Post view client event (#9408)

* Adds post:view client event tracking in feeds

* Add post:view event on the post page itself

* Don't send post:view to statsig for now

* convert to non reactive callback to reduce rerenders

---------

Co-authored-by: Samuel Newman <mozzius@protonmail.com>

src/logger/metrics.ts

@@ -263,6 +263,13 @@ export type MetricEvents = {
   'post:unbookmark': {
     logContext: 'FeedItem' | 'PostThreadItem' | 'Post' | 'ImmersiveVideo'
   }
+  'post:view': {
+    uri: string
+    authorDid: string
+    logContext: 'FeedItem' | 'PostThreadItem' | 'Post' | 'ImmersiveVideo'
+    feedDescriptor?: string
+    position?: number
+  }
   'bookmarks:view': {}
   'bookmarks:post-clicked': {}
   'profile:follow': {

src/screens/PostThread/index.tsx

@@ -1,10 +1,11 @@
-import {useCallback, useMemo, useRef, useState} from 'react'
+import {useCallback, useEffect, useMemo, useRef, useState} from 'react'
 import {useWindowDimensions, View} from 'react-native'
 import Animated, {useAnimatedStyle} from 'react-native-reanimated'
 import {Trans} from '@lingui/macro'
 
 import {useInitialNumToRender} from '#/lib/hooks/useInitialNumToRender'
 import {useOpenComposer} from '#/lib/hooks/useOpenComposer'
+import {logger} from '#/logger'
 import {useFeedFeedback} from '#/state/feed-feedback'
 import {type ThreadViewOption} from '#/state/queries/preferences/useThreadPreferences'
 import {
@@ -73,6 +74,29 @@ export function PostThread({uri}: {uri: string}) {
     return {hasParents}
   }, [thread.data.items])
 
+  // Track post:view event when anchor post is viewed
+  const seenPostUriRef = useRef<string | null>(null)
+  useEffect(() => {
+    if (
+      anchor?.type === 'threadPost' &&
+      anchor.value.post.uri !== seenPostUriRef.current
+    ) {
+      const post = anchor.value.post
+      seenPostUriRef.current = post.uri
+
+      logger.metric(
+        'post:view',
+        {
+          uri: post.uri,
+          authorDid: post.author.did,
+          logContext: 'Post',
+          feedDescriptor: feedFeedback.feedDescriptor,
+        },
+        {statsig: false},
+      )
+    }
+  }, [anchor, feedFeedback.feedDescriptor])
+
   const {openComposer} = useOpenComposer()
   const optimisticOnPostReply = useCallback(
     (payload: OnPostSuccessData) => {

src/view/com/posts/PostFeed.tsx

@@ -840,12 +840,67 @@ let PostFeed = ({
   const liveNowConfig = useLiveNowConfig()
 
   const seenActorWithStatusRef = useRef<Set<string>>(new Set())
+  const seenPostUrisRef = useRef<Set<string>>(new Set())
+
+  // Helper to calculate position in feed (count only root posts, not interstitials or thread replies)
+  const getPostPosition = useNonReactiveCallback(
+    (type: FeedRow['type'], key: string) => {
+      // Calculate position: find the row index in feedItems, then calculate position
+      const rowIndex = feedItems.findIndex(
+        row => row.type === 'sliceItem' && row.key === key,
+      )
+
+      if (rowIndex >= 0) {
+        let position = 0
+        for (let i = 0; i < rowIndex && i < feedItems.length; i++) {
+          const row = feedItems[i]
+          if (row.type === 'sliceItem') {
+            // Only count root posts (indexInSlice === 0), not thread replies
+            if (row.indexInSlice === 0) {
+              position++
+            }
+          } else if (row.type === 'videoGridRow') {
+            // Count each video in the grid row
+            position += row.items.length
+          }
+        }
+        return position
+      }
+    },
+  )
+
   const onItemSeen = useCallback(
     (item: FeedRow) => {
       feedFeedback.onItemSeen(item)
-      if (item.type === 'sliceItem') {
-        const actor = item.slice.items[item.indexInSlice].post.author
 
+      // Track post:view events
+      if (item.type === 'sliceItem') {
+        const slice = item.slice
+        const indexInSlice = item.indexInSlice
+        const postItem = slice.items[indexInSlice]
+        const post = postItem.post
+
+        // Only track the root post of each slice (index 0) to avoid double-counting thread items
+        if (indexInSlice === 0 && !seenPostUrisRef.current.has(post.uri)) {
+          seenPostUrisRef.current.add(post.uri)
+
+          const position = getPostPosition('sliceItem', item.key)
+
+          logger.metric(
+            'post:view',
+            {
+              uri: post.uri,
+              authorDid: post.author.did,
+              logContext: 'FeedItem',
+              feedDescriptor: feedFeedback.feedDescriptor || feed,
+              position,
+            },
+            {statsig: false},
+          )
+        }
+
+        // Live status tracking (existing code)
+        const actor = post.author
         if (
           actor.status &&
           validateStatus(actor.did, actor.status, liveNowConfig) &&
@@ -863,9 +918,33 @@ let PostFeed = ({
             )
           }
         }
+      } else if (item.type === 'videoGridRow') {
+        // Track each video in the grid row
+        for (let i = 0; i < item.items.length; i++) {
+          const postItem = item.items[i]
+          const post = postItem.post
+
+          if (!seenPostUrisRef.current.has(post.uri)) {
+            seenPostUrisRef.current.add(post.uri)
+
+            const position = getPostPosition('videoGridRow', item.key)
+
+            logger.metric(
+              'post:view',
+              {
+                uri: post.uri,
+                authorDid: post.author.did,
+                logContext: 'FeedItem',
+                feedDescriptor: feedFeedback.feedDescriptor || feed,
+                position,
+              },
+              {statsig: false},
+            )
+          }
+        }
       }
     },
-    [feedFeedback, feed, liveNowConfig],
+    [feedFeedback, feed, liveNowConfig, getPostPosition],
   )
 
   return (