feat(chain-connectivity): warn when the user is not receiving blocks (#2123)

* logic for tracking time since last block

* add polling times to chain info

* pr feedback

* add gui for chain connectivity warning

* add arb support

* update title of warning to indicate internet connectivity issues may be the problem

* pr review

* clean up useBlockWarningTimer

* softer language on mainnet

* only show warning if user has the window visible

src/components/Header/ChainConnectivityWarning.tsx

+import { Trans } from '@lingui/macro'
+import { CHAIN_INFO, L2ChainInfo, SupportedChainId } from 'constants/chains'
+import { useActiveWeb3React } from 'hooks/web3'
+import { AlertOctagon } from 'react-feather'
+import styled from 'styled-components/macro'
+import { ExternalLink, MEDIA_WIDTHS } from 'theme'
+
+const BodyRow = styled.div`
+  color: ${({ theme }) => theme.black};
+  font-size: 12px;
+`
+const CautionIcon = styled(AlertOctagon)`
+  color: ${({ theme }) => theme.black};
+`
+const Link = styled(ExternalLink)`
+  color: ${({ theme }) => theme.black};
+  text-decoration: underline;
+`
+const TitleRow = styled.div`
+  align-items: center;
+  display: flex;
+  justify-content: flex-start;
+  margin-bottom: 8px;
+`
+const TitleText = styled.div`
+  color: black;
+  font-weight: 600;
+  font-size: 16px;
+  line-height: 20px;
+  margin: 0px 12px;
+`
+const Wrapper = styled.div`
+  background-color: ${({ theme }) => theme.yellow3};
+  border-radius: 12px;
+  bottom: 60px;
+  display: none;
+  max-width: 348px;
+  padding: 16px 20px;
+  position: absolute;
+  right: 16px;
+  @media screen and (min-width: ${MEDIA_WIDTHS.upToMedium}px) {
+    display: block;
+  }
+`
+
+export function ChainConnectivityWarning() {
+  const { chainId } = useActiveWeb3React()
+  const info = CHAIN_INFO[chainId ?? SupportedChainId.MAINNET]
+  const label = info?.label
+
+  return (
+    <Wrapper>
+      <TitleRow>
+        <CautionIcon />
+        <TitleText>
+          <Trans>Network Warning</Trans>
+        </TitleText>
+      </TitleRow>
+      <BodyRow>
+        {chainId === SupportedChainId.MAINNET ? (
+          <Trans>You may have lost your network connection.</Trans>
+        ) : (
+          <Trans>{label} may be down right now, or you may have lost your network connection.</Trans>
+        )}{' '}
+        {(info as L2ChainInfo).statusPage !== undefined && (
+          <span>
+            <Trans>Check network status</Trans>{' '}
+            <Link href={(info as L2ChainInfo).statusPage || ''}>
+              <Trans>here.</Trans>
+            </Link>
+          </span>
+        )}
+      </BodyRow>
+    </Wrapper>
+  )
+}

src/components/Header/Polling.tsx

 import { useEffect, useState } from 'react'
+import { useAppSelector } from 'state/hooks'
 import styled, { keyframes } from 'styled-components/macro'
 import { useActiveWeb3React } from '../../hooks/web3'
-
 import { useBlockNumber } from '../../state/application/hooks'
 import { ExternalLink, TYPE } from '../../theme'
 import { ExplorerDataType, getExplorerLink } from '../../utils/getExplorerLink'
+import { ChainConnectivityWarning } from './ChainConnectivityWarning'
 
-const StyledPolling = styled.div`
+const StyledPolling = styled.div<{ warning: boolean }>`
   position: fixed;
   display: flex;
   align-items: center;
   right: 0;
   bottom: 0;
   padding: 1rem;
-  color: ${({ theme }) => theme.green1};
+  color: ${({ theme, warning }) => (warning ? theme.yellow3 : theme.green1)};
+  transition: 250ms ease color;
 
