class SiteSettingsForm

class SiteSettingsForm extends FormBase {
    
    /**
     * The site path.
     *
     * @var string
     */
    protected $sitePath;
    
    /**
     * The renderer.
     *
     * @var \Drupal\Core\Render\RendererInterface
     */
    protected $renderer;
    
    /**
     * Constructs a new SiteSettingsForm.
     *
     * @param string $site_path
     *   The site path.
     */
    public function __construct($site_path, RendererInterface $renderer) {
        $this->sitePath = $site_path;
        $this->renderer = $renderer;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('site.path'), $container->get('renderer'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'install_settings_form';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $settings_file = './' . $this->sitePath . '/settings.php';
        $form['#title'] = $this->t('Database configuration');
        $drivers = drupal_get_database_types();
        $drivers_keys = array_keys($drivers);
        // Unless there is input for this form (for a non-interactive installation,
        // input originates from the $settings array passed into install_drupal()),
        // check whether database connection settings have been prepared in
        // settings.php already.
        // Note: The installer even executes this form if there is a valid database
        // connection already, since the submit handler of this form is responsible
        // for writing all $settings to settings.php (not limited to $databases).
        $input =& $form_state->getUserInput();
        if (!isset($input['driver']) && ($database = Database::getConnectionInfo())) {
            $input['driver'] = $database['default']['driver'];
            $input[$database['default']['driver']] = $database['default'];
        }
        if (isset($input['driver'])) {
            $default_driver = $input['driver'];
            // In case of database connection info from settings.php, as well as for a
            // programmed form submission (non-interactive installer), the table prefix
            // information is usually normalized into an array already, but the form
            // element only allows to configure one default prefix for all tables.
            $prefix =& $input[$default_driver]['prefix'];
            if (isset($prefix) && is_array($prefix)) {
                $prefix = $prefix['default'];
            }
            $default_options = $input[$default_driver];
        }
        else {
            $default_driver = current($drivers_keys);
            $default_options = [];
        }
        $form['driver'] = [
            '#type' => 'radios',
            '#title' => $this->t('Database type'),
            '#required' => TRUE,
            '#default_value' => $default_driver,
        ];
        if (count($drivers) == 1) {
            $form['driver']['#disabled'] = TRUE;
        }
        // Add driver specific configuration options.
        foreach ($drivers as $key => $driver) {
            $form['driver']['#options'][$key] = $driver->name();
            $form['settings'][$key] = $driver->getFormOptions($default_options);
            $form['settings'][$key]['#prefix'] = '<h2 class="js-hide">' . $this->t('@driver_name settings', [
                '@driver_name' => $driver->name(),
            ]) . '</h2>';
            $form['settings'][$key]['#type'] = 'container';
            $form['settings'][$key]['#tree'] = TRUE;
            $form['settings'][$key]['advanced_options']['#parents'] = [
                $key,
            ];
            $form['settings'][$key]['#states'] = [
                'visible' => [
                    ':input[name=driver]' => [
                        'value' => $key,
                    ],
                ],
            ];
        }
        $form['actions'] = [
            '#type' => 'actions',
        ];
        $form['actions']['save'] = [
            '#type' => 'submit',
            '#value' => $this->t('Save and continue'),
            '#button_type' => 'primary',
            '#limit_validation_errors' => [
                [
                    'driver',
                ],
                [
                    $default_driver,
                ],
            ],
            '#submit' => [
                '::submitForm',
            ],
        ];
        $form['errors'] = [];
        $form['settings_file'] = [
            '#type' => 'value',
            '#value' => $settings_file,
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateForm(array &$form, FormStateInterface $form_state) {
        $driver = $form_state->getValue('driver');
        $database = $form_state->getValue($driver);
        $drivers = drupal_get_database_types();
        $reflection = new \ReflectionClass($drivers[$driver]);
        $install_namespace = $reflection->getNamespaceName();
        // Cut the trailing \Install from namespace.
        $database['namespace'] = substr($install_namespace, 0, strrpos($install_namespace, '\\'));
        $database['driver'] = $driver;
        // See default.settings.php for an explanation of the 'autoload' key.
        if ($autoload = Database::findDriverAutoloadDirectory($database['namespace'], DRUPAL_ROOT)) {
            $database['autoload'] = $autoload;
        }
        $form_state->set('database', $database);
        foreach ($this->getDatabaseErrors($database, $form_state->getValue('settings_file')) as $name => $message) {
            $form_state->setErrorByName($name, $message);
        }
    }
    
