import { useState, useCallback } from 'react';
import { Alert } from 'react-native';
// @ts-ignore
import RazorpayCheckout from 'react-native-razorpay';
import { PlaceOrderResponse } from '@interfaces';
import { verifyPaymentApi } from '@api';
import { useAppSelector } from '@store';
import { ENV } from '../../../../config';

/**
 * Custom hook that encapsulates the entire Razorpay UPI payment flow:
 *  1. Extract session details (gatewayOrderId, amount) from the place-order response
 *  2. Configure Razorpay checkout options with prefilled customer profile details
 *  3. Present the Razorpay Checkout overlay to the user
 *  4. Verify the payment signature on the backend via /payments/process
 *
 * Returns:
 *  - processRazorpayPayment: async function to execute the Razorpay flow
 *  - isPaymentProcessing: loading flag for UPI payment step
 */
export const useRazorPayment = () => {
  const [isPaymentProcessing, setIsPaymentProcessing] = useState(false);
  const user = useAppSelector(
    state => state.customerProfile.customerDetails?.user,
  );

  /**
   * Runs the complete Razorpay payment flow.
   * @param response – the PlaceOrderResponse from the backend
   * @returns `true` if payment was completed and verified successfully, `false` otherwise
   */
  const processRazorpayPayment = useCallback(
    async (
      response: PlaceOrderResponse,
      paymentMethod: 'upi' | 'card' | undefined = undefined,
    ): Promise<boolean> => {
      try {
        setIsPaymentProcessing(true);

        // ── 1. Extract session details ─────────────────────────────────────
        const session = response.checkoutSessions?.[0];
        if (!session) {
          Alert.alert('Error', 'Payment session not found.');
          return false;
        }

        const { gatewayOrderId, amount } = session;
        if (!gatewayOrderId) {
          Alert.alert('Error', 'Razorpay Order ID not found.');
          return false;
        }

        // Amount in checkoutSessions represents standard rupees.
        // Fallback to first order's total amount if needed.
        const amountVal =
          amount ?? parseFloat(response.orders?.[0]?.totalAmount || '0');
        // Razorpay SDK requires the amount in the smallest currency sub-units (paise for INR)
        const amountInPaise = Math.round(amountVal * 100);

        // ── 2. Configure Checkout Options ──────────────────────────────────
        const options = {
          key: ENV.RAZORPAY_KEY_ID,
          amount: amountInPaise,
          currency: 'INR',
          name: 'SG Delivery',
          description: `Payment for Order #${
            session.orderNumber || response.orders?.[0]?.orderNumber || ''
          }`,
          order_id: gatewayOrderId,
          method: 'upi',
          prefill: {
            name: user?.name || '',
            email: user?.email || '',
            contact: user?.phone || '',
          },
          theme: { color: '#05824C' }, // Matching brand green primary color
        };

        // ── 3. Present Razorpay Checkout SDK ───────────────────────────────
        const rzpData = await RazorpayCheckout.open(options);

        // ── 4. Verify payment cryptographically on backend ────────────────
        const verifyRes = await verifyPaymentApi({
          gatewayOrderId: rzpData.razorpay_order_id || gatewayOrderId,
          gatewayPaymentId: rzpData.razorpay_payment_id,
          gatewaySignature: rzpData.razorpay_signature,
        });

        if (verifyRes.success) {
          return true;
        } else {
          Alert.alert(
            'Verification Failed',
            verifyRes.message || 'Unable to confirm payment.',
          );
          return false;
        }
      } catch (error: any) {
        // Razorpay Checkout library throws an error if user cancels or transaction fails
        if (error && error.code) {
          Alert.alert(
            'Payment Cancelled',
            error.description || 'You cancelled the payment process.',
          );
        } else {
          Alert.alert(
            'Payment Error',
            error?.message || 'Something went wrong during payment.',
          );
        }
        return false;
      } finally {
        setIsPaymentProcessing(false);
      }
    },
    [user],
  );

  return { processRazorpayPayment, isPaymentProcessing };
};