From 9f54c0aca088ac8c6839504755d1530dbf1f3707 Mon Sep 17 00:00:00 2001
From: sergeych <real.sergeych@gmail.com>
Date: Mon, 25 May 2026 20:48:44 +0300
Subject: [PATCH] Improved TOC scrolling behavior and fixed incorrect content
 indentation logic. Added test for image-only sections.

---
 .../net/sergeych/toread/ReaderContent.kt      | 15 +++++++-
 .../net/sergeych/toread/ReaderScreen.kt       | 12 ++++++
 .../toread/ReadAloudContentPlanTest.kt        | 37 +++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderContent.kt b/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderContent.kt
index 61c6de0..98fc8f2 100644
--- a/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderContent.kt
+++ b/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderContent.kt
@@ -1551,7 +1551,7 @@ internal fun buildReaderContentPlan(book: Fb2Book): ReaderContentPlan {
                 }
             }
         }
-        val childDepth = if (blocks.isEmpty()) readerDepth else readerDepth + 1
+        val childDepth = if (blocks.hasIndentBearingContent()) readerDepth + 1 else readerDepth
         addSections(section.sections, childDepth)
     }
 
@@ -1811,6 +1811,19 @@ private fun Fb2Section.readableBlocks(): List<Fb2Block> =
         images.map(Fb2Block::Image) + paragraphs.map { Fb2Block.Paragraph(Fb2Text(listOf(Fb2TextSpan(it)))) }
     }
 
+private fun List<Fb2Block>.hasIndentBearingContent(): Boolean =
+    any { block ->
+        when (block) {
+            Fb2Block.EmptyLine,
+            is Fb2Block.Image,
+            is Fb2Block.Subtitle -> false
+            is Fb2Block.Cite,
+            is Fb2Block.Epigraph,
+            is Fb2Block.Paragraph,
+            is Fb2Block.Poem -> true
+        }
+    }
+
 private data class ChapterEntry(
     val title: String,
     val section: Fb2Section,
diff --git a/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderScreen.kt b/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderScreen.kt
index 8612ce0..77b8ca7 100644
--- a/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderScreen.kt
+++ b/composeApp/src/commonMain/kotlin/net/sergeych/toread/ReaderScreen.kt
@@ -693,11 +693,23 @@ private fun TableOfContentsDialog(
     onOpenEntry: (ReaderTocEntry) -> Unit,
     onDismiss: () -> Unit,
 ) {
+    val selectedEntryIndex = currentItemIndex?.let { itemIndex ->
+        contentPlan.tocEntries.indexOfFirst { it.itemIndex == itemIndex }.takeIf { it >= 0 }
+    }
+    val listState = rememberLazyListState(
+        initialFirstVisibleItemIndex = selectedEntryIndex?.let { it + 1 } ?: 0,
+    )
+
+    LaunchedEffect(contentPlan, selectedEntryIndex) {
+        selectedEntryIndex?.let { listState.scrollToItem(it + 1) }
+    }
+
     AlertDialog(
         onDismissRequest = onDismiss,
         title = { Text(strings.tableOfContents) },
         text = {
             LazyColumn(
+                state = listState,
                 modifier = Modifier.fillMaxWidth().heightIn(max = 480.dp),
             ) {
                 item(key = "back") {
diff --git a/composeApp/src/commonTest/kotlin/net/sergeych/toread/ReadAloudContentPlanTest.kt b/composeApp/src/commonTest/kotlin/net/sergeych/toread/ReadAloudContentPlanTest.kt
index 1213f2b..764c1e3 100644
--- a/composeApp/src/commonTest/kotlin/net/sergeych/toread/ReadAloudContentPlanTest.kt
+++ b/composeApp/src/commonTest/kotlin/net/sergeych/toread/ReadAloudContentPlanTest.kt
@@ -6,6 +6,7 @@ import net.sergeych.toread.fb2.Fb2Block
 import net.sergeych.toread.fb2.Fb2Book
 import net.sergeych.toread.fb2.Fb2Epigraph
 import net.sergeych.toread.fb2.Fb2EpigraphBlock
+import net.sergeych.toread.fb2.Fb2ImageRef
 import net.sergeych.toread.fb2.Fb2Poem
 import net.sergeych.toread.fb2.Fb2PoemBlock
 import net.sergeych.toread.fb2.Fb2Section
@@ -275,6 +276,42 @@ class ReadAloudContentPlanTest {
         )
     }
 
+    @Test
+    fun imageOnlyPartStructureDoesNotIndentWholeBook() {
+        val plan = buildReaderContentPlan(
+            Fb2Book(
+                title = "Book",
+                sections = listOf(
+                    Fb2Section(
+                        title = "Wrapper title",
+                        sections = listOf(
+                            Fb2Section(
+                                images = listOf(Fb2ImageRef("#front.jpg")),
+                            ),
+                            Fb2Section(
+                                title = "Part one",
+                                blocks = listOf(Fb2Block.Image(Fb2ImageRef("#part.png"))),
+                                sections = listOf(
+                                    Fb2Section(
+                                        title = "Chapter one",
+                                        blocks = listOf(paragraph("Chapter text.")),
+                                    ),
+                                ),
+                            ),
+                        ),
+                    ),
+                ),
+            ),
+        )
+
+        assertEquals(0, plan.elements.filterIsInstance<ReaderElement.Paragraph>().single().depth)
+        assertEquals(
+            listOf(0, 0, 0),
+            plan.elements.filterIsInstance<ReaderElement.SectionTitle>().map { it.depth },
+        )
+        assertEquals(listOf(0, 0, 0, 0), plan.tocEntries.map { it.depth })
+    }
+
     @Test
     fun realNestedSectionsKeepRelativeIndent() {
         val plan = buildReaderContentPlan(