    /**
     * Get any database errors and links them to a form element.
     *
     * @param array $database
     *   An array of database settings.
     * @param string $settings_file
     *   The settings file that contains the database settings.
     *
     * @return array
     *   An array of form errors keyed by the element name and parents.
     */
    protected function getDatabaseErrors(array $database, $settings_file) {
        $errors = install_database_errors($database, $settings_file);
        $form_errors = array_filter($errors, function ($value) {
            // Errors keyed by something other than an integer already are linked to
            // form elements.
            return is_int($value);
        });
        // Find the generic errors.
        $errors = array_diff_key($errors, $form_errors);
        if (count($errors)) {
            $error_message = static::getDatabaseErrorsTemplate($errors);
            // These are generic errors, so we do not have any specific key of the
            // database connection array to attach them to; therefore, we just put
            // them in the error array with standard numeric keys.
            $form_errors[$database['driver'] . '][0'] = $this->renderer
                ->renderPlain($error_message);
        }
        return $form_errors;
    }
    
    /**
     * Gets the inline template render array to display the database errors.
     *
     * @param \Drupal\Core\StringTranslation\TranslatableMarkup[] $errors
     *   The database errors to list.
     *
     * @return mixed[]
     *   The inline template render array to display the database errors.
     */
    public static function getDatabaseErrorsTemplate(array $errors) {
        return [
            '#type' => 'inline_template',
            '#template' => '{% trans %}Resolve all issues below to continue the installation. For help configuring your database server, see the <a href="https://www.drupal.org/docs/8/install">installation handbook</a>, or contact your hosting provider.{% endtrans %}{{ errors }}',
            '#context' => [
                'errors' => [
                    '#theme' => 'item_list',
                    '#items' => $errors,
                ],
            ],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        global $install_state;
        // Update global settings array and save.
        $settings = [];
        $database = $form_state->get('database');
        $settings['databases']['default']['default'] = (object) [
            'value' => $database,
            'required' => TRUE,
        ];
        $settings['settings']['hash_salt'] = (object) [
            'value' => Crypt::randomBytesBase64(55),
            'required' => TRUE,
        ];
        // If settings.php does not contain a config sync directory name we need to
        // configure one.
        if (empty(Settings::get('config_sync_directory'))) {
            if (empty($install_state['config_install_path'])) {
                // Add a randomized config directory name to settings.php
                $config_sync_directory = $this->createRandomConfigDirectory();
            }
            else {
                // Install profiles can contain a config sync directory. If they do,
                // 'config_install_path' is a path to the directory.
                $config_sync_directory = $install_state['config_install_path'];
            }
            $settings['settings']['config_sync_directory'] = (object) [
                'value' => $config_sync_directory,
                'required' => TRUE,
            ];
        }
        drupal_rewrite_settings($settings);
        // Indicate that the settings file has been verified, and check the database
        // for the last completed task, now that we have a valid connection. This
        // last step is important since we want to trigger an error if the new
        // database already has Drupal installed.
        $install_state['settings_verified'] = TRUE;
        $install_state['config_verified'] = TRUE;
        $install_state['database_verified'] = TRUE;
        $install_state['completed_task'] = install_verify_completed_task();
    }
    
    /**
     * Create a random config sync directory.
     *
     * @return string
     *   The path to the generated config sync directory.
     */
    protected function createRandomConfigDirectory() {
        $config_sync_directory = \Drupal::service('site.path') . '/files/config_' . Crypt::randomBytesBase64(55) . '/sync';
        // This should never fail, it is created here inside the public files
        // directory, which has already been verified to be writable itself.
        if (\Drupal::service('file_system')->prepareDirectory($config_sync_directory, FileSystemInterface::CREATE_DIRECTORY | FileSystemInterface::MODIFY_PERMISSIONS)) {
            // Put a README.txt into the sync config directory. This is required so
            // that they can later be added to git. Since this directory is
            // auto-created, we have to write out the README rather than just adding
            // it to the drupal core repo.
            $text = 'This directory contains configuration to be imported into your Drupal site. To make this configuration active, visit admin/config/development/configuration/sync.' . ' For information about deploying configuration between servers, see https://www.drupal.org/documentation/administer/config';
            file_put_contents($config_sync_directory . '/README.txt', $text);
        }
        return $config_sync_directory;
    }

}