<?php

namespace Drupal\KernelTests\Core\Database;

use Drupal\Core\Database\Database;
use Drupal\KernelTests\KernelTestBase;

/**
 * Tests management of database connections.
 *
 * @group Database
 */
class ConnectionUnitTest extends KernelTestBase {

  protected $key;
  protected $target;

  protected $monitor;
  protected $originalCount;

  protected function setUp() {
    parent::setUp();

    $this->key = 'default';
    $this->originalTarget = 'default';
    $this->target = 'DatabaseConnectionUnitTest';

    // Determine whether the database driver is MySQL. If it is not, the test
    // methods will not be executed.
    // @todo Make this test driver-agnostic, or find a proper way to skip it.
    //   See https://www.drupal.org/node/1273478.
    $connection_info = Database::getConnectionInfo('default');
    $this->skipTest = (bool) ($connection_info['default']['driver'] != 'mysql');
    if ($this->skipTest) {
      // Insert an assertion to prevent Simpletest from interpreting the test
      // as failure.
      $this->pass('This test is only compatible with MySQL.');
    }

    // Create an additional connection to monitor the connections being opened
    // and closed in this test.
    // @see TestBase::changeDatabasePrefix()
    Database::addConnectionInfo('default', 'monitor', $connection_info['default']);
    $this->monitor = Database::getConnection('monitor');
  }

  /**
   * Adds a new database connection info to Database.
   */
  protected function addConnection() {
    // Add a new target to the connection, by cloning the current connection.
    $connection_info = Database::getConnectionInfo($this->key);
    Database::addConnectionInfo($this->key, $this->target, $connection_info[$this->originalTarget]);

    // Verify that the new target exists.
    $info = Database::getConnectionInfo($this->key);
    // Note: Custom assertion message to not expose database credentials.
    $this->assertIdentical($info[$this->target], $connection_info[$this->key], 'New connection info found.');
  }

  /**
   * Returns the connection ID of the current test connection.
   *
   * @return int
   */
  protected function getConnectionID() {
    return (int) Database::getConnection($this->target, $this->key)->query('SELECT CONNECTION_ID()')->fetchField();
  }

  /**
   * Asserts that a connection ID exists.
   *
   * @param int $id
   *   The connection ID to verify.
   */
  protected function assertConnection($id) {
    $list = $this->monitor->query('SHOW PROCESSLIST')->fetchAllKeyed(0, 0);
    return $this->assertTrue(isset($list[$id]), format_string('Connection ID @id found.', ['@id' => $id]));
  }

  /**
   * Asserts that a connection ID does not exist.
   *
   * @param int $id
   *   The connection ID to verify.
   */
  protected function assertNoConnection($id) {
    $list = $this->monitor->query('SHOW PROCESSLIST')->fetchAllKeyed(0, 0);
    return $this->assertFalse(isset($list[$id]), format_string('Connection ID @id not found.', ['@id' => $id]));
  }

  /**
   * Tests Database::closeConnection() without query.
   *
   * @todo getConnectionID() executes a query.
   */
  public function testOpenClose() {
    if ($this->skipTest) {
      return;
    }
    // Add and open a new connection.
    $this->addConnection();
    $id = $this->getConnectionID();
    Database::getConnection($this->target, $this->key);

    // Verify that there is a new connection.
    $this->assertConnection($id);

    // Close the connection.
    Database::closeConnection($this->target, $this->key);
    // Wait 20ms to give the database engine sufficient time to react.
    usleep(20000);

    // Verify that we are back to the original connection count.
    $this->assertNoConnection($id);
  }

  /**
   * Tests Database::closeConnection() with a query.
   */
  public function testOpenQueryClose() {
    if ($this->skipTest) {
      return;
    }
    // Add and open a new connection.
    $this->addConnection();
    $id = $this->getConnectionID();
    Database::getConnection($this->target, $this->key);

