feat(v1-support): Enable executing swaps on v1 or v2

src/components/Header/VersionSwitch.tsx

@@ -0,0 +1,64 @@
+import { stringify } from 'qs'
+import React, { useCallback, useMemo } from 'react'
+import { Link, useLocation } from 'react-router-dom'
+import styled from 'styled-components'
+import useParsedQueryString from '../../hooks/useParsedQueryString'
+import useToggledVersion, { Version } from '../../hooks/useToggledVersion'
+
+const VersionLabel = styled.span<{ enabled: boolean }>`
+  padding: ${({ enabled }) => (enabled ? '0.15rem 0.5rem 0.16rem 0.45rem' : '0.15rem 0.5rem 0.16rem 0.35rem')};
+  border-radius: 14px;
+  background: ${({ theme, enabled }) => (enabled ? theme.primary1 : 'none')};
+  color: ${({ theme, enabled }) => (enabled ? theme.white : theme.primary1)};
+  font-size: 0.825rem;
+  font-weight: 400;
+  :hover {
+    user-select: ${({ enabled }) => (enabled ? 'none' : 'initial')};
+    background: ${({ theme, enabled }) => (enabled ? theme.primary1 : 'none')};
+    color: ${({ theme, enabled }) => (enabled ? theme.white : theme.primary3)};
+  }
+`
+const VersionToggle = styled(Link)<{ enabled: boolean }>`
+  border-radius: 16px;
+  opacity: ${({ enabled }) => (enabled ? 1 : 0.5)};
+  cursor: ${({ enabled }) => (enabled ? 'pointer' : 'default')};
+  background: ${({ theme }) => theme.primary5};
+  border: 1px solid ${({ theme }) => theme.primary4};
+  color: ${({ theme }) => theme.primary1};
+  display: flex;
+  width: fit-content;
+  text-decoration: none;
+  :hover {
+    text-decoration: none;
+  }
+`
+
+export function VersionSwitch() {
+  const version = useToggledVersion()
+  const location = useLocation()
+  const query = useParsedQueryString()
+  const versionSwitchAvailable = location.pathname === '/swap' || location.pathname === '/send'
+
+  const toggleDest = useMemo(() => {
+    return versionSwitchAvailable
+      ? {
+          ...location,
+          search: `?${stringify({ ...query, use: version === Version.v1 ? undefined : Version.v1 })}`
+        }
+      : location
+  }, [location, query, version, versionSwitchAvailable])
+
+  const handleClick = useCallback(
+    e => {
+      if (!versionSwitchAvailable) e.preventDefault()
+    },
+    [versionSwitchAvailable]
+  )
+
+  return (
+    <VersionToggle enabled={versionSwitchAvailable} to={toggleDest} onClick={handleClick}>
+      <VersionLabel enabled={version === Version.v2 || !versionSwitchAvailable}>V2</VersionLabel>
+      <VersionLabel enabled={version === Version.v1 && versionSwitchAvailable}>V1</VersionLabel>
+    </VersionToggle>
+  )
+}

src/components/Header/index.tsx

@@ -1,27 +1,27 @@
+import { ChainId, WETH } from '@uniswap/sdk'
 import React from 'react'
+import { isMobile } from 'react-device-detect'
 import { Link as HistoryLink } from 'react-router-dom'
+import { Text } from 'rebass'
 
 import styled from 'styled-components'
-import { useTokenBalanceTreatingWETHasETH } from '../../state/wallet/hooks'
-
-import Row from '../Row'
-import Menu from '../Menu'
-import Web3Status from '../Web3Status'
-
-import { ExternalLink, StyledInternalLink } from '../../theme'
-import { Text } from 'rebass'
-import { WETH, ChainId } from '@uniswap/sdk'
-import { isMobile } from 'react-device-detect'
-import { YellowCard } from '../Card'
-import { useActiveWeb3React } from '../../hooks'
-import { useDarkModeManager } from '../../state/user/hooks'
 
