import { loadStripe } from "@stripe/stripe-js";
import {
  CreateFormOptions,
  GatewayType,
  PaymentForm,
  PaymentHubParams,
  PaymentIntent,
  StripeFormCreateOptions,
} from "./types";

export class PaymentHub {
  private publishableKey: string;
  private host: string;

  constructor(params: PaymentHubParams) {
    this.publishableKey = params.publishableKey;
    this.host = params.apiHost;
  }

  async getPaymentIntent(paymentIntentId: string): Promise<PaymentIntent> {
    const url = new URL(
      `${this.host}/client/payment-intents/${paymentIntentId}`
    );
    url.searchParams.append("publishableKey", this.publishableKey);

    const response = await fetch(url.toString());

    if (!response.ok) {
      throw new Error(
        `[PAYMENT-HUB] Error getting Payment Intent. Status - ${response.status}. ${response.statusText}`
      );
    }

    return response.json();
  }

  async createForm(paymentIntentId: string, options: CreateFormOptions) {
    const paymentIntent = await this.getPaymentIntent(paymentIntentId);

    switch (paymentIntent.gatewayType) {
      case GatewayType.STRIPE:
        return this.createStripeForm(
          paymentIntent.gatewayPaymentIntent,
          options
        );
      default:
        throw new Error(`Not supported gateway ${paymentIntent.gatewayType}`);
    }
  }

  private async createStripeForm(
    stripeOptions: StripeFormCreateOptions,
    options: CreateFormOptions
  ): Promise<PaymentForm> {
    const stripe = await loadStripe(stripeOptions.stripePublishableKey);

    if (!stripe) {
      throw new Error(
        `Invalid publishable key ${stripeOptions.stripePublishableKey}`
      );
    }

    const elements = stripe.elements({
      clientSecret: stripeOptions.stripePaymentIntentSecret,
    });
    const paymentElement = elements.create("payment");
    paymentElement.mount(this.getContainerById(options.containerElementId));

    paymentElement.on("change", function (event) {
      options.onChange({
        isValid: event.complete,
        paymentMethodType: event.value.type,
      });
    });

    return {
      confirmPayment: async () => {
        await stripe.confirmPayment({
          elements,
          redirect: 'if_required'
        });
      },
    };
  }

  private getContainerById(elementId: string) {
    const element = document.getElementById(elementId);

    if (!element) {
      throw new Error(`Element by id ${elementId} not found`);
    }

    return element;
  }
}