import { LocalEvent } from "../../commons/types/local-event";
import { EventEmitter } from "../../commons/utils/event-emitter";
import { Http } from "../../commons/utils/http";
import { Event } from "../../event/core/event";
import { PageCartEvent } from "../../event/types/page/cart";
import { OrderProduct, PageConfirmationEvent } from "../../event/types/page/confirmation";
import { PageHomeEvent } from "../../event/types/page/home";
import { SessionUserEvent } from "../../event/types/session/user";
import { CartProduct } from "../types/base/cart-event";

/**
 * Error thrown whenever the user tries to send a
 * closed batch request.
 *
 * @class BatchAlreadyClosedError
 * @extends {Error}
 */
export class BatchAlreadyClosedError extends Error {
    /**
     * Creates an instance of BatchAlreadyClosedError.
     *
     * @memberof BatchAlreadyClosedError
     */
    constructor() {
        super("Batch request already closed.");
    }
}

/**
 * A Batch event builder.
 *
 * Use this class to send multiple events at once,
 * without opening unnecessary requests. The batch
 * can only be sent once.
 *
 * @export
 * @class BatchEventBuilder
 */
export class BatchEventBuilder {
    /**
     * Start a new batch.
     *
     * @static
     * @return {BatchEventBuilder}
     * @memberof BatchEventBuilder
     */
    public static start(): BatchEventBuilder {
        return new BatchEventBuilder();
    }

    public events: Event[] = [];
    private closed = false;

    /**
     * Push all events to the server. This method can
     * only be called once pper batch, otherwise a
     * `BatchAlreadyClosedError` will be thrown.
     *
     * @return {Promise<boolean>}
     * @memberof BatchEventBuilder
     */
    public async push(): Promise<Response> {
        if (this.closed) {
            throw new BatchAlreadyClosedError();
        }

        this.closed = true;

        EventEmitter.trigger(LocalEvent.EventBatch, this);

        return Http.post(
            `${window._RecSys.Bundle.Properties.event.url}/${window._RecSys.Bundle.Configuration.store.slug}/${window._RecSys.Bundle.Properties.event.endpoint.event}`,
            this,
        );
    }

    /**
     * Append a generic Event to the batch request.
     *
     * @param {Event} event Event to be appended.
     * @return {BatchEventBuilder}
     * @memberof BatchEventBuilder
     */
    public withEvent(event: Event): BatchEventBuilder {
        this.events.push(event);
        return this;
    }

    /**
     * Append an Order Confirmation Event.
     *
     * @param {string} orderId Order's ID.
     * @param {OrderProduct[]} [products=[]] Products bought.
     * @return {BatchEventBuilder}
     * @memberof BatchEventBuilder
     */
    public withPageConfirmationEvent(orderId: string, products: OrderProduct[] = []): BatchEventBuilder {
        this.events.push(new PageConfirmationEvent(orderId).withProducts(products));
        return this;
    }

    /**
     * Append a Cart Pageview Event.
     *
     * @param {CartProduct[]} [products=[]] Product's inside the cart.
     * @return {BatchEventBuilder}
     * @memberof BatchEventBuilder
     */
    public withCartPageviewEvent(products: CartProduct[] = []): BatchEventBuilder {
        this.events.push(new PageCartEvent().withProducts(products));
        return this;
    }

    /**
     * Append a Home Pageview Event.
     *
     * @return {BatchEventBuilder}
     * @memberof BatchEventBuilder
     */
    public withHomePageViewEvent(): BatchEventBuilder {
        this.events.push(new PageHomeEvent());
        return this;
    }

    /**
     * Append a User Login Event.
     *
     * @param {string} email User's email.
     * @param {boolean} [allowMailMarketing=true] Wheter mail sould be sent to this user.
     * @return {BatchEventBuilder}
     * @memberof BatchEventBuilder
     */
    public withUserLoginEvent(email: string, allowMailMarketing = true): BatchEventBuilder {
        this.events.push(new SessionUserEvent(email, allowMailMarketing));
        return this;
    }
}