class MigrateTestBase

abstract class MigrateTestBase extends KernelTestBase implements MigrateMessageInterface {
    
    /**
     * TRUE to collect messages instead of displaying them.
     *
     * @var bool
     */
    protected $collectMessages = FALSE;
    
    /**
     * A two dimensional array of messages.
     *
     * The first key is the type of message, the second is just numeric. Values
     * are the messages.
     *
     * @var array
     */
    protected $migrateMessages;
    
    /**
     * The primary migration being tested.
     *
     * @var \Drupal\migrate\Plugin\MigrationInterface
     */
    protected $migration;
    
    /**
     * The source database connection.
     *
     * @var \Drupal\Core\Database\Connection
     */
    protected $sourceDatabase;
    
    /**
     * A logger prophecy object.
     *
     * Using ::setTestLogger(), this prophecy will be configured and injected into
     * the container. Using $this->logger->function(args)->shouldHaveBeenCalled()
     * you can assert that the logger was called.
     *
     * @var \Prophecy\Prophecy\ObjectProphecy
     */
    protected $logger;
    protected static $modules = [
        'migrate',
    ];
    
    /**
     * {@inheritdoc}
     */
    protected function setUp() {
        parent::setUp();
        $this->createMigrationConnection();
        $this->sourceDatabase = Database::getConnection('default', 'migrate');
        // Attach the original test prefix as a database, for SQLite to attach its
        // database file.
        $this->sourceDatabase
            ->attachDatabase(substr($this->sourceDatabase
            ->getConnectionOptions()['prefix'], 0, -1));
    }
    
    /**
     * Changes the database connection to the prefixed one.
     *
     * @todo Remove when we don't use global. https://www.drupal.org/node/2552791
     */
    private function createMigrationConnection() {
        // If the backup already exists, something went terribly wrong.
        // This case is possible, because database connection info is a static
        // global state construct on the Database class, which at least persists
        // for all test methods executed in one PHP process.
        if (Database::getConnectionInfo('simpletest_original_migrate')) {
            throw new \RuntimeException("Bad Database connection state: 'simpletest_original_migrate' connection key already exists. Broken test?");
        }
        // Clone the current connection and replace the current prefix.
        $connection_info = Database::getConnectionInfo('migrate');
        if ($connection_info) {
            Database::renameConnection('migrate', 'simpletest_original_migrate');
        }
        $connection_info = Database::getConnectionInfo('default');
        foreach ($connection_info as $target => $value) {
            $prefix = $value['prefix'];
            // Simpletest uses 7 character prefixes at most so this can't cause
            // collisions.
            $connection_info[$target]['prefix'] = $prefix . '0';
        }
        Database::addConnectionInfo('migrate', 'default', $connection_info['default']);
    }
    
    /**
     * {@inheritdoc}
     */
    protected function tearDown() {
        $this->cleanupMigrateConnection();
        parent::tearDown();
        $this->collectMessages = FALSE;
        unset($this->migration, $this->migrateMessages);
    }
    
    /**
     * Cleans up the test migrate connection.
     *
     * @todo Remove when we don't use global. https://www.drupal.org/node/2552791
     */
    private function cleanupMigrateConnection() {
        Database::removeConnection('migrate');
        $original_connection_info = Database::getConnectionInfo('simpletest_original_migrate');
        if ($original_connection_info) {
            Database::renameConnection('simpletest_original_migrate', 'migrate');
        }
    }
    
    /**
     * Prepare any dependent migrations.
     *
     * @param array $id_mappings
     *   A list of ID mappings keyed by migration IDs. Each ID mapping is a list
     *   of two arrays, the first are source IDs and the second are destination
     *   IDs.
     */
    protected function prepareMigrations(array $id_mappings) {
        $manager = $this->container
            ->get('plugin.manager.migration');
        foreach ($id_mappings as $migration_id => $data) {
            foreach ($manager->createInstances($migration_id) as $migration) {
                $id_map = $migration->getIdMap();
                $id_map->setMessage($this);
                $source_ids = $migration->getSourcePlugin()
                    ->getIds();
                foreach ($data as $id_mapping) {
                    $row = new Row(array_combine(array_keys($source_ids), $id_mapping[0]), $source_ids);
                    $id_map->saveIdMapping($row, $id_mapping[1]);
                }
            }
        }
    }
    
