<?php

/**
 * @file
 * Provides functionality for handling AMP.
 */

use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\node\NodeInterface;
use Symfony\Component\HttpFoundation\RedirectResponse;

/**
 * Implements hook_help().
 */
function amp_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the amp module.
    case 'help.page.amp':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Accelerated Mobile Pages (AMP) integration. Read about it online at <a href=":url">AMP Documentation</a>.', [':url' => 'https://www.drupal.org/docs/8/modules/accelerated-mobile-pages-amp']) . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_preprocess_html().
 */
function amp_preprocess_html(&$variables) {
  $amp_context = \Drupal::service('router.amp_context');
  if ($amp_context->isAmpRoute()) {

    foreach ($variables['page']['#attached']['html_head'] as $key => $value) {
      if ($value[1] === 'viewport') {
        $value[0]['#attributes']['content'] = 'width=device-width,minimum-scale=1,initial-scale=1';
        $variables['page']['#attached']['html_head'][$key] = $value;
      }
      // Remove Big Pipe's meta tag, which is invalid AMP markup.
      // We are generating placeholders on the server so should not be needed.
      if ($key == 'big_pipe_detect_nojs') {
        unset($variables['page']['#attached']['html_head'][$key]);
      }
    }

    // Remove RDF and Metatag properties incompatible with AMP specification.
    $attribute_list = [
      'prefix',
      'xmlns:dc',
      'xmlns:og',
      'xmlns:article',
      'xmlns:book',
      'xmlns:product',
      'xmlns:profile',
      'xmlns:video',
      'itemtype',
      'itemscope',
    ];
    if (isset($variables['html_attributes'])) {
      foreach ($attribute_list as $attribute_item) {
        if (isset($variables['html_attributes'][$attribute_item])) {
          unset($variables['html_attributes'][$attribute_item]);
        }
      }
    }
  }
}

/**
 * Implements hook_page_attachments().
 */
function amp_page_attachments(array &$attachments) {

  // Pages with development messages should not be stored in Google's AMP cache.
  // We prevent caching by making the page invalid.
  // @see https://www.ampproject.org/docs/fundamentals/how_cached#can-i-opt-out-of-caching?
  $ampService = \Drupal::service('amp.utilities');
  if ($ampService->isDevPage()) {
    $tag = [
      '#tag' => 'base',
      '#attributes' => [
        'name' => 'invalid-do-not-cache',
        'content' => 'invalid-do-not-cache',
      ],
    ];
    $attachments['#attached']['html_head'][] = [$tag, 'no-cache'];

  }
}

/**
 * Implements hook_amp_rules_alter().
 *
 * @see Drupal\amp\Service\DrupalParsedValidatorRules::updatedRules()
 */
function amp_amp_rules_alter(&$rules) {
  foreach ($rules->tags as $delta => $tag) {
    // Multiple amp-sidebar elements are now allowed.
    if ($tag->tag_name == 'amp-sidebar') {
      $rules->tags[$delta]->unique = 'false';
      break;
    }
  }
}

/**
 * Implements hook_entity_view_mode_alter().
 */
function amp_entity_view_mode_alter(&$view_mode, EntityInterface $entity, $context) {
  $amp_context = \Drupal::service('router.amp_context');

  // If on AMP route, and in full view mode, switch to AMP view mode.
  if ($amp_context->isAmpRoute(NULL, $entity) && $view_mode == 'full') {
    $view_mode = 'amp';
  }
}

/**
 * Implements hook_entity_view_alter().
 */
function amp_entity_view_alter(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display) {
  // Check if entity is a non-new node in either full or AMP view mode.
  $canonical_links = ['canonical', 'canonical_url'];
  $protected_links = $canonical_links + ['shortlink'];

