Add follow button to highlighted post (#2828)

* add user-minus icon

* add follow button to highlighted post

* web hack for animations

* adjustments

* remove static string width, use flexbox

* Revert "add user-minus icon"

This reverts commit f1aafb3e39dce131b729864924d63a22368f9187.

* better displaying of display name

src/view/com/post-thread/PostThreadFollowBtn.tsx

@@ -0,0 +1,154 @@
+import React from 'react'
+import {StyleSheet, TouchableOpacity, View} from 'react-native'
+import {useNavigation} from '@react-navigation/native'
+import {AppBskyActorDefs} from '@atproto/api'
+import {msg, Trans} from '@lingui/macro'
+import {useLingui} from '@lingui/react'
+import {FontAwesomeIcon} from '@fortawesome/react-native-fontawesome'
+
+import {logger} from '#/logger'
+import {Text} from 'view/com/util/text/Text'
+import * as Toast from 'view/com/util/Toast'
+import {s} from 'lib/styles'
+import {usePalette} from 'lib/hooks/usePalette'
+import {useWebMediaQueries} from 'lib/hooks/useWebMediaQueries'
+import {Shadow, useProfileShadow} from 'state/cache/profile-shadow'
+import {track} from 'lib/analytics/analytics'
+import {
+  useProfileFollowMutationQueue,
+  useProfileQuery,
+} from 'state/queries/profile'
+import {useRequireAuth} from 'state/session'
+
+export function PostThreadFollowBtn({did}: {did: string}) {
+  const {data: profile, isLoading} = useProfileQuery({did})
+
+  // We will never hit this - the profile will always be cached or loaded above
+  // but it keeps the typechecker happy
+  if (isLoading || !profile) return null
+
+  return <PostThreadFollowBtnLoaded profile={profile} />
+}
+
+function PostThreadFollowBtnLoaded({
+  profile: profileUnshadowed,
+}: {
+  profile: AppBskyActorDefs.ProfileViewDetailed
+}) {
+  const navigation = useNavigation()
+  const {_} = useLingui()
+  const pal = usePalette('default')
+  const palInverted = usePalette('inverted')
+  const {isTabletOrDesktop} = useWebMediaQueries()
+  const profile: Shadow<AppBskyActorDefs.ProfileViewBasic> =
+    useProfileShadow(profileUnshadowed)
+  const [queueFollow, queueUnfollow] = useProfileFollowMutationQueue(profile)
+  const requireAuth = useRequireAuth()
+
+  const isFollowing = !!profile.viewer?.following
+  const [wasFollowing, setWasFollowing] = React.useState<boolean>(isFollowing)
+
+  // This prevents the button from disappearing as soon as we follow.
+  const showFollowBtn = React.useMemo(
+    () => !isFollowing || !wasFollowing,
+    [isFollowing, wasFollowing],
+  )
+
+  /**
+   * We want this button to stay visible even after following, so that the user can unfollow if they want.
+   * However, we need it to disappear after we push to a screen and then come back. We also need it to
+   * show up if we view the post while following, go to the profile and unfollow, then come back to the
+   * post.
+   *
+   * We want to update wasFollowing both on blur and on focus so that we hit all these cases. On native,
+   * we could do this only on focus because the transition animation gives us time to not notice the
+   * sudden rendering of the button. However, on web if we do this, there's an obvious flicker once the
+   * button renders. So, we update the state in both cases.
+   */
+  React.useEffect(() => {
+    const updateWasFollowing = () => {
+      if (wasFollowing !== isFollowing) {
+        setWasFollowing(isFollowing)
+      }
+    }
+
+    const unsubscribeFocus = navigation.addListener('focus', updateWasFollowing)
+    const unsubscribeBlur = navigation.addListener('blur', updateWasFollowing)
+
+    return () => {
+      unsubscribeFocus()
+      unsubscribeBlur()
+    }
+  }, [isFollowing, wasFollowing, navigation])
+
+  const onPress = React.useCallback(() => {
+    if (!isFollowing) {
+      requireAuth(async () => {
+        try {
+          track('ProfileHeader:FollowButtonClicked')
+          await queueFollow()
+        } catch (e: any) {
+          if (e?.name !== 'AbortError') {
+            logger.error('Failed to follow', {message: String(e)})
+            Toast.show(_(msg`There was an issue! ${e.toString()}`))
+          }
+        }
+      })
+    } else {
+      requireAuth(async () => {
+        try {
+          track('ProfileHeader:UnfollowButtonClicked')
+          await queueUnfollow()
+        } catch (e: any) {
+          if (e?.name !== 'AbortError') {
+            logger.error('Failed to unfollow', {message: String(e)})
+            Toast.show(_(msg`There was an issue! ${e.toString()}`))
+          }
+        }
+      })
+    }
+  }, [isFollowing, requireAuth, queueFollow, _, queueUnfollow])
+
+  if (!showFollowBtn) return null
+
+  return (
+    <View style={{width: isTabletOrDesktop ? 130 : 120}}>
+      <View style={styles.btnOuter}>
+        <TouchableOpacity
+          testID="followBtn"
+          onPress={onPress}
+          style={[styles.btn, !isFollowing ? palInverted.view : pal.viewLight]}
+          accessibilityRole="button"
+          accessibilityLabel={_(msg`Follow ${profile.handle}`)}
+          accessibilityHint={_(
+            msg`Shows posts from ${profile.handle} in your feed`,
+          )}>
+          {isTabletOrDesktop && (
+            <FontAwesomeIcon
+              icon={!isFollowing ? 'plus' : 'check'}
+              style={[!isFollowing ? palInverted.text : pal.text, s.mr5]}
+            />
+          )}
+          <Text
+            type="button"
+            style={[!isFollowing ? palInverted.text : pal.text, s.bold]}
+            numberOfLines={1}>
+            {!isFollowing ? <Trans>Follow</Trans> : <Trans>Following</Trans>}
+          </Text>
+        </TouchableOpacity>
+      </View>
+    </View>
+  )
+}
+
+const styles = StyleSheet.create({
+  btnOuter: {
+    marginLeft: 'auto',
+  },
+  btn: {
+    flexDirection: 'row',
+    borderRadius: 50,
+    paddingVertical: 8,
+    paddingHorizontal: 14,
+  },
+})