Fix up traversal metadata

src/screens/PostThread/components/ReadMore.tsx

@@ -4,7 +4,7 @@ import {useLingui} from '@lingui/react'
 
 import {makeProfileLink} from '#/lib/routes/links'
 import {type PostThreadParams, type Slice} from '#/state/queries/usePostThread'
-import {TREE_AVI_WIDTH,TREE_INDENT} from '#/screens/PostThread/const'
+import {TREE_AVI_WIDTH, TREE_INDENT} from '#/screens/PostThread/const'
 import {atoms as a, useTheme} from '#/alf'
 import {CirclePlus_Stroke2_Corner0_Rounded as CirclePlus} from '#/components/icons/CirclePlus'
 import {Link} from '#/components/Link'
@@ -20,7 +20,7 @@ export function ReadMore({
   const t = useTheme()
   const {_} = useLingui()
   const isTreeView = view === 'tree'
-  const indentCount = item.indent - 1
+  const indentCount = Math.max(0, item.indent - 1)
 
   const treeIndents = isTreeView ? (
     Array.from(Array(indentCount)).map((_, n: number) => (

src/state/queries/usePostThread/traversal.ts

@@ -8,7 +8,12 @@ import {
   HiddenReplyKind,
   type PostThreadParams,
   type Slice,
+  type TraversalMetadata,
 } from '#/state/queries/usePostThread/types'
+import {
+  getPostRecord,
+  getPostTraversalMetadata,
+} from '#/state/queries/usePostThread/utils'
 import * as views from '#/state/queries/usePostThread/views'
 
 export function flatten(
@@ -168,6 +173,7 @@ export function sort(
   const items: Slice[] = []
   const hidden: Slice[] = []
   const muted: Slice[] = []
+  const postDataMap = new Map<string, TraversalMetadata | undefined>()
 
   traversal: for (let i = 0; i < thread.length; i++) {
     const item = thread[i]
@@ -193,6 +199,8 @@ export function sort(
       ) {
         items.push(views.threadPostBlocked(item))
       } else if (AppBskyUnspeccedGetPostThreadV2.isThreadItemPost(item.value)) {
+        postDataMap.set(item.uri, getPostTraversalMetadata(item))
+
         items.push(
           views.threadPost({
             uri: item.uri,
@@ -261,14 +269,16 @@ export function sort(
         i = branch.end
         continue traversal
       } else if (AppBskyUnspeccedGetPostThreadV2.isThreadItemPost(item.value)) {
+        postDataMap.set(item.uri, getPostTraversalMetadata(item))
+
         const oneUp = thread.at(i - 1)
         const oneDown = thread.at(i + 1)
         const post = views.threadPost({
           uri: item.uri,
           depth: item.depth,
           value: item.value,
-          parent: thread.find(
-            p => p.uri === item.value.post.record.reply.parent.uri,
+          traversalMetadata: postDataMap.get(
+            getPostRecord(item.value.post)?.reply?.parent?.uri || '',
           ),
           oneUp,
           oneDown,
@@ -308,12 +318,14 @@ export function sort(
               if (
                 AppBskyUnspeccedGetPostThreadV2.isThreadItemPost(child.value)
               ) {
+                postDataMap.set(child.uri, getPostTraversalMetadata(child))
+
                 const childPost = views.threadPost({
                   uri: child.uri,
                   depth: child.depth,
                   value: child.value,
-                  parent: thread.find(
-                    p => p.uri === child.value.post.record.reply.parent.uri,
+                  traversalMetadata: postDataMap.get(
+                    getPostRecord(child.value.post)?.reply?.parent?.uri || '',
                   ),
                   oneUp: thread[ci - 1],
                   oneDown: thread[ci + 1],

src/state/queries/usePostThread/types.ts

@@ -91,3 +91,8 @@ export type Slice =
       nextAnchor: Extract<Slice, {type: 'threadPost'}>
       nextAnchorUri: AtUri
     }
+
+export type TraversalMetadata = {
+  depth: number
+  hasBranchingReplies: boolean
+}

src/state/queries/usePostThread/utils.ts

@@ -2,10 +2,11 @@ import {
   type AppBskyFeedDefs,
   AppBskyFeedPost,
   AppBskyFeedThreadgate,
-  type AppBskyUnspeccedGetPostThreadV2,
+  AppBskyUnspeccedGetPostThreadV2,
   AtUri,
 } from '@atproto/api'
 
