import { Http } from "./http";
import { Event } from "../../event/core/event";
import { CookieUtils } from "./cookie-utils";

/**
 * Queue of pending events.
 *
 * @export
 * @abstract
 * @class EventQueue
 */
export abstract class EventQueue {
    /**
     * Enqueue a pending event.
     *
     * @static
     * @template T Event type.
     * @param {T} event Event to enqueue.
     * @memberof EventQueue
     */
    public static enqueue<T extends Event>(event: T): void {
        const domain = CookieUtils.getDomain();
        CookieUtils.set(
            window._RecSys.Bundle.Properties.event.queue.key,
            btoa(unescape(encodeURIComponent(JSON.stringify(event)))),
            {
                domain,
            },
        );
    }

    /**
     * Remove the pending event from queue.
     *
     * @static
     * @memberof EventQueue
     */
    public static dequeue(): void {
        const domain = CookieUtils.getDomain();
        CookieUtils.set(window._RecSys.Bundle.Properties.event.queue.key, "", {
            domain,
        });
    }

    /**
     * Resend pending event.
     *
     * @static
     * @return {Promise<Response>} The return of the request.
     * @memberof EventQueue
     */
    public static resend(): Promise<Response> {
        const pending = CookieUtils.get(window._RecSys.Bundle.Properties.event.queue.key);
        if (!pending) {
            return null;
        }

        EventQueue.dequeue();
        return Http.post(
            `${window._RecSys.Bundle.Properties.event.url}/${window._RecSys.Bundle.Configuration.store.slug}/${window._RecSys.Bundle.Properties.event.endpoint.event}`,
            JSON.parse(decodeURIComponent(escape(atob(pending)))),
        );
    }
}