feat(llc): add batch follow and unfollow support

packages/stream_feeds/CHANGELOG.md

@@ -3,6 +3,7 @@
 - Add appeal-related methods to moderation client: `appeal`, `getAppeal`, and `queryAppeals`.
 - Add `activityCount` field to `FeedData` model to track the number of activities in a feed.
 - Add `ownFollowings` field to `FeedData` model to track feeds that the current user is following from this feed.
+- Add batch follow and unfollow support.
 
 ## 0.5.0
 - [BREAKING] Unified `ThreadedCommentData` into `CommentData` to handle both flat and threaded comments.

packages/stream_feeds/lib/src/client/feeds_client_impl.dart

@@ -9,8 +9,11 @@ import '../feeds_client.dart';
 import '../generated/api/api.dart' as api;
 import '../models/activity_data.dart';
 import '../models/app_data.dart';
+import '../models/batch_follow_data.dart';
 import '../models/feed_id.dart';
 import '../models/feeds_config.dart';
+import '../models/follow_data.dart';
+import '../models/model_updates.dart';
 import '../models/push_notifications_config.dart';
 import '../repository/activities_repository.dart';
 import '../repository/app_repository.dart';
@@ -502,6 +505,42 @@ class StreamFeedsClientImpl implements StreamFeedsClient {
     return _cdnClient.deleteImage(url);
   }
 
+  @override
+  Future<Result<BatchFollowData>> getOrCreateFollows(
+    api.FollowBatchRequest request,
+  ) async {
+    final result = await _feedsRepository.getOrCreateFollows(request);
+
+    result.onSuccess((data) {
+      final createdIds = data.created.map((f) => f.id).toSet();
+      final updates = ModelUpdates<FollowData>(
+        added: data.created,
+        updated: data.follows.where((f) => !createdIds.contains(f.id)).toList(),
+      );
+
+      _stateUpdateEmitter.tryEmit(FollowBatchUpdate(updates: updates));
+    });
+
+    return result;
+  }
+
+  @override
+  Future<Result<List<FollowData>>> getOrCreateUnfollows(
+    api.UnfollowBatchRequest request,
+  ) async {
+    final result = await _feedsRepository.getOrCreateUnfollows(request);
+
+    result.onSuccess((data) {
+      final updates = ModelUpdates<FollowData>(
+        removedIds: data.map((f) => f.id).toSet(),
+      );
+
+      _stateUpdateEmitter.tryEmit(FollowBatchUpdate(updates: updates));
+    });
+
+    return result;
+  }
+
   Stream<void> get onReconnectEmitter {
     return connectionState.scan(
       (state, connectionStatus, i) => switch (connectionStatus) {

packages/stream_feeds/lib/src/feeds_client.dart

@@ -6,8 +6,10 @@ import 'client/moderation_client.dart';
 import 'generated/api/api.dart' as api;
 import 'models/activity_data.dart';
 import 'models/app_data.dart';
+import 'models/batch_follow_data.dart';
 import 'models/feed_id.dart';
 import 'models/feeds_config.dart';
+import 'models/follow_data.dart';
 import 'models/push_notifications_config.dart';
 import 'state/activity.dart';
 import 'state/activity_comment_list.dart';
@@ -779,6 +781,77 @@ abstract interface class StreamFeedsClient {
   /// Returns a [Result] indicating success or failure of the deletion operation.
   Future<Result<void>> deleteImage({required String url});
 
