import { Currency, Token } from "@uniswap/sdk-core";
import { FeeAmount, Pool } from "@uniswap/v3-sdk";
import { useMemo } from "react";
import { useAllCurrencyCombinations } from "./useAllCurrencyCombinations";
import { PoolState, usePools } from "./usePools";

/**
 * Returns all the existing pools that should be considered for swapping between an input currency and an output currency
 * @param currencyIn the input currency
 * @param currencyOut the output currency
 */
export function useV3SwapPools(
  currencyIn?: Currency,
  currencyOut?: Currency
): {
  pools: Pool[];
  loading: boolean;
} {
  const allCurrencyCombinations = useAllCurrencyCombinations(
    currencyIn,
    currencyOut
  );

  const allCurrencyCombinationsWithAllFees: [
    Token,
    Token,
    FeeAmount
  ][] = useMemo(
    () =>
      allCurrencyCombinations.reduce<[Token, Token, FeeAmount][]>(
        (list, [tokenA, tokenB]) => {
          return list.concat([
            [tokenA, tokenB, FeeAmount.LOW],
            [tokenA, tokenB, FeeAmount.MEDIUM],
            [tokenA, tokenB, FeeAmount.HIGH],
          ]);
        },
        []
      ),
    [allCurrencyCombinations]
  );

  const pools = usePools(allCurrencyCombinationsWithAllFees);

  return useMemo(() => {
    return {
      pools: pools
        .filter((tuple): tuple is [PoolState.EXISTS, Pool] => {
          return tuple[0] === PoolState.EXISTS && tuple[1] !== null;
        })
        .map(([, pool]) => pool),
      loading: pools.some(([state]) => state === PoolState.LOADING),
    };
  }, [pools]);
}