user [nfc]: Factor out a userDisplayName

Author: gnprice

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 'localizations.dart';
 
 /// The portion of [PerAccountStore] describing the users in the realm.
 mixin UserStore {
@@ -21,8 +22,17 @@ mixin UserStore {
   /// Code that looks up a user in this map should therefore always handle
   /// the possibility that the user is not found (except
   /// where there is a specific reason to know the user should be found).
-  /// Consider using [ZulipLocalizations.unknownUserName].
+  /// Consider using [userDisplayName].
   Map<int, User> get users;
+
+  /// The name to show the given user as in the UI, even for unknown users.
+  ///
+  /// This is the user's [User.fullName] if the user is known,
+  /// and otherwise a translation of "(unknown user)".
+  String userDisplayName(int userId) {
+    return users[userId]?.fullName
+      ?? GlobalLocalizations.zulipLocalizations.unknownUserName;
+  }
 }
 
 /// The implementation of [UserStore] that does the work.

lib/widgets/emoji_reaction.dart

@@ -162,7 +162,7 @@ class ReactionChip extends StatelessWidget {
       ? userIds.map((id) {
           return id == store.selfUserId
             ? zulipLocalizations.reactedEmojiSelfUser
-            : store.users[id]?.fullName ?? zulipLocalizations.unknownUserName;
+            : store.userDisplayName(id);
         }).join(', ')
       : userIds.length.toString();
 

lib/widgets/inbox.dart

@@ -384,20 +384,16 @@ class _DmItem extends StatelessWidget {
     final store = PerAccountStoreWidget.of(context);
     final selfUser = store.users[store.selfUserId]!;
 
-    final zulipLocalizations = ZulipLocalizations.of(context);
     final designVariables = DesignVariables.of(context);
 
     final title = switch (narrow.otherRecipientIds) { // TODO dedupe with [RecentDmConversationsItem]
       [] => selfUser.fullName,
-      [var otherUserId] =>
-        store.users[otherUserId]?.fullName ?? zulipLocalizations.unknownUserName,
+      [var otherUserId] => store.userDisplayName(otherUserId),
 
       // TODO(i18n): List formatting, like you can do in JavaScript:
       //   new Intl.ListFormat('ja').format(['Chris', 'Greg', 'Alya', 'Shu'])
       //   // 'Chris、Greg、Alya、Shu'
-      _ => narrow.otherRecipientIds.map(
-        (id) => store.users[id]?.fullName ?? zulipLocalizations.unknownUserName
-      ).join(', '),
+      _ => narrow.otherRecipientIds.map(store.userDisplayName).join(', '),
     };
 
     return Material(

lib/widgets/message_list.dart

@@ -417,8 +417,7 @@ class MessageListAppBarTitle extends StatelessWidget {
         if (otherRecipientIds.isEmpty) {
           return Text(zulipLocalizations.dmsWithYourselfPageTitle);
         } else {
-          final names = otherRecipientIds.map(
-            (id) => store.users[id]?.fullName ?? zulipLocalizations.unknownUserName);
+          final names = otherRecipientIds.map(store.userDisplayName);
           // TODO show avatars
           return Text(
             zulipLocalizations.dmsWithOthersPageTitle(names.join(', ')));
@@ -756,10 +755,10 @@ class _TypingStatusWidgetState extends State<TypingStatusWidget> with PerAccount
     if (typistIds.isEmpty) return const SizedBox();
     final text = switch (typistIds.length) {
       1 => localizations.onePersonTyping(
-        store.users[typistIds.first]?.fullName ?? localizations.unknownUserName),
+             store.userDisplayName(typistIds.first)),
       2 => localizations.twoPeopleTyping(
-        store.users[typistIds.first]?.fullName ?? localizations.unknownUserName,
-        store.users[typistIds.last]?.fullName  ?? localizations.unknownUserName),
+             store.userDisplayName(typistIds.first),
+             store.userDisplayName(typistIds.last)),
       _ => localizations.manyPeopleTyping,
     };
 