   ${({ theme }) => theme.mediaWidth.upToMedium`
     display: none;
@@ -26,14 +28,15 @@ const StyledPollingNumber = styled(TYPE.small)<{ breathe: boolean; hovering: boo
     opacity: 1;
   }
 `
-const StyledPollingDot = styled.div`
+const StyledPollingDot = styled.div<{ warning: boolean }>`
   width: 8px;
   height: 8px;
   min-height: 8px;
   min-width: 8px;
   border-radius: 50%;
   position: relative;
-  background-color: ${({ theme }) => theme.green1};
+  background-color: ${({ theme, warning }) => (warning ? theme.yellow3 : theme.green1)};
+  transition: 250ms ease background-color;
 `
 
 const rotate360 = keyframes`
@@ -45,19 +48,20 @@ const rotate360 = keyframes`
   }
 `
 
-const Spinner = styled.div`
+const Spinner = styled.div<{ warning: boolean }>`
   animation: ${rotate360} 1s cubic-bezier(0.83, 0, 0.17, 1) infinite;
   transform: translateZ(0);
 
   border-top: 1px solid transparent;
   border-right: 1px solid transparent;
   border-bottom: 1px solid transparent;
-  border-left: 2px solid ${({ theme }) => theme.green1};
+  border-left: 2px solid ${({ theme, warning }) => (warning ? theme.yellow3 : theme.green1)};
   background: transparent;
   width: 14px;
   height: 14px;
   border-radius: 50%;
   position: relative;
+  transition: 250ms ease border-color;
 
   left: -3px;
   top: -3px;
@@ -65,11 +69,10 @@ const Spinner = styled.div`
 
 export default function Polling() {
   const { chainId } = useActiveWeb3React()
-
   const blockNumber = useBlockNumber()
-
   const [isMounting, setIsMounting] = useState(false)
   const [isHover, setIsHover] = useState(false)
+  const chainConnectivityWarning = useAppSelector((state) => state.application.chainConnectivityWarning)
 
   useEffect(
     () => {
@@ -90,15 +93,24 @@ export default function Polling() {
   )
 
   return (
-    <ExternalLink
-      href={chainId && blockNumber ? getExplorerLink(chainId, blockNumber.toString(), ExplorerDataType.BLOCK) : ''}
-    >
-      <StyledPolling onMouseEnter={() => setIsHover(true)} onMouseLeave={() => setIsHover(false)}>
-        <StyledPollingNumber breathe={isMounting} hovering={isHover}>
-          {blockNumber}&ensp;
-        </StyledPollingNumber>
-        <StyledPollingDot>{isMounting && <Spinner />}</StyledPollingDot>
-      </StyledPolling>
-    </ExternalLink>
+    <>
+      <ExternalLink
+        href={chainId && blockNumber ? getExplorerLink(chainId, blockNumber.toString(), ExplorerDataType.BLOCK) : ''}
+      >
+        <StyledPolling
+          onMouseEnter={() => setIsHover(true)}
+          onMouseLeave={() => setIsHover(false)}
+          warning={chainConnectivityWarning}
+        >
+          <StyledPollingNumber breathe={isMounting} hovering={isHover}>
+            {blockNumber}&ensp;
+          </StyledPollingNumber>
+          <StyledPollingDot warning={chainConnectivityWarning}>
+            {isMounting && <Spinner warning={chainConnectivityWarning} />}
+          </StyledPollingDot>{' '}
+        </StyledPolling>
+      </ExternalLink>
+      {chainConnectivityWarning && <ChainConnectivityWarning />}
+    </>
   )
 }

src/constants/chains.ts

 import arbitrumLogoUrl from 'assets/svg/arbitrum_logo.svg'
 import optimismLogoUrl from 'assets/svg/optimism_logo.svg'
+import ms from 'ms.macro'
 
 export enum SupportedChainId {
   MAINNET = 1,
@@ -47,6 +48,7 @@ export const L2_CHAIN_IDS = [
 export type SupportedL2ChainId = typeof L2_CHAIN_IDS[number]
 
