class CredentialForm

class CredentialForm extends MigrateUpgradeFormBase {
    
    /**
     * The HTTP client to fetch the files with.
     *
     * @var \GuzzleHttp\ClientInterface
     */
    protected $httpClient;
    
    /**
     * An array of error information.
     *
     * @var array
     */
    protected $errors = [];
    
    /**
     * CredentialForm constructor.
     *
     * @param \Drupal\Core\TempStore\PrivateTempStoreFactory $tempstore_private
     *   The private tempstore factory service.
     * @param \GuzzleHttp\ClientInterface $http_client
     *   A Guzzle client object.
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config factory service.
     * @param \Drupal\migrate\Plugin\MigrationPluginManagerInterface $migration_plugin_manager
     *   The migration plugin manager service.
     * @param \Drupal\Core\State\StateInterface $state
     *   The state service.
     */
    public function __construct(PrivateTempStoreFactory $tempstore_private, ClientInterface $http_client, ConfigFactoryInterface $config_factory, MigrationPluginManagerInterface $migration_plugin_manager, StateInterface $state) {
        parent::__construct($config_factory, $migration_plugin_manager, $state, $tempstore_private);
        $this->httpClient = $http_client;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('tempstore.private'), $container->get('http_client'), $container->get('config.factory'), $container->get('plugin.manager.migration'), $container->get('state'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'migrate_drupal_ui_credential_form';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        if ($this->store
            ->get('step') != 'credential') {
            return $this->restartUpgradeForm();
        }
        $form = parent::buildForm($form, $form_state);
        $form['actions']['submit']['#value'] = $this->t('Review upgrade');
        $form['#title'] = $this->t('Drupal Upgrade');
        $drivers = $this->getDatabaseTypes();
        $drivers_keys = array_keys($drivers);
        $default_driver = current($drivers_keys);
        $default_options = [];
        $form['help'] = [
            '#type' => 'item',
            '#description' => $this->t('Provide the information to access the Drupal site you want to upgrade. Files can be imported into the upgraded site as well.  See the <a href=":url">Upgrade documentation for more detailed instructions</a>.', [
                ':url' => 'https://www.drupal.org/upgrade/migrate',
            ]),
        ];
        $migrate_source_version = Settings::get('migrate_source_version') == '6' ? '6' : '7';
        $form['version'] = [
            '#type' => 'radios',
            '#default_value' => $migrate_source_version,
            '#title' => $this->t('Drupal version of the source site'),
            '#options' => [
                '6' => $this->t('Drupal 6'),
                '7' => $this->t('Drupal 7'),
            ],
            '#required' => TRUE,
        ];
        $available_connections = array_diff(array_keys(Database::getAllConnectionInfo()), [
            'default',
        ]);
        $options = array_combine($available_connections, $available_connections);
        $migrate_source_connection = Settings::get('migrate_source_connection');
        $preferred_connections = $migrate_source_connection ? [
            'migrate',
            $migrate_source_connection,
        ] : [
            'migrate',
        ];
        $default_options = array_intersect($preferred_connections, $available_connections);
        $form['source_connection'] = [
            '#type' => 'select',
            '#title' => $this->t('Source connection'),
            '#options' => $options,
            '#default_value' => array_pop($default_options),
            '#empty_option' => $this->t('- User defined -'),
            '#description' => $this->t('Choose one of the keys from the $databases array or else select "User defined" and enter database credentials.'),
            '#access' => !empty($options),
        ];
        $form['database'] = [
            '#type' => 'details',
            '#title' => $this->t('Source database'),
            '#description' => $this->t('Provide credentials for the database of the Drupal site you want to upgrade.'),
            '#open' => TRUE,
            '#states' => [
                'visible' => [
                    ':input[name=source_connection]' => [
                        'value' => '',
                    ],
                ],
            ],
        ];
        $form['database']['driver'] = [
            '#type' => 'radios',
            '#title' => $this->t('Database type'),
            '#required' => TRUE,
            '#default_value' => $default_driver,
            '#states' => [
                'required' => [
                    ':input[name=source_connection]' => [
                        'value' => '',
                    ],
                ],
            ],
        ];
        if (count($drivers) == 1) {
            $form['database']['driver']['#disabled'] = TRUE;
        }
        // Add driver-specific configuration options.
        foreach ($drivers as $key => $driver) {
            $form['database']['driver']['#options'][$key] = $driver->name();
            $form['database']['settings'][$key] = $driver->getFormOptions($default_options);
            unset($form['database']['settings'][$key]['advanced_options']['prefix']['#description']);
            // This is a multi-step form and is not rebuilt during submission so
            // #limit_validation_errors is not used. The database and username fields
            // for mysql and pgsql must not be required.
            $form['database']['settings'][$key]['database']['#required'] = FALSE;
            $form['database']['settings'][$key]['username']['#required'] = FALSE;
            $form['database']['settings'][$key]['database']['#states'] = [
                'required' => [
                    ':input[name=source_connection]' => [
                        'value' => '',
                    ],
                    ':input[name=driver]' => [
                        'value' => $key,
                    ],
                ],
            ];
            if (!str_ends_with($key, '\\sqlite')) {
                $form['database']['settings'][$key]['username']['#states'] = [
                    'required' => [
                        ':input[name=source_connection]' => [
                            'value' => '',
                        ],
                        ':input[name=driver]' => [
                            'value' => $key,
                        ],
                    ],
                ];
                $form['database']['settings'][$key]['password']['#states'] = [
                    'required' => [
                        ':input[name=source_connection]' => [
                            'value' => '',
                        ],
                        ':input[name=driver]' => [
                            'value' => $key,
                        ],
                    ],
                ];
            }
            $form['database']['settings'][$key]['#prefix'] = '<h2 class="js-hide">' . $this->t('@driver_name settings', [
                '@driver_name' => $driver->name(),
            ]) . '</h2>';
            $form['database']['settings'][$key]['#type'] = 'container';
            $form['database']['settings'][$key]['#tree'] = TRUE;
            $form['database']['settings'][$key]['advanced_options']['#parents'] = [
                $key,
            ];
            $form['database']['settings'][$key]['#states'] = [
                'visible' => [
                    ':input[name=driver]' => [