 import Logo from '../../assets/svg/logo.svg'
-import Wordmark from '../../assets/svg/wordmark.svg'
 import LogoDark from '../../assets/svg/logo_white.svg'
+import Wordmark from '../../assets/svg/wordmark.svg'
 import WordmarkDark from '../../assets/svg/wordmark_white.svg'
+import { useActiveWeb3React } from '../../hooks'
+import { useDarkModeManager } from '../../state/user/hooks'
+import { useTokenBalanceTreatingWETHasETH } from '../../state/wallet/hooks'
+
+import { ExternalLink, StyledInternalLink } from '../../theme'
+import { YellowCard } from '../Card'
 import { AutoColumn } from '../Column'
-import { RowBetween } from '../Row'
+import Menu from '../Menu'
+
+import Row, { RowBetween } from '../Row'
+import Web3Status from '../Web3Status'
+import { VersionSwitch } from './VersionSwitch'
 
 const HeaderFrame = styled.div`
   display: flex;
@@ -122,33 +122,13 @@ const MigrateBanner = styled(AutoColumn)`
   `};
 `
 
-const VersionLabel = styled.span<{ isV2?: boolean }>`
-  padding: ${({ isV2 }) => (isV2 ? '0.15rem 0.5rem 0.16rem 0.45rem' : '0.15rem 0.5rem 0.16rem 0.35rem')};
-  border-radius: 14px;
-  background: ${({ theme, isV2 }) => (isV2 ? theme.primary1 : 'none')};
-  color: ${({ theme, isV2 }) => (isV2 ? theme.white : theme.primary1)};
-  font-size: 0.825rem;
-  font-weight: 400;
-  :hover {
-    user-select: ${({ isV2 }) => (isV2 ? 'none' : 'initial')};
-    background: ${({ theme, isV2 }) => (isV2 ? theme.primary1 : 'none')};
-    color: ${({ theme, isV2 }) => (isV2 ? theme.white : theme.primary3)};
-  }
-`
-
-const VersionToggle = styled.a`
-  border-radius: 16px;
-  background: ${({ theme }) => theme.primary5};
-  border: 1px solid ${({ theme }) => theme.primary4};
-  color: ${({ theme }) => theme.primary1};
-  display: flex;
-  width: fit-content;
-  cursor: pointer;
-  text-decoration: none;
-  :hover {
-    text-decoration: none;
-  }
-`
+const NETWORK_LABELS: { [chainId in ChainId]: string | null } = {
+  [ChainId.MAINNET]: null,
+  [ChainId.RINKEBY]: 'Rinkeby',
+  [ChainId.ROPSTEN]: 'Ropsten',
+  [ChainId.GÖRLI]: 'Görli',
+  [ChainId.KOVAN]: 'Kovan'
+}
 
 export default function Header() {
   const { account, chainId } = useActiveWeb3React()
@@ -187,21 +167,11 @@ export default function Header() {
               </TitleText>
             )}
           </Title>
-          <TestnetWrapper style={{ pointerEvents: 'auto' }}>
-            {!isMobile && (
-              <VersionToggle target="_self" href="https://v1.uniswap.exchange">
-                <VersionLabel isV2={true}>V2</VersionLabel>
-                <VersionLabel isV2={false}>V1</VersionLabel>
-              </VersionToggle>
-            )}
-          </TestnetWrapper>
+          <TestnetWrapper style={{ pointerEvents: 'auto' }}>{!isMobile && <VersionSwitch />}</TestnetWrapper>
         </HeaderElement>
         <HeaderElement>
           <TestnetWrapper>
-            {!isMobile && chainId === ChainId.ROPSTEN && <NetworkCard>Ropsten</NetworkCard>}
-            {!isMobile && chainId === ChainId.RINKEBY && <NetworkCard>Rinkeby</NetworkCard>}
-            {!isMobile && chainId === ChainId.GÖRLI && <NetworkCard>Görli</NetworkCard>}
-            {!isMobile && chainId === ChainId.KOVAN && <NetworkCard>Kovan</NetworkCard>}
+            {!isMobile && NETWORK_LABELS[chainId] && <NetworkCard>{NETWORK_LABELS[chainId]}</NetworkCard>}
           </TestnetWrapper>
           <AccountElement active={!!account} style={{ pointerEvents: 'auto' }}>
             {account && userEthBalance ? (

src/components/TxnPopup/index.tsx

@@ -1,7 +1,7 @@
-import React, { useCallback, useState } from 'react'
+import React, { useCallback, useContext, useState } from 'react'
 import { AlertCircle, CheckCircle } from 'react-feather'
 
