<?php
/**
 * @file
 * Allows site builders and administrator to view a module's README file.
 */

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Render\Element;
use Drupal\Core\Url;

/**
 * Implements hook_form_FORM_ID_alter().
 */
function readme_form_system_modules_alter(&$form, FormStateInterface $form_state) {
  /** @var \Drupal\readme\ReadmeManagerInterface $readme_manager */
  $readme_manager = \Drupal::service('readme.manager');

  foreach ($form['modules'] as $package => &$modules) {
    if (!Element::child($package) || !is_array($modules)) {
      continue;
    }
    foreach ($modules as $module_name => &$module) {
      if (!Element::child($module_name) || !is_array($module)) {
        continue;
      }
      $readme_path = $readme_manager->getPath($module_name);
      if ($readme_path) {
        $readme_link = [
          '#type' => 'link',
          '#title' => t('Readme'),
          '#url' => Url::fromRoute('readme.page', ['name' => $module_name]),
          '#options' => ['attributes' => ['class' => ['module-link', 'module-link-help', 'module-link-readme'], 'title' => t('Readme')]],
        ];

        if (isset($module['links']['help'])) {
          $module['links']['help'] = [
            $readme_link,
            $module['links']['help'],
          ];
        }
        else {
          $module['links']['help'] = $readme_link;
        }
      }
    }
  }

  $form['#attached']['library'][] = 'readme/readme';
}