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  <?php
namespace Drupal\diff\Form;
use Drupal\Component\Utility\Xss;
use Drupal\Core\Entity\ContentEntityInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Language\LanguageManagerInterface;
use Drupal\Core\Link;
use Drupal\diff\DiffEntityComparison;
use Drupal\diff\DiffLayoutManager;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Drupal\Core\Form\FormBase;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Datetime\DateFormatter;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;
use Drupal\Core\Render\RendererInterface;
class RevisionOverviewForm extends FormBase {
  
  protected $entityTypeManager;
  
  protected $currentUser;
  
  protected $date;
  
  protected $renderer;
  
  protected $languageManager;
  
  protected $config;
  
  protected $diffLayoutManager;
  
  protected $entityComparison;
  
  public function __construct(EntityTypeManagerInterface $entity_type_manager, AccountInterface $current_user, DateFormatter $date, RendererInterface $renderer, LanguageManagerInterface $language_manager, DiffLayoutManager $diff_layout_manager, DiffEntityComparison $entity_comparison) {
    $this->entityTypeManager = $entity_type_manager;
    $this->currentUser = $current_user;
    $this->date = $date;
    $this->renderer = $renderer;
    $this->languageManager = $language_manager;
    $this->config = $this
      ->config('diff.settings');
    $this->diffLayoutManager = $diff_layout_manager;
    $this->entityComparison = $entity_comparison;
  }
  
  public static function create(ContainerInterface $container) {
    return new static($container
      ->get('entity_type.manager'), $container
      ->get('current_user'), $container
      ->get('date.formatter'), $container
      ->get('renderer'), $container
      ->get('language_manager'), $container
      ->get('plugin.manager.diff.layout'), $container
      ->get('diff.entity_comparison'));
  }
  
  public function getFormId() {
    return 'revision_overview_form';
  }
  
  public function buildForm(array $form, FormStateInterface $form_state, $node = NULL) {
    $account = $this->currentUser;
    
    $langcode = $node
      ->language()
      ->getId();
    $langname = $node
      ->language()
      ->getName();
    $languages = $node
      ->getTranslationLanguages();
    $has_translations = count($languages) > 1;
    $node_storage = $this->entityTypeManager
      ->getStorage('node');
    $type = $node
      ->getType();
    $pagerLimit = $this->config
      ->get('general_settings.revision_pager_limit');
    $query = $this->entityTypeManager
      ->getStorage('node')
      ->getQuery()
      ->condition($node
      ->getEntityType()
      ->getKey('id'), $node
      ->id())
      ->pager($pagerLimit)
      ->allRevisions()
      ->sort($node
      ->getEntityType()
      ->getKey('revision'), 'DESC')
      ->accessCheck(FALSE)
      ->execute();
    $vids = array_keys($query);
    $revision_count = count($vids);
    $build['#title'] = $has_translations ? $this
      ->t('@langname revisions for %title', [
      '@langname' => $langname,
      '%title' => $node
        ->label(),
    ]) : $this
      ->t('Revisions for %title', [
      '%title' => $node
        ->label(),
    ]);
    $build['nid'] = array(
      '#type' => 'hidden',
      '#value' => $node
        ->id(),
    );
    $table_header = [];
    $table_header['revision'] = $this
      ->t('Revision');
    
    if ($revision_count > 1) {
      $table_header += array(
        'select_column_one' => '',
        'select_column_two' => '',
      );
    }
    $table_header['operations'] = $this
      ->t('Operations');
    $rev_revert_perm = $account
      ->hasPermission("revert {$type} revisions") || $account
      ->hasPermission('revert all revisions') || $account
      ->hasPermission('administer nodes');
    $rev_delete_perm = $account
      ->hasPermission("delete {$type} revisions") || $account
      ->hasPermission('delete all revisions') || $account
      ->hasPermission('administer nodes');
    $revert_permission = $rev_revert_perm && $node
      ->access('update');
    $delete_permission = $rev_delete_perm && $node
      ->access('delete');
    
    $build['node_revisions_table'] = array(
      '#type' => 'table',
      '#header' => $table_header,
      '#attributes' => array(
        'class' => array(
          'diff-revisions',
        ),
      ),
    );
    $build['node_revisions_table']['#attached']['library'][] = 'diff/diff.general';
    $build['node_revisions_table']['#attached']['drupalSettings']['diffRevisionRadios'] = $this->config
      ->get('general_settings.radio_behavior');
    $default_revision = $node
      ->getRevisionId();
    
    foreach ($vids as $key => $vid) {
      $previous_revision = NULL;
      if (isset($vids[$key + 1])) {
        $previous_revision = $node_storage
          ->loadRevision($vids[$key + 1]);
      }
      
      if ($revision = $node_storage
        ->loadRevision($vid)) {
        if ($revision
          ->hasTranslation($langcode) && $revision
          ->getTranslation($langcode)
          ->isRevisionTranslationAffected()) {
          $username = array(
            '#theme' => 'username',
            '#account' => $revision
              ->getRevisionUser(),
          );
          $revision_date = $this->date
            ->format($revision
            ->getRevisionCreationTime(), 'short');
          