@@ -1159,7 +1158,7 @@ class DmRecipientHeader extends StatelessWidget {
     if (message.allRecipientIds.length > 1) {
       title = zulipLocalizations.messageListGroupYouAndOthers(message.allRecipientIds
         .where((id) => id != store.selfUserId)
-        .map((id) => store.users[id]?.fullName ?? zulipLocalizations.unknownUserName)
+        .map(store.userDisplayName)
         .sorted()
         .join(", "));
     } else {

lib/widgets/poll.dart

@@ -80,8 +80,7 @@ class _PollWidgetState extends State<PollWidget> {
       //   new Intl.ListFormat('ja').format(['Chris', 'Greg', 'Alya', 'Zixuan'])
       //   // 'Chris、Greg、Alya、Zixuan'
       final voterNames = option.voters
-        .map((userId) =>
-          store.users[userId]?.fullName ?? zulipLocalizations.unknownUserName)
+        .map(store.userDisplayName)
         .join(', ');
 
       return Row(

lib/widgets/profile.dart

@@ -291,19 +291,19 @@ class _UserWidget extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final store = PerAccountStoreWidget.of(context);
-    final zulipLocalizations = ZulipLocalizations.of(context);
-    final user = store.users[userId];
-    final fullName = user?.fullName ?? zulipLocalizations.unknownUserName;
     return InkWell(
       onTap: () => Navigator.push(context,
         ProfilePage.buildRoute(context: context,
           userId: userId)),
       child: Padding(
         padding: const EdgeInsets.all(8),
         child: Row(children: [
+          // TODO(#196) render active status
           Avatar(userId: userId, size: 32, borderRadius: 32 / 8),
           const SizedBox(width: 8),
-          Expanded(child: Text(fullName, style: _TextStyles.customProfileFieldText)), // TODO(#196) render active status
+          Expanded(
+            child: Text(store.userDisplayName(userId),
+              style: _TextStyles.customProfileFieldText)),
         ])));
   }
 }

lib/widgets/recent_dm_conversations.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 
-import '../generated/l10n/zulip_localizations.dart';
 import '../model/narrow.dart';
 import '../model/recent_dm_conversations.dart';
 import '../model/unreads.dart';
@@ -82,7 +81,6 @@ class RecentDmConversationsItem extends StatelessWidget {
     final store = PerAccountStoreWidget.of(context);
     final selfUser = store.users[store.selfUserId]!;
 
-    final zulipLocalizations = ZulipLocalizations.of(context);
     final designVariables = DesignVariables.of(context);
 
     final String title;
@@ -95,16 +93,14 @@ class RecentDmConversationsItem extends StatelessWidget {
         // TODO(#296) actually don't show this row if the user is muted?
         //   (should we offer a "spam folder" style summary screen of recent
         //   1:1 DM conversations from muted users?)
-        final otherUser = store.users[otherUserId];
-        title = otherUser?.fullName ?? zulipLocalizations.unknownUserName;
+        title = store.userDisplayName(otherUserId);
         avatar = AvatarImage(userId: otherUserId, size: _avatarSize);
       default:
         // TODO(i18n): List formatting, like you can do in JavaScript:
         //   new Intl.ListFormat('ja').format(['Chris', 'Greg', 'Alya'])
         //   // 'Chris、Greg、Alya'
-        title = narrow.otherRecipientIds.map(
-          (id) => store.users[id]?.fullName ?? zulipLocalizations.unknownUserName
-        ).join(', ');
+        title = narrow.otherRecipientIds.map(store.userDisplayName)
+          .join(', ');
         avatar = ColoredBox(color: designVariables.groupDmConversationIconBg,
           child: Center(
             child: Icon(color: designVariables.groupDmConversationIcon,

test/model/user_test.dart

@@ -5,8 +5,22 @@ import 'package:zulip/api/model/model.dart';
 
 import '../api/model/model_checks.dart';
 import '../example_data.dart' as eg;
+import 'test_store.dart';
 
 void main() {
+  group('userDisplayName', () {
+    test('on a known user', () {
+      final user = eg.user(fullName: 'Some User');
+      final store = eg.store()..addUser(user);
+      check(store.userDisplayName(user.userId)).equals('Some User');
+    });
+
+    test('on an unknown user', () {
+      final store = eg.store();
+      check(store.userDisplayName(eg.user().userId)).equals('(unknown user)');
+    });
+  });
+
   group('RealmUserUpdateEvent', () {
     // TODO write more tests for handling RealmUserUpdateEvent