  /**
   * @var NodeInterface $entity
   */
  if ($entity instanceof NodeInterface && !$entity->isNew() && in_array($build['#view_mode'], ['full', 'amp'])) {
    // Get a list of available view modes for the current entity.
    $view_modes = \Drupal::service('entity_display.repository')->getViewModeOptionsByBundle('node', $entity->bundle());
    // Double-check that the AMP view mode is enabled for this node type.
    if (isset($view_modes['amp'])) {
      $build['#cache']['contexts'][] = 'url.query_args:amp';
      $absolute_canonical = $entity->toUrl('canonical', ['absolute' => TRUE])->toString();

      if (!empty($build['#attached']['html_head_link'])) {
        foreach ($build['#attached']['html_head_link'] as $key => $config) {
          if ($build['#view_mode'] === 'amp') {
            if (!in_array($config[0]['rel'], $protected_links)) {
              unset($build['#attached']['html_head_link'][$key]);
            }
          }
          elseif ($build['#view_mode'] === 'full') {
            if (in_array($config[0]['rel'], $canonical_links) && !empty($config[0]['href'])) {
              // Check if the canonical link is absolute and external. Do not
              // expose AMP for those.
              $current_canonical = $config[0]['href'];
              if (UrlHelper::isExternal($current_canonical) && !UrlHelper::externalIsLocal($current_canonical, \Drupal::service('router.request_context')->getCompleteBaseUrl())) {
                continue;
              }

              $amp_href = \Drupal::service('amp.query_parameters')->add($absolute_canonical);

              $build['#attached']['html_head_link'][] = [
                [
                  'rel' => 'amphtml',
                  'href' => $amp_href,
                ],
                TRUE,
              ];
              $build['#cache']['contexts'][] = 'url.site';
            }
          }
        }
      }
    }
  }
}

/**
 * Implements hook_theme().
 */
function amp_theme() {
  $theme = [
    'amp_iframe' => [
      'variables' => [
        'iframe' => NULL,
      ],
    ],
    'amp_ad' => [
      'variables' => [
        'type' => NULL, 'attributes' => [],
      ],
    ],
    'amp_analytics' => [
      'variables' => [
        'account' => NULL,
        'attributes' => [],
      ],
    ],
    'block__amp_system_branding_block' => [
      'render element' => 'elements',
      'base hook' => 'block',
    ],
    'amp_custom_style' => [
      'render element' => 'element',
    ],
    'amp_video' => [
      'variables' => [
        'attributes' => [],
      ],
    ],
    'amp_image_carousel' => [
      'variables' => [
        'items' => [],
        'attributes' => [],
      ],
    ],
    'amp_views_carousel' => [
      'variables' => [
        'view' => NULL,
        'options' => NULL,
        'rows' => NULL,
        'title' => NULL,
        'attributes' => [],
      ],
      'file' => 'amp.theme.inc',
    ],
    'amp_sidebar' => [
      'render element' => 'element',
      'id' => NULL,
      'tabindex' => NULL,
      'attributes' => [],
      'content_attributes' => [],
      'file' => 'amp.theme.inc',
    ],
    'amp_sidebar_toggle' => [
      'variables' => [
        'sidebarid' => NULL,
        'tabindex' => NULL,
        'title' => NULL,
        'attributes' => [],
      ],
    ],
    'amp_social_share' => [
      'variables' => [
        'providers' => [],
        'app_id' => '',
      ],
    ],
    'amp_social_post_theme' => [
      'render element' => 'element',
      'variables' => [
        'url' => NULL,
        'provider' => NULL,
        'placeholder' => NULL,
        'attributes' => [],
      ],
    ],
    'amp_pixel' => [
      'variables' => [
        'domain' => NULL,
        'query_string' => NULL,
        'subs' => [
          'AMPDOC_HOST' => ['active' => FALSE],
          'AMPDOC_URL' => ['active' => FALSE],
          'CANONICAL_HOST' => ['active' => FALSE],
          'CANONICAL_PATH' => ['active' => FALSE],
          'CANONICAL_URL' => ['active' => FALSE],
          'SOURCE_URL' => ['active' => FALSE],
          'SOURCE_HOST' => ['active' => FALSE],
          'DOCUMENT_CHARSET' => ['active' => FALSE],
          'DOCUMENT_REFERRER' => ['active' => FALSE],
          'TITLE' => ['active' => FALSE],
          'VIEWER' => ['active' => FALSE],
          'CONTENT_LOAD_TIME' => ['active' => FALSE],
          'DOMAIN_LOOKUP_TIME' => ['active' => FALSE],
          'DOM_INTERACTIVE_TIME' => ['active' => FALSE],
          'PAGE_DOWNLOAD_TIME' => ['active' => FALSE],
          'PAGE_LOAD_TIME' => ['active' => FALSE],
          'REDIRECT_TIME' => ['active' => FALSE],
          'SERVER_RESPONSE_TIME' => ['active' => FALSE],
          'TCP_CONNECT_TIME' => ['active' => FALSE],
          'AVAILABLE_SCREEN_HEIGHT' => ['active' => FALSE],
          'AVAILABLE_SCREEN_WIDTH' => ['active' => FALSE],
          'BROWSER_LANGUAGE' => ['active' => FALSE],
          'SCREEN_COLOR_DEPTH' => ['active' => FALSE],
          'VIEWPORT_HEIGHT' => ['active' => FALSE],
          'VIEWPORT_WIDTH' => ['active' => FALSE],
          'PAGE_VIEW_ID' => ['active' => FALSE],
          'RANDOM' => ['active' => FALSE],
          'TIMESTAMP' => ['active' => FALSE],
          'TOTAL_ENGAGED_TIME' => ['active' => FALSE],
        ],
      ],
    ],
  ];
  return $theme;
}

