action_sheet: Support muting/unmuting/following topics

Currently, we don't have buttons, like "resolve topic", other than the
ones added here.

The switch statements follow the layout of the legacy app
implementation.

See also:
  https://github.com/zulip/zulip-mobile/blob/715d60a5e87fe37032bce58bd72edb99208e15be/src/action-sheets/index.js#L656-L753

Fixes: #348

Signed-off-by: Zixuan James Li <zixuan@zulip.com>

Author: PIG208

assets/l10n/app_en.arb

@@ -43,6 +43,22 @@
   "@permissionsDeniedReadExternalStorage": {
     "description": "Message for dialog asking the user to grant permissions for external storage read access."
   },
+  "actionSheetOptionMuteTopic": "Mute topic",
+  "@actionSheetOptionMuteTopic":  {
+    "description": "Label for muting a topic on action sheet."
+  },
+  "actionSheetOptionUnmuteTopic": "Unmute topic",
+  "@actionSheetOptionUnmuteTopic":  {
+    "description": "Label for unmuting a topic on action sheet."
+  },
+  "actionSheetOptionFollowTopic": "Follow topic",
+  "@actionSheetOptionFollowTopic":  {
+    "description": "Label for following a topic on action sheet."
+  },
+  "actionSheetOptionUnfollowTopic": "Unfollow topic",
+  "@actionSheetOptionUnfollowTopic":  {
+    "description": "Label for unfollowing a topic on action sheet."
+  },
   "actionSheetOptionCopyMessageText": "Copy message text",
   "@actionSheetOptionCopyMessageText":  {
     "description": "Label for copy message text button on action sheet."
@@ -172,6 +188,22 @@
       "error": {"type": "String", "example": "Invalid format"}
     }
   },
+  "errorMuteTopicFailed": "Failed to mute topic",
+  "@errorMuteTopicFailed": {
+    "description": "Error message when muting a topic failed."
+  },
+  "errorUnmuteTopicFailed": "Failed to unmute topic",
+  "@errorUnmuteTopicFailed": {
+    "description": "Error message when unmuting a topic failed."
+  },
+  "errorFollowTopicFailed": "Failed to follow topic",
+  "@errorFollowTopicFailed": {
+    "description": "Error message when following a topic failed."
+  },
+  "errorUnfollowTopicFailed": "Failed to unfollow topic",
+  "@errorUnfollowTopicFailed": {
+    "description": "Error message when unfollowing a topic failed."
+  },
   "errorSharingFailed": "Sharing failed",
   "@errorSharingFailed": {
     "description": "Error message when sharing a message failed."

lib/widgets/action_sheet.dart

@@ -8,6 +8,7 @@ import 'package:share_plus/share_plus.dart';
 
 import '../api/exception.dart';
 import '../api/model/model.dart';
+import '../api/route/channels.dart';
 import '../api/route/messages.dart';
 import '../model/internal_link.dart';
 import '../model/narrow.dart';
@@ -140,6 +141,199 @@ class ActionSheetCancelButton extends StatelessWidget {
   }
 }
 
