look.module

<?php

/**
 * @file
 * Look module.
 */

use Drupal\Component\Utility\Html;
use Drupal\Core\Cache\Cache;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\look\LookConfig;

/**
 * Implements hook_help().
 */
function look_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'entity.look.collection':
      $output = '<p>' . t('Table contains looks grouped under parent looks. You can reorganize the looks using their drag-and-drop handles.') . '</p>';
      return $output;
  }
}

/**
 * Implements hook_preprocess_HOOK().
 */
function look_preprocess_html(&$variables) {

  // Add look config as cache context.
  $variables['#cache']['contexts'][] = 'look';

  $look = \Drupal::service('look.config')->get();

  if (empty($look)) {
    return;
  }

  $variables['#look'] = $look;

  $classes = [
    'look',
    'look--' . $look['name'],
  ];
  foreach ($classes as $class) {
    $variables['attributes']['class'][] = Html::getClass($class);
  }

  // Get mappings for specific theme.
  $look_config = \Drupal::config('look.settings');
  $theme = \Drupal::service('theme.manager')->getActiveTheme()->getName();
  $mappings = $look_config->get('mapping.' . $theme);

  if (empty($mappings)) {
    return;
  }

  // Initialize modifiers service.
  /** @var \Drupal\modifiers\Modifiers $modifiers */
  $modifiers = \Drupal::service('modifiers');

  $modifications = [];

  foreach ($mappings as $name => $mapping) {
    $namespace = $modifiers->getShortField($name);

    if (isset($look['config'][$namespace])) {
      // Fill current namespace modifications.
      $modifiers->process($modifications, $look['config'][$namespace], $mapping['selector']);
    }
  }

  if (!empty($modifications)) {
    $modifiers->apply($modifications, $variables, 'look-' . $look['id']);
  }
}

/**
 * Implements hook_entity_update().
 */
function look_entity_update(EntityInterface $entity) {

  if ($entity->getEntityTypeId() === 'look') {

    Cache::invalidateTags(['look:' . $entity->id()]);
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function look_form_look_add_form_alter(&$form, FormStateInterface $form_state, $form_id) {

  _look_form_field_look_theme_alter($form);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function look_form_look_edit_form_alter(&$form, FormStateInterface $form_state, $form_id) {

  _look_form_field_look_theme_alter($form);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function look_form_block_form_alter(&$form, FormStateInterface $form_state, $form_id) {

  if (isset($form['visibility']['look'])) {
    $form['visibility']['look']['#attached']['library'][] = 'look/block-settings';
  }
}

/**
 * Convert field_look_theme widget to select with all available themes.
 */
function _look_form_field_look_theme_alter(&$form) {

  if (!empty($form[LookConfig::THEME_FIELD])) {
    $themes = \Drupal::service('theme_handler')->listInfo();
    $options = [
      '' => t('- None -'),
    ];
    foreach ($themes as $key => $theme) {
      if (empty($theme->info['hidden'])) {
        $options[$key] = $theme->info['name'];
      }
    }
    $element = &$form[LookConfig::THEME_FIELD]['widget'][0]['value'];
    $element['#type'] = 'select';
    $element['#options'] = $options;
    $element['#default_value'] = [$element['#default_value']];
    unset($element['#size']);
  }
}