narrow: Support MentionsNarrow.

Because of how narrow interacts with the entire app, there are test
updates all over the place. The way I checked for the completeness of
this change is by looking at places where CombinedFeedNarrow is
referenced.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

assets/l10n/app_en.arb

@@ -344,6 +344,10 @@
   "@loginErrorMissingUsername": {
     "description": "Error message when an empty username was provided."
   },
+  "mentionsPageTitle": "Mentions",
+  "@mentionsPageTitle": {
+    "description": "Title for the page of @-mentions."
+  },
   "topicValidationErrorTooLong": "Topic length shouldn't be greater than 60 characters.",
   "@topicValidationErrorTooLong": {
     "description": "Topic validation error when topic is too long."

lib/model/autocomplete.dart

@@ -188,6 +188,7 @@ class MentionAutocompleteView extends ChangeNotifier {
     required Narrow narrow,
   }) {
     assert(narrow is! CombinedFeedNarrow);
+    assert(narrow is! MentionsNarrow);
     return store.users.values.toList()
       ..sort((userA, userB) => compareByDms(userA, userB, store: store));
   }

lib/model/message_list.dart

@@ -370,6 +370,7 @@ class MessageListView with ChangeNotifier, _MessageSequence {
 
       case TopicNarrow():
       case DmNarrow():
+      case MentionsNarrow():
         return true;
     }
   }
@@ -385,6 +386,7 @@ class MessageListView with ChangeNotifier, _MessageSequence {
 
       case TopicNarrow():
       case DmNarrow():
+      case MentionsNarrow():
         return true;
     }
   }

lib/model/narrow.dart

@@ -286,4 +286,27 @@ class DmNarrow extends Narrow implements SendableNarrow {
   int get hashCode => Object.hash('DmNarrow', _key);
 }
 
-// TODO other narrow types: starred, mentioned; searches; arbitrary
+class MentionsNarrow extends Narrow {
+  const MentionsNarrow();
+
+  @override
+  bool containsMessage(Message message) {
+    return message.flags.any((flag) =>
+      flag == MessageFlag.mentioned || flag == MessageFlag.wildcardMentioned);
+  }
+
+  @override
+  ApiNarrow apiEncode() => [ApiNarrowIsMentioned()];
+
+  @override
+  bool operator ==(Object other) {
+    if (other is! MentionsNarrow) return false;
+    // Conceptually there's only one value of this type.
+    return true;
+  }
+
+  @override
+  int get hashCode => 'MentionedNarrow'.hashCode;
+}
+
+// TODO other narrow types: starred; searches; arbitrary

lib/model/unreads.dart

@@ -193,6 +193,8 @@ class Unreads extends ChangeNotifier {
 
   int countInDmNarrow(DmNarrow narrow) => dms[narrow]?.length ?? 0;
 
+  int countInMentionsNarrow() => mentions.length;
+
   int countInNarrow(Narrow narrow) {
     switch (narrow) {
       case CombinedFeedNarrow():
@@ -203,6 +205,8 @@ class Unreads extends ChangeNotifier {
         return countInTopicNarrow(narrow.streamId, narrow.topic);
       case DmNarrow():
         return countInDmNarrow(narrow);
+      case MentionsNarrow():
+        return countInMentionsNarrow();
     }
   }
 

lib/widgets/compose_box.dart

@@ -967,7 +967,7 @@ class ComposeBox extends StatelessWidget {
       return _FixedDestinationComposeBox(key: controllerKey, narrow: narrow);
     } else if (narrow is DmNarrow) {
       return _FixedDestinationComposeBox(key: controllerKey, narrow: narrow);
-    } else if (narrow is CombinedFeedNarrow) {
+    } else if (narrow is CombinedFeedNarrow || narrow is MentionsNarrow) {
       return const SizedBox.shrink();
     } else {
       throw Exception("impossible narrow"); // TODO(dart-3): show this statically

lib/widgets/message_list.dart

@@ -63,6 +63,7 @@ class _MessageListPageState extends State<MessageListPage> {
     bool removeAppBarBottomBorder = false;
     switch(widget.narrow) {
       case CombinedFeedNarrow():
+      case MentionsNarrow():
         appBarBackgroundColor = null; // i.e., inherit
 