                        'value' => $key,
                    ],
                ],
            ];
            // Move the host fields out of advanced settings.
            if (isset($form['database']['settings'][$key]['advanced_options']['host'])) {
                $form['database']['settings'][$key]['host'] = $form['database']['settings'][$key]['advanced_options']['host'];
                $form['database']['settings'][$key]['host']['#title'] = 'Database host';
                $form['database']['settings'][$key]['host']['#weight'] = -1;
                unset($form['database']['settings'][$key]['database']['#default_value']);
                unset($form['database']['settings'][$key]['advanced_options']['host']);
            }
        }
        $form['source'] = [
            '#type' => 'details',
            '#title' => $this->t('Source files'),
            '#open' => TRUE,
        ];
        $form['source']['d6_source_base_path'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Document root for files'),
            '#default_value' => Settings::get('migrate_file_public_path') ?? '',
            '#description' => $this->t('To import files from your current Drupal site, enter a local file directory containing your site (e.g. /var/www/docroot), or your site address (for example http://example.com).'),
            '#states' => [
                'visible' => [
                    ':input[name="version"]' => [
                        'value' => '6',
                    ],
                ],
            ],
            '#element_validate' => [
                '::validatePaths',
            ],
        ];
        $form['source']['source_base_path'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Document root for public files'),
            '#default_value' => Settings::get('migrate_file_public_path') ?? '',
            '#description' => $this->t('To import public files from your current Drupal site, enter a local file directory containing your site (e.g. /var/www/docroot), or your site address (for example http://example.com).'),
            '#states' => [
                'visible' => [
                    ':input[name="version"]' => [
                        'value' => '7',
                    ],
                ],
            ],
            '#element_validate' => [
                '::validatePaths',
            ],
        ];
        $form['source']['source_private_file_path'] = [
            '#type' => 'textfield',
            '#title' => $this->t('Document root for private files'),
            '#default_value' => Settings::get('migrate_file_private_path') ?? '',
            '#description' => $this->t('To import private files from your current Drupal site, enter a local file directory containing your site (e.g. /var/www/docroot). Leave blank to use the same value as Public files directory.'),
            '#states' => [
                'visible' => [
                    ':input[name="version"]' => [
                        'value' => '7',
                    ],
                ],
            ],
            '#element_validate' => [
                '::validatePaths',
            ],
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        $connection = NULL;
        $source_connection = $form_state->getValue('source_connection');
        if ($source_connection) {
            $info = Database::getConnectionInfo($source_connection);
            $database = reset($info);
        }
        else {
            // Retrieve the database driver from the form, use reflection to get the
            // namespace, and then construct a valid database array the same as in
            // settings.php.
            $driver = $form_state->getValue('driver');
            $drivers = $this->getDatabaseTypes();
            $reflection = new \ReflectionClass($drivers[$driver]);
            $install_namespace = $reflection->getNamespaceName();
            $database = $form_state->getValue($driver);
            // Cut the trailing \Install from namespace.
            $database['namespace'] = substr($install_namespace, 0, strrpos($install_namespace, '\\'));
            $database['driver'] = $driver;
            // Validate the driver settings and just end here if we have any issues.
            if ($errors = $drivers[$driver]->validateDatabaseSettings($database)) {
                foreach ($errors as $name => $message) {
                    $this->errors[$name] = $message;
                }
            }
        }
        // Check the connection with the source database.
        $error_key = $database['driver'] . '][database';
        if (!$this->errors) {
            try {
                $connection = $this->getConnection($database);
            } catch (\Exception $e) {
                $msg = $this->t('Failed to connect to your database server. The server reports the following message: %error.<ul><li>Is the database server running?</li><li>Does the database exist, and have you entered the correct database name?</li><li>Have you entered the correct username and password?</li><li>Have you entered the correct database hostname?</li></ul>', [
                    '%error' => $e->getMessage(),
                ]);
                $this->errors[$error_key] = $msg;
            }
        }
        // Check that the source database is not the site database.
        if (!$this->errors) {
            $options = array_flip([
                'database',
                'host',
                'port',
                'prefix',
                'namespace',
            ]);
            $source = array_map('strval', array_intersect_key($connection->getConnectionOptions(), $options));
            $destination = array_map('strval', array_intersect_key(Database::getConnection()->getConnectionOptions(), $options));
            ksort($source);
            ksort($destination);
            if ($source === $destination) {
                $this->errors[$error_key] = $this->t('Enter credentials for the database of the Drupal site you want to upgrade, not the new site.');
            }
        }
        // Get the Drupal version of the source database so it can be validated.
        if (!$this->errors) {
            $version = (string) $this->getLegacyDrupalVersion($connection);
            if (!$version) {
                $this->errors[$error_key] = $this->t('Source database does not contain a recognizable Drupal version.');
            }
            elseif ($version !== (string) $form_state->getValue('version')) {
                $this->errors['version'] = $this->t('Source database is Drupal version @version but version @selected was selected.', [
                    '@version' => $version,
                    '@selected' => $form_state->getValue('version'),
                ]);
            }
        }
        // Setup migrations and save form data to private store.
        if (!$this->errors) {
            try {
                $this->setupMigrations($connection, $version, $database, $form_state);
            } catch (BadPluginDefinitionException $e) {
                // BadPluginDefinitionException occurs if the source_module is not
                // defined, which happens during testing.
                $this->errors[$error_key] = $e->getMessage();
            } catch (RequirementsException $e) {
                $this->errors[$error_key] = $e->getMessage();
            }
        }
        // Display all errors as a list of items.
        if ($this->errors) {
            $form_state->setError($form, $this->t('<h3>Resolve all issues below to continue the upgrade.</h3>'));
            foreach ($this->errors as $name => $message) {
                $form_state->setErrorByName($name, $message);
            }
        }
    }
    
