<?php
/**
 * @package Polylang
 */

namespace WP_Syntex\Polylang\Capabilities;

use WP_User;
use WP_Syntex\Polylang\Capabilities\User\Creator;
use WP_Syntex\Polylang\Capabilities\User\User_Interface;
use WP_Syntex\Polylang\Capabilities\User\Creator_Interface;

/**
 * A class allowing to map Polylang's custom user capabilities to WP's native ones.
 *
 * @since 3.8
 */
class Capabilities {
	public const LANGUAGES    = 'manage_languages';
	public const TRANSLATIONS = 'manage_translations';

	/**
	 * The user creator to be used for capability checks.
	 *
	 * @var Creator_Interface|null
	 */
	private static ?Creator_Interface $creator = null;

	/**
	 * Constructor.
	 *
	 * @since 3.8
	 */
	public function __construct() {
		add_filter( 'map_meta_cap', array( $this, 'map_custom_caps' ), 1, 2 );
	}

	/**
	 * Filters user capabilities to handle PLL's custom capabilities.
	 *
	 * @since 3.8
	 *
	 * @param string[] $caps Primitive capabilities required by the user.
	 * @param string   $cap  Capability being checked.
	 * @return string[]
	 */
	public function map_custom_caps( $caps, $cap ) {
		if ( in_array( $cap, array( self::TRANSLATIONS, self::LANGUAGES ), true ) ) {
			$caps   = array_diff( $caps, array( $cap ) );
			$caps[] = 'manage_options';
		}

		return $caps;
	}

	/**
	 * Returns the user instance to be used for capability checks.
	 *
	 * @since 3.8
	 *
	 * @param WP_User|null $user The user to decorate. If null, the current user is used.
	 * @return User_Interface The user instance.
	 */
	public static function get_user( ?WP_User $user = null ): User_Interface {
		if ( ! self::$creator ) {
			self::$creator = new Creator();
		}

		return self::$creator->get( $user ?? wp_get_current_user() );
	}

	/**
	 * Sets the user creator to be used for capability checks.
	 *
	 * Having a separate class to create the decorated user allows for better decoupling.
	 * This allows to set a creator object without dependence to a `WP_User`.
	 *
	 * @since 3.8
	 *
	 * @param Creator_Interface $creator The user creator to be used for capability checks.
	 * @return void
	 */
	public static function set_user_creator( Creator_Interface $creator ): void {
		self::$creator = $creator;
	}
}