autocomplete: Add and test MentionAutocompleteView

lib/model/autocomplete.dart

@@ -1,4 +1,176 @@
+import 'package:flutter/foundation.dart';
+
+import '../api/model/events.dart';
 import '../api/model/model.dart';
+import 'narrow.dart';
+import 'store.dart';
+
+/// A per-account manager for the view-models of autocomplete interactions.
+///
+/// There should be exactly one of these per PerAccountStore.
+///
+/// Since this manages a cache of user data, the handleRealmUser…Event functions
+/// must be called as appropriate.
+///
+/// On reassemble, call [reassemble].
+class AutocompleteViewManager {
+  final Set<MentionAutocompleteView> _mentionAutocompleteViews = {};
+
+  AutocompleteDataCache autocompleteDataCache = AutocompleteDataCache();
+
+  void registerMentionAutocomplete(MentionAutocompleteView view) {
+    final added = _mentionAutocompleteViews.add(view);
+    assert(added);
+  }
+
+  void unregisterMentionAutocomplete(MentionAutocompleteView view) {
+    final removed = _mentionAutocompleteViews.remove(view);
+    assert(removed);
+  }
+
+  void handleRealmUserAddEvent(RealmUserAddEvent event) {
+    for (final view in _mentionAutocompleteViews) {
+      view.refreshStaleUserResults();
+    }
+  }
+
+  void handleRealmUserRemoveEvent(RealmUserRemoveEvent event) {
+    for (final view in _mentionAutocompleteViews) {
+      view.refreshStaleUserResults();
+    }
+    autocompleteDataCache.invalidateUser(event.userId);
+  }
+
+  void handleRealmUserUpdateEvent(RealmUserUpdateEvent event) {
+    for (final view in _mentionAutocompleteViews) {
+      view.refreshStaleUserResults();
+    }
+    autocompleteDataCache.invalidateUser(event.userId);
+  }
+
+  /// Called when the app is reassembled during debugging, e.g. for hot reload.
+  ///
+  /// Calls [MentionAutocompleteView.reassemble] for all that are registered.
+  ///
+  void reassemble() {
+    for (final view in _mentionAutocompleteViews) {
+      view.reassemble();
+    }
+  }
+}
+
+/// A view-model for a mention-autocomplete interaction.
+///
+/// The owner of one of these objects must call [dispose] when the object
+/// will no longer be used, in order to free resources on the [PerAccountStore].
+///
+/// Lifecycle:
+///  * Create with [init].
+///  * Add listeners with [addListener].
+///  * Use the [query] setter to start a search for a query.
+///  * On reassemble, call [reassemble].
+///  * When the object will no longer be used, call [dispose] to free
+///    resources on the [PerAccountStore].
+class MentionAutocompleteView extends ChangeNotifier {
+  MentionAutocompleteView._({required this.store, required this.narrow});
+
+  factory MentionAutocompleteView.init({
+    required PerAccountStore store,
+    required Narrow narrow,
+  }) {
+    final view = MentionAutocompleteView._(store: store, narrow: narrow);
+    store.autocompleteViewManager.registerMentionAutocomplete(view);
+    return view;
+  }
+
+  @override
+  void dispose() {
+    store.autocompleteViewManager.unregisterMentionAutocomplete(this);
+    // TODO cancel in-progress computations if possible
+    super.dispose();
+  }
+
+  final PerAccountStore store;
+  final Narrow narrow;
+
+  MentionAutocompleteQuery? _currentQuery;
+  set query(MentionAutocompleteQuery query) {
+    _currentQuery = query;
+    _startSearch(query);
+  }
+
+  /// Recompute user results for the current query, if any.
+  ///
+  /// Called in particular when we get a [RealmUserEvent].
+  void refreshStaleUserResults() {
+    if (_currentQuery != null) {
+      _startSearch(_currentQuery!);
+    }
+  }
+
+  /// Called when the app is reassembled during debugging, e.g. for hot reload.
+  ///
+  /// This will redo the search from scratch for the current query, if any.
+  void reassemble() {
+    if (_currentQuery != null) {
+      _startSearch(_currentQuery!);
+    }
+  }
+
+  Iterable<MentionAutocompleteResult> get results => _results;
+  List<MentionAutocompleteResult> _results = [];
+
+  _startSearch(MentionAutocompleteQuery query) async {
+    List<MentionAutocompleteResult>? newResults;
+
+    while (true) {
+      try {
+        newResults = await _computeResults(query);
+        break;
+      } on ConcurrentModificationError {
+        // Retry
+        // TODO backoff?
+      }
+    }
+
+    if (newResults == null) {
+      // Query was old; new search is in progress.
+      return;
+    }
+
+    _results = newResults;
+    notifyListeners();
+  }
+
+  Future<List<MentionAutocompleteResult>?> _computeResults(MentionAutocompleteQuery query) async {
+    final List<MentionAutocompleteResult> results = [];
+    final Iterable<User> users = store.users.values;
+
+    final iterator = users.iterator;
+    bool isDone = false;
+    while (!isDone) {
+      // CPU perf: End this task; enqueue a new one for resuming this work
+      await Future(() {});
+
+      if (query != _currentQuery) {
+        return null;
+      }
+
+      for (int i = 0; i < 1000; i++) {
+        if (!iterator.moveNext()) { // Can throw ConcurrentModificationError
+          isDone = true;
+          break;
+        }
+
+        final User user = iterator.current;
+        if (query.testUser(user, store.autocompleteViewManager.autocompleteDataCache)) {
+          results.add(UserMentionAutocompleteResult(userId: user.userId));
+        }
+      }
+    }
+    return results;
+  }
+}
 
