */
  final public static function getAllConnectionInfo() {
    return self::$databaseInfo;
  }

  /**
   * Sets connection information for multiple databases.
   *
   * @param array $databases
   *   A multi-dimensional array specifying database connection parameters, as
   *   defined in settings.php.
   * @param \Composer\Autoload\ClassLoader $class_loader
   *   The class loader. Used for adding the database driver(s) to the
   *   autoloader if $databases[$key][$target]['autoload'] is set.
   * @param string $app_root
   *   The app root.
   */
  final public static function setMultipleConnectionInfo(array $databases, $class_loader = NULL, $app_root = NULL) {
    foreach ($databases as $key => $targets) {
      foreach ($targets as $target => $info) {
        self::addConnectionInfo($key, $target, $info, $class_loader, $app_root);
      }
    }
  }

  /**
   * Rename a connection and its corresponding connection information.
   *
   * @param string $old_key
   *   The old connection key.
   * @param string $new_key
   *   The new connection key.
   *
   * @return bool
   *   TRUE in case of success, FALSE otherwise.
   */
  final public static function renameConnection($old_key, $new_key) {
    if (!empty(self::$databaseInfo[$old_key]) && empty(self::$databaseInfo[$new_key])) {
      // Migrate the database connection information.
      self::$databaseInfo[$new_key] = self::$databaseInfo[$old_key];
      unset(self::$databaseInfo[$old_key]);

      // Migrate over the DatabaseConnection object if it exists.
      if (isset(self::$connections[$old_key])) {
        self::$connections[$new_key] = self::$connections[$old_key];
        unset(self::$connections[$old_key]);
      }

      return TRUE;
    }
    else {
      return FALSE;
    }
  }

  /**
   * Remove a connection and its corresponding connection information.
   *
   * @param string $key
   *   The connection key.
   *
   * @return bool
   *   TRUE in case of success, FALSE otherwise.
   */
  final public static function removeConnection($key) {
    if (isset(self::$databaseInfo[$key])) {
      self::closeConnection(NULL, $key);
      unset(self::$databaseInfo[$key]);
      return TRUE;
    }
    else {
      return FALSE;
    }
  }

  /**
   * Opens a connection to the server specified by the given key and target.
   *
   * @param string $key
   *   The database connection key, as specified in settings.php. The default is
   *   "default".
   * @param string $target
   *   The database target to open.
   *
   * @throws \Drupal\Core\Database\ConnectionNotDefinedException
   * @throws \Drupal\Core\Database\DriverNotSpecifiedException
   */
  final protected static function openConnection($key, $target) {
    // If the requested database does not exist then it is an unrecoverable
    // error.
    if (!isset(self::$databaseInfo[$key])) {
      throw new ConnectionNotDefinedException('The specified database connection is not defined: ' . $key);
    }

    if (!self::$databaseInfo[$key][$target]['driver']) {
      throw new DriverNotSpecifiedException('Driver not specified for this database connection: ' . $key);
    }

    $driver_class = self::$databaseInfo[$key][$target]['namespace'] . '\\Connection';

    $client_connection = $driver_class::open(self::$databaseInfo[$key][$target]);
    $new_connection = new $driver_class($client_connection, self::$databaseInfo[$key][$target]);
    $new_connection->setTarget($target);
    $new_connection->setKey($key);

    // If we have any active logging objects for this connection key, we need
    // to associate them with the connection we just opened.
    if (!empty(self::$logs[$key])) {
      $new_connection->enableEvents(StatementEvent::all());
      $new_connection->setLogger(self::$logs[$key]);
    }

    return $new_connection;
  }

  /**
   * Closes a connection to the server specified by the given key and target.
   *
   * @param string $target
   *   The database target name.  Defaults to NULL meaning that all target
   *   connections will be closed.
   * @param string $key
   *   The database connection key. Defaults to NULL which means the active key.
   */
  public static function closeConnection($target = NULL, $key = NULL) {
    // Gets the active connection by default.
    if (!isset($key)) {
      $key = self::$activeKey;
    }
    if (isset($target) && isset(self::$connections[$key][$target])) {
      if (self::$connections[$key][$target] instanceof Connection) {
        self::$connections[$key][$target]->commitAll();
      }
      unset(self::$connections[$key][$target]);
    }
    elseif (isset(self::$connections[$key])) {
      foreach (self::$connections[$key] as $connection) {
        if ($connection instanceof Connection) {
          $connection->commitAll();
        }
      }
      unset(self::$connections[$key]);
    }

    // When last connection for $key is closed, we also stop any active
    // logging.
    if (empty(self::$connections[$key])) {
      unset(self::$logs[$key]);
    }

    // Force garbage collection to run. This ensures that client connection
    // objects and results in the connection being closed are destroyed.
    gc_collect_cycles();
  }

  /**
   * Instructs the system to temporarily ignore a given key/target.
   *
   * At times we need to temporarily disable replica queries. To do so, call
   * this method with the database key and the target to disable. That database
   * key will then always fall back to 'default' for that key, even if it's
   * defined.
   *
   * @param string $key
   *   The database connection key.
   * @param string $target
   *   The target of the specified key to ignore.
   */
  public static function ignoreTarget($key, $target) {
    self::$ignoreTargets[$key][$target] = TRUE;
  }

