abstract wordpress AdminMenu class

AdminMenu.php

<?php # -*- coding: utf-8 -*-

namespace my_plugin\admin_menu;

use my_plugin\functions as Functions;

/**
 * Abstract AdminMenu class
 *
 * Provides methods to create admin menues
 */
abstract class AdminMenu{

	private $textdomain;

	public function register_menu( $menu ){

		$instance = $this;
		$instance->textdomain = Functions\get_textdomain();

		add_action( 'admin_menu', function() use ( $instance, $menu ){

			if( ! property_exists( $menu, 'type' ) ) {

				return new \WP_Error(
					'menu-type-missing',
					__( 'The menutype you want to register is missed', $instance->textdomain )
				);

			}

			if( $menu->type == 'main' ){

				$instance->add_menu( $menu );

			}else if( $menu->type == 'sub' ){

				$instance->add_submenu( $menu );

			}

			return true;

		} );

	}

	/**
	 * Add a main menu
	 *
	 * @see add_menu_page()
	 * @param object $args
	 */
	private function add_menu( $args = false ){

		$defaults['page_title'] = 'Mainmenu';
		$defaults['menu_title'] = 'Mainmenu';
		$defaults['capability'] = 'administrator';
		$defaults['menu_slug']  = 'mainmenu';
		$defaults['function']   = '';
		$defaults['icon_url']   = '';
		$defaults['position']   = null;

		$args = wp_parse_args( $args, $defaults );

		add_menu_page(
			esc_html__( $args['page_title'], $this->textdomain ),
			esc_html__( $args['menu_title'], $this->textdomain ),
			$args['capability'],
			$args['menu_slug'],
			$args['function'],
			$args['icon_url'],
			$args['position']
		);

	}

	/**
	 * * Add a submenu
	 *
	 * @see add_submenu_page()
	 * @param $args
	 */
	private function add_submenu( $args = false ){

		$defaults['parent_slug']    = 'submenu';
		$defaults['page_title']     = 'Submenu';
		$defaults['menu_title']     = 'submenu';
		$defaults['capability']     = 'administrator';
		$defaults['menu_slug']      = 'submenu';
		$defaults['function']       = 'submenu';

		$args = wp_parse_args( $args, $defaults );

		add_submenu_page(
			$args['parent_slug'],
			esc_html__( $args['page_title'], $this->textdomain ),
			esc_html__( $args['menu_title'], $this->textdomain ),
			$args['capability'],
			$args['menu_slug'],
			$args['function']
		);

	}

}