From b8d298a95dd9161fd432e184daae4e67cf73605f Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Tue, 17 Dec 2024 21:48:41 +0000
Subject: [PATCH] Track seen in post thread too

---
 src/state/feed-feedback.tsx             |  2 +-
 src/view/com/post-thread/PostThread.tsx | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/state/feed-feedback.tsx b/src/state/feed-feedback.tsx
index bb4292d9c6..e46728d58c 100644
--- a/src/state/feed-feedback.tsx
+++ b/src/state/feed-feedback.tsx
@@ -265,7 +265,7 @@ const m = Math.ceil((n * Math.log(p)) / Math.log(1 / Math.pow(2, Math.log(2))))
 const k = Math.round((m / n) * Math.log(2))
 let globalBloomFilter = new BloomFilter(m, k)
 
-function markGloballySeenPost(uri: string) {
+export function markGloballySeenPost(uri: string) {
   if (globalBloomFilter.size >= n) {
     // If we ever get here, just restart to avoid saturation.
     globalBloomFilter = new BloomFilter(m, k)
diff --git a/src/view/com/post-thread/PostThread.tsx b/src/view/com/post-thread/PostThread.tsx
index a0073b02f9..942cc37408 100644
--- a/src/view/com/post-thread/PostThread.tsx
+++ b/src/view/com/post-thread/PostThread.tsx
@@ -1,4 +1,4 @@
-import React, {memo, useRef, useState} from 'react'
+import React, {memo, useEffect, useRef, useState} from 'react'
 import {StyleSheet, useWindowDimensions, View} from 'react-native'
 import {runOnJS} from 'react-native-reanimated'
 import Animated from 'react-native-reanimated'
@@ -18,6 +18,7 @@ import {ScrollProvider} from '#/lib/ScrollContext'
 import {sanitizeDisplayName} from '#/lib/strings/display-names'
 import {cleanError} from '#/lib/strings/errors'
 import {isAndroid, isNative, isWeb} from '#/platform/detection'
+import {markGloballySeenPost} from '#/state/feed-feedback'
 import {useModerationOpts} from '#/state/preferences/moderation-opts'
 import {
   fillThreadModerationCache,
@@ -391,6 +392,22 @@ export function PostThread({uri}: {uri: string | undefined}) {
     [refetch],
   )
 
+  useEffect(() => {
+    if (skeleton) {
+      // We're not tracking linger time here so conservatively mark
+      // just the highlighted post and the parent. Presumably,
+      // if you're already midthread, you know what was above.
+      const {parents, highlightedPost} = skeleton
+      markGloballySeenPost(highlightedPost.uri)
+      for (let i = 0; i < parents.length; i++) {
+        const parent = parents[i]
+        if (isThreadPost(parent)) {
+          markGloballySeenPost(parent.uri)
+        }
+      }
+    }
+  }, [skeleton])
+
   const {openComposer} = useComposerControls()
   const onPressReply = React.useCallback(() => {
     if (thread?.type !== 'post') {