msglist: In combined/mentions/starred, exclude DMs if all recipients muted

In the future, this should apply to the ReactionsNarrow from the Web
app too, once we have it.

Co-authored-by: Sayed Mahmood Sayedi <[email protected]>

Author: chrisbobbe

lib/model/message.dart

@@ -287,6 +287,12 @@ class MessageStoreImpl extends PerAccountStoreBase with MessageStore, _OutboxMes
     }
   }
 
+  void handleMutedUsersEvent(MutedUsersEvent event) {
+    for (final view in _messageListViews) {
+      view.handleMutedUsersEvent(event);
+    }
+  }
+
   void handleMessageEvent(MessageEvent event) {
     // If the message is one we already know about (from a fetch),
     // clobber it with the one from the event system.

lib/model/message_list.dart

@@ -13,6 +13,7 @@ import 'content.dart';
 import 'message.dart';
 import 'narrow.dart';
 import 'store.dart';
+import 'user.dart';
 
 export '../api/route/messages.dart' show Anchor, AnchorCode, NumericAnchor;
 
@@ -622,10 +623,12 @@ class MessageListView with ChangeNotifier, _MessageSequence {
   bool _messageVisible(MessageBase message) {
     switch (narrow) {
       case CombinedFeedNarrow():
-        return switch (message.conversation) {
+        final conversation = message.conversation;
+        return switch (conversation) {
           StreamConversation(:final streamId, :final topic) =>
             store.isTopicVisible(streamId, topic),
-          DmConversation() => true,
+          DmConversation() => !store.shouldMuteDmConversation(
+            DmNarrow.ofConversation(conversation, selfUserId: store.selfUserId)),
         };
 
       case ChannelNarrow(:final streamId):
@@ -636,8 +639,14 @@ class MessageListView with ChangeNotifier, _MessageSequence {
 
       case TopicNarrow():
       case DmNarrow():
+        return true;
+
       case MentionsNarrow():
       case StarredMessagesNarrow():
+        if (message.conversation case DmConversation(:final allRecipientIds)) {
+          return !store.shouldMuteDmConversation(DmNarrow(
+            allRecipientIds: allRecipientIds, selfUserId: store.selfUserId));
+        }
         return true;
     }
   }
@@ -653,9 +662,11 @@ class MessageListView with ChangeNotifier, _MessageSequence {
 
       case TopicNarrow():
       case DmNarrow():
+        return true;
+
       case MentionsNarrow():
       case StarredMessagesNarrow():
-        return true;
+        return false;
     }
   }
 
@@ -678,6 +689,24 @@ class MessageListView with ChangeNotifier, _MessageSequence {
     }
   }
 
+  /// Whether this event could affect the result that [_messageVisible]
+  /// would ever have returned for any possible message in this message list.
+  MutedUsersVisibilityEffect _mutedUsersEventCanAffectVisibility(MutedUsersEvent event) {
+    switch(narrow) {
+      case CombinedFeedNarrow():
+        return store.mightChangeShouldMuteDmConversation(event);
+
+      case ChannelNarrow():
+      case TopicNarrow():
+      case DmNarrow():
+        return MutedUsersVisibilityEffect.none;
+
+      case MentionsNarrow():
+      case StarredMessagesNarrow():
+        return store.mightChangeShouldMuteDmConversation(event);
+    }
+  }
+
   void _setStatus(FetchingStatus value, {FetchingStatus? was}) {
     assert(was == null || _status == was);
     _status = value;
@@ -981,6 +1010,34 @@ class MessageListView with ChangeNotifier, _MessageSequence {
     }
   }
 
+  void handleMutedUsersEvent(MutedUsersEvent event) {
+    switch (_mutedUsersEventCanAffectVisibility(event)) {
+      case MutedUsersVisibilityEffect.none:
+        return;
+
+      case MutedUsersVisibilityEffect.muted:
+        final anyRemoved = _removeMessagesWhere((message) {
+          if (message is! DmMessage) return false;
+          final narrow = DmNarrow.ofMessage(message, selfUserId: store.selfUserId);
+          return store.shouldMuteDmConversation(narrow, event: event);
+        });
+        if (anyRemoved) {
+          notifyListeners();
+        }
+
+      case MutedUsersVisibilityEffect.mixed:
+      case MutedUsersVisibilityEffect.unmuted:
+        // TODO get the newly-unmuted messages from the message store
+        // For now, we simplify the task by just refetching this message list
+        // from scratch.
+        if (fetched) {
+          _reset();
+          notifyListeners();
+          fetchInitial();
+        }
+    }
+  }
+
   void handleDeleteMessageEvent(DeleteMessageEvent event) {
     if (_removeMessagesById(event.messageIds)) {
       notifyListeners();

lib/model/narrow.dart

@@ -200,11 +200,21 @@ class DmNarrow extends Narrow implements SendableNarrow {
     required int selfUserId,
   }) {
     return DmNarrow(
+      // TODO should this really be making a copy of `allRecipientIds`?
       allRecipientIds: List.unmodifiable(message.conversation.allRecipientIds),
       selfUserId: selfUserId,
     );
   }
 
