import { atom, useRecoilState } from "recoil";
import { BigNumber } from "ethers";
import { __, add, assoc, evolve, subtract } from "ramda";
import { useWeb3Provider } from "../useWeb3Provider/useWeb3Provider";
import { weiBigNumAsFloat } from "../../utils/parse/parse";
import { formatUnits } from "ethers/lib/utils";
import { Erc20ABI__factory } from "digit-shared/src/types/generatedContractTypes";
import { config } from "../../config";

type TokenDetail = {
  address: string;
  allowance: number;
  depositHelperAllowance: number;
  decimalPlaces: number;
  userBalance: string;
};

export const tokenDetailState = atom<Record<string, TokenDetail>>({
  key: "tokenDetailState",
  default: {},
});

export const useTokenDetails = () => {
  const [tokenDetails, setTokenDetails] = useRecoilState(tokenDetailState);

  const { account, signer, provider } = useWeb3Provider();

  const approveTokenSpend = (contractAddress: string, amount: number) =>
    setTokenDetails(
      evolve({
        [contractAddress]: {
          allowance: add(amount),
        },
      })
    );
  const creditUserTokenBalance = (contractAddress: string, amount: number) =>
    setTokenDetails(
      evolve({
        [contractAddress]: {
          userBalance: (balance: string) =>
            BigNumber.from(balance).add(amount).toString(),
        },
      })
    );

  const debitUserTokenBalance = (contractAddress: string, amount: number) =>
    setTokenDetails(
      evolve({
        [contractAddress]: {
          allowance: subtract(__, amount),
          userBalance: (balance: string) =>
            BigNumber.from(balance).sub(amount).toString(),
        },
      })
    );

  const fetchNativeTokenDetails = async () => {
    const balance = await provider!.getBalance(account!);
    setTokenDetails(
      assoc("0x", {
        address: "0x",
        allowance: 999999999,
        depositHelperAllowance: 999999999,
        decimalPlaces: 18,
        userBalance: formatUnits(balance, 18),
      })
    );
  };

  const fetchTokenDetails = async (contractAddress: string) => {
    if (contractAddress === "0x") return fetchNativeTokenDetails();
    fetchNativeTokenDetails(); //shouldn't do this
    const contract = Erc20ABI__factory.connect(contractAddress, signer!);
    const [balance, decimals, allowance, depositHelperAllowance] =
      await Promise.all([
        contract.balanceOf(account!),
        contract.decimals(),
        contract.allowance(
          account!,
          config!.reliquaryContractAddress
        ),
        contract.allowance(
          account!,
          config!.reliquaryHelperContractAddress
        ),
      ]);

    const decimalPlaces = decimals;

    setTokenDetails(
      assoc(contractAddress, {
        address: contractAddress,
        allowance: weiBigNumAsFloat(allowance, decimalPlaces),
        depositHelperAllowance: weiBigNumAsFloat(
          depositHelperAllowance,
          decimalPlaces
        ),
        decimalPlaces,
        userBalance: formatUnits(balance, decimalPlaces),
      })
    );
  };

  return {
    approveTokenSpend,
    creditUserTokenBalance,
    debitUserTokenBalance,
    fetchTokenDetails,
    fetchNativeTokenDetails,
    tokenDetails,
  };
};