    // Verify that there is a new connection.
    $this->assertConnection($id);

    // Execute a query.
    Database::getConnection($this->target, $this->key)->query('SHOW TABLES');

    // Close the connection.
    Database::closeConnection($this->target, $this->key);
    // Wait 20ms to give the database engine sufficient time to react.
    usleep(20000);

    // Verify that we are back to the original connection count.
    $this->assertNoConnection($id);
  }

  /**
   * Tests Database::closeConnection() with a query and custom prefetch method.
   */
  public function testOpenQueryPrefetchClose() {
    if ($this->skipTest) {
      return;
    }
    // Add and open a new connection.
    $this->addConnection();
    $id = $this->getConnectionID();
    Database::getConnection($this->target, $this->key);

    // Verify that there is a new connection.
    $this->assertConnection($id);

    // Execute a query.
    Database::getConnection($this->target, $this->key)->query('SHOW TABLES')->fetchCol();

    // Close the connection.
    Database::closeConnection($this->target, $this->key);
    // Wait 20ms to give the database engine sufficient time to react.
    usleep(20000);

    // Verify that we are back to the original connection count.
    $this->assertNoConnection($id);
  }

  /**
   * Tests Database::closeConnection() with a select query.
   */
  public function testOpenSelectQueryClose() {
    if ($this->skipTest) {
      return;
    }
    // Add and open a new connection.
    $this->addConnection();
    $id = $this->getConnectionID();
    Database::getConnection($this->target, $this->key);

    // Verify that there is a new connection.
    $this->assertConnection($id);

    // Create a table.
    $name = 'foo';
    Database::getConnection($this->target, $this->key)->schema()->createTable($name, [
      'fields' => [
        'name' => [
          'type' => 'varchar',
          'length' => 255,
        ],
      ],
    ]);

    // Execute a query.
    Database::getConnection($this->target, $this->key)->select('foo', 'f')
      ->fields('f', ['name'])
      ->execute()
      ->fetchAll();

    // Drop the table.
    Database::getConnection($this->target, $this->key)->schema()->dropTable($name);

    // Close the connection.
    Database::closeConnection($this->target, $this->key);
    // Wait 20ms to give the database engine sufficient time to react.
    usleep(20000);

    // Verify that we are back to the original connection count.
    $this->assertNoConnection($id);
  }

  /**
   * Tests pdo options override.
   */
  public function testConnectionOpen() {
    $connection = Database::getConnection('default');
    $reflection = new \ReflectionObject($connection);
    $connection_property = $reflection->getProperty('connection');
    $connection_property->setAccessible(TRUE);
    // Skip this test when a database driver does not implement PDO.
    // An alternative database driver that does not implement PDO
    // should implement its own connection test.
    if (get_class($connection_property->getValue($connection)) !== 'PDO') {
      $this->markTestSkipped('Ignored PDO connection unit test for this driver because it does not implement PDO.');
    }
    $error_mode = $connection_property->getValue($connection)
      ->getAttribute(\PDO::ATTR_ERRMODE);
    $this->assertEqual($error_mode, \PDO::ERRMODE_EXCEPTION, 'Ensure the default error mode is set to exception.');

    $connection = Database::getConnectionInfo('default');
    $connection['default']['pdo'][\PDO::ATTR_ERRMODE] = \PDO::ERRMODE_SILENT;
    Database::addConnectionInfo('test', 'default', $connection['default']);
    $connection = Database::getConnection('default', 'test');

    $reflection = new \ReflectionObject($connection);
    $connection_property = $reflection->getProperty('connection');
    $connection_property->setAccessible(TRUE);
    $error_mode = $connection_property->getValue($connection)
      ->getAttribute(\PDO::ATTR_ERRMODE);
    $this->assertEqual($error_mode, \PDO::ERRMODE_SILENT, 'Ensure PDO connection options can be overridden.');

    Database::removeConnection('test');
  }

}