user: Add UserStore.mutedUsers and helper methods

Author: sm-sayedi

lib/model/store.dart

@@ -644,6 +644,13 @@ class PerAccountStore extends PerAccountStoreBase with ChangeNotifier, EmojiStor
   @override
   Iterable<User> get allUsers => _users.allUsers;
 
+  @override
+  List<MutedUserItem> get mutedUsers => _users.mutedUsers;
+
+  @override
+  bool isUserMuted(int id, {List<MutedUserItem>? mutedUsers}) =>
+    _users.isUserMuted(id, mutedUsers: mutedUsers);
+
   final UserStoreImpl _users;
 
   final TypingStatus typingStatus;

lib/model/user.dart

@@ -1,7 +1,9 @@
 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';
 
 /// The portion of [PerAccountStore] describing the users in the realm.
@@ -66,6 +68,24 @@ mixin UserStore on PerAccountStoreBase {
     return getUser(message.senderId)?.fullName
       ?? message.senderFullName;
   }
+
+  /// All the users muted by [selfUser], sorted by [MutedUserItem.id] ascending.
+  List<MutedUserItem> get mutedUsers;
+
+  /// Whether the user with the given [id] is muted by [selfUser].
+  ///
+  /// By default, looks for the user id in [UserStore.mutedUsers] unless
+  /// [mutedUsers] is non-null, in which case looks in the latter.
+  bool isUserMuted(int id, {List<MutedUserItem>? mutedUsers});
+
+  /// Whether all of the users corresponding to [DmNarrow.otherRecipientIds]
+  /// are muted by [selfUser];
+  ///
+  /// By default, looks for the recipients in [UserStore.mutedUsers] unless
+  /// [mutedUsers] is non-null, in which case looks in the latter.
+  bool allRecipientsMuted(DmNarrow narrow, {List<MutedUserItem>? mutedUsers}) {
+    return !narrow.otherRecipientIds.any((id) => !isUserMuted(id, mutedUsers: mutedUsers));
+  }
 }
 
 /// The implementation of [UserStore] that does the work.
@@ -81,16 +101,31 @@ class UserStoreImpl extends PerAccountStoreBase with UserStore {
          initialSnapshot.realmUsers
          .followedBy(initialSnapshot.realmNonActiveUsers)
          .followedBy(initialSnapshot.crossRealmBots)
-         .map((user) => MapEntry(user.userId, user)));
+         .map((user) => MapEntry(user.userId, user))),
+       mutedUsers = _sortMutedUsers(initialSnapshot.mutedUsers);
 
   final Map<int, User> _users;
 
+  @override
+  final List<MutedUserItem> mutedUsers;
+
   @override
   User? getUser(int userId) => _users[userId];
 
   @override
   Iterable<User> get allUsers => _users.values;
 
+  @override
+  bool isUserMuted(int id, {List<MutedUserItem>? mutedUsers}) {
+    return binarySearchByKey(
+      mutedUsers == null ? this.mutedUsers : _sortMutedUsers(mutedUsers), id,
+      (item, id) => item.id.compareTo(id)) >= 0;
+  }
+
+  static List<MutedUserItem> _sortMutedUsers(List<MutedUserItem> mutedUsers) {
+    return mutedUsers..sort((a, b) => a.id.compareTo(b.id));
+  }
+
   void handleRealmUserEvent(RealmUserEvent event) {
     switch (event) {
       case RealmUserAddEvent():