+  factory DmNarrow.ofConversation(DmConversation conversation, {
+    required int selfUserId,
+  }) {
+    return DmNarrow(
+      allRecipientIds: conversation.allRecipientIds,
+      selfUserId: selfUserId,
+    );
+  }
+
   /// A [DmNarrow] from an item in [InitialSnapshot.recentPrivateConversations].
   factory DmNarrow.ofRecentDmConversation(RecentDmConversation conversation, {required int selfUserId}) {
     return DmNarrow.withOtherUsers(conversation.userIds, selfUserId: selfUserId);

lib/model/store.dart

@@ -649,6 +649,10 @@ class PerAccountStore extends PerAccountStoreBase with ChangeNotifier, EmojiStor
   bool isUserMuted(int userId, {MutedUsersEvent? event}) =>
     _users.isUserMuted(userId, event: event);
 
+  @override
+  MutedUsersVisibilityEffect mightChangeShouldMuteDmConversation(MutedUsersEvent event) =>
+    _users.mightChangeShouldMuteDmConversation(event);
+
   final UserStoreImpl _users;
 
   final TypingStatus typingStatus;
@@ -958,6 +962,8 @@ class PerAccountStore extends PerAccountStoreBase with ChangeNotifier, EmojiStor
 
       case MutedUsersEvent():
         assert(debugLog("server event: muted_users"));
+        _messages.handleMutedUsersEvent(event);
+        // Update _users last, so other handlers can compare to the old value.
         _users.handleMutedUsersEvent(event);
         notifyListeners();
 

lib/model/user.dart

@@ -1,6 +1,7 @@
 import '../api/model/events.dart';
 import '../api/model/initial_snapshot.dart';
 import '../api/model/model.dart';
+import 'algorithms.dart';
 import 'localizations.dart';
 import 'narrow.dart';
 import 'store.dart';
@@ -97,6 +98,27 @@ mixin UserStore on PerAccountStoreBase {
     return narrow.otherRecipientIds.every(
       (userId) => isUserMuted(userId, event: event));
   }
+
+  /// Whether the given event might change the result of [shouldMuteDmConversation]
+  /// for its list of muted users, compared to the current state.
+  MutedUsersVisibilityEffect mightChangeShouldMuteDmConversation(MutedUsersEvent event);
+}
+
+/// Whether and how a given [MutedUsersEvent] may affect the results
+/// that [UserStore.shouldMuteDmConversation] would give for some messages.
+enum MutedUsersVisibilityEffect {
+  /// The event will have no effect on the visibility results.
+  none,
+
+  /// The event may change some visibility results from true to false.
+  muted,
+
+  /// The event may change some visibility results from false to true.
+  unmuted,
+
+  /// The event may change some visibility results from false to true,
+  /// and some from true to false.
+  mixed;
 }
 
 /// The implementation of [UserStore] that does the work.
@@ -130,6 +152,29 @@ class UserStoreImpl extends PerAccountStoreBase with UserStore {
     return (event?.mutedUsers.map((item) => item.id) ?? _mutedUsers).contains(userId);
   }
 
+  @override
+  MutedUsersVisibilityEffect mightChangeShouldMuteDmConversation(MutedUsersEvent event) {
+    final sortedOld = _mutedUsers.toList()..sort();
+    final sortedNew = event.mutedUsers.map((u) => u.id).toList()..sort();
+    assert(isSortedWithoutDuplicates(sortedOld));
+    assert(isSortedWithoutDuplicates(sortedNew));
+    final union = setUnion(sortedOld, sortedNew);
+
+    final willMuteSome = sortedOld.length < union.length;
+    final willUnmuteSome = sortedNew.length < union.length;
+
+    switch ((willUnmuteSome, willMuteSome)) {
+      case (true, false):
+        return MutedUsersVisibilityEffect.unmuted;
+      case (false, true):
+        return MutedUsersVisibilityEffect.muted;
+      case (true, true):
+        return MutedUsersVisibilityEffect.mixed;
+      case (false, false): // TODO(log)?
+        return MutedUsersVisibilityEffect.none;
+    }
+  }
+
   void handleRealmUserEvent(RealmUserEvent event) {
     switch (event) {
       case RealmUserAddEvent():