+/// Show a sheet of actions you can take on a topic.
+void showTopicActionSheet(BuildContext context, {
+  required int channelId,
+  required String topic,
+}) {
+  final narrow = TopicNarrow(channelId, topic);
+  UserTopicUpdateButton button({
+    UserTopicVisibilityPolicy? from,
+    required UserTopicVisibilityPolicy to,
+  }) {
+    return UserTopicUpdateButton(
+      currentVisibilityPolicy: from,
+      newVisibilityPolicy: to,
+      narrow: narrow,
+      pageContext: context);
+  }
+
+  final mute =                 button(to:   UserTopicVisibilityPolicy.muted);
+  final unmute =               button(from: UserTopicVisibilityPolicy.muted,
+                                      to:   UserTopicVisibilityPolicy.none);
+  final unmuteInMutedChannel = button(to:   UserTopicVisibilityPolicy.unmuted);
+  final follow =               button(to:   UserTopicVisibilityPolicy.followed);
+  final unfollow =             button(from: UserTopicVisibilityPolicy.followed,
+                                      to:   UserTopicVisibilityPolicy.none);
+
+  final store = PerAccountStoreWidget.of(context);
+  final channelMuted = store.subscriptions[channelId]?.isMuted;
+  final visibilityPolicy = store.topicVisibilityPolicy(channelId, topic);
+
+  // TODO(server-7): simplify this condition away
+  final supportsUnmutingTopics = store.connection.zulipFeatureLevel! >= 170;
+  // TODO(server-8): simplify this condition away
+  final supportsFollowingTopics = store.connection.zulipFeatureLevel! >= 219;
+
+  final optionButtons = <Widget>[];
+  if (channelMuted != null && !channelMuted) {
+    switch (visibilityPolicy) {
+      case UserTopicVisibilityPolicy.muted:
+        optionButtons.add(unmute);
+        if (supportsFollowingTopics) {
+          optionButtons.add(follow);
+        }
+      case UserTopicVisibilityPolicy.none:
+      case UserTopicVisibilityPolicy.unmuted:
+        optionButtons.add(mute);
+        if (supportsFollowingTopics) {
+          optionButtons.add(follow);
+        }
+      case UserTopicVisibilityPolicy.followed:
+        optionButtons.add(mute);
+        if (supportsFollowingTopics) {
+          optionButtons.add(unfollow);
+        }
+      case UserTopicVisibilityPolicy.unknown:
+        assert(false);
+        return;
+    }
+  } else if (channelMuted != null && channelMuted) {
+    if (supportsUnmutingTopics) {
+      switch (visibilityPolicy) {
+        case UserTopicVisibilityPolicy.none:
+        case UserTopicVisibilityPolicy.muted:
+          optionButtons.add(unmuteInMutedChannel);
+          if (supportsFollowingTopics) {
+            optionButtons.add(follow);
+          }
+        case UserTopicVisibilityPolicy.unmuted:
+          optionButtons.add(mute);
+          if (supportsFollowingTopics) {
+            optionButtons.add(follow);
+          }
+        case UserTopicVisibilityPolicy.followed:
+          optionButtons.add(mute);
+          if (supportsFollowingTopics) {
+            optionButtons.add(unfollow);
+          }
+        case UserTopicVisibilityPolicy.unknown:
+          assert(false);
+          return;
+      }
+    }
+  } else {
+    // Not subscribed to the channel; there is no user topic change to be made.
+    return;
+  }
+
+  if (optionButtons.isEmpty) {
+    assert(!supportsUnmutingTopics);
+    return;
+  }
+
+  _showActionSheet(context, optionButtons: optionButtons);
+}
+
+class UserTopicUpdateButton extends ActionSheetMenuItemButton {
+  const UserTopicUpdateButton({
+    super.key,
+    this.currentVisibilityPolicy,
+    required this.newVisibilityPolicy,
+    required this.narrow,
+    required super.pageContext,
+  });
+
+  final UserTopicVisibilityPolicy? currentVisibilityPolicy;
+  final UserTopicVisibilityPolicy newVisibilityPolicy;
+  final TopicNarrow narrow;
+
+  @override IconData get icon {
+    switch (newVisibilityPolicy) {
+      case UserTopicVisibilityPolicy.none:
+        return ZulipIcons.inherit;
+      case UserTopicVisibilityPolicy.muted:
+        return ZulipIcons.mute;
+      case UserTopicVisibilityPolicy.unmuted:
+        return ZulipIcons.unmute;
+      case UserTopicVisibilityPolicy.followed:
+        return ZulipIcons.follow;
+      case UserTopicVisibilityPolicy.unknown:
+        assert(false);
+        return ZulipIcons.inherit;
+    }
+  }
+
+  @override
+  String label(ZulipLocalizations zulipLocalizations) {
+    switch ((currentVisibilityPolicy, newVisibilityPolicy)) {
+      case (UserTopicVisibilityPolicy.muted, UserTopicVisibilityPolicy.none):
+        return zulipLocalizations.actionSheetOptionUnmuteTopic;
+      case (UserTopicVisibilityPolicy.followed, UserTopicVisibilityPolicy.none):
+        return zulipLocalizations.actionSheetOptionUnfollowTopic;
+
+      case (_, UserTopicVisibilityPolicy.muted):
+        return zulipLocalizations.actionSheetOptionMuteTopic;
+      case (_, UserTopicVisibilityPolicy.unmuted):
+        return zulipLocalizations.actionSheetOptionUnmuteTopic;
+      case (_, UserTopicVisibilityPolicy.followed):
+        return zulipLocalizations.actionSheetOptionFollowTopic;
+
+      case (_, UserTopicVisibilityPolicy.none):
+      case (_, UserTopicVisibilityPolicy.unknown):
+        assert(false);
+        return '';
+    }
+  }
+
+  String _errorTitle(ZulipLocalizations zulipLocalizations) {
+    switch ((currentVisibilityPolicy, newVisibilityPolicy)) {
+      case (UserTopicVisibilityPolicy.muted, UserTopicVisibilityPolicy.none):
+        return zulipLocalizations.errorUnmuteTopicFailed;
+      case (UserTopicVisibilityPolicy.followed, UserTopicVisibilityPolicy.none):
+        return zulipLocalizations.errorUnfollowTopicFailed;
+
+      case (_, UserTopicVisibilityPolicy.muted):
+        return zulipLocalizations.errorMuteTopicFailed;
+      case (_, UserTopicVisibilityPolicy.unmuted):
+        return zulipLocalizations.errorUnmuteTopicFailed;
+      case (_, UserTopicVisibilityPolicy.followed):
+        return zulipLocalizations.errorFollowTopicFailed;
+
+      case (_, UserTopicVisibilityPolicy.none):
+      case (_, UserTopicVisibilityPolicy.unknown):
+        assert(false);
+        return '';
+    }
+  }
+
+  @override void onPressed() async {
+    try {
+      await updateUserTopic(
+        PerAccountStoreWidget.of(pageContext).connection,
+        streamId: narrow.streamId,
+        topic: narrow.topic,
+        visibilityPolicy: newVisibilityPolicy);
+    } catch (e) {
+      if (!pageContext.mounted) return;
+
+      String? errorMessage;
+
+      switch (e) {
+        case ZulipApiException():
+          errorMessage = e.message;
+          // TODO(#741) specific messages for common errors, like network errors
+          //   (support with reusable code)
+        default:
+      }
+
+      final zulipLocalizations = ZulipLocalizations.of(pageContext);
+      showErrorDialog(context: pageContext,
+        title: _errorTitle(zulipLocalizations), message: errorMessage);
+    }
+  }
+}
+
 /// Show a sheet of actions you can take on a message in the message list.
 ///
 /// Must have a [MessageListPage] ancestor.

