From 55eb6c56287c512128d9d47e65cbaf9ee88be5b0 Mon Sep 17 00:00:00 2001
From: Samuel Newman <mozzius@protonmail.com>
Date: Fri, 5 Dec 2025 01:09:54 +0200
Subject: [PATCH] add shadow filter to post feeds (#9406)

---
 src/state/cache/profile-shadow.ts | 80 ++++++++++++++++++++++++++++++-
 src/view/com/posts/PostFeed.tsx   | 19 +++++++-
 2 files changed, 97 insertions(+), 2 deletions(-)

diff --git a/src/state/cache/profile-shadow.ts b/src/state/cache/profile-shadow.ts
index e1cff94092..5ee7c9c423 100644
--- a/src/state/cache/profile-shadow.ts
+++ b/src/state/cache/profile-shadow.ts
@@ -13,7 +13,10 @@ import {findAllProfilesInQueryData as findAllProfilesInListConvosQueryData} from
 import {findAllProfilesInQueryData as findAllProfilesInMyBlockedAccountsQueryData} from '#/state/queries/my-blocked-accounts'
 import {findAllProfilesInQueryData as findAllProfilesInMyMutedAccountsQueryData} from '#/state/queries/my-muted-accounts'
 import {findAllProfilesInQueryData as findAllProfilesInNotifsQueryData} from '#/state/queries/notifications/feed'
-import {findAllProfilesInQueryData as findAllProfilesInFeedsQueryData} from '#/state/queries/post-feed'
+import {
+  type FeedPage,
+  findAllProfilesInQueryData as findAllProfilesInFeedsQueryData,
+} from '#/state/queries/post-feed'
 import {findAllProfilesInQueryData as findAllProfilesInPostLikedByQueryData} from '#/state/queries/post-liked-by'
 import {findAllProfilesInQueryData as findAllProfilesInPostQuotesQueryData} from '#/state/queries/post-quotes'
 import {findAllProfilesInQueryData as findAllProfilesInPostRepostedByQueryData} from '#/state/queries/post-reposted-by'
@@ -110,6 +113,81 @@ export function useMaybeProfileShadow<
   }, [profile, shadow])
 }
 
+/**
+ * Takes a list of posts, and returns a list of DIDs that should be filtered out
+ *
+ * Note: it doesn't retroactively scan the cache, but only listens to new updates.
+ * The use case here is intended for removing a post from a feed after you mute the author
+ */
+export function usePostAuthorShadowFilter(data?: FeedPage[]) {
+  const [trackedDids, setTrackedDids] = useState<string[]>(
+    () =>
+      data?.flatMap(page =>
+        page.slices.flatMap(slice =>
+          slice.items.map(item => item.post.author.did),
+        ),
+      ) ?? [],
+  )
+  const [authors, setAuthors] = useState(
+    new Map<string, {muted: boolean; blocked: boolean}>(),
+  )
+
+  const [prevData, setPrevData] = useState(data)
+  if (data !== prevData) {
+    const newAuthors = new Set(trackedDids)
+    let hasNew = false
+    for (const slice of data?.flatMap(page => page.slices) ?? []) {
+      for (const item of slice.items) {
+        const author = item.post.author
+        if (!newAuthors.has(author.did)) {
+          hasNew = true
+          newAuthors.add(author.did)
+        }
+      }
+    }
+    if (hasNew) setTrackedDids([...newAuthors])
+    setPrevData(data)
+  }
+
+  useEffect(() => {
+    const unsubs: Array<() => void> = []
+
+    for (const did of trackedDids) {
+      function onUpdate(value: Partial<ProfileShadow>) {
+        setAuthors(prev => {
+          const prevValue = prev.get(did)
+          const next = new Map(prev)
+          next.set(did, {
+            blocked: Boolean(value.blockingUri ?? prevValue?.blocked ?? false),
+            muted: Boolean(value.muted ?? prevValue?.muted ?? false),
+          })
+          return next
+        })
+      }
+      emitter.addListener(did, onUpdate)
+      unsubs.push(() => {
+        emitter.removeListener(did, onUpdate)
+      })
+    }
+
+    return () => {
+      unsubs.map(fn => fn())
+    }
+  }, [trackedDids])
+
+  return useMemo(() => {
+    const dids: Array<string> = []
+
+    for (const [did, value] of authors.entries()) {
+      if (value.blocked || value.muted) {
+        dids.push(did)
+      }
+    }
+
+    return dids
+  }, [authors])
+}
+
 export function updateProfileShadow(
   queryClient: QueryClient,
   did: string,
diff --git a/src/view/com/posts/PostFeed.tsx b/src/view/com/posts/PostFeed.tsx
index 4f4e6352ab..7e70d918c3 100644
--- a/src/view/com/posts/PostFeed.tsx
+++ b/src/view/com/posts/PostFeed.tsx
@@ -35,6 +35,7 @@ import {logEvent} from '#/lib/statsig/statsig'
 import {isNetworkError} from '#/lib/strings/errors'
 import {logger} from '#/logger'
 import {isIOS, isNative, isWeb} from '#/platform/detection'
+import {usePostAuthorShadowFilter} from '#/state/cache/profile-shadow'
 import {listenPostCreated} from '#/state/events'
 import {useFeedFeedbackContext} from '#/state/feed-feedback'
 import {useTrendingSettings} from '#/state/preferences/trending'
@@ -363,6 +364,11 @@ let PostFeed = ({
    */
   const [isCurrentFeedAtStartupSelected] = useState(selectedFeed === feed)
 
+  const blockedOrMutedAuthors = usePostAuthorShadowFilter(
+    // author feeds have their own handling
+    feed.startsWith('author|') ? undefined : data?.pages,
+  )
+
   const feedItems: FeedRow[] = useMemo(() => {
     // wraps a slice item, and replaces it with a showLessFollowup item
     // if the user has pressed show less on it
@@ -423,7 +429,11 @@ let PostFeed = ({
                 // eslint-disable-next-line @typescript-eslint/no-shadow
                 item => item.uri === slice.feedPostUri,
               )
-              if (item && AppBskyEmbedVideo.isView(item.post.embed)) {
+              if (
+                item &&
+                AppBskyEmbedVideo.isView(item.post.embed) &&
+                !blockedOrMutedAuthors.includes(item.post.author.did)
+              ) {
                 videos.push({
                   item,
                   feedContext: slice.feedContext,
@@ -541,6 +551,12 @@ let PostFeed = ({
                   key:
                     'sliceFallbackMarker-' + sliceIndex + '-' + lastFetchedAt,
                 })
+              } else if (
+                slice.items.some(item =>
+                  blockedOrMutedAuthors.includes(item.post.author.did),
+                )
+              ) {
+                // skip
               } else if (slice.isIncompleteThread && slice.items.length >= 3) {
                 const beforeLast = slice.items.length - 2
                 const last = slice.items.length - 1
@@ -636,6 +652,7 @@ let PostFeed = ({
     hasPressedShowLessUris,
     ageAssuranceBannerState,
     isCurrentFeedAtStartupSelected,
+    blockedOrMutedAuthors,
   ])
 
   // events