From 99c74f0df9a43e820b0c6c53d8fd7ab44684908f Mon Sep 17 00:00:00 2001
From: Josiah Campbell <9521010+jocmp@users.noreply.github.com>
Date: Sun, 2 Aug 2026 17:18:56 -0500
Subject: [PATCH] Clamp scroll high water mark to list size

---
 .../capyreader/app/ui/articles/ArticleScreen.kt   |  8 ++++++++
 .../app/ui/articles/ArticleScreenViewModel.kt     | 15 +++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreen.kt b/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreen.kt
index 796fb4174..a0a9c6ef0 100644
--- a/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreen.kt
+++ b/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreen.kt
@@ -293,6 +293,7 @@ fun ArticleScreen(
             articles = articles,
             scrollHighWaterMark = viewModel.scrollHighWaterMark,
             updateScrollHighWaterMark = viewModel::updateScrollHighWaterMark,
+            clampScrollHighWaterMark = viewModel::clampScrollHighWaterMark,
             markReadOnScroll = viewModel::markReadOnScroll,
             resetScrollBehaviorOffset = resetScrollBehaviorOffset,
         )
@@ -903,6 +904,7 @@ private fun MarkReadOnScroll(
     articles: LazyPagingItems<Article>,
     scrollHighWaterMark: Int,
     updateScrollHighWaterMark: (Int) -> Unit,
+    clampScrollHighWaterMark: (Int) -> Unit,
     markReadOnScroll: (String) -> Unit,
     resetScrollBehaviorOffset: () -> Unit,
 ) {
@@ -923,6 +925,12 @@ private fun MarkReadOnScroll(
                 }
         }
 
+        LaunchedEffect(listState) {
+            snapshotFlow { articles.itemCount }
+                .distinctUntilChanged()
+                .collect(clampScrollHighWaterMark)
+        }
+
         LaunchedEffect(listState) {
             snapshotFlow {
                 listState.firstVisibleItemIndex - 1
diff --git a/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreenViewModel.kt b/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreenViewModel.kt
index d498c0a54..b9af26556 100644
--- a/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreenViewModel.kt
+++ b/app/src/main/java/com/capyreader/app/ui/articles/ArticleScreenViewModel.kt
@@ -503,6 +503,21 @@ class ArticleScreenViewModel(
         }
     }
 
+    fun clampScrollHighWaterMark(itemCount: Int) {
+        val lastIndex = itemCount - 1
+
+        if (_scrollHighWaterMark <= lastIndex) {
+            return
+        }
+
+        CapyLog.debug(
+            "scroll_high_water_mark:clamp",
+            mapOf("previous" to _scrollHighWaterMark, "new" to lastIndex)
+        )
+
+        _scrollHighWaterMark = lastIndex
+    }
+
     fun resetScrollHighWaterMark() {
         CapyLog.debug(
             "scroll_high_water_mark:reset",