lib/widgets/inbox.dart

@@ -4,6 +4,7 @@ import '../api/model/model.dart';
 import '../model/narrow.dart';
 import '../model/recent_dm_conversations.dart';
 import '../model/unreads.dart';
+import 'action_sheet.dart';
 import 'app_bar.dart';
 import 'icons.dart';
 import 'message_list.dart';
@@ -514,6 +515,8 @@ class _TopicItem extends StatelessWidget {
           Navigator.push(context,
             MessageListPage.buildRoute(context: context, narrow: narrow));
         },
+        onLongPress: () => showTopicActionSheet(context,
+          channelId: streamId, topic: topic),
         child: ConstrainedBox(constraints: const BoxConstraints(minHeight: 34),
           child: Row(crossAxisAlignment: CrossAxisAlignment.center, children: [
             const SizedBox(width: 63),

lib/widgets/message_list.dart

@@ -305,7 +305,7 @@ class MessageListAppBarTitle extends StatelessWidget {
   }) {
     // A null [Icon.icon] makes a blank space.
     final icon = (stream != null) ? iconDataForStream(stream) : null;
-    return Row(
+    final appBar = Row(
       mainAxisSize: MainAxisSize.min,
       // TODO(design): The vertical alignment of the stream privacy icon is a bit ad hoc.
       //   For screenshots of some experiments, see:
@@ -316,6 +316,17 @@ class MessageListAppBarTitle extends StatelessWidget {
         const SizedBox(width: 4),
         Flexible(child: Text(text)),
       ]);
+
+    if (narrow case TopicNarrow(:final streamId, :final topic)) {
+      return SizedBox(
+        width: double.infinity,
+        child: GestureDetector(
+          onLongPress: () => showTopicActionSheet(context,
+            channelId: streamId, topic: topic),
+          child: appBar));
+    }
+
+    return appBar;
   }
 
   @override
@@ -1016,6 +1027,8 @@ class StreamMessageRecipientHeader extends StatelessWidget {
       onTap: () => Navigator.push(context,
         MessageListPage.buildRoute(context: context,
           narrow: TopicNarrow.ofMessage(message))),
+      onLongPress: () => showTopicActionSheet(context,
+        channelId: message.streamId, topic: topic),
       child: ColoredBox(
         color: backgroundColor,
         child: Row(