    /**
     * The #element_validate handler for the source path elements.
     *
     * Ensures that entered path can be read.
     */
    public function validatePaths($element, FormStateInterface $form_state) {
        $version = $form_state->getValue('version');
        // Only validate the paths relevant to the legacy Drupal version.
        if ($version !== '7' && ($element['#name'] == 'source_base_path' || $element['#name'] == 'source_private_file_path')) {
            return;
        }
        if ($version !== '6' && $element['#name'] == 'd6_source_base_path') {
            return;
        }
        if ($source = $element['#value']) {
            $msg = $this->t('Failed to read from @title.', [
                '@title' => $element['#title'],
            ]);
            if (UrlHelper::isExternal($source)) {
                try {
                    $this->httpClient
                        ->head($source);
                } catch (ClientExceptionInterface $e) {
                    $msg .= ' ' . $this->t('The server reports the following message: %error.', [
                        '%error' => $e->getMessage(),
                    ]);
                    $this->errors[$element['#name']] = $msg;
                }
            }
            elseif (!file_exists($source) || !is_dir($source) || !is_readable($source)) {
                $this->errors[$element['#name']] = $msg;
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        $this->store
            ->set('step', 'idconflict');
        $form_state->setRedirect('migrate_drupal_ui.upgrade_idconflict');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getConfirmText() {
        return $this->t('Review upgrade');
    }
    
