From 466f2f60887bc5d7b5d33f791dc07768c98c62d4 Mon Sep 17 00:00:00 2001
From: atsunatsu <atsunatsu@users.noreply.github.com>
Date: Tue, 22 Sep 2026 12:23:50 +0800
Subject: [PATCH] fix(mutual): map Match prefill scrolls to time-range card via
 scrollToItem

Compose ui 1.11.x (BOM 2026.06.01) ignores the LazyListState
firstVisibleItemIndex constructor parameter - the list always starts at
item 0. Restore the scrollToItem approach (verified effective by
Robolectric Compose UI tests) and keep the auto-started query.
---
 .../look4sat/feature/mutual/MutualScreen.kt   | 14 +++++++++++++
 .../feature/mutual/MutualViewModel.kt         | 20 +++++++++++++------
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt b/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt
index da4aa5f9..19ccc658 100644
--- a/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt
+++ b/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt
@@ -369,6 +369,20 @@ private fun MutualContent(
             )
         }
     }
+
+    // Prefill from the map's grid-QSO dialog "Match" button: once the page is
+    // laid out, jump straight to the time-range card. Index accounts for the
+    // optional error card at the top (error = 0, station inputs = 1, time
+    // range = 2; else 1). scrollToItem is used instead of initializing the
+    // LazyListState at index 1: the constructor parameter is ignored by this
+    // Compose version (verified in tests), while scrollToItem lands correctly.
+    val matchSearchIndex = if (state.errorMessage != null) 2 else 1
+    LaunchedEffect(state.scrollToTimeRange, matchSearchIndex) {
+        if (state.scrollToTimeRange) {
+            listState.scrollToItem(matchSearchIndex)
+            viewModel.consumeScrollToTimeRange()
+        }
+    }
 }
 
 @Composable
diff --git a/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt b/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt
index 90c054be..71e95434 100644
--- a/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt
+++ b/feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt
@@ -55,7 +55,11 @@ data class MutualUiState(
     val hasSearched: Boolean = false,
     val selectedPassIndex: Int = -1,
     val isUtc: Boolean = false,
-    val errorMessage: String? = null
+    val errorMessage: String? = null,
+    // One-shot flag set by prefillMatchFromGrid() (map grid → Match button):
+    // the page scrolls to the time-range card after the first layout, then
+    // consumeScrollToTimeRange() clears it.
+    val scrollToTimeRange: Boolean = false
 )
 
 class MutualViewModel(
@@ -187,9 +191,8 @@ class MutualViewModel(
      * Pre-fill the match page for a target grid picked from the map's grid-QSO
      * dialog ("Match" button): set the opposite-station grid (with its
      * coordinates), reset the time range to 24h, start the query immediately
-     * so results are ready when the page opens, and position the list at the
-     * time-range card (LazyColumn item 1, the card right below the station
-     * inputs) so the page opens showing it at the top.
+     * so results are ready when the page opens, and flag the page to scroll
+     * straight to the time-range card once it is laid out.
      */
     fun prefillMatchFromGrid(grid: String) {
         val g = grid.trim().uppercase()
@@ -199,10 +202,15 @@ class MutualViewModel(
                 stationBGrid = g,
                 stationBLat = pos?.let { p -> "%.4f".format(p.latitude) } ?: it.stationBLat,
                 stationBLon = pos?.let { p -> "%.4f".format(p.longitude) } ?: it.stationBLon,
-                hoursAhead = 24
+                hoursAhead = 24,
+                scrollToTimeRange = true
             )
         }
-        queryMutualPasses(initialScrollIndex = 1)
+        queryMutualPasses()
+    }
+
+    fun consumeScrollToTimeRange() {
+        _uiState.update { it.copy(scrollToTimeRange = false) }
     }
 
     fun queryMutualPasses(initialScrollIndex: Int = 0) {