<?php

namespace TwoFAS\TwoFAS\Authentication;

use TwoFAS\TwoFAS\Http\JSON_Response;
use TwoFAS\TwoFAS\Http\Redirection_Response;
use TwoFAS\TwoFAS\Http\View_Response;
use WP_Error;
use WP_User;

class Login_Process {

	/**
	 * @var array
	 */
	private $handlers = array();

	/**
	 * @param Login_Handler $handler
	 *
	 * @return Login_Process
	 */
	public function add_handler( Login_Handler $handler ) {
		$this->handlers[] = $handler;

		return $this;
	}

	/**
	 * @param null|WP_Error|WP_User $user
	 *
	 * @return bool|JSON_Response|Redirection_Response|View_Response
	 */
	public function authenticate( $user ) {
		if ( empty( $this->handlers ) ) {
			return false;
		}

		$handler = $this->create_handler();

		return $handler->authenticate( $user );
	}

	/**
	 * @return Login_Handler
	 */
	private function create_handler() {
		$first = array_shift( $this->handlers );

		array_reduce( $this->handlers, function ( Login_Handler $current, Login_Handler $next ) {
			$current->then( $next );

			return $next;
		}, $first );

		return $first;
	}
}