core/app/Providers/AppServiceProvider.php

<?php

namespace App\Providers;

use App\Handlers\Registrators\MenuExtensionRegistrator;
use App\Handlers\Registrators\SearchEngineRegistrator;
use App\Handlers\Registrators\SettingsExtensionRegistrator;
use App\Handlers\Registrators\TemplateRegistrator;
use App\Handlers\Registrators\WidgetRegistrator;
use App\Handlers\Search\Content;
use App\Handlers\Search\Files;
use App\Handlers\Search\Presenters\AdminContent as AdminContentPresenter;
use App\Handlers\Search\Presenters\AdminFiles;
use App\Models\Template;
use App\Widgets\HtmlCode\HtmlCode;
use App\Widgets\Menu\Menu;
use App\Widgets\OrbitSlider\OrbitSlider;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Facades\File;
use Illuminate\Support\ServiceProvider;
use Symfony\Component\Process\Exception\InvalidArgumentException;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     * @return void
     */
    public function boot()
    {
        // ignore running from artisan
        if (App::runningInConsole()) {
            $this->publishViewResources();

            return;
        }

        $this->registerWidgets();
        $this->registerTemplates();
        $this->registerSettings();
        $this->registerSearch();

        // check if given template is valid
        $theme = config('app.theme');
        $themeDir = resource_path('views/visitor/' . $theme);
        if (!$theme || empty($theme) || !is_dir($themeDir)) {
            throw new InvalidArgumentException('No or invalid theme set! Use artisan theme:set or edit .env file manually and include THEME option, please');
        }
    }

    /**
     * Register any application services.
     * @return void
     */
    public function register()
    {
        if ($this->app->environment() == 'local') {
            try {
                $this->app->register('Barryvdh\Debugbar\ServiceProvider');
            } catch (\Exception $e) {
                // this service provider may not exist when switching from other environment than local
                // until composer install is run
                // just ignore this exception and when no service provider is available, do not use debugbar
            }
        }

        // register PingPong module extension
        $this->app->register('Pingpong\Modules\ModulesServiceProvider');
        $this->app->register('Pingpong\Menus\MenusServiceProvider');

        // create singletons for registering widgets
        $this->app->singleton('registerWidget', function ($app) {
            return new WidgetRegistrator($app);
        });

        $this->app->singleton('registerMenuExtension', function ($app) {
            return new MenuExtensionRegistrator($app);
        });

        // create registrator for template directories
        $this->app->singleton('registerTemplateDir', function ($app) {
            return new TemplateRegistrator($app);
        });

        $this->app->singleton('registerSettingsExtension', function ($app) {
            return new SettingsExtensionRegistrator($app);
        });

        $this->app->singleton('registerSearchEngine', function ($app) {
            return new SearchEngineRegistrator($app);
        });
    }

    /**
     * Method for registering widgets.
     */
    private function registerWidgets()
    {
        /**
         * @var $registrator WidgetRegistrator
         */
        $registrator = $this->app->make('registerWidget');

        // register all available widgets
        $registrator->register(HtmlCode::class);
        $registrator->register(Menu::class);
        $registrator->register(OrbitSlider::class);

        // register some menu extensions
        //        $menuExtensions = $this->app->make('registerMenuExtension');
        //        $menuExtensions->register(new URL());
    }

    /**
     * Register path with editable contents
     */
    private function registerTemplates()
    {
        /**
         * @var $registrator TemplateRegistrator
         */
        $registrator = $this->app->make('registerTemplateDir');
        $registrator->setBaseDirectory('resources/views/visitor');

        $registrator->register(config('app.theme'), 'admin/templates.core');
    }

    /**
     * Register setting sections
     */
    private function registerSettings()
    {
        $registrator = $this->app->make('registerSettingsExtension');

        $registrator->register('basic', 'admin/settings.basic', 'admin.settings.parts.basic');
        $registrator->register('meta', 'admin/settings.meta', 'admin.settings.parts.meta');
    }

    /**
     * Register callbacks used for searching
     */
    private function registerSearch()
    {
        $registrator = $this->app->make('registerSearchEngine');

        $registrator->register(new Content(), new AdminContentPresenter(), SearchEngineRegistrator::ADMIN);
        $registrator->register(new Files(), new AdminFiles(), SearchEngineRegistrator::ADMIN);
    }

    /**
     * Publish all public assets from all themes
     */
    private function publishViewResources()
    {
        $theme = config('app.theme');
        $themeDir = resource_path('views/visitor/' . $theme);

        // publish assets if exists for current theme
        if (is_dir($themeDir . '/' . Template::ASSETS_DIRECTORY)) {
            $this->publishes([$themeDir . '/' . Template::ASSETS_DIRECTORY => public_path('assets/' . $theme)], 'public-assets');
        }

        if (is_dir($themeDir . '/' . Template::MODULES_DIRECTORY)) {
            $this->publishModuleViews($themeDir . '/' . Template::MODULES_DIRECTORY);
        }
    }

    private function publishModuleViews($themeModules)
    {
        $theme = config('app.theme');
        $modules = File::directories($themeModules);

        $moduleViews = [];
        foreach ($modules as $module) {
            $moduleName = strtolower(basename($module));
            $moduleViews[$module] = resource_path('views/modules/' . $moduleName . '/visitor/' . $theme);
        }

        if (!empty($moduleViews)) {
            $this->publishes($moduleViews, 'module-views');
        }
    }
}