 interface L1ChainInfo {
+  readonly blockWaitMsBeforeWarning?: number
   readonly docs: string
   readonly explorer: string
   readonly infoLink: string
@@ -55,6 +57,7 @@ interface L1ChainInfo {
 export interface L2ChainInfo extends L1ChainInfo {
   readonly bridge: string
   readonly logoUrl: string
+  readonly statusPage?: string
 }
 
 type ChainInfo = { readonly [chainId: number]: L1ChainInfo | L2ChainInfo } & {
@@ -64,6 +67,7 @@ type ChainInfo = { readonly [chainId: number]: L1ChainInfo | L2ChainInfo } & {
 
 export const CHAIN_INFO: ChainInfo = {
   [SupportedChainId.ARBITRUM_ONE]: {
+    blockWaitMsBeforeWarning: ms`10m`,
     bridge: 'https://bridge.arbitrum.io/',
     docs: 'https://offchainlabs.com/',
     explorer: 'https://arbiscan.io/',
@@ -72,6 +76,7 @@ export const CHAIN_INFO: ChainInfo = {
     logoUrl: arbitrumLogoUrl,
   },
   [SupportedChainId.ARBITRUM_RINKEBY]: {
+    blockWaitMsBeforeWarning: ms`10m`,
     bridge: 'https://bridge.arbitrum.io/',
     docs: 'https://offchainlabs.com/',
     explorer: 'https://rinkeby-explorer.arbitrum.io/',
@@ -110,19 +115,23 @@ export const CHAIN_INFO: ChainInfo = {
     label: 'Görli',
   },
   [SupportedChainId.OPTIMISM]: {
+    blockWaitMsBeforeWarning: ms`10m`,
     bridge: 'https://gateway.optimism.io/',
     docs: 'https://optimism.io/',
     explorer: 'https://optimistic.etherscan.io/',
     infoLink: 'https://info.uniswap.org/#/optimism/',
     label: 'Optimism',
     logoUrl: optimismLogoUrl,
+    statusPage: 'https://optimism.io/status',
   },
   [SupportedChainId.OPTIMISTIC_KOVAN]: {
+    blockWaitMsBeforeWarning: ms`10m`,
     bridge: 'https://gateway.optimism.io/',
     docs: 'https://optimism.io/',
     explorer: 'https://optimistic.etherscan.io/',
     infoLink: 'https://info.uniswap.org/#/optimism',
     label: 'Optimistic Kovan',
     logoUrl: optimismLogoUrl,
+    statusPage: 'https://optimism.io/status',
   },
 }

src/state/application/actions.ts

@@ -27,3 +27,4 @@ export const setOpenModal = createAction<ApplicationModal | null>('application/s
 export const addPopup =
   createAction<{ key?: string; removeAfterMs?: number | null; content: PopupContent }>('application/addPopup')
 export const removePopup = createAction<{ key: string }>('application/removePopup')
+export const setChainConnectivityWarning = createAction<{ warn: boolean }>('application/setChainConnectivityWarning')

src/state/application/reducer.ts

@@ -8,6 +8,7 @@ import {
   ApplicationModal,
   setOpenModal,
   updateChainId,
+  setChainConnectivityWarning,
 } from './actions'
 
 type PopupList = Array<{ key: string; show: boolean; content: PopupContent; removeAfterMs: number | null }>
@@ -15,6 +16,7 @@ type PopupList = Array<{ key: string; show: boolean; content: PopupContent; remo
 export interface ApplicationState {
   // used by RTK-Query to build dynamic subgraph urls
   readonly chainId: number | null
+  readonly chainConnectivityWarning: boolean
   readonly blockNumber: { readonly [chainId: number]: number }
   readonly popupList: PopupList
   readonly openModal: ApplicationModal | null
@@ -22,6 +24,7 @@ export interface ApplicationState {
 