+  /// Creates or updates multiple follow relationships in a batch operation.
+  ///
+  /// Creates or updates follow relationships for multiple feeds using the provided [request] data.
+  /// Returns both newly created follows and existing follows that were already present.
+  ///
+  /// Example:
+  /// ```dart
+  /// final result = await client.getOrCreateFollows(
+  ///   api.FollowBatchRequest(
+  ///     follows: [
+  ///       api.FollowRequest(
+  ///         source: FeedId.user('john').rawValue,
+  ///         target: FeedId.user('jane').rawValue,
+  ///       ),
+  ///       api.FollowRequest(
+  ///         source: FeedId.user('john').rawValue,
+  ///         target: FeedId.user('bob').rawValue,
+  ///       ),
+  ///     ],
+  ///   ),
+  /// );
+  ///
+  /// switch (result) {
+  ///   case Success(value: final batchFollowData):
+  ///     print('Created ${batchFollowData.created.length} new follows');
+  ///     print('Total follows: ${batchFollowData.follows.length}');
+  ///   case Failure(error: final error):
+  ///     print('Failed to get or create follows: $error');
+  /// }
+  /// ```
+  ///
+  /// Returns a [Result] containing a [BatchFollowData] with the follows or an error.
+  Future<Result<BatchFollowData>> getOrCreateFollows(
+    api.FollowBatchRequest request,
+  );
+
+  /// Removes multiple follow relationships in a batch operation.
+  ///
+  /// Unfollows multiple feeds using the provided [request] data. Returns the list of
+  /// follow relationships that were removed.
+  ///
+  /// Example:
+  /// ```dart
+  /// final result = await client.getOrCreateUnfollows(
+  ///   api.UnfollowBatchRequest(
+  ///     follows: [
+  ///       api.FollowPair(
+  ///         source: FeedId.user('john').rawValue,
+  ///         target: FeedId.user('jane').rawValue,
+  ///       ),
+  ///       api.FollowPair(
+  ///         source: FeedId.user('john').rawValue,
+  ///         target: FeedId.user('bob').rawValue,
+  ///       ),
+  ///     ],
+  ///   ),
+  /// );
+  ///
+  /// switch (result) {
+  ///   case Success(value: final unfollowedFollows):
+  ///     print('Unfollowed ${unfollowedFollows.length} feeds');
+  ///   case Failure(error: final error):
+  ///     print('Failed to unfollow feeds: $error');
+  /// }
+  /// ```
+  ///
+  /// Returns a [Result] containing a list of [FollowData] with the unfollowed feeds or an error.
+  Future<Result<List<FollowData>>> getOrCreateUnfollows(
+    api.UnfollowBatchRequest request,
+  );
+
   /// The moderation client for managing moderation-related operations.
   ///
   /// Provides access to moderation configurations, content moderation, and moderation-related

packages/stream_feeds/lib/src/models.dart

@@ -2,6 +2,7 @@ export 'models/activity_data.dart';
 export 'models/activity_pin_data.dart';
 export 'models/aggregated_activity_data.dart';
 export 'models/app_data.dart';
+export 'models/batch_follow_data.dart';
 export 'models/bookmark_data.dart';
 export 'models/bookmark_folder_data.dart';
 export 'models/comment_data.dart';
@@ -15,6 +16,7 @@ export 'models/feeds_config.dart';
 export 'models/feeds_reaction_data.dart';
 export 'models/file_upload_config_data.dart';
 export 'models/follow_data.dart';
+export 'models/model_updates.dart';
 export 'models/moderation.dart';
 export 'models/moderation_config_data.dart';
 export 'models/pagination_data.dart';

packages/stream_feeds/lib/src/models/batch_follow_data.dart

@@ -0,0 +1,46 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+import '../generated/api/models.dart';
+import 'follow_data.dart';
+
+part 'batch_follow_data.freezed.dart';
+
+/// Represents the result of a batch follow operation.
+///
+/// Contains information about follows that were created and all follows
+/// (including existing and newly created ones).
+@freezed
+class BatchFollowData with _$BatchFollowData {
+  const BatchFollowData({
+    required this.created,
+    required this.follows,
+  });
+
+  /// The follows that were created as a result of the batch operation.
+  ///
+  /// Contains only the newly created follow relationships. For getOrCreate
+  /// operations, this will be empty if all follows already existed.
+  @override
+  final List<FollowData> created;
+
+  /// All follows, including existing and newly created ones.
+  ///
+  /// Contains the complete list of follow relationships returned from the
+  /// batch operation, regardless of whether they were newly created or already existed.
+  @override
+  final List<FollowData> follows;
+}
+
+/// Extension function to convert a [FollowBatchResponse] to a [BatchFollowData] model.
+extension FollowBatchResponseMapper on FollowBatchResponse {
+  /// Converts this API batch follow response to a domain [BatchFollowData] instance.
+  ///
+  /// Maps the created and follows lists from API responses to domain models
+  /// with proper type conversions.
+  BatchFollowData toModel() {
+    return BatchFollowData(
+      created: created.map((f) => f.toModel()).toList(),
+      follows: follows.map((f) => f.toModel()).toList(),
+    );
+  }
+}