/**
 * Implements hook_theme_suggestions_HOOK_alter().
 *
 * Add amp-image template suggestion, but only for images that have the AMP
 * layout attribute. This will output these images as <amp-image></amp-image>.
 * We want to control this from the module so the components will work on
 * non-AMP pages, not just AMP pages using AMP theme. The logical name would
 * be amp_image but that name has been used by the image formatter and is in
 * production, it's too hard to replace it with a different implementation.
 */
function amp_theme_suggestions_image_alter(array &$suggestions, array $variables) {
  if (!empty($variables['attributes']['layout'])) {
    $suggestions[] = 'amp_image_wrapper';
  }
}

/**
 * Implements hook_theme_registry_alter().
 *
 * We still want the image_theme to process the image, just output it
 * in a different template, and only when it used in an AMP component.
 * A theme could do this with just theme_suggestions_alter(), but if a module
 * provides an alternate template it won't be discovered automatically by the
 * theme system. Using theme_register_alter() we can force the theme system to
 * discover the alternate template by providing it in a theme we will never
 * actually use directly, then it will be available for the suggestion.
 */
function amp_theme_registry_alter(&$theme_registry) {
  $theme_registry['amp_image_wrapper'] = $theme_registry['image'];
  $theme_registry['amp_image_wrapper']['template'] = 'amp-image-wrapper';
  $theme_registry['amp_image_wrapper']['path'] = \Drupal::service('extension.list.module')->getPath('amp') . '/templates';
}

/**
 * Implements hook_page_bottom() for page bottom.
 */
function amp_page_bottom(array &$page_bottom) {

  $amp_context = \Drupal::service('router.amp_context');
  if ($amp_context->isAmpRoute()) {

    $config = \Drupal::config('amp.analytics.settings');
    $google_analytics_id = $config->get('google_analytics_id');
    if (!empty($google_analytics_id)) {
      $amp_analytics = [
        '#type' => 'amp_analytics',
        '#attributes' => [
          'type' => 'googleanalytics',
        ],
        '#account' => $google_analytics_id,
      ];
      $page_bottom['amp_analytics'] = $amp_analytics;
    }

    $amp_gtm_id = $config->get('amp_gtm_id');
    if (!empty($amp_gtm_id)) {

      $amp_gtm = [
        '#type' => 'amp_analytics',
        '#attributes' => [
          'config' => 'https://www.googletagmanager.com/amp.json?id=' . $amp_gtm_id . '&gtm.url=SOURCE_URL',
          'data-credentials' => 'include',
        ],
      ];
      $page_bottom['amp_gtm'] = $amp_gtm;
    }

    if ($config->get('amp_pixel')) {
      $domain = $config->get('amp_pixel_domain_name');
      $query_string = $config->get('amp_pixel_query_string');
      if (!empty($domain) && !empty($query_string)) {
        $subs_random = $config->get('amp_pixel_random_number');

        $subs = [
          'RANDOM' => [
            'active' => $subs_random ? TRUE : FALSE,
          ],
        ];

        $amp_pixel = [
          '#theme' => 'amp_pixel',
          '#domain' => $domain,
          '#query_string' => $query_string,
          '#subs' => $subs,
        ];

