// ─── Pricing Utilities ─────────────────────────────────────────────────────────

import { PAYME_CONFIG, PRICING } from './constant';
import {
  PaymePaymentRequest,
  PaymePaymentResponse,
  ServicePricing,
} from './types';

export const getPricing = (): ServicePricing => ({
  serviceFee: PRICING.SERVICE_FEE,
  certificateFee: PRICING.CERTIFICATE_FEE,
  currency: PRICING.CURRENCY,
});

export const calculateTotal = (hasCertificate: boolean): number => {
  const base = PRICING.SERVICE_FEE;
  return hasCertificate ? base + PRICING.CERTIFICATE_FEE : base;
};

export const toTiyin = (uzs: number): number => uzs * PRICING.TIYIN_MULTIPLIER;

export const formatPrice = (amount: number, currency: string): string =>
  `${amount.toLocaleString('uz-UZ')} ${currency}`;

// ─── Order ID Generator ────────────────────────────────────────────────────────

export const generateOrderId = (): string => {
  const timestamp = Date.now();
  const random = Math.random().toString(36).slice(2, 8).toUpperCase();
  return `ORDER-${timestamp}-${random}`;
};

// ─── Payme API ─────────────────────────────────────────────────────────────────

/**
 * Sends payment details to the backend, which creates a Payme transaction
 * and returns a redirect URL to the Payme checkout page.
 */
export const createPaymePayment = async (
  request: PaymePaymentRequest,
): Promise<PaymePaymentResponse> => {
  const response = await fetch(PAYME_CONFIG.API_ENDPOINT, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      amount: request.amount, // in tiyin
      order_id: request.orderId,
      description: request.description,
      return_url: request.returnUrl,
    }),
  });

  if (!response.ok) {
    const errorBody = await response.json().catch(() => ({}));
    throw new Error(
      (errorBody as { message?: string }).message ??
        `Payment request failed with status ${response.status}`,
    );
  }

  const data = (await response.json()) as PaymePaymentResponse;
  return data;
};

/**
 * Redirects the user to the Payme checkout page.
 */
export const redirectToPayme = (redirectUrl: string): void => {
  window.location.href = redirectUrl;
};