packages/stream_feeds/lib/src/models/follow_data.dart

@@ -100,6 +100,14 @@ class FollowData with _$FollowData {
   ///   - fid: The feed ID to check against.
   /// - Returns: true if this is an accepted follow relationship where the source feed matches the given ID.
   bool isFollowingFeed(FeedId fid) => isFollowing && sourceFeed.fid == fid;
+
+  /// Checks if this is a follow request for the specified feed.
+  ///
+  /// - Parameters:
+  ///   - fid: The feed ID to check against.
+  /// - Returns: true if this is a pending follow request where the target feed matches the given ID.
+  bool isFollowRequestFor(FeedId fid) =>
+      isFollowRequest && targetFeed.fid == fid;
 }
 
 /// Extension type representing the status of a follow relationship.

packages/stream_feeds/lib/src/models/model_updates.dart

@@ -1,4 +1,6 @@
+import 'package:collection/collection.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:stream_core/stream_core.dart';
 
 part 'model_updates.freezed.dart';
 
@@ -12,19 +14,66 @@ class ModelUpdates<T> with _$ModelUpdates<T> {
   /// Creates a new [ModelUpdates] instance.
   const ModelUpdates({
     this.added = const [],
-    this.removedIds = const [],
+    this.removedIds = const {},
     this.updated = const [],
   });
 
   /// A list of items that have been added to the collection.
   @override
   final List<T> added;
 
-  /// A list of IDs of items that have been removed from the collection.
+  /// A set of IDs of items that have been removed from the collection.
   @override
-  final List<String> removedIds;
+  final Set<String> removedIds;
 
   /// A list of items that have been updated in the collection.
   @override
   final List<T> updated;
 }
+
+/// Extension providing utilities for working with [ModelUpdates].
+extension ModelUpdatesExtension<T extends Object> on ModelUpdates<T> {
+  /// Applies these updates to the given [list].
+  ///
+  /// Applies all changes from this [ModelUpdates] instance to the provided list:
+  /// - Replaces items in [list] that match items in [updated] by their key
+  /// - Adds items from [added] that don't already exist in [list]
+  /// - Removes items from [list] whose keys are in [removedIds]
+  ///
+  /// The [key] function is used to extract a unique identifier from each item
+  /// for matching and comparison purposes.
+  ///
+  /// When [compare] is provided, the resulting list will be sorted using the
+  /// comparator. This is useful for maintaining a specific sort order after
+  /// applying updates.
+  ///
+  /// Returns a new list with all updates applied. The original [list] is not modified.
+  ///
+  /// Example:
+  /// ```dart
+  /// final updates = ModelUpdates<FollowData>(
+  ///   added: [newFollow1, newFollow2],
+  ///   updated: [updatedFollow],
+  ///   removedIds: {'follow-id-to-remove'},
+  /// );
+  ///
+  /// final updatedList = updates.applyTo(
+  ///   currentFollows,
+  ///   key: (follow) => follow.id,
+  ///   compare: followsSort.compare,
+  /// );
+  /// ```
+  List<T> applyTo(
+    List<T> list, {
+    required String Function(T item) key,
+    Comparator<T>? compare,
+  }) {
+    final updatedList = list
+        .batchReplace(updated, key: key) // replace updated items
+        .merge(added, key: key) // merge added items
+        .whereNot((it) => removedIds.contains(key(it))); // remove deleted items
+
+    // Return sorted list if comparator is provided
+    return compare?.let(updatedList.sorted) ?? updatedList.toList();
+  }
+}