From 4c0141d3f0b64a29781c318206e64fc4152924cf Mon Sep 17 00:00:00 2001
From: Jordan Frankfurt <jordanwfrankfurt@gmail.com>
Date: Tue, 14 Jul 2020 20:58:04 -0400
Subject: [PATCH] add basic keyboard navigation

---
 src/components/Search/index.js | 167 ++++++++++++++++++++-------------
 src/hooks/index.ts             |  25 +++++
 2 files changed, 126 insertions(+), 66 deletions(-)

diff --git a/src/components/Search/index.js b/src/components/Search/index.js
index e56bc0358..0b8403059 100644
--- a/src/components/Search/index.js
+++ b/src/components/Search/index.js
@@ -13,6 +13,8 @@ import { useMedia } from 'react-use'
 import { useAllPairsInUniswap, useAllTokensInUniswap } from '../../contexts/GlobalData'
 import { OVERVIEW_TOKEN_BLACKLIST, OVERVIEW_PAIR_BLACKLIST } from '../../constants'
 
+import { useKeyPress } from '../../hooks'
+
 const Wrapper = styled.div`
   display: flex;
   position: relative;
@@ -68,7 +70,7 @@ const Menu = styled.div`
   width: 100%;
   top: 50px;
   max-height: 540px;
-  overflow: scroll;
+  overflow-y: scroll;
   left: 0;
   padding-bottom: 20px;
   background: white;
@@ -89,6 +91,10 @@ const MenuItem = styled(Row)`
     cursor: pointer;
     background-color: #f7f8fa;
   }
+  :focus {
+    background-color: #f7f8fa;
+    outline: black auto 1px;
+  }
 `
 
 const Heading = styled(Row)`
@@ -119,7 +125,13 @@ export const Search = ({ small = false }) => {
   const allPairs = useAllPairsInUniswap()
   const allPairData = useAllPairData()
 
-  const [showMenu, toggleMenu] = useState(false)
+  const [cursor, setCursor] = useState(null)
+  const downKeyPressed = useKeyPress('ArrowDown')
+  const escapeKeyPressed = useKeyPress('Escape')
+  const tabKeyPressed = useKeyPress('Tab')
+  const upKeyPressed = useKeyPress('ArrowUp')
+
+  const [showMenu, setShowMenu] = useState(false)
   const [value, setValue] = useState('')
   const [, toggleShadow] = useState(false)
   const [, toggleBottomShadow] = useState(false)
@@ -134,9 +146,9 @@ export const Search = ({ small = false }) => {
 
   useEffect(() => {
     if (value !== '') {
-      toggleMenu(true)
+      setShowMenu(true)
     } else {
-      toggleMenu(false)
+      setShowMenu(false)
     }
   }, [value])
 
@@ -278,10 +290,50 @@ export const Search = ({ small = false }) => {
     setPairsShown(Math.min(Object.keys(filteredPairList).length, 3))
   }, [filteredPairList])
 
+  useEffect(() => {
+    if (pairsShown + tokensShown === 0) {
+      setCursor(undefined)
+    } else if (showMenu && downKeyPressed && cursor === undefined) {
+      setCursor(0)
+    } else if (showMenu && downKeyPressed && cursor < pairsShown + tokensShown) {
+      setCursor(cursor + 1)
+    }
+  }, [showMenu, downKeyPressed])
+
+  useEffect(() => {
+    if (pairsShown + tokensShown === 0) {
+      setCursor(undefined)
+    } else if (showMenu && upKeyPressed && cursor === undefined) {
+      setCursor(pairsShown + tokensShown - 1)
+    } else if (showMenu && upKeyPressed && cursor === 0) {
+      setCursor(pairsShown + tokensShown - 1)
+    } else if (showMenu && upKeyPressed && cursor > 0) {
+      setCursor(cursor - 1)
+    }
+  }, [showMenu, upKeyPressed])
+
+  useEffect(() => {
+    setCursor(undefined)
+  }, [tabKeyPressed])
+
+  useEffect(() => {
+    setCursor(undefined)
+    setShowMenu(false)
+  }, [escapeKeyPressed])
+
+  useEffect(() => {
+    const canUseCursor = Boolean(
+      Number.isInteger(cursor) && menuRef.current && menuRef.current.querySelectorAll('a')[cursor]
+    )
+    if (canUseCursor) {
+      menuRef.current.querySelectorAll('a')[cursor].focus()
+    }
+  }, [cursor])
+
   function onDismiss() {
     setPairsShown(3)
     setTokensShown(3)
-    toggleMenu(false)
+    setShowMenu(false)
     setValue('')
   }
 
@@ -296,7 +348,7 @@ export const Search = ({ small = false }) => {
     ) {
       setPairsShown(3)
       setTokensShown(3)
-      toggleMenu(false)
+      setShowMenu(false)
     }
   }
 
