diff --git a/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/extensions/ModelExtensions.kt b/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/extensions/ModelExtensions.kt
index 7c621f4..fdd1c97 100644
--- a/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/extensions/ModelExtensions.kt
+++ b/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/extensions/ModelExtensions.kt
@@ -241,6 +241,19 @@ fun io.github.kdroidfilter.seforimlibrary.db.SelectByLineId.toModel(): TocEntry
     )
 }
 
+fun io.github.kdroidfilter.seforimlibrary.db.SelectAncestorPath.toModel(): TocEntry =
+    TocEntry(
+        id = id,
+        bookId = bookId,
+        parentId = parentId,
+        textId = textId,
+        text = text,
+        level = level.toInt(),
+        lineId = lineId,
+        isLastChild = isLastChild == 1L,
+        hasChildren = hasChildren == 1L
+    )
+
 // --- Alternative TOC mappings ---
 
 fun io.github.kdroidfilter.seforimlibrary.db.Alt_toc_structure.toModel(): AltTocStructure =
diff --git a/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/LineSelectionRepository.kt b/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/LineSelectionRepository.kt
new file mode 100644
index 0000000..fd516bf
--- /dev/null
+++ b/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/LineSelectionRepository.kt
@@ -0,0 +1,55 @@
+package io.github.kdroidfilter.seforimlibrary.dao.repository
+
+import io.github.kdroidfilter.seforimlibrary.core.models.Line
+import io.github.kdroidfilter.seforimlibrary.core.models.TocEntry
+
+/**
+ * Interface for line selection and navigation related repository operations.
+ * This interface is extracted to allow mocking in tests.
+ */
+interface LineSelectionRepository {
+    /**
+     * Returns the TOC entry whose heading line is the given line id, or null if not a TOC heading.
+     */
+    suspend fun getHeadingTocEntryByLineId(lineId: Long): TocEntry?
+
+    /**
+     * Returns all line ids that belong to the given TOC entry (section), ordered by lineIndex.
+     */
+    suspend fun getLineIdsForTocEntry(tocEntryId: Long): List<Long>
+
+    /**
+     * Returns the TOC entry ID for a given line, or null if the line has no TOC mapping.
+     */
+    suspend fun getTocEntryIdForLine(lineId: Long): Long?
+
+    /**
+     * Returns a TOC entry by its ID.
+     */
+    suspend fun getTocEntry(id: Long): TocEntry?
+
+    /**
+     * Returns the ancestor path from the given TOC entry up to the root, ordered by level ASC.
+     */
+    suspend fun getAncestorPath(tocId: Long): List<TocEntry>
+
+    /**
+     * Returns a line by its ID.
+     */
+    suspend fun getLine(id: Long): Line?
+
+    /**
+     * Returns the previous line in the book, or null if at the beginning.
+     */
+    suspend fun getPreviousLine(bookId: Long, currentLineIndex: Int): Line?
+
+    /**
+     * Returns the next line in the book, or null if at the end.
+     */
+    suspend fun getNextLine(bookId: Long, currentLineIndex: Int): Line?
+
+    /**
+     * Returns lines in a range for a book.
+     */
+    suspend fun getLines(bookId: Long, startIndex: Int, endIndex: Int): List<Line>
+}
diff --git a/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/SeforimRepository.kt b/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/SeforimRepository.kt
index 06727d5..4c9ffd3 100644
--- a/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/SeforimRepository.kt
+++ b/dao/src/commonMain/kotlin/io/github/kdroidfilter/seforimlibrary/dao/repository/SeforimRepository.kt
@@ -64,6 +64,16 @@ class SeforimRepository(databasePath: String, private val driver: SqlDriver) {
         } catch (e: Exception) {
             logger.d{"Error counting books: ${e.message}"}
         }
+
+        // Warm up SQLite page cache by touching the line table index
+        try {
+            driver.executeQuery(
+                null,
+                "SELECT COUNT(*) FROM line WHERE bookId = 1",
+                { c -> QueryResult.Value(if (c.next().value) c.getLong(0) else 0L) },
+                0,
+            )
+        } catch (_: Exception) { }
     }
 
     
@@ -1158,6 +1168,14 @@ class SeforimRepository(databasePath: String, private val driver: SqlDriver) {
         database.tocQueriesQueries.selectChildren(parentId).executeAsList().map { it.toModel() }
     }
 
+    override suspend fun getAncestorPath(tocId: Long): List<TocEntry> = withContext(Dispatchers.IO) {
+        database.tocQueriesQueries.selectAncestorPath(tocId).executeAsList().map { it.toModel() }
+    }
+
+    suspend fun getFirstLeafTocId(tocId: Long): Long? = withContext(Dispatchers.IO) {
+        database.tocQueriesQueries.selectFirstLeafUnder(tocId).executeAsOneOrNull()
+    }
+
     // --- Alternative TOC structures ---
 
     suspend fun getAltTocStructuresForBook(bookId: Long): List<AltTocStructure> = withContext(Dispatchers.IO) {
diff --git a/dao/src/commonMain/sqldelight/io/github/kdroidfilter/seforimlibrary/db/TocQueries.sq b/dao/src/commonMain/sqldelight/io/github/kdroidfilter/seforimlibrary/db/TocQueries.sq
index d40a1dc..09d99ad 100644
--- a/dao/src/commonMain/sqldelight/io/github/kdroidfilter/seforimlibrary/db/TocQueries.sq
+++ b/dao/src/commonMain/sqldelight/io/github/kdroidfilter/seforimlibrary/db/TocQueries.sq
@@ -54,4 +54,29 @@ deleteByBookId:
 DELETE FROM tocEntry WHERE bookId = ?;
 
 lastInsertRowId:
-SELECT last_insert_rowid();
\ No newline at end of file
+SELECT last_insert_rowid();
+
+selectAncestorPath:
+WITH RECURSIVE ancestors(id, bookId, parentId, textId, level, lineId, isLastChild, hasChildren) AS (
+    SELECT id, bookId, parentId, textId, level, lineId, isLastChild, hasChildren
+    FROM tocEntry WHERE id = ?
+    UNION ALL
+    SELECT t.id, t.bookId, t.parentId, t.textId, t.level, t.lineId, t.isLastChild, t.hasChildren
+    FROM tocEntry t
+    JOIN ancestors a ON t.id = a.parentId
+)
+SELECT a.*, tt.text
+FROM ancestors a
+JOIN tocText tt ON a.textId = tt.id
+ORDER BY a.level ASC;
+
+selectFirstLeafUnder:
+WITH RECURSIVE descent(id, hasChildren) AS (
+    SELECT id, hasChildren FROM tocEntry WHERE id = ?
+    UNION ALL
+    SELECT (SELECT t.id FROM tocEntry t WHERE t.parentId = d.id ORDER BY t.id LIMIT 1),
+           (SELECT t.hasChildren FROM tocEntry t WHERE t.parentId = d.id ORDER BY t.id LIMIT 1)
+    FROM descent d
+    WHERE d.hasChildren = 1
+)
+SELECT id FROM descent WHERE hasChildren = 0 LIMIT 1;
\ No newline at end of file