@ledgerhq/live-common/src/exchange/swap/getExchangeRates.ts

Common ground for the Ledger Live apps

import network from "@ledgerhq/live-network/network";
import type { Unit } from "@ledgerhq/types-cryptoassets";
import { BigNumber } from "bignumber.js";
import { getAccountCurrency } from "../../account";
import { formatCurrencyUnit } from "../../currencies";
import {
  SwapExchangeRateAmountTooHigh,
  SwapExchangeRateAmountTooLow,
  SwapExchangeRateAmountTooLowOrTooHigh,
} from "../../errors";
import { getSwapAPIBaseURL, getSwapAPIError, getSwapUserIP } from "./";
import { mockGetExchangeRates } from "./mock";
import type { CustomMinOrMaxError, GetExchangeRates } from "./types";
import { isIntegrationTestEnv } from "./utils/isIntegrationTestEnv";
import { getSwapProvider } from "../providers/swap";

const getExchangeRates: GetExchangeRates = async ({
  exchange,
  transaction,
  currencyTo,
  providers = [],
  timeout,
  timeoutErrorMessage,
}) => {
  if (isIntegrationTestEnv()) return mockGetExchangeRates(exchange, transaction, currencyTo);

  const from = getAccountCurrency(exchange.fromAccount).id;
  const unitFrom = getAccountCurrency(exchange.fromAccount).units[0];
  const to = (currencyTo ?? getAccountCurrency(exchange.toAccount)).id;
  const unitTo =
    (currencyTo && currencyTo.units[0]) ?? getAccountCurrency(exchange.toAccount).units[0];
  const amountFrom = transaction.amount;
  const tenPowMagnitude = new BigNumber(10).pow(unitFrom.magnitude);
  const apiAmount = new BigNumber(amountFrom).div(tenPowMagnitude);

  const providerList = providers
    .filter(provider => provider.pairs.some(pair => pair.from === from && pair.to === to))
    .map(item => item.provider);

  const request = {
    from,
    to,
    amountFrom: apiAmount.toString(),
    providers: providerList,
  };

  const headers = getSwapUserIP();
  const res = await network({
    method: "POST",
    url: `${getSwapAPIBaseURL()}/rate`,
    ...(timeout ? { timeout } : {}),
    ...(timeoutErrorMessage ? { timeoutErrorMessage } : {}),
    data: request,
    ...(headers !== undefined ? headers : {}),
  });

  const rates = res.data.map(async responseData => {
    const {
      rate: maybeRate,
      payoutNetworkFees: maybePayoutNetworkFees,
      rateId,
      provider,
      providerType,
      amountFrom,
      amountTo,
      tradeMethod,
      providerURL,
      expirationTime,
    } = responseData;

    const error = await inferError(apiAmount, unitFrom, responseData);
    if (error) {
      return {
        provider,
        tradeMethod,
        error,
      };
    }

    const payoutNetworkFees = new BigNumber(maybePayoutNetworkFees || 0);

    const magnitudeAwarePayoutNetworkFees = payoutNetworkFees.times(
      new BigNumber(10).pow(unitTo.magnitude),
    );

    const rate = maybeRate
      ? new BigNumber(maybeRate)
      : new BigNumber(amountTo).minus(payoutNetworkFees).div(amountFrom);

    // NB Allows us to simply multiply satoshi values from/to
    const magnitudeAwareRate = rate.div(
      new BigNumber(10).pow(unitFrom.magnitude - unitTo.magnitude),
    );

    const toAmount = new BigNumber(amountTo).minus(payoutNetworkFees);

    const magnitudeAwareToAmount = toAmount.times(new BigNumber(10).pow(unitTo.magnitude));
    // Nb no longer need to break it down on UI

    const out = {
      magnitudeAwareRate,
      provider,
      providerType,
      rate,
      rateId,
      expirationTime,
      toAmount: magnitudeAwareToAmount,
      tradeMethod,
      providerURL,
    };

    if (tradeMethod === "fixed") {
      return {
        ...out,
        payoutNetworkFees: magnitudeAwarePayoutNetworkFees,
        rateId,
      };
    } else {
      return {
        ...out,
        payoutNetworkFees: magnitudeAwarePayoutNetworkFees,
      };
    }
  });
  return rates;
};

const inferError = async (
  apiAmount: BigNumber,
  unitFrom: Unit,
  responseData: {
    amountTo: string;
    minAmountFrom: string;
    maxAmountFrom: string;
    errorCode?: number;
    errorMessage?: string;
    status?: string;
    provider: string;
  },
): Promise<Error | CustomMinOrMaxError | undefined> => {
  const tenPowMagnitude = new BigNumber(10).pow(unitFrom.magnitude);
  const { amountTo, minAmountFrom, maxAmountFrom, errorCode, errorMessage, provider, status } =
    responseData;
  const isDex = (await getSwapProvider(provider)).type === "DEX";

  // DEX quotes are out of limits error. We do not know if it is a low or high limit, neither the amount.
  if ((!minAmountFrom || !maxAmountFrom) && status === "error" && errorCode !== 300 && isDex) {
    return new SwapExchangeRateAmountTooLowOrTooHigh(undefined, {
      message: "",
    });
  }

  if (!amountTo) {
    // We are in an error case regardless of api version.
    if (errorCode) {
      return getSwapAPIError(errorCode, errorMessage);
    }

    // For out of range errors we will have a min/max pairing
    const hasAmountLimit = minAmountFrom || maxAmountFrom;
    if (hasAmountLimit) {
      const isTooSmall = minAmountFrom ? new BigNumber(apiAmount).lte(minAmountFrom) : false;

      const MinOrMaxError = isTooSmall
        ? SwapExchangeRateAmountTooLow
        : SwapExchangeRateAmountTooHigh;

      const key: string = isTooSmall ? "minAmountFromFormatted" : "maxAmountFromFormatted";

      const amount = isTooSmall ? minAmountFrom : maxAmountFrom;

      return new MinOrMaxError(undefined, {
        [key]: formatCurrencyUnit(unitFrom, new BigNumber(amount).times(tenPowMagnitude), {
          alwaysShowSign: false,
          disableRounding: true,
          showCode: true,
        }),
        amount: new BigNumber(amount),
      });
    }
  }
  return;
};

export default getExchangeRates;