@@ -338,7 +390,7 @@ export const Search = ({ small = false }) => {
             setValue(e.target.value)
           }}
           onFocus={() => {
-            toggleMenu(true)
+            setShowMenu(true)
           }}
         />
       </Wrapper>
@@ -350,68 +402,51 @@ export const Search = ({ small = false }) => {
         <Heading>
           <Gray>Pairs</Gray>
         </Heading>
-        <div>
-          {filteredPairList && Object.keys(filteredPairList).length === 0 && <MenuItem>No results</MenuItem>}
-          {filteredPairList &&
-            filteredPairList.slice(0, pairsShown).map(pair => {
-              if (pair?.token0?.id === '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2') {
-                pair.token0.name = 'ETH (Wrapped)'
-                pair.token0.symbol = 'ETH'
-              }
-              if (pair?.token1.id === '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2') {
-                pair.token1.name = 'ETH (Wrapped)'
-                pair.token1.symbol = 'ETH'
-              }
-              return (
-                <BasicLink to={'/pair/' + pair.id} key={pair.id} onClick={onDismiss}>
-                  <MenuItem>
-                    <DoubleTokenLogo a0={pair?.token0?.id} a1={pair?.token1?.id} margin={true} />
-                    <span style={{ marginLeft: '10px' }}>{pair.token0.symbol + '-' + pair.token1.symbol} Pair</span>
-                  </MenuItem>
-                </BasicLink>
-              )
-            })}
-          <Heading
-            hide={!(Object.keys(filteredPairList).length > 3 && Object.keys(filteredPairList).length >= pairsShown)}
-          >
-            <Blue
-              onClick={() => {
-                setPairsShown(pairsShown + 5)
-              }}
-            >
-              See more...
-            </Blue>
-          </Heading>
-        </div>
+        {Object.keys(filteredPairList).length === 0 && <MenuItem>No results</MenuItem>}
+        {filteredPairList.slice(0, pairsShown).map(pair => {
+          if (pair?.token0?.id === '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2') {
+            pair.token0.name = 'ETH (Wrapped)'
+            pair.token0.symbol = 'ETH'
+          }
+          if (pair?.token1.id === '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2') {
+            pair.token1.name = 'ETH (Wrapped)'
+            pair.token1.symbol = 'ETH'
+          }
+          return (
+            <BasicLink to={'/pair/' + pair.id} key={pair.id} onClick={onDismiss}>
+              <MenuItem>
+                <DoubleTokenLogo a0={pair?.token0?.id} a1={pair?.token1?.id} margin={true} />
+                <span style={{ marginLeft: '10px' }}>{pair.token0.symbol + '-' + pair.token1.symbol} Pair</span>
+              </MenuItem>
+            </BasicLink>
+          )
+        })}
+        <Heading
+          hide={!(Object.keys(filteredPairList).length > 3 && Object.keys(filteredPairList).length >= pairsShown)}
+        >
+          <Blue onClick={() => setPairsShown(pairsShown + 5)}>See more...</Blue>
+        </Heading>
         <Heading>
           <Gray>Tokens</Gray>
         </Heading>
-        <div>
-          {Object.keys(filteredTokenList).length === 0 && <MenuItem>No results</MenuItem>}
-          {filteredTokenList.slice(0, tokensShown).map(token => {
-            return (
-              <BasicLink to={'/token/' + token.id} key={token.id} onClick={onDismiss}>
-                <MenuItem>
-                  <TokenLogo address={token.id} style={{ marginRight: '10px' }} />
-                  <span>{token.name}</span>
-                  <span>({token.symbol})</span>
-                </MenuItem>
-              </BasicLink>
-            )
-          })}
-
-          <Heading
-            hide={!(Object.keys(filteredTokenList).length > 3 && Object.keys(filteredTokenList).length >= tokensShown)}
-          >
-            <Blue
-              onClick={() => {
-                setTokensShown(tokensShown + 5)
-              }}
-            >
-              See more...
-            </Blue>
-          </Heading>
-        </div>
+        {Object.keys(filteredTokenList).length === 0 && <MenuItem>No results</MenuItem>}
+        {filteredTokenList.slice(0, tokensShown).map(token => {
+          return (
+            <BasicLink to={'/token/' + token.id} key={token.id} onClick={onDismiss}>
+              <MenuItem>
+                <TokenLogo address={token.id} style={{ marginRight: '10px' }} />
+                <span>{token.name}</span>
+                <span>({token.symbol})</span>
+              </MenuItem>
+            </BasicLink>
+          )
+        })}
+
+        <Heading
+          hide={!(Object.keys(filteredTokenList).length > 3 && Object.keys(filteredTokenList).length >= tokensShown)}
+        >
+          <Blue onClick={() => setTokensShown(tokensShown + 5)}>See more...</Blue>
+        </Heading>
       </Menu>
     </div>
   )
diff --git a/src/hooks/index.ts b/src/hooks/index.ts
index 5082f6f6a..51a8193f3 100644
--- a/src/hooks/index.ts
+++ b/src/hooks/index.ts
@@ -55,6 +55,31 @@ export function useCopyClipboard(timeout = 500) {
   return [isCopied, staticCopy]
 }
 
+export function useKeyPress(targetKey: string) {
+  const [keyPressed, setKeyPressed] = useState(false)
+
+  const downHandler = useRef(undefined)
+  downHandler.current = ({ key }) => {
+    if (key === targetKey) setKeyPressed(true)
+  }
+
+  const upHandler = useRef(undefined)
+  upHandler.current = ({ key }) => {
+    if (key === targetKey) setKeyPressed(false)
+  }
+
+  useEffect(() => {
+    window.addEventListener('keydown', downHandler.current)
+    window.addEventListener('keyup', upHandler.current)
+    return () => {
+      window.removeEventListener('keydown', downHandler.current)
+      window.removeEventListener('keyup', upHandler.current)
+    }
+  }, [])
+
+  return keyPressed
+}
+
 export const useOutsideClick = (ref, ref2, callback) => {
   const handleClick = e => {
     if (ref.current && ref.current && !ref2.current) {