<?php

/**
 * @file
 * Provides basic Blazy integration for lazy loading and multi-serving images.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Component\Serialization\Json;
use Drupal\blazy\Blazy;

/**
 * Implements hook_theme().
 */
function blazy_theme() {
  return ['blazy' => ['render element' => 'element']];
}

/**
 * Prepares variables for blazy.html.twig templates.
 */
function template_preprocess_blazy(&$variables) {
  Blazy::buildAttributes($variables);
}

/**
 * Overrides variables for responsive-image.html.twig templates.
 */
function blazy_preprocess_responsive_image(&$variables) {
  $config = Blazy::getConfig();

  // Do not proceed if disabled globally, or not a Blazy formatter.
  if (!$config['responsive_image'] || !isset($variables['attributes']['data-srcset'])) {
    return;
  }

  // We are here either using Blazy, or core Responsive image formatters.
  // Is picture element.
  if (!$variables['output_image_tag']) {
    // Prepare all <picture> [data-srcset] attributes on <source> elements.
    _blazy_preprocess_responsive_image_picture_sources($variables);

    // Fetches the picture element fallback URI, and empty it later.
    $fallback_uri = $variables['img_element']['#srcset'][0]['uri'];

    // Cleans up the no-longer relevant attributes for controlling element.
    unset($variables['attributes']['data-srcset'], $variables['img_element']['#attributes']['data-srcset']);
    $variables['img_element']['#srcset'] = '';
    // Prevents invalid IMG tag when one pixel placeholder is disabled.
    $variables['img_element']['#uri'] = Blazy::PLACEHOLDER;
  }
  else {
    $srcset = $variables['attributes']['srcset'];
    $srcset_values = $srcset->value();
    $fallback_uri = $variables['img_element']['#uri'];

    $variables['attributes']['data-srcset'] = $srcset_values;
    $variables['img_element']['#attributes']['data-srcset'] = $srcset_values;
    $variables['img_element']['#attributes']['srcset'] = '';
  }

  // Blazy needs controlling element to have a fallback [data-src], else error.
  $variables['img_element']['#attributes']['data-src'] = $fallback_uri;
  $variables['img_element']['#attributes']['class'][] = 'b-lazy b-responsive';

  // Only replace fallback image URI with 1px placeholder, if so configured.
  // This will prevent downloading the fallback image.
  if ($config['one_pixel']) {
    $variables['img_element']['#uri'] = Blazy::PLACEHOLDER;
  }

  $variables['img_element']['#attached']['drupalSettings']['blazy'] = $config['blazy'];
}

/**
 * Adds [data-srcset] attribute to picture source element to support lazyload.
 */
function _blazy_preprocess_responsive_image_picture_sources(&$variables) {
  /** @var \Drupal\Core\Template\Attribute $source */
  foreach ($variables['sources'] as &$source) {
    $srcset = $source['srcset'];
    $srcset_values = $srcset->value();

    $source->setAttribute('data-srcset', $srcset_values);
    $source->removeAttribute('srcset');
  }
}

/**
 * Implements hook_preprocess_field().
 */
function blazy_preprocess_field(array &$variables) {
  $element = $variables['element'];

  // Only proceed if an image field and using Blazy formatter.
  if (!isset($element['#blazy'])) {
    return;
  }

  // Defines [data-blazy] attribute as required by the Blazy loader.
  $settings = $element['#blazy'];
  $variables['attributes']['class'][] = 'blazy';
  $variables['attributes']['data-blazy'] = empty($settings['blazy_data']) ? '' : Json::encode($settings['blazy_data']);
  if (!empty($settings['media_switch'])) {
    $switch = str_replace('_', '-', $settings['media_switch']);
    $variables['attributes']['data-' . $switch . '-gallery'] = TRUE;
  }
}

/**
 * Implements hook_views_pre_render().
 */
function blazy_views_pre_render($view) {
  if (!isset($view)) {
    return;
  }
  \Drupal\blazy\BlazyViews::viewsPreRender($view);
}

/**
 * Implements hook_field_formatter_info_alter().
 */
function blazy_field_formatter_info_alter(array &$info) {
  // Supports optional Media Entity via VEM within VEF if available.
  if (function_exists('video_embed_media_media_bundle_insert')) {
    $info['blazy_file'] = [
      'id'          => 'blazy_file',
      'label'       => t('Blazy Image with Media'),
      'description' => t('Display the images associated to VEM/ME as videos.'),
      'class'       => 'Drupal\blazy\Plugin\Field\FieldFormatter\BlazyFileFormatter',
      'field_types' => ['entity_reference', 'image'],
      'quickedit'   => ['editor' => 'disabled'],
      'provider'    => 'blazy',
    ];
  }
}

/**
 * Implements hook_config_schema_info_alter().
 */
function blazy_config_schema_info_alter(array &$definitions) {
  Blazy::configSchemaInfoAlter($definitions, 'blazy_base');
}

/**
 * Implements hook_library_info_alter().
 */
function blazy_library_info_alter(&$libraries, $extension) {
  if ($extension === 'blazy' && function_exists('libraries_get_path')) {
    $libraries['blazy']['js'] = ['/' . libraries_get_path('blazy') . '/blazy.min.js' => []];
  }
}

/**
 * Implements hook_help().
 */
function blazy_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.blazy':
      return check_markup(file_get_contents(dirname(__FILE__) . '/README.txt'));
  }
}