import { useCallback } from 'react';
import { type Address, formatUnits } from 'viem';
import { useConfig } from 'wagmi';
import type { UseCommerceContractsParams } from '../types';
import { getCommerceContracts } from '../utils/getCommerceContracts';
import { getUSDCBalance } from '../utils/getUSDCBalance';
import { handlePayRequest } from '../utils/handlePayRequest';

export const useCommerceContracts = ({
  chargeHandler,
  productId,
}: UseCommerceContractsParams) => {
  const config = useConfig();

  return useCallback(
    async (address: Address) => {
      try {
        // Make the Pay request to the appropriate endpoint
        // `productId` to create and hydrate a charge for a product (serverless)
        // `chargeHandler` for a developer-provided callback used to return a charge ID (e.g. from the merchant backend)
        const [response, usdcBalance] = await Promise.all([
          handlePayRequest({
            address,
            chargeHandler,
            productId,
          }),
          getUSDCBalance({
            address,
            config,
          }),
        ]);

        // Set the `chargeId`
        const { id: chargeId } = response;

        // Retrieve commerce contracts from response
        const contracts = getCommerceContracts({
          transaction: response,
        });

        // Calculate user's USDC balance
        const priceInUSDC = formatUnits(
          BigInt(response.callData.feeAmount) +
            BigInt(response.callData.recipientAmount),
          6,
        );

        // Set insufficient balance flag, if applicable
        const insufficientBalance =
          Number.parseFloat(usdcBalance) < Number.parseFloat(priceInUSDC);

        return { chargeId, contracts, insufficientBalance, priceInUSDC };
      } catch (error) {
        console.error('Unexpected error fetching contracts:', error);
        return {
          chargeId: '',
          contracts: null,
          insufficientBalance: false,
          error,
        };
      }
    },
    [config, chargeHandler, productId],
  );
};