    /**
     * Returns all supported database driver installer objects.
     *
     * @return \Drupal\Core\Database\Install\Tasks[]
     *   An array of available database driver installer objects.
     */
    protected function getDatabaseTypes() {
        // Make sure the install API is available.
        include_once DRUPAL_ROOT . '/core/includes/install.inc';
        $database_types = [];
        foreach (Database::getDriverList()->getInstallableList() as $name => $driver) {
            $database_types[$name] = $driver->getInstallTasks();
        }
        return $database_types;
    }
    
    /**
     * Gets and stores information for this migration in temporary store.
     *
     * Gets all the migrations, converts each to an array and stores it in the
     * form state. The source base path for public and private files is also
     * put into form state.
     *
     * @param \Drupal\Core\Database\Connection $connection
     *   The database connection used.
     * @param string $version
     *   The Drupal version.
     * @param array $database
     *   Database array representing the source Drupal database.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     *
     * @throws \Drupal\Core\TempStore\TempStoreException
     *   Thrown when a lock for the backend storage could not be acquired.
     */
    protected function setupMigrations(Connection $connection, $version, array $database, FormStateInterface $form_state) {
        $this->createDatabaseStateSettings($database, $version);
        $migrations = $this->getMigrations('migrate_drupal_' . $version, $version);
        // Get the system data from source database.
        $system_data = $this->getSystemData($connection);
        // Convert the migration object into array
        // so that it can be stored in form storage.
        $migration_array = [];
        foreach ($migrations as $migration) {
            $migration_array[$migration->id()] = $migration->label();
        }
        // Store information in the private store.
        $this->store
            ->set('version', $version);
        $this->store
            ->set('migrations', $migration_array);
        if ($version == 6) {
            $this->store
                ->set('source_base_path', $form_state->getValue('d6_source_base_path'));
        }
        else {
            $this->store
                ->set('source_base_path', $form_state->getValue('source_base_path'));
        }
        $this->store
            ->set('source_private_file_path', $form_state->getValue('source_private_file_path'));
        // Store the retrieved system data in the private store.
        $this->store
            ->set('system_data', $system_data);
    }

}