 const initialState: ApplicationState = {
   chainId: null,
+  chainConnectivityWarning: false,
   blockNumber: {},
   popupList: [],
   openModal: null,
@@ -61,4 +64,7 @@ export default createReducer(initialState, (builder) =>
         }
       })
     })
+    .addCase(setChainConnectivityWarning, (state, { payload: { warn } }) => {
+      state.chainConnectivityWarning = warn
+    })
 )

src/state/application/updater.ts

-import { useCallback, useEffect, useState } from 'react'
+import { CHAIN_INFO } from 'constants/chains'
+import useDebounce from 'hooks/useDebounce'
+import useIsWindowVisible from 'hooks/useIsWindowVisible'
+import { useActiveWeb3React } from 'hooks/web3'
+import ms from 'ms.macro'
+import { useCallback, useEffect, useRef, useState } from 'react'
 import { api, CHAIN_TAG } from 'state/data/enhanced'
 import { useAppDispatch, useAppSelector } from 'state/hooks'
 import { supportedChainId } from 'utils/supportedChainId'
-import useDebounce from '../../hooks/useDebounce'
-import useIsWindowVisible from '../../hooks/useIsWindowVisible'
-import { useActiveWeb3React } from '../../hooks/web3'
-import { updateBlockNumber, updateChainId } from './actions'
+import { setChainConnectivityWarning, updateBlockNumber, updateChainId } from './actions'
+import { useBlockNumber } from './hooks'
 
 function useQueryCacheInvalidator() {
   const dispatch = useAppDispatch()
@@ -20,10 +23,46 @@ function useQueryCacheInvalidator() {
   }, [chainId, dispatch])
 }
 
+const NETWORK_HEALTH_CHECK_MS = ms`15s`
+const DEFAULT_MS_BEFORE_WARNING = ms`10m`
+
+function useBlockWarningTimer() {
+  const { chainId } = useActiveWeb3React()
+  const dispatch = useAppDispatch()
+  const chainConnectivityWarningActive = useAppSelector((state) => state.application.chainConnectivityWarning)
+  const timeout = useRef<NodeJS.Timeout>()
+  const isWindowVisible = useIsWindowVisible()
+  const [msSinceLastBlock, setMsSinceLastBlock] = useState(0)
+  const currentBlock = useBlockNumber()
+
+  useEffect(() => {
+    setMsSinceLastBlock(0)
+  }, [currentBlock])
+
+  useEffect(() => {
+    const waitMsBeforeWarning =
+      (chainId ? CHAIN_INFO[chainId]?.blockWaitMsBeforeWarning : DEFAULT_MS_BEFORE_WARNING) ?? DEFAULT_MS_BEFORE_WARNING
+
+    timeout.current = setTimeout(() => {
+      setMsSinceLastBlock(NETWORK_HEALTH_CHECK_MS + msSinceLastBlock)
+      if (msSinceLastBlock > waitMsBeforeWarning && isWindowVisible) {
+        dispatch(setChainConnectivityWarning({ warn: true }))
+      } else if (chainConnectivityWarningActive) {
+        dispatch(setChainConnectivityWarning({ warn: false }))
+      }
+    }, NETWORK_HEALTH_CHECK_MS)
+
+    return function cleanup() {
+      if (timeout.current) {
+        clearTimeout(timeout.current)
+      }
+    }
+  }, [chainId, chainConnectivityWarningActive, dispatch, isWindowVisible, msSinceLastBlock, setMsSinceLastBlock])
+}
+
 export default function Updater(): null {
   const { library, chainId } = useActiveWeb3React()
   const dispatch = useAppDispatch()
-
   const windowVisible = useIsWindowVisible()
 
   const [state, setState] = useState<{ chainId: number | undefined; blockNumber: number | null }>({
@@ -31,6 +70,7 @@ export default function Updater(): null {
     blockNumber: null,
   })
 
+  useBlockWarningTimer()
   useQueryCacheInvalidator()
 
   const blockNumberCallback = useCallback(