        $page_bottom['amp_pixel'] = $amp_pixel;
      }
    }

  }

}

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function amp_form_node_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  // Check if the content is AMP enabled.
  $amp_entity_type_service = \Drupal::service('amp.entity_type');
  $type = $form_state->getFormObject()->getEntity()->bundle();
  if (!$amp_entity_type_service->isAmpEnabledType($type)) {
    return;
  }

  // Exit if the AMP submit button has been disabled.
  if (!\Drupal::config('amp.settings')->get('show_extra_save_buttons')) {
    return;
  }

  // Add another option to go to the AMP page after saving.
  $form['actions']['save_view_amp'] = [
    '#type' => 'submit',
    '#value' => t('Save and view AMP page'),
    '#submit' => ['::submitForm', '::save'],
    '#access' => TRUE,
    '#weight' => 10,
  ];

  // Add a submit handler to redirect to the AMP page.
  $form['actions']['save_view_amp']['#submit'][] = 'amp_node_form_submit';
  $form['actions']['save_view_amp_with_warn']['#submit'][] = 'amp_node_form_submit_with_warn';
}

/**
 * Submit handler for viewing the AMP page.
 */
function amp_node_form_submit(&$form, FormStateInterface $form_state) {
  $path = $form_state->getValue('path');
  // Redirect to the alias if it exists, otherwise use the node URL.
  $url = !empty($path[0]['alias']) ? $path[0]['alias'] : $path[0]['source'];
  if (isset($url)) {
    $amp_url = \Drupal::service('amp.query_parameters')->add($url);
    $response = new RedirectResponse($amp_url);
    $response->send();
  }
}

/**
 * Implements hook_form_alter().
 */
function amp_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  if ($form_id == 'entity_view_display_edit_form') {
    $form['actions']['submit']['#submit'][] = 'amp_view_modes_submit';
  }
}

/**
 * Submit handler for enabling or disabling AMP view modes.
 */
function amp_view_modes_submit(&$form, FormStateInterface $form_state) {
  $new_values = [];
  $old_values = [];
  if (isset($form_state->getValues()['display_modes_custom'])) {
    $new_values = array_filter($form_state->getValues()['display_modes_custom']);
  }
  if (isset($form_state->getCompleteForm()['modes']['display_modes_custom']['#default_value'])) {
    $old_values = $form_state->getCompleteForm()['modes']['display_modes_custom']['#default_value'];
  }
  $removed = array_diff($old_values, $new_values);
  $added = array_diff($new_values, $old_values);
  if (is_array($removed) && in_array('amp', $removed) && $type = $form['#bundle']) {
    // If the AMP view was removed, clear cache of AMP-enabled content.
    \Drupal::cache()->delete('amp_enabled_types');
    \Drupal::service('cache_tags.invalidator')->invalidateTags(['amp_types']);
  }
  if (is_array($added) && in_array('amp', $added)) {
    // If the AMP view was added, clear cache of AMP-enabled content.
    \Drupal::cache()->delete('amp_enabled_types');
    \Drupal::service('cache_tags.invalidator')->invalidateTags(['amp_types']);
  }
}

/**
 * Implements hook_preprocess_HOOK() for block templates.
 */
function amp_preprocess_block(&$variables) {
  switch ($variables['base_plugin_id']) {
    case 'amp_system_branding_block':
      $variables['site_logo'] = '';
      if ($variables['content']['site_logo']['#access'] && $variables['content']['site_logo']['#uri']) {
        $variables['site_logo'] = $variables['content']['site_logo']['#uri'];
        $variables['logo_width'] = $variables['content']['logo_width'];
        $variables['logo_height'] = $variables['content']['logo_height'];
      }
      $variables['site_name'] = '';
      if ($variables['content']['site_name']['#access'] && $variables['content']['site_name']['#markup']) {
        $variables['site_name'] = $variables['content']['site_name']['#markup'];
      }
      $variables['site_slogan'] = '';
      if ($variables['content']['site_slogan']['#access'] && $variables['content']['site_slogan']['#markup']) {
        $variables['site_slogan'] = [
          '#markup' => $variables['content']['site_slogan']['#markup'],
        ];
      }
      break;

  }

}