          if ($vid != $node
            ->getRevisionId()) {
            $link = Link::fromTextAndUrl($revision_date, new Url('entity.node.revision', [
              'node' => $node
                ->id(),
              'node_revision' => $vid,
            ]));
          }
          else {
            $link = $node
              ->toLink($revision_date);
          }
          if ($vid == $default_revision) {
            $row = [
              'revision' => $this
                ->buildRevision($link, $username, $revision, $previous_revision),
            ];
            
            if ($revision_count > 1) {
              $row += [
                'select_column_one' => $this
                  ->buildSelectColumn('radios_left', $vid, FALSE),
                'select_column_two' => $this
                  ->buildSelectColumn('radios_right', $vid, $vid),
              ];
            }
            $row['operations'] = array(
              '#prefix' => '<em>',
              '#markup' => $this
                ->t('Current revision'),
              '#suffix' => '</em>',
              '#attributes' => array(
                'class' => array(
                  'revision-current',
                ),
              ),
            );
            $row['#attributes'] = [
              'class' => [
                'revision-current',
              ],
            ];
          }
          else {
            $route_params = array(
              'node' => $node
                ->id(),
              'node_revision' => $vid,
              'langcode' => $langcode,
            );
            $links = array();
            if ($revert_permission) {
              $links['revert'] = [
                'title' => $vid < $node
                  ->getRevisionId() ? $this
                  ->t('Revert') : $this
                  ->t('Set as current revision'),
                'url' => $has_translations ? Url::fromRoute('node.revision_revert_translation_confirm', [
                  'node' => $node
                    ->id(),
                  'node_revision' => $vid,
                  'langcode' => $langcode,
                ]) : Url::fromRoute('node.revision_revert_confirm', [
                  'node' => $node
                    ->id(),
                  'node_revision' => $vid,
                ]),
              ];
            }
            if ($delete_permission) {
              $links['delete'] = array(
                'title' => $this
                  ->t('Delete'),
                'url' => Url::fromRoute('node.revision_delete_confirm', $route_params),
              );
            }
            
            $row = [
              'revision' => $this
                ->buildRevision($link, $username, $revision, $previous_revision),
              'select_column_one' => $this
                ->buildSelectColumn('radios_left', $vid, isset($vids[1]) ? $vids[1] : FALSE),
              'select_column_two' => $this
                ->buildSelectColumn('radios_right', $vid, FALSE),
              'operations' => [
                '#type' => 'operations',
                '#links' => $links,
              ],
            ];
          }
          
          $build['node_revisions_table'][] = $row;
        }
      }
    }
    
    if ($revision_count > 1) {
      $build['submit'] = array(
        '#type' => 'submit',
        '#button_type' => 'primary',
        '#value' => t('Compare selected revisions'),
        '#attributes' => array(
          'class' => array(
            'diff-button',
          ),
        ),
      );
    }
    $build['pager'] = array(
      '#type' => 'pager',
    );
    $build['#attached']['library'][] = 'node/drupal.node.admin';
    return $build;
  }
  
  protected function buildSelectColumn($name, $return_val, $default_val) {
    return [
      '#type' => 'radio',
      '#title_display' => 'invisible',
      '#name' => $name,
      '#return_value' => $return_val,
      '#default_value' => $default_val,
    ];
  }
  
  protected function buildRevision(Link $link, $username, ContentEntityInterface $revision, ContentEntityInterface $previous_revision = NULL) {
    return [
      '#type' => 'inline_template',
      '#template' => '{% trans %}{{ date }} by {{ username }}{% endtrans %}{% if message %}<p class="revision-log">{{ message }}</p>{% endif %}',
      '#context' => [
        'date' => $link
          ->toString(),
        'username' => $this->renderer
          ->renderPlain($username),
        'message' => [
          '#markup' => $this->entityComparison
            ->getRevisionDescription($revision, $previous_revision),
          '#allowed_tags' => Xss::getAdminTagList(),
        ],
      ],
    ];
  }
  
  public function validateForm(array &$form, FormStateInterface $form_state) {
    $input = $form_state
      ->getUserInput();
    if (count($form_state
      ->getValue('node_revisions_table')) <= 1) {
      $form_state
        ->setErrorByName('node_revisions_table', $this
        ->t('Multiple revisions are needed for comparison.'));
    }
    elseif (!isset($input['radios_left']) || !isset($input['radios_right'])) {
      $form_state
        ->setErrorByName('node_revisions_table', $this
        ->t('Select two revisions to compare.'));
    }
    elseif ($input['radios_left'] == $input['radios_right']) {
      
      $form_state
        ->setErrorByName('node_revisions_table', $this
        ->t('Select different revisions to compare.'));
    }
  }
  
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $input = $form_state
      ->getUserInput();
    $vid_left = $input['radios_left'];
    $vid_right = $input['radios_right'];
    $nid = $input['nid'];
    
    if ($vid_left > $vid_right) {
      $aux = $vid_left;
      $vid_left = $vid_right;
      $vid_right = $aux;
    }
    
    $redirect_url = Url::fromRoute('diff.revisions_diff', array(
      'node' => $nid,
      'left_revision' => $vid_left,
      'right_revision' => $vid_right,
      'filter' => $this->diffLayoutManager
        ->getDefaultLayout(),
    ));
    $form_state
      ->setRedirectUrl($redirect_url);
  }
}