  /**
   * Converts a URL to a database connection info array.
   *
   * @param string $url
   *   The URL.
   * @param bool|null $include_test_drivers
   *   (optional) Whether to include test extensions. If FALSE, all 'tests'
   *   directories are excluded in the search. When NULL will be determined by
   *   the extension_discovery_scan_tests setting.
   *
   * @return array
   *   The database connection info.
   *
   * @throws \InvalidArgumentException
   *   Exception thrown when the provided URL does not meet the minimum
   *   requirements.
   * @throws \RuntimeException
   *   Exception thrown when a module provided database driver does not exist.
   */
  public static function convertDbUrlToConnectionInfo(string $url, ?bool $include_test_drivers = NULL): array {
    // Check that the URL is well formed, starting with 'scheme://', where
    // 'scheme' is a database driver name.
    if (preg_match('/^(.*):\/\//', $url, $matches) !== 1) {
      throw new \InvalidArgumentException("Missing scheme in URL '$url'");
    }
    $driverName = $matches[1];

    // Determine if the database driver is provided by a module.
    // @todo https://www.drupal.org/project/drupal/issues/3250999. Refactor when
    // all database drivers are provided by modules.
    $url_components = parse_url($url);
    $url_component_query = $url_components['query'] ?? '';
    parse_str($url_component_query, $query);

    // Use the driver name as the module name when the module name is not
    // provided.
    $module = $query['module'] ?? $driverName;

    $driverNamespace = "Drupal\\{$module}\\Driver\\Database\\{$driverName}";

    /** @var \Drupal\Core\Extension\DatabaseDriver $driver */
    $driver = self::getDriverList()
      ->includeTestDrivers($include_test_drivers)
      ->get($driverNamespace);

    // Set up an additional autoloader. We don't use the main autoloader as
    // this method can be called before Drupal is installed and is never
    // called during regular runtime.
    $additional_class_loader = new ClassLoader();
    $additional_class_loader->addPsr4($driverNamespace . '\\', $driver->getPath());
    $additional_class_loader->register();
    $connection_class = $driverNamespace . '\\Connection';
    if (!class_exists($connection_class)) {
      throw new \InvalidArgumentException("Can not convert '$url' to a database connection, class '$connection_class' does not exist");
    }

    // When the database driver is extending another database driver, then
    // add autoload info for the parent database driver as well.
    $autoloadInfo = $driver->getAutoloadInfo();
    if (isset($autoloadInfo['dependencies'])) {
      foreach ($autoloadInfo['dependencies'] as $dependency) {
        $additional_class_loader->addPsr4($dependency['namespace'] . '\\', $dependency['autoload']);
      }
    }

    $additional_class_loader->register(TRUE);

    $options = $connection_class::createConnectionOptionsFromUrl($url);

    // Add the necessary information to autoload code.
    // @see \Drupal\Core\Site\Settings::initialize()
    $options['autoload'] = $driver->getPath() . DIRECTORY_SEPARATOR;
    if (isset($autoloadInfo['dependencies'])) {
      $options['dependencies'] = $autoloadInfo['dependencies'];
    }

    return $options;
  }

  /**
   * Returns the list provider for available database drivers.
   *
   * @return \Drupal\Core\Extension\DatabaseDriverList
   *   The list provider for available database drivers.
   */
  public static function getDriverList(): DatabaseDriverList {
    if (\Drupal::hasContainer() && \Drupal::hasService('extension.list.database_driver')) {
      return \Drupal::service('extension.list.database_driver');
    }
    else {
      return new DatabaseDriverList(DRUPAL_ROOT, 'database_driver', new NullBackend('database_driver'));
    }
  }

  /**
   * Gets database connection info as a URL.
   *
   * @param string $key
   *   (Optional) The database connection key.
   *
   * @return string
   *   The connection info as a URL.
   *
   * @throws \RuntimeException
   *   When the database connection is not defined.
   */
  public static function getConnectionInfoAsUrl($key = 'default') {
    $db_info = static::getConnectionInfo($key);
    if (empty($db_info) || empty($db_info['default'])) {
      throw new \RuntimeException("Database connection $key not defined or missing the 'default' settings");
    }
    $namespace = $db_info['default']['namespace'];
    // Add the module name to the connection options to make it easy for the
    // connection class's createUrlFromConnectionOptions() method to add it to
    // the URL.
    $db_info['default']['module'] = explode('\\', $namespace)[1];
    $connection_class = $namespace . '\\Connection';
    return $connection_class::createUrlFromConnectionOptions($db_info['default']);
  }

  /**
   * Calls commitAll() on all the open connections.
   *
   * If drupal_register_shutdown_function() exists the commit will occur during
   * shutdown so that it occurs at the latest possible moment.
   *
   * @param bool $shutdown
   *   Internal param to denote that the method is being called by
   *   _drupal_shutdown_function().
   *
   * @internal
   *   This method exists only to work around a bug caused by Drupal incorrectly
   *   relying on object destruction order to commit transactions. Xdebug 3.3.0
   *   changes the order of object destruction when the develop mode is enabled.
   */
  public static function commitAllOnShutdown(bool $shutdown = FALSE): void {
    static $registered = FALSE;

    if ($shutdown) {
      foreach (self::$connections as $targets) {
        foreach ($targets as $connection) {
          if ($connection instanceof Connection) {
            $connection->commitAll();
          }
        }
      }
      return;
    }

    if (!function_exists('drupal_register_shutdown_function')) {
      return;
    }

    if (!$registered) {
      $registered = TRUE;
      drupal_register_shutdown_function('\Drupal\Core\Database\Database::commitAllOnShutdown', TRUE);
    }
  }

}
