metamask-extension/ui/app/pages/swaps/build-quote/build-quote.js

import React, { useContext, useEffect, useState, useCallback } from 'react'
import PropTypes from 'prop-types'
import { useDispatch, useSelector } from 'react-redux'
import classnames from 'classnames'
import { uniqBy } from 'lodash'
import { useHistory } from 'react-router-dom'
import { MetaMetricsContext } from '../../../contexts/metametrics.new'
import { useTokensToSearch } from '../../../hooks/useTokensToSearch'
import { useEqualityCheck } from '../../../hooks/useEqualityCheck'
import { useSwapsEthToken } from '../../../hooks/useSwapsEthToken'
import { I18nContext } from '../../../contexts/i18n'
import DropdownInputPair from '../dropdown-input-pair'
import DropdownSearchList from '../dropdown-search-list'
import SlippageButtons from '../slippage-buttons'
import { getTokens } from '../../../ducks/metamask/metamask'
import InfoTooltip from '../../../components/ui/info-tooltip'

import {
  fetchQuotesAndSetQuoteState,
  setSwapsFromToken,
  setSwapToToken,
  getFromToken,
  getToToken,
  getBalanceError,
  getTopAssets,
  getFetchParams,
} from '../../../ducks/swaps/swaps'
import {
  getValueFromWeiHex,
  hexToDecimal,
} from '../../../helpers/utils/conversions.util'
import { calcTokenAmount } from '../../../helpers/utils/token-util'
import { usePrevious } from '../../../hooks/usePrevious'
import { useTokenTracker } from '../../../hooks/useTokenTracker'
import { useTokenFiatAmount } from '../../../hooks/useTokenFiatAmount'
import { useEthFiatAmount } from '../../../hooks/useEthFiatAmount'

import { ETH_SWAPS_TOKEN_OBJECT } from '../../../helpers/constants/swaps'

import { resetSwapsPostFetchState, removeToken } from '../../../store/actions'
import { fetchTokenPrice, fetchTokenBalance } from '../swaps.util'
import SwapsFooter from '../swaps-footer'

const fuseSearchKeys = [
  { name: 'name', weight: 0.499 },
  { name: 'symbol', weight: 0.499 },
  { name: 'address', weight: 0.002 },
]

const MAX_ALLOWED_SLIPPAGE = 15

export default function BuildQuote({
  inputValue,
  onInputChange,
  ethBalance,
  setMaxSlippage,
  maxSlippage,
  selectedAccountAddress,
}) {
  const t = useContext(I18nContext)
  const dispatch = useDispatch()
  const history = useHistory()
  const metaMetricsEvent = useContext(MetaMetricsContext)

  const [fetchedTokenExchangeRate, setFetchedTokenExchangeRate] = useState(
    undefined,
  )

  const balanceError = useSelector(getBalanceError)
  const fetchParams = useSelector(getFetchParams)
  const { sourceTokenInfo = {}, destinationTokenInfo = {} } =
    fetchParams?.metaData || {}
  const tokens = useSelector(getTokens)
  const topAssets = useSelector(getTopAssets)
  const fromToken = useSelector(getFromToken)
  const toToken = useSelector(getToToken) || destinationTokenInfo
  const swapsEthToken = useSwapsEthToken()
  const fetchParamsFromToken =
    sourceTokenInfo?.symbol === 'ETH' ? swapsEthToken : sourceTokenInfo

  const { loading, tokensWithBalances } = useTokenTracker(tokens)

  // If the fromToken was set in a call to `onFromSelect` (see below), and that from token has a balance
  // but is not in tokensWithBalances or tokens, then we want to add it to the usersTokens array so that
  // the balance of the token can appear in the from token selection dropdown
  const fromTokenArray =
    fromToken?.symbol !== 'ETH' && fromToken?.balance ? [fromToken] : []
  const usersTokens = uniqBy(
    [...tokensWithBalances, ...tokens, ...fromTokenArray],
    'address',
  )
  const memoizedUsersTokens = useEqualityCheck(usersTokens)

  const selectedFromToken = useTokensToSearch({
    providedTokens:
      fromToken || fetchParamsFromToken
        ? [fromToken || fetchParamsFromToken]
        : [],
    usersTokens: memoizedUsersTokens,
    onlyEth: (fromToken || fetchParamsFromToken)?.symbol === 'ETH',
    singleToken: true,
  })[0]

  const tokensToSearch = useTokensToSearch({
    usersTokens: memoizedUsersTokens,
    topTokens: topAssets,
  })
  const selectedToToken =
    tokensToSearch.find(({ address }) => address === toToken?.address) ||
    toToken

  const {
    address: fromTokenAddress,
    symbol: fromTokenSymbol,
    string: fromTokenString,
    decimals: fromTokenDecimals,
    balance: rawFromTokenBalance,
  } = selectedFromToken || {}

