From 53f1b25745ab5bc96037dab50a03ae27e1b5a13f Mon Sep 17 00:00:00 2001
From: chungwwei <chungwwei223@gmail.com>
Date: Tue, 11 Nov 2025 09:48:10 -0500
Subject: [PATCH 1/2] compose_box: Add BuildContext context arg to
 buildTopicInput

---
 lib/widgets/compose_box.dart | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/widgets/compose_box.dart b/lib/widgets/compose_box.dart
index 6e83356042..c9ad6cca09 100644
--- a/lib/widgets/compose_box.dart
+++ b/lib/widgets/compose_box.dart
@@ -1435,7 +1435,7 @@ abstract class _ComposeBoxBody extends StatelessWidget {
 
   ComposeBoxController get controller;
 
-  Widget? buildTopicInput();
+  Widget? buildTopicInput(BuildContext context);
   Widget buildContentInput();
   bool getComposeButtonsEnabled(BuildContext context);
   Widget? buildSendButton();
@@ -1471,7 +1471,7 @@ abstract class _ComposeBoxBody extends StatelessWidget {
       _AttachFromCameraButton(controller: controller, enabled: composeButtonsEnabled),
     ];
 
-    final topicInput = buildTopicInput();
+    final topicInput = buildTopicInput(context);
     final sendButton = buildSendButton();
     return Column(children: [
       Padding(
@@ -1509,7 +1509,7 @@ class _StreamComposeBoxBody extends _ComposeBoxBody {
   @override
   final StreamComposeBoxController controller;
 
-  @override Widget buildTopicInput() => _TopicInput(
+  @override Widget? buildTopicInput(BuildContext context) => _TopicInput(
     streamId: narrow.streamId,
     controller: controller,
   );
@@ -1537,7 +1537,7 @@ class _FixedDestinationComposeBoxBody extends _ComposeBoxBody {
   @override
   final FixedDestinationComposeBoxController controller;
 
-  @override Widget? buildTopicInput() => null;
+  @override Widget? buildTopicInput(BuildContext context) => null;
 
   @override Widget buildContentInput() => _FixedDestinationContentInput(
     narrow: narrow,
@@ -1562,7 +1562,7 @@ class _EditMessageComposeBoxBody extends _ComposeBoxBody {
   @override
   final EditMessageComposeBoxController controller;
 
-  @override Widget? buildTopicInput() => null;
+  @override Widget? buildTopicInput(BuildContext context) => null;
 
   @override Widget buildContentInput() => _EditMessageContentInput(
     narrow: narrow,

From d714978dbc4a91c47d5e6e56724c1c48500b0d2e Mon Sep 17 00:00:00 2001
From: chungwwei <chungwwei223@gmail.com>
Date: Tue, 11 Nov 2025 10:02:13 -0500
Subject: [PATCH 2/2] compose_box: Hide topic input on a general chat only
 channel

Closes: #1604
Fixes: #1843
---
 lib/widgets/compose_box.dart       | 19 +++++++++++++++----
 test/widgets/compose_box_test.dart | 24 ++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/lib/widgets/compose_box.dart b/lib/widgets/compose_box.dart
index c9ad6cca09..925ec17d98 100644
--- a/lib/widgets/compose_box.dart
+++ b/lib/widgets/compose_box.dart
@@ -1509,10 +1509,21 @@ class _StreamComposeBoxBody extends _ComposeBoxBody {
   @override
   final StreamComposeBoxController controller;
 
-  @override Widget? buildTopicInput(BuildContext context) => _TopicInput(
-    streamId: narrow.streamId,
-    controller: controller,
-  );
+  @override
+  Widget? buildTopicInput(BuildContext context) {
+    final store = PerAccountStoreWidget.of(context);
+    final stream = store.streams[narrow.streamId];
+    final topicsPolicy = stream?.topicsPolicy;
+
+    if (topicsPolicy == TopicsPolicy.emptyTopicOnly) {
+      return null;
+    }
+
+    return _TopicInput(
+      streamId: narrow.streamId,
+      controller: controller,
+    );
+  }
 
   @override Widget buildContentInput() => _StreamContentInput(
     narrow: narrow,
diff --git a/test/widgets/compose_box_test.dart b/test/widgets/compose_box_test.dart
index d27e374e3b..ff1a0012d7 100644
--- a/test/widgets/compose_box_test.dart
+++ b/test/widgets/compose_box_test.dart
@@ -2360,6 +2360,30 @@ void main() {
     // testCancel(narrow: topicNarrow,   start: _EditInteractionStart.restoreFailedEdit);
     // testCancel(narrow: dmNarrow,      start: _EditInteractionStart.restoreFailedEdit);
   });
+
+  group('compose box inputs visibility by topic policy', () {
+    void testComposeBoxWidgetVisibility({required TopicsPolicy topicsPolicy, required bool shouldShowTopicInput}) {
+      final description = shouldShowTopicInput ?
+        'show topic input when topic policy is $topicsPolicy':
+        'hide topic input when topic policy is $topicsPolicy';
+
+      testWidgets(description, (tester) async {
+        final channel = eg.stream(topicsPolicy: topicsPolicy);
+
+        await prepareComposeBox(tester, narrow: ChannelNarrow(channel.streamId), streams: [channel]);
+
+        check(contentInputFinder).findsOne();
+        shouldShowTopicInput ?
+          check(topicInputFinder).findsOne():
+          check(topicInputFinder).findsNothing();
+      });
+    }
+
+    testComposeBoxWidgetVisibility(topicsPolicy: TopicsPolicy.inherit, shouldShowTopicInput: true);
+    testComposeBoxWidgetVisibility(topicsPolicy: TopicsPolicy.allowEmptyTopic, shouldShowTopicInput: true);
+    testComposeBoxWidgetVisibility(topicsPolicy: TopicsPolicy.disableEmptyTopic, shouldShowTopicInput: true);
+    testComposeBoxWidgetVisibility(topicsPolicy: TopicsPolicy.emptyTopicOnly, shouldShowTopicInput: false);
+  });
 }
 
 /// How the edit interaction is started: