class SelectProfileForm

class SelectProfileForm extends FormBase {
  
  /**
   * The key used in the profile list for the install from config option.
   *
   * This key must not be a valid profile extension name.
   */
  const CONFIG_INSTALL_PROFILE_KEY = '::existing_config::';
  
  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'install_select_profile_form';
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, $install_state = NULL) {
    $form['#title'] = $this->t('Select an installation profile');
    $profiles = [];
    $names = [];
    foreach ($install_state['profiles'] as $profile) {
      /** @var \Drupal\Core\Extension\Extension $profile */
      $details = install_profile_info($profile->getName());
      // Don't show hidden profiles. This is used by to hide the testing
      // profile, which only exists to speed up test runs.
      if ($details['hidden'] === TRUE && !drupal_valid_test_ua()) {
        continue;
      }
      $profiles[$profile->getName()] = $details;
      // Determine the name of the profile; default to file name if defined name
      // is unspecified.
      $name = $details['name'] ?? $profile->getName();
      $names[$profile->getName()] = $name;
    }
    // Display radio buttons alphabetically by human-readable name, but always
    // put the core profiles first (if they are present in the filesystem).
    natcasesort($names);
    if (isset($names['minimal'])) {
      // If the expert ("Minimal") core profile is present, put it in front of
      // any non-core profiles rather than including it with them
      // alphabetically, since the other profiles might be intended to group
      // together in a particular way.
      $names = [
        'minimal' => $names['minimal'],
      ] + $names;
    }
    if (isset($names['standard'])) {
      // If the default ("Standard") core profile is present, put it at the very
      // top of the list. This profile will have its radio button pre-selected,
      // so we want it to always appear at the top.
      $names = [
        'standard' => $names['standard'],
      ] + $names;
    }
    // The profile name and description are extracted for translation from the
    // .info file, so we can use $this->t() on them even though they are dynamic
    // data at this point.
    $form['profile'] = [
      '#type' => 'radios',
      '#title' => $this->t('Select an installation profile'),
      '#title_display' => 'invisible',
      '#options' => array_map([
        $this,
        't',
      ], $names),
      '#default_value' => 'standard',
    ];
    foreach (array_keys($names) as $profile_name) {
      // phpcs:ignore Drupal.Semantics.FunctionT.NotLiteralString
      $form['profile'][$profile_name]['#description'] = isset($profiles[$profile_name]['description']) ? $this->t($profiles[$profile_name]['description']) : '';
    }
    $config_sync_directory = Settings::get('config_sync_directory');
    if (!empty($config_sync_directory)) {
      $sync = new FileStorage($config_sync_directory);
      $extensions = $sync->read('core.extension');
      $site = $sync->read('system.site');
      if (isset($site['name'])) {
        $install_from_config = FALSE;
        if (isset($extensions['profile']) && array_key_exists($extensions['profile'], $names)) {
          // Ensure the profile can be installed from configuration. Install
          // profile's which implement hook_INSTALL() are not supported.
          // @todo https://www.drupal.org/project/drupal/issues/2982052 Remove
          //   this restriction.
          $root = \Drupal::root();
          include_once $root . '/core/includes/install.inc';
          $file = $root . '/' . $install_state['profiles'][$extensions['profile']]->getPath() . "/{$extensions['profile']}.install";
          if (is_file($file)) {
            require_once $file;
          }
          if (!function_exists($extensions['profile'] . '_install')) {
            $install_from_config = TRUE;
          }
        }
        elseif (empty($extensions['profile'])) {
          // Allow sites without a profile to be installed.
          $install_from_config = TRUE;
        }
        if ($install_from_config) {
          $form['profile']['#options'][static::CONFIG_INSTALL_PROFILE_KEY] = $this->t('Use existing configuration');
          $form['profile'][static::CONFIG_INSTALL_PROFILE_KEY]['#description'] = [
            'description' => [
              '#markup' => $this->t('Install %name using existing configuration.', [
                '%name' => $site['name'],
              ]),
            ],
            'info' => [
              '#type' => 'item',
              '#markup' => $this->t('The configuration from the directory %sync_directory will be used.', [
                '%sync_directory' => $config_sync_directory,
              ]),
              '#wrapper_attributes' => [
                'class' => [
                  'messages',
                  'messages--status',
                ],
              ],
              '#states' => [
                'visible' => [
                  ':input[name="profile"]' => [
                    'value' => static::CONFIG_INSTALL_PROFILE_KEY,
                  ],
                ],
              ],
            ],
          ];
        }
      }
    }
    $form['actions'] = [
      '#type' => 'actions',
    ];
    $form['actions']['submit'] = [
      '#type' => 'submit',
      '#value' => $this->t('Save and continue'),
      '#button_type' => 'primary',
    ];
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    global $install_state;
    $profile = $form_state->getValue('profile');
    if ($profile === static::CONFIG_INSTALL_PROFILE_KEY) {
      $sync = new FileStorage(Settings::get('config_sync_directory'));
      $profile = $sync->read('core.extension')['profile'] ?? FALSE;
      $install_state['parameters']['existing_config'] = TRUE;
    }
    $install_state['parameters']['profile'] = $profile;
  }

}