 class MentionAutocompleteQuery {
   MentionAutocompleteQuery(this.raw)
@@ -8,12 +180,11 @@ class MentionAutocompleteQuery {
 
   final List<String> _lowercaseWords;
 
-  bool testUser(User user) {
+  bool testUser(User user, AutocompleteDataCache cache) {
     // TODO test email too, not just name
     // TODO test with diacritics stripped, where appropriate
 
-    // TODO cache, elsewhere
-    final List<String> nameWords = user.fullName.toLowerCase().split(' ');
+    final List<String> nameWords = cache.nameWordsForUser(user);
 
     int nameWordsIndex = 0;
     int queryWordsIndex = 0;
@@ -40,3 +211,42 @@ class MentionAutocompleteQuery {
   @override
   int get hashCode => Object.hash('MentionAutocompleteQuery', raw);
 }
+
+class AutocompleteDataCache {
+  final Map<int, List<String>> _nameWordsByUser = {};
+
+  List<String> nameWordsForUser(User user) {
+    return _nameWordsByUser[user.userId] ??= user.fullName.toLowerCase().split(' ');
+  }
+
+  void invalidateUser(int userId) {
+    _nameWordsByUser.remove(userId);
+  }
+}
+
+abstract class MentionAutocompleteResult {}
+
+class UserMentionAutocompleteResult extends MentionAutocompleteResult {
+  UserMentionAutocompleteResult({required this.userId});
+
+  final int userId;
+}
+
+enum WildcardMentionType {
+  all,
+  everyone,
+  stream,
+}
+
+class WildcardMentionAutocompleteResult extends MentionAutocompleteResult {
+  WildcardMentionAutocompleteResult({required this.type});
+
+  final WildcardMentionType type;
+}
+
+
+class UserGroupMentionAutocompleteResult extends MentionAutocompleteResult {
+  UserGroupMentionAutocompleteResult({required this.userGroupId});
+
+  final int userGroupId;
+}

lib/model/store.dart

@@ -12,6 +12,8 @@ import '../api/model/initial_snapshot.dart';
 import '../api/model/model.dart';
 import '../api/route/events.dart';
 import '../api/route/messages.dart';
+import '../log.dart';
+import 'autocomplete.dart';
 import 'database.dart';
 import 'message_list.dart';
 
@@ -177,6 +179,8 @@ class PerAccountStore extends ChangeNotifier {
     assert(removed);
   }
 
+  final AutocompleteViewManager autocompleteViewManager = AutocompleteViewManager();
+
   /// Called when the app is reassembled during debugging, e.g. for hot reload.
   ///
   /// This will redo from scratch any computations we can, such as parsing
@@ -185,24 +189,27 @@ class PerAccountStore extends ChangeNotifier {
     for (final view in _messageListViews) {
       view.reassemble();
     }
+    autocompleteViewManager.reassemble();
   }
 