  const fromTokenBalance =
    rawFromTokenBalance &&
    calcTokenAmount(rawFromTokenBalance, fromTokenDecimals).toString(10)

  const prevFromTokenBalance = usePrevious(fromTokenBalance)

  const swapFromTokenFiatValue = useTokenFiatAmount(
    fromTokenAddress,
    inputValue || 0,
    fromTokenSymbol,
    {
      showFiat: true,
    },
    true,
  )
  const swapFromEthFiatValue = useEthFiatAmount(
    inputValue || 0,
    { showFiat: true },
    true,
  )
  const swapFromFiatValue =
    fromTokenSymbol === 'ETH' ? swapFromEthFiatValue : swapFromTokenFiatValue

  const onFromSelect = (token) => {
    if (
      token?.address &&
      !swapFromFiatValue &&
      fetchedTokenExchangeRate !== null
    ) {
      fetchTokenPrice(token.address).then((rate) => {
        if (rate !== null && rate !== undefined) {
          setFetchedTokenExchangeRate(rate)
        }
      })
    } else {
      setFetchedTokenExchangeRate(null)
    }
    if (
      token?.address &&
      !memoizedUsersTokens.find(
        (usersToken) => usersToken.address === token.address,
      )
    ) {
      fetchTokenBalance(token.address, selectedAccountAddress).then(
        (fetchedBalance) => {
          if (fetchedBalance?.balance) {
            const balanceAsDecString = fetchedBalance.balance.toString(10)
            const userTokenBalance = calcTokenAmount(
              balanceAsDecString,
              token.decimals,
            )
            dispatch(
              setSwapsFromToken({
                ...token,
                string: userTokenBalance.toString(10),
                balance: balanceAsDecString,
              }),
            )
          }
        },
      )
    }
    dispatch(setSwapsFromToken(token))
    onInputChange(
      token?.address ? inputValue : '',
      token.string,
      token.decimals,
    )
  }

  const { destinationTokenAddedForSwap } = fetchParams || {}
  const { address: toAddress } = toToken || {}
  const onToSelect = useCallback(
    (token) => {
      if (destinationTokenAddedForSwap && token.address !== toAddress) {
        dispatch(removeToken(toAddress))
      }
      dispatch(setSwapToToken(token))
    },
    [dispatch, destinationTokenAddedForSwap, toAddress],
  )

  const hideDropdownItemIf = useCallback(
    (item) => item.address === fromTokenAddress,
    [fromTokenAddress],
  )

  const tokensWithBalancesFromToken = tokensWithBalances.find(
    (token) => token.address === fromToken?.address,
  )
  const previousTokensWithBalancesFromToken = usePrevious(
    tokensWithBalancesFromToken,
  )

  useEffect(() => {
    const notEth =
      tokensWithBalancesFromToken?.address !== ETH_SWAPS_TOKEN_OBJECT.address
    const addressesAreTheSame =
      tokensWithBalancesFromToken?.address ===
      previousTokensWithBalancesFromToken?.address
    const balanceHasChanged =
      tokensWithBalancesFromToken?.balance !==
      previousTokensWithBalancesFromToken?.balance
    if (notEth && addressesAreTheSame && balanceHasChanged) {
      dispatch(
        setSwapsFromToken({
          ...fromToken,
          balance: tokensWithBalancesFromToken?.balance,
          string: tokensWithBalancesFromToken?.string,
        }),
      )
    }
  }, [
    dispatch,
    tokensWithBalancesFromToken,
    previousTokensWithBalancesFromToken,
    fromToken,
  ])

  // If the eth balance changes while on build quote, we update the selected from token
  useEffect(() => {
    if (
      fromToken?.address === ETH_SWAPS_TOKEN_OBJECT.address &&
      fromToken?.balance !== hexToDecimal(ethBalance)
    ) {
      dispatch(
        setSwapsFromToken({
          ...fromToken,
          balance: hexToDecimal(ethBalance),
          string: getValueFromWeiHex({
            value: ethBalance,
            numberOfDecimals: 4,
            toDenomination: 'ETH',
          }),
        }),
      )
    }
  }, [dispatch, fromToken, ethBalance])

  useEffect(() => {
    if (prevFromTokenBalance !== fromTokenBalance) {
      onInputChange(inputValue, fromTokenBalance)
    }
  }, [onInputChange, prevFromTokenBalance, inputValue, fromTokenBalance])

  useEffect(() => {
    dispatch(resetSwapsPostFetchState())
  }, [dispatch])

