Snippet controllers

<?php

use Kirby\Cms\App;
use Kirby\Template\Snippet;
use Kirby\Toolkit\Str;

class SnippetWithController extends Snippet
{
  // cache for controllers
  protected static $controllers = [];

  /**
   * Loads a controller for the snippet, if available,
   * and merges $data with the returned data from
   * the controller
   */
  public static function controller(
    string|null $file,
    array $data = []
  ): array {
    if (
      $file === null ||
      str_starts_with($file, static::root()) === false
    ) {
      return $data;
    }

    // use cached controller
    if (isset(static::$controllers[$file]) === true) {
      return array_replace_recursive(
        $data,
        static::$controllers[$file]
      );
    }

    // get controller name/path within root directory
    $name = ltrim(Str::before(Str::after($file, static::root()), '.php'), '/');

    // if the snippet has a name, we can load the controller
    // and merge the data with the controller's data
    if ($name !== null) {
      $data = array_replace_recursive(
        $data,
        static::$controllers[$file] = App::instance()->controller('snippets/' . $name, $data)
      );
    }

    return $data;
  }

  public static function factory(
    string|array|null $name,
    array $data = [],
    bool $slots = false
  ): static|string {
    $file = $name !== null ? static::file($name) : null;
    $data = static::controller($file, $data);
    return parent::factory($name, $data, $slots);
  }

  public function render(array $data = [], array $slots = []): string
  {
    $data = array_replace_recursive(
      static::controller($this->file, $data),
      $data
    );

    return parent::render($data, $slots);
  }
}

App::plugin('getkirby/snippet-controllers', [
  'components' => [
    'snippet' => function (
      App $kirby,
      string|array|null $name,
      array $data = [],
      bool $slots = false
    ): Snippet|string {
      return SnippetWithController::factory($name, $data, $slots);
    },
  ]
]);