    /**
     * Modify a migration's configuration before executing it.
     *
     * @param \Drupal\migrate\Plugin\MigrationInterface $migration
     *   The migration to execute.
     */
    protected function prepareMigration(MigrationInterface $migration) {
        // Default implementation for test classes not requiring modification.
    }
    
    /**
     * Executes a single migration.
     *
     * @param string|\Drupal\migrate\Plugin\MigrationInterface $migration
     *   The migration to execute, or its ID.
     */
    protected function executeMigration($migration) {
        if (is_string($migration)) {
            $this->migration = $this->getMigration($migration);
        }
        else {
            $this->migration = $migration;
        }
        if ($this instanceof MigrateDumpAlterInterface) {
            static::migrateDumpAlter($this);
        }
        $this->prepareMigration($this->migration);
        (new MigrateExecutable($this->migration, $this))
            ->import();
    }
    
    /**
     * Executes a set of migrations in dependency order.
     *
     * @param string[] $ids
     *   Array of migration IDs, in any order. If any of these migrations use a
     *   deriver, the derivatives will be made before execution.
     */
    protected function executeMigrations(array $ids) {
        $manager = $this->container
            ->get('plugin.manager.migration');
        array_walk($ids, function ($id) use ($manager) {
            // This is possibly a base plugin ID and we want to run all derivatives.
            $instances = $manager->createInstances($id);
            $this->assertNotEmpty($instances, sprintf("No migrations created for id '%s'.", $id));
            array_walk($instances, [
                $this,
                'executeMigration',
            ]);
        });
    }
    
    /**
     * {@inheritdoc}
     */
    public function display($message, $type = 'status') {
        if ($this->collectMessages) {
            $this->migrateMessages[$type][] = $message;
        }
        else {
            $this->assertEquals('status', $type, $message);
        }
    }
    
    /**
     * Start collecting messages and erase previous messages.
     */
    public function startCollectingMessages() {
        $this->collectMessages = TRUE;
        $this->migrateMessages = [];
    }
    
    /**
     * Stop collecting messages.
     */
    public function stopCollectingMessages() {
        $this->collectMessages = FALSE;
    }
    
    /**
     * Records a failure in the map table of a specific migration.
     *
     * This is done in order to test scenarios which require a failed row.
     *
     * @param string|\Drupal\migrate\Plugin\MigrationInterface $migration
     *   The migration entity, or its ID.
     * @param array $row
     *   The raw source row which "failed".
     * @param int $status
     *   (optional) The failure status. Should be one of the
     *   MigrateIdMapInterface::STATUS_* constants. Defaults to
     *   MigrateIdMapInterface::STATUS_FAILED.
     */
    protected function mockFailure($migration, array $row, $status = MigrateIdMapInterface::STATUS_FAILED) {
        if (is_string($migration)) {
            $migration = $this->getMigration($migration);
        }
        
        /** @var \Drupal\migrate\Plugin\MigrationInterface $migration */
        $destination = array_map(function () {
            return NULL;
        }, $migration->getDestinationPlugin()
            ->getIds());
        $row = new Row($row, $migration->getSourcePlugin()
            ->getIds());
        $migration->getIdMap()
            ->saveIdMapping($row, $destination, $status);
    }
    
    /**
     * Gets the migration plugin.
     *
     * @param $plugin_id
     *   The plugin ID of the migration to get.
     *
     * @return \Drupal\migrate\Plugin\Migration
     *   The migration plugin.
     */
    protected function getMigration($plugin_id) {
        return $this->container
            ->get('plugin.manager.migration')
            ->createInstance($plugin_id);
    }
    
    /**
     * Injects the test logger into the container.
     */
    protected function setTestLogger() {
        $this->logger = $this->prophesize(LoggerChannelInterface::class);
        $this->container
            ->set('logger.channel.migrate', $this->logger
            ->reveal());
        \Drupal::setContainer($this->container);
    }

}