-import styled from 'styled-components'
+import styled, { ThemeContext } from 'styled-components'
 
 import { useActiveWeb3React } from '../../hooks'
 import useInterval from '../../hooks/useInterval'
@@ -51,13 +51,16 @@ export default function TxnPopup({
     isRunning ? delay : null
   )
 
+  const handleMouseEnter = useCallback(() => setIsRunning(false), [])
+  const handleMouseLeave = useCallback(() => setIsRunning(true), [])
+
+  const theme = useContext(ThemeContext)
+
   return (
-    <AutoRow onMouseEnter={() => setIsRunning(false)} onMouseLeave={() => setIsRunning(true)}>
-      {success ? (
-        <CheckCircle color={'#27AE60'} size={24} style={{ paddingRight: '24px' }} />
-      ) : (
-        <AlertCircle color={'#FF6871'} size={24} style={{ paddingRight: '24px' }} />
-      )}
+    <AutoRow onMouseEnter={handleMouseEnter} onMouseLeave={handleMouseLeave}>
+      <div style={{ paddingRight: 16 }}>
+        {success ? <CheckCircle color={theme.green1} size={24} /> : <AlertCircle color={theme.red1} size={24} />}
+      </div>
       <AutoColumn gap="8px">
         <TYPE.body fontWeight={500}>
           {summary ? summary : 'Hash: ' + hash.slice(0, 8) + '...' + hash.slice(58, 65)}

src/components/swap/BetterTradeLink.tsx

@@ -0,0 +1,40 @@
+import { stringify } from 'qs'
+import React, { useContext, useMemo } from 'react'
+import { useLocation } from 'react-router'
+import { Text } from 'rebass'
+import { ThemeContext } from 'styled-components'
+import useParsedQueryString from '../../hooks/useParsedQueryString'
+import { Version } from '../../hooks/useToggledVersion'
+
+import { StyledInternalLink } from '../../theme'
+import { YellowCard } from '../Card'
+import { AutoColumn } from '../Column'
+
+export default function BetterTradeLink({ version }: { version: Version }) {
+  const theme = useContext(ThemeContext)
+  const location = useLocation()
+  const search = useParsedQueryString()
+
+  const linkDestination = useMemo(() => {
+    return {
+      ...location,
+      search: `?${stringify({
+        ...search,
+        use: version
+      })}`
+    }
+  }, [location, search, version])
+
+  return (
+    <YellowCard style={{ marginTop: '12px', padding: '8px 4px' }}>
+      <AutoColumn gap="sm" justify="center" style={{ alignItems: 'center', textAlign: 'center' }}>
+        <Text lineHeight="145.23%;" fontSize={14} fontWeight={400} color={theme.text1}>
+          There is a better price for this trade on{' '}
+          <StyledInternalLink to={linkDestination}>
+            <b>Uniswap {version.toUpperCase()} ↗</b>
+          </StyledInternalLink>
+        </Text>
+      </AutoColumn>
+    </YellowCard>
+  )
+}

src/constants/index.ts

@@ -159,4 +159,4 @@ export const PRICE_IMPACT_WITHOUT_FEE_CONFIRM_MIN: Percent = new Percent(JSBI.Bi
 
 // used to ensure the user doesn't send so much ETH so they end up with <.01
 export const MIN_ETH: JSBI = JSBI.exponentiate(JSBI.BigInt(10), JSBI.BigInt(16)) // .01 ETH
-export const V1_TRADE_LINK_THRESHOLD = new Percent(JSBI.BigInt(75), JSBI.BigInt(10000))
+export const BETTER_TRADE_LINK_THRESHOLD = new Percent(JSBI.BigInt(75), JSBI.BigInt(10000))