<?php

/**
 * @file
 */

use Drupal\block\Hook\BlockHooks;
use Drupal\Core\Installer\InstallerKernel;

/**
 * Initializes blocks for installed themes.
 *
 * @param string[] $theme_list
 *   An array of theme names.
 *
 * @see block_modules_installed()
 */
function block_themes_installed($theme_list): void {
  // Do not create blocks during config sync.
  if (\Drupal::service('config.installer')->isSyncing()) {
    return;
  }
  // Disable this functionality prior to install profile installation because
  // block configuration is often optional or provided by the install profile
  // itself. block_theme_initialize() will be called when the install profile is
  // installed.
  if (InstallerKernel::installationAttempted() && \Drupal::config('core.extension')->get('module.' . \Drupal::installProfile()) === NULL) {
    return;
  }

  foreach ($theme_list as $theme) {
    // Don't initialize themes that are not displayed in the UI.
    if (\Drupal::service('theme_handler')->hasUi($theme)) {
      block_theme_initialize($theme);
    }
  }
}

/**
 * Assigns an initial, default set of blocks for a theme.
 *
 * This function is called the first time a new theme is installed. The new
 * theme gets a copy of the default theme's blocks, with the difference that if
 * a particular region isn't available in the new theme, the block is assigned
 * to the new theme's default region.
 *
 * @param string $theme
 *   The name of a theme.
 */
function block_theme_initialize($theme): void {
  // Initialize theme's blocks if none already registered.
  $has_blocks = \Drupal::entityTypeManager()->getStorage('block')->loadByProperties(['theme' => $theme]);
  if (!$has_blocks) {
    $default_theme = \Drupal::config('system.theme')->get('default');
    // Apply only to new theme's visible regions.
    $regions = system_region_list($theme, REGIONS_VISIBLE);
    $default_theme_blocks = \Drupal::entityTypeManager()->getStorage('block')->loadByProperties(['theme' => $default_theme]);
    foreach ($default_theme_blocks as $default_theme_block_id => $default_theme_block) {
      if (str_starts_with($default_theme_block_id, $default_theme . '_')) {
        $id = str_replace($default_theme . '_', '', $default_theme_block_id);
      }
      else {
        $id = $default_theme_block_id;
      }
      $id = \Drupal::service('block.repository')->getUniqueMachineName($id, $theme);
      $block = $default_theme_block->createDuplicateBlock($id, $theme);
      // If the region isn't supported by the theme, assign the block to the
      // theme's default region.
      if (!isset($regions[$block->getRegion()])) {
        $block->setRegion(system_default_region($theme));
      }
      $block->save();
    }
  }
}

/**
 * Implements hook_theme_suggestions_HOOK().
 */
function block_theme_suggestions_block(array $variables): array {
  $suggestions = [];

  $suggestions[] = 'block__' . $variables['elements']['#configuration']['provider'];
  // Hyphens (-) and underscores (_) play a special role in theme suggestions.
  // Theme suggestions should only contain underscores, because within
  // drupal_find_theme_templates(), underscores are converted to hyphens to
  // match template file names, and then converted back to underscores to match
  // pre-processing and other function names. So if your theme suggestion
  // contains a hyphen, it will end up as an underscore after this conversion,
  // and your function names won't be recognized. So, we need to convert
  // hyphens to underscores in block deltas for the theme suggestions.

  // We can safely explode on : because we know the Block plugin type manager
  // enforces that delimiter for all derivatives.
  $parts = explode(':', $variables['elements']['#plugin_id']);
  $suggestion = 'block';
  while ($part = array_shift($parts)) {
    $suggestions[] = $suggestion .= '__' . strtr($part, '-', '_');
  }

  if (!empty($variables['elements']['#id'])) {
    $suggestions[] = 'block__' . $variables['elements']['#id'];
  }

  return $suggestions;
}

/**
 * Prepares variables for block templates.
 *
 * Default template: block.html.twig.
 *
 * Prepares the values passed to the theme_block function to be passed
 * into a pluggable template engine. Uses block properties to generate a
 * series of template file suggestions. If none are found, the default
 * block.html.twig is used.
 *
 * Most themes use their own copy of block.html.twig. The default is located
 * inside "core/modules/block/templates/block.html.twig". Look in there for the
 * full list of available variables.
 *
 * @param array $variables
 *   An associative array containing:
 *   - elements: An associative array containing the properties of the element.
 *     Properties used: #block, #configuration, #children, #plugin_id.
 *
 * @deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. Initial
 *  template_preprocess functions are registered directly in hook_theme().
 *
 * @see https://www.drupal.org/node/3504125
 */
function template_preprocess_block(&$variables): void {
  @trigger_error(__FUNCTION__ . '() is deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. Initial template_preprocess functions are registered directly in hook_theme(). See https://www.drupal.org/node/3504125', E_USER_DEPRECATED);
  \Drupal::service(BlockHooks::class)->preprocessBlock($variables);
}