   void handleEvent(Event event) {
     if (event is HeartbeatEvent) {
-      debugPrint("server event: heartbeat");
+      assert(debugLog("server event: heartbeat"));
     } else if (event is AlertWordsEvent) {
-      debugPrint("server event: alert_words");
+      assert(debugLog("server event: alert_words"));
       // We don't yet store this data, so there's nothing to update.
     } else if (event is RealmUserAddEvent) {
-      debugPrint("server event: realm_user/add");
+      assert(debugLog("server event: realm_user/add"));
       users[event.person.userId] = event.person;
+      autocompleteViewManager.handleRealmUserAddEvent(event);
       notifyListeners();
     } else if (event is RealmUserRemoveEvent) {
-      debugPrint("server event: realm_user/remove");
+      assert(debugLog("server event: realm_user/remove"));
       users.remove(event.userId);
+      autocompleteViewManager.handleRealmUserRemoveEvent(event);
       notifyListeners();
     } else if (event is RealmUserUpdateEvent) {
-      debugPrint("server event: realm_user/update");
+      assert(debugLog("server event: realm_user/update"));
       final user = users[event.userId];
       if (user == null) {
         return; // TODO log
@@ -225,14 +232,15 @@ class PerAccountStore extends ChangeNotifier {
           profileData.remove(update.id);
         }
       }
+      autocompleteViewManager.handleRealmUserUpdateEvent(event);
       notifyListeners();
     } else if (event is MessageEvent) {
-      debugPrint("server event: message ${jsonEncode(event.message.toJson())}");
+      assert(debugLog("server event: message ${jsonEncode(event.message.toJson())}"));
       for (final view in _messageListViews) {
         view.maybeAddMessage(event.message);
       }
     } else if (event is UnexpectedEvent) {
-      debugPrint("server event: ${jsonEncode(event.toJson())}"); // TODO log better
+      assert(debugLog("server event: ${jsonEncode(event.toJson())}")); // TODO log better
     } else {
       // TODO(dart-3): Use a sealed class / pattern-matching to exclude this.
       throw Exception("Event object of impossible type: ${event.toString()}");

pubspec.lock

@@ -274,7 +274,7 @@ packages:
     source: hosted
     version: "2.7.0"
   fake_async:
-    dependency: transitive
+    dependency: "direct dev"
     description:
       name: fake_async
       sha256: "511392330127add0b769b75a987850d136345d9227c6b94c96a04cf4a391bf78"

pubspec.yaml

@@ -71,6 +71,7 @@ dev_dependencies:
   test: ^1.23.1
   checks: ^0.2.2
   drift_dev: ^2.5.2
+  fake_async: ^1.3.1
 
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec

test/example_data.dart

@@ -2,17 +2,19 @@ import 'package:zulip/api/model/initial_snapshot.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/model/store.dart';
 
+import 'api/fake_api.dart';
+
 final Uri realmUrl = Uri.parse('https://chat.example/');
 
 const String recentZulipVersion = '6.1';
 const int recentZulipFeatureLevel = 164;
 
-User user({int? userId, String? fullName}) {
+User user({int? userId, String? email, String? fullName}) {
   return User(
     userId: userId ?? 123, // TODO generate example IDs
     deliveryEmailStaleDoNotUse: '[email protected]',
-    email: '[email protected]', // TODO generate example emails
-    fullName: fullName ?? 'A user',// TODO generate example names
+    email: email ?? '[email protected]', // TODO generate example emails
+    fullName: fullName ?? 'A user', // TODO generate example names
     dateJoined: '2023-04-28',
     isActive: true,
     isOwner: false,
@@ -28,28 +30,32 @@ User user({int? userId, String? fullName}) {
   );
 }
 
+final User selfUser = user(fullName: 'Self User', email: 'self@example', userId: 123);
 final Account selfAccount = Account(
   id: 1001,
   realmUrl: realmUrl,
-  email: 'self@example',
+  email: selfUser.email,
   apiKey: 'asdfqwer',
-  userId: 123,
+  userId: selfUser.userId,
   zulipFeatureLevel: recentZulipFeatureLevel,
   zulipVersion: recentZulipVersion,
   zulipMergeBase: recentZulipVersion,
 );
 
+final User otherUser = user(fullName: 'Other User', email: 'other@example', userId: 234);
 final Account otherAccount = Account(
   id: 1002,
   realmUrl: realmUrl,
-  email: 'other@example',
+  email: otherUser.email,
   apiKey: 'sdfgwert',
-  userId: 234,
+  userId: otherUser.userId,
   zulipFeatureLevel: recentZulipFeatureLevel,
   zulipVersion: recentZulipVersion,
   zulipMergeBase: recentZulipVersion,
 );
 
+final User thirdUser = user(fullName: 'Third User', email: 'third@example', userId: 345);
+
 final _messagePropertiesBase = {
   'is_me_message': false,
   'last_edit_timestamp': null,
@@ -108,3 +114,11 @@ final InitialSnapshot initialSnapshot = InitialSnapshot(
   realmNonActiveUsers: [],
   crossRealmBots: [],
 );
+
+PerAccountStore store() {
+  return PerAccountStore.fromInitialSnapshot(
+    account: selfAccount,
+    connection: FakeApiConnection.fromAccount(selfAccount),
+    initialSnapshot: initialSnapshot,
+  );
+}

test/model/autocomplete_checks.dart

@@ -0,0 +1,6 @@
+import 'package:checks/checks.dart';
+import 'package:zulip/model/autocomplete.dart';
+
+extension UserMentionAutocompleteResultChecks on Subject<UserMentionAutocompleteResult> {
+  Subject<int> get userId => has((r) => r.userId, 'userId');
+}