felixarntz/oop-admin-pages

<?php
/**
 * WordPress_Admin_Page class
 *
 * @package Leaves_And_Love\OOP_Admin_Pages\Admin_Page
 * @since 1.0.0
 */

namespace Leaves_And_Love\OOP_Admin_Pages\Admin_Page;

use Leaves_And_Love\OOP_Admin_Pages\Admin_Page\WordPress_Admin_Panels\WordPress_Admin_Panel;
use Leaves_And_Love\OOP_Admin_Pages\Admin_Page\WordPress_Admin_Panels\WordPress_Admin_Panels;

/**
 * Class representing a basic WordPress admin page.
 *
 * @since 1.0.0
 */
class WordPress_Admin_Page extends Abstract_Admin_Page {

    const CAPABILITY  = 'capability';
    const ADMIN_PANEL = 'admin_panel';

    /**
     * Gets the URL of the admin page.
     *
     * @since 1.0.0
     *
     * @return string Admin page URL.
     */
    public function get_url() : string {
        $parent_file = $this->get_parent_file();

        $url_callback = $this->get_admin_panel()->get_url_callback();
        $base_url     = call_user_func( $url_callback, $parent_file );

        return add_query_arg( 'page', $this->getConfigKey( self::SLUG ), $base_url );
    }

    /**
     * Registers the admin page within the environment.
     *
     * @since 1.0.0
     */
    public function register() {
        $callback = $this->get_register_hook_callback();

        $hook_name = $this->get_admin_panel()->get_hook_name();

        if ( doing_action( $hook_name ) ) {
            call_user_func( $callback );
        } else {
            add_action( $hook_name, $callback );
        }
    }

    /**
     * Gets the admin panel instance this admin page is part of.
     *
     * @since 1.0.0
     *
     * @return WordPress_Admin_Panel Admin panel instance.
     */
    protected function get_admin_panel() : WordPress_Admin_Panel {
        if ( $this->hasConfigKey( self::ADMIN_PANEL ) ) {
            return WordPress_Admin_Panels::get_panel( $this->getConfigKey( self::ADMIN_PANEL ) );
        }

        return WordPress_Admin_Panels::get_current_panel();
    }

    /**
     * Gets the callback to use to register the admin page within WordPress.
     *
     * @since 1.0.0
     *
     * @return callable Callback to hook into the respective menu action.
     */
    protected function get_register_hook_callback() {
        return function() {
            $slug       = $this->getConfigKey( self::SLUG );
            $title      = $this->getConfigKey( self::TITLE );
            $capability = $this->getConfigKey( self::CAPABILITY );

            $hook_suffix = add_submenu_page( null, $title, $title, $capability, $slug, array( $this, 'render' ) );

            add_action( "load-{$hook_suffix}", array( $this, 'initialize' ) );
        };
    }

    /**
     * Gets the parent file for the admin page URL in WordPress.
     *
     * May contain query parameters.
     *
     * @since 1.0.0
     *
     * @return string Parent file for the URL.
     */
    protected function get_parent_file() {
        return 'admin.php';
    }

    /**
     * Gets the configuration keys that are required for an admin page.
     *
     * @since 1.0.0
     *
     * @return array Array of configuration keys.
     */
    protected function get_required_config_keys() {
        $required_keys   = parent::get_required_config_keys();
        $required_keys[] = self::CAPABILITY;

        return $required_keys;
    }
}