  return (
    <div className="build-quote">
      <div className="build-quote__content">
        <div className="build-quote__dropdown-input-pair-header">
          <div className="build-quote__input-label">{t('swapSwapFrom')}</div>
          {fromTokenSymbol !== 'ETH' && (
            <div
              className="build-quote__max-button"
              onClick={() =>
                onInputChange(fromTokenBalance || '0', fromTokenBalance)
              }
            >
              {t('max')}
            </div>
          )}
        </div>
        <DropdownInputPair
          onSelect={onFromSelect}
          itemsToSearch={tokensToSearch}
          onInputChange={(value) => {
            onInputChange(value, fromTokenBalance)
          }}
          inputValue={inputValue}
          leftValue={inputValue && swapFromFiatValue}
          selectedItem={selectedFromToken}
          maxListItems={30}
          loading={
            loading &&
            (!tokensToSearch?.length ||
              !topAssets ||
              !Object.keys(topAssets).length)
          }
          selectPlaceHolderText={t('swapSelect')}
          hideItemIf={(item) => item.address === selectedToToken?.address}
          listContainerClassName="build-quote__open-dropdown"
          autoFocus
        />
        <div
          className={classnames('build-quote__balance-message', {
            'build-quote__balance-message--error': balanceError,
          })}
        >
          {!balanceError &&
            fromTokenSymbol &&
            t('swapYourTokenBalance', [
              fromTokenString || '0',
              fromTokenSymbol,
            ])}
          {balanceError && fromTokenSymbol && (
            <div className="build-quite__insufficient-funds">
              <div className="build-quite__insufficient-funds-first">
                {t('swapsNotEnoughForTx', [fromTokenSymbol])}
              </div>
              <div className="build-quite__insufficient-funds-second">
                {t('swapYourTokenBalance', [
                  fromTokenString || '0',
                  fromTokenSymbol,
                ])}
              </div>
            </div>
          )}
        </div>
        <div className="build-quote__swap-arrows-row">
          <button
            className="build-quote__swap-arrows"
            onClick={() => {
              onToSelect(selectedFromToken)
              onFromSelect(selectedToToken)
            }}
          >
            <img
              src="/images/icons/swap2.svg"
              alt={t('swapSwapSwitch')}
              width="12"
              height="16"
            />
          </button>
        </div>
        <div className="build-quote__dropdown-swap-to-header">
          <div className="build-quote__input-label">{t('swapSwapTo')}</div>
        </div>
        <div className="dropdown-input-pair dropdown-input-pair__to">
          <DropdownSearchList
            startingItem={selectedToToken}
            itemsToSearch={tokensToSearch}
            searchPlaceholderText={t('swapSearchForAToken')}
            fuseSearchKeys={fuseSearchKeys}
            selectPlaceHolderText={t('swapSelectAToken')}
            maxListItems={30}
            onSelect={onToSelect}
            loading={
              loading &&
              (!tokensToSearch?.length ||
                !topAssets ||
                !Object.keys(topAssets).length)
            }
            externallySelectedItem={selectedToToken}
            hideItemIf={hideDropdownItemIf}
            listContainerClassName="build-quote__open-to-dropdown"
            hideRightLabels
            defaultToAll
          />
        </div>
        {selectedToToken?.address &&
          selectedToToken?.address !== ETH_SWAPS_TOKEN_OBJECT.address && (
            <div className="build-quote__token-message">
              {t('verifyThisTokenOn', [
                <a
                  className="build-quote__token-etherscan-link"
                  key="build-quote-etherscan-link"
                  href={`https://etherscan.io/token/${selectedToToken.address}`}
                  target="_blank"
                  rel="noopener noreferrer"
                >
                  {t('etherscan')}
                </a>,
              ])}
              <InfoTooltip
                position="top"
                contentText={t('swapVerifyTokenExplanation')}
                containerClassName="build-quote__token-tooltip-container"
              />
            </div>
          )}
        <div className="build-quote__slippage-buttons-container">
          <SlippageButtons
            onSelect={(newSlippage) => {
              setMaxSlippage(newSlippage)
            }}
            maxAllowedSlippage={MAX_ALLOWED_SLIPPAGE}
          />
        </div>
      </div>
      <SwapsFooter
        onSubmit={() => {
          dispatch(
            fetchQuotesAndSetQuoteState(
              history,
              inputValue,
              maxSlippage,
              metaMetricsEvent,
            ),
          )
        }}
        submitText={t('swapGetQuotes')}
        disabled={
          !Number(inputValue) ||
          !selectedToToken?.address ||
          Number(maxSlippage) === 0 ||
          Number(maxSlippage) > MAX_ALLOWED_SLIPPAGE
        }
        hideCancel
        showTermsOfService
      />
    </div>
  )
}

BuildQuote.propTypes = {
  maxSlippage: PropTypes.number,
  inputValue: PropTypes.string,
  onInputChange: PropTypes.func,
  ethBalance: PropTypes.string,
  setMaxSlippage: PropTypes.func,
  selectedAccountAddress: PropTypes.string,
}