       case StreamNarrow(:final streamId):
@@ -109,7 +110,8 @@ class _MessageListPageState extends State<MessageListPage> {
               //   if those details get complicated, refactor to avoid copying.
               // TODO(#311) If we have a bottom nav, it will pad the bottom
               //   inset, and this should always be true.
-              removeBottom: widget.narrow is! CombinedFeedNarrow,
+              removeBottom: widget.narrow is! CombinedFeedNarrow
+                            && widget.narrow is! MentionsNarrow,
 
               child: Expanded(
                 child: MessageList(narrow: widget.narrow))),
@@ -170,6 +172,9 @@ class MessageListAppBarTitle extends StatelessWidget {
           final names = otherRecipientIds.map((id) => store.users[id]?.fullName ?? '(unknown user)');
           return Text("DMs with ${names.join(", ")}"); // TODO show avatars
         }
+
+      case MentionsNarrow():
+        return Text(zulipLocalizations.mentionsPageTitle);
     }
   }
 }
@@ -340,7 +345,7 @@ class _MessageListState extends State<MessageList> with PerAccountStoreAwareStat
           return _buildItem(data, i);
         }));
 
-    if (widget.narrow is CombinedFeedNarrow) {
+    if (widget.narrow is CombinedFeedNarrow || widget.narrow is MentionsNarrow) {
       // TODO(#311) If we have a bottom nav, it will pad the bottom
       //   inset, and this shouldn't be necessary
       sliver = SliverSafeArea(sliver: sliver);
@@ -521,7 +526,7 @@ class RecipientHeader extends StatelessWidget {
     final message = this.message;
     return switch (message) {
       StreamMessage() => StreamMessageRecipientHeader(message: message,
-        showStream: narrow is CombinedFeedNarrow),
+        showStream: narrow is CombinedFeedNarrow || narrow is MentionsNarrow),
       DmMessage() => DmRecipientHeader(message: message),
     };
   }
@@ -1111,5 +1116,12 @@ Future<void> _legacyMarkNarrowAsRead(BuildContext context, Narrow narrow) async
         messages: unreadDms,
         op: UpdateMessageFlagsOp.add,
         flag: MessageFlag.read);
+    case MentionsNarrow():
+      final unreadMentions = store.unreads.mentions.toList();
+      if (unreadMentions.isEmpty) return;
+      await updateMessageFlags(connection,
+        messages: unreadMentions,
+        op: UpdateMessageFlagsOp.add,
+        flag: MessageFlag.read);
   }
 }

test/api/route/messages_test.dart

@@ -188,6 +188,9 @@ void main() {
         {'operator': 'stream', 'operand': 12},
         {'operator': 'topic', 'operand': 'stuff'},
       ]));
+      checkNarrow(const MentionsNarrow().apiEncode(), jsonEncode([
+        {'operator': 'is', 'operand': 'mentioned'},
+      ]));
 
       checkNarrow([ApiNarrowDm([123, 234])], jsonEncode([
         {'operator': 'dm', 'operand': [123, 234]},

test/model/autocomplete_test.dart

@@ -472,6 +472,15 @@ void main() {
           expected: [0, 1, 2, 3, 4])
         ).throws();
       });
+
+      test('MentionsNarrow', () async {
+        // As we do not expect a compose box in [MentionsNarrow], it should
+        // not proceed to show any results.
+        await check(checkResultsIn(
+          const MentionsNarrow(),
+          expected: [0, 1, 2, 3, 4])
+        ).throws();
+      });
     });
   });
 }

test/model/compose_test.dart

@@ -299,8 +299,16 @@ hello
         '#narrow/pm-with/1,2-pm/near/12345');
     });
 
+    test('MentionsNarrow', () {
+      final store = eg.store();
+      check(narrowLink(store, const MentionsNarrow()))
+        .equals(store.realmUrl.resolve('#narrow/is/mentioned'));
+      check(narrowLink(store, const MentionsNarrow(), nearMessageId: 1))
+        .equals(store.realmUrl.resolve('#narrow/is/mentioned/near/1'));
+    });
+
     // TODO other Narrow subclasses as we add them:
-    //   starred, mentioned; searches; arbitrary
+    //   starred; searches; arbitrary
   });
 
   group('mention', () {