import { Token, CurrencyAmount, Currency } from "@uniswap/sdk-core";
import { useMemo } from "react";
import { useAllTokenBalances } from "../../hooks/Balances";

// compare two token amounts with highest one coming first
function balanceComparator(
  balanceA?: CurrencyAmount<Currency>,
  balanceB?: CurrencyAmount<Currency>
) {
  if (balanceA && balanceB) {
    return balanceA.greaterThan(balanceB)
      ? -1
      : balanceA.equalTo(balanceB)
      ? 0
      : 1;
  } else if (balanceA && balanceA.greaterThan("0")) {
    return -1;
  } else if (balanceB && balanceB.greaterThan("0")) {
    return 1;
  }
  return 0;
}

function getTokenComparator(balances: {
  [tokenAddress: string]: CurrencyAmount<Currency> | undefined;
}): (tokenA: Token, tokenB: Token) => number {
  return function sortTokens(tokenA: Token, tokenB: Token): number {
    // -1 = a is first
    // 1 = b is first

    // sort by balances
    const balanceA = balances[tokenA.address];
    const balanceB = balances[tokenB.address];

    const balanceComp = balanceComparator(balanceA, balanceB);
    if (balanceComp !== 0) return balanceComp;

    if (tokenA.symbol && tokenB.symbol) {
      // sort by symbol
      return tokenA.symbol.toLowerCase() < tokenB.symbol.toLowerCase() ? -1 : 1;
    } else {
      return tokenA.symbol ? -1 : tokenB.symbol ? -1 : 0;
    }
  };
}

export function useTokenComparator(
  inverted: boolean
): (tokenA: Token, tokenB: Token) => number {
  const balances = useAllTokenBalances();

  const comparator = useMemo(() => getTokenComparator(balances ?? {}), [
    balances,
  ]);
  return useMemo(() => {
    if (inverted) {
      return (tokenA: Token, tokenB: Token) => comparator(tokenA, tokenB) * -1;
    } else {
      return comparator;
    }
  }, [inverted, comparator]);
}