<?php

namespace phpnotify;

use \TypeError as TypeError;

/**
 * This represents notification server, in library named notifier.
 * 
 * This class represents notification server in the system. It is required
 * to subscribe new subject. It also store auth service like login and 
 * password, or auth token. That class would be used to generate new subjects
 * with same server url, and potentially same authorization methods. It makes 
 * generating that subjects much easier, without passing same authentication 
 * and server URL to all new subjects. Change authentication method in new 
 * subject generated by notifier would not change notifier authentication
 * method.
 */
class notifier extends authorization_store {
    /**
     * This store URL of the notifications server.
     * @var string
     */
    private string $url;

    /** 
     * This function initialize new notifier by the server URL.
     *
     * This create new notifications server wrapper, from that URL. It 
     * use empty authorization as default authorization method. URL is 
     * validating, and when incorrect URL format had been incorrect throws
     * TypeError.
     * 
     * @throws TypeError When URL is bad formated.
     *
     * @param string URL of the server.
     */
    public function __construct(string $url) {
        parent::__construct();
        
        if (!filter_var($url, FILTER_VALIDATE_URL)) {
            throw new TypeError('"'.$url.'" is not property URL.');
        }
        
        $this->url = $url;
    }

    /**
     * This function create new notifier from URL.
     * 
     * That function create new notifier from URL, but it not use 'new' 
     * keyword, which results in the better look code with chainloading.
     * It use same constructor as {@see notifier::__construct}.
     *
     * @throws TypeError Whem URL is bad formated.
     *
     * @param string $url URL for the notifications server.
     * @return notifier New notification server.
     */
    public static function create(string $url): object {
        return new self($url);
    }

    /** 
     * This function would be use to select a subject.
     * 
     * This function select a subject to notify in. It return new subject 
     * which is initialized from notifier URL and authorization method.
     * When authorization method of the subject had been changed, notifier 
     * still use own authorization method for new subjects.
     *
     * @param string $subject Name of the subject to use.
     *
     * @return subject New subject to send notifications in.
     */
    public function topic(string $subject): subject {
        return new subject(
            $this->url, 
            $subject, 
            $this->get_access_method()
        );
    }
}