+import {type TraversalMetadata} from '#/state/queries/usePostThread/types'
 import * as bsky from '#/types/bsky'
 
 export function getThreadgateRecord(
@@ -31,3 +32,25 @@ export function getRootPostAtUri(post: AppBskyFeedDefs.PostView) {
     }
   }
 }
+
+export function getPostRecord(post: AppBskyFeedDefs.PostView) {
+  return post.record as AppBskyFeedPost.Record
+}
+
+export function getPostTraversalMetadata(
+  item: AppBskyUnspeccedGetPostThreadV2.ThreadItem,
+): TraversalMetadata | undefined {
+  if (!AppBskyUnspeccedGetPostThreadV2.isThreadItemPost(item.value)) return
+  const replyCount = item.value.post.replyCount || 0
+  const unhydratedReplies = item.value.moreReplies || 0
+  return {
+    depth: item.depth,
+    /**
+     * If the post has more than a single reply, and the total reply count
+     * minus the number of replies not present in the response is greater than
+     * 1, then we must have more than a single branch of replies present in the
+     * response, which can affect how we render tree view.
+     */
+    hasBranchingReplies: replyCount > 1 && replyCount - unhydratedReplies > 1,
+  }
+}

src/state/queries/usePostThread/views.ts

@@ -8,7 +8,10 @@ import {
   type ModerationOpts,
 } from '@atproto/api'
 
-import {type Slice} from '#/state/queries/usePostThread/types'
+import {
+  type Slice,
+  type TraversalMetadata,
+} from '#/state/queries/usePostThread/types'
 
 export function threadPostNoUnauthenticated({
   uri,
@@ -65,32 +68,18 @@ export function threadPost({
   uri,
   depth,
   value,
-  parent: up,
   oneUp,
   moderationOpts,
+  traversalMetadata,
 }: {
   uri: string
   depth: number
   value: $Typed<AppBskyUnspeccedGetPostThreadV2.ThreadItemPost>
-  parent?: AppBskyUnspeccedGetPostThreadV2.OutputSchema['thread'][number]
   oneUp?: AppBskyUnspeccedGetPostThreadV2.OutputSchema['thread'][number]
   oneDown?: AppBskyUnspeccedGetPostThreadV2.OutputSchema['thread'][number]
   moderationOpts: ModerationOpts
+  traversalMetadata?: TraversalMetadata
 }): Extract<Slice, {type: 'threadPost'}> {
-  const parent = (up && 'post' in up?.value
-    ? up.value
-    : undefined) as unknown as AppBskyUnspeccedGetPostThreadV2.ThreadItemPost
-  const parentReplyCount = parent?.post?.replyCount || 0
-  const parentAdditionalReplies = parent?.moreReplies || 0
-  const parentHasBranchingReplies =
-    parentReplyCount > 1 && parentReplyCount - parentAdditionalReplies > 1
-  // if (!parentHasBranchingReplies) {
-  //   console.log(value.post.record.text, {
-  //     parentReplyCount,
-  //     parentAdditionalReplies,
-  //   })
-  // }
-
   return {
     type: 'threadPost',
     key: uri,
@@ -111,8 +100,10 @@ export function threadPost({
       isAnchor: depth === 0,
       showParentReplyLine: !!oneUp && oneUp.depth !== 0 && oneUp.depth < depth,
       showChildReplyLine: (value.post.replyCount || 0) > 0,
-      indent: parentHasBranchingReplies ? depth : up?.depth || depth,
-      parentHasBranchingReplies,
+      indent: traversalMetadata?.hasBranchingReplies
+        ? depth
+        : traversalMetadata?.depth || depth,
+      parentHasBranchingReplies: !!traversalMetadata?.hasBranchingReplies,
     },
   }
 }
@@ -127,7 +118,7 @@ export function readMore({
     key: `readMore:${parent.uri}`,
     indent: parent.ui.parentHasBranchingReplies
       ? parent.depth
-      : parent.depth - 1,
+      : Math.max(0, parent.depth - 1),
     replyCount: parent.value.moreReplies,
     nextAnchor: parent,
     nextAnchorUri: new AtUri(parent.uri),