Fix delays when removing reactions in reaction details (#1417)

Author: martinmitrevski

Sources/StreamChatSwiftUI/ChatMessageList/Reactions/ReactionsDetailViewModel.swift

@@ -109,6 +109,7 @@ class ReactionsDetailViewModel: ObservableObject, ChatReactionListControllerDele
     func messageController(_ controller: ChatMessageController, didChangeMessage change: EntityChange<ChatMessage>) {
         if let message = controller.message {
             self.message = message
+            syncCurrentUserReactions(from: message)
         }
     }
 
@@ -146,4 +147,26 @@ class ReactionsDetailViewModel: ObservableObject, ChatReactionListControllerDele
     private var userReactionIDs: Set<MessageReactionType> {
         Set(message.currentUserReactions.map(\.type))
     }
+
+    private func syncCurrentUserReactions(from message: ChatMessage) {
+        guard let currentUserId = chatClient.currentUserId else { return }
+
+        let currentUserReactions = message.currentUserReactions
+            .sorted { $0.updatedAt > $1.updatedAt }
+        let hadCurrentUserReactions = reactions.contains { $0.author.id == currentUserId }
+
+        guard hadCurrentUserReactions || !currentUserReactions.isEmpty else { return }
+
+        let mergedReactions = reactions
+            .filter { $0.author.id != currentUserId }
+            + currentUserReactions
+
+        let sortedReactions = mergedReactions.sorted { first, second in
+            first.updatedAt > second.updatedAt
+        }
+
+        if reactions != sortedReactions {
+            reactions = sortedReactions
+        }
+    }
 }

StreamChatSwiftUITests/Tests/ChatChannel/ReactionsDetailViewModel_Tests.swift

@@ -8,6 +8,8 @@
 import XCTest
 
 @MainActor final class ReactionsDetailViewModel_Tests: StreamChatTestCase {
+    private let currentUserId = StreamChatTestCase.currentUserId
+
     // MARK: - Init
 
     func test_init_thenSynchronizeCalled() {
@@ -612,6 +614,98 @@ import XCTest
         XCTAssertEqual(viewModel.message.text, "Updated text")
     }
 
+    func test_messageControllerDidChangeMessage_thenCurrentUserReactionIsInsertedImmediately() {
+        // Given
+        let cid = ChannelId.unique
+        let like = MessageReactionType(rawValue: "like")
+        let love = MessageReactionType(rawValue: "love")
+        let message = ChatMessage.mock(cid: cid)
+        let controller = makeReactionListController(messageId: message.id)
+        let existingReaction = ChatMessageReaction.mock(
+            id: "existing",
+            type: love,
+            updatedAt: Date(timeIntervalSince1970: 100),
+            author: .mock(id: "other-user")
+        )
+        controller.reactions_simulated = [existingReaction]
+
+        let viewModel = ReactionsDetailViewModel(message: message, reactionListController: controller)
+        viewModel.controller(controller, didChangeReactions: [])
+
+        let messageController = ChatMessageControllerSUI_Mock.mock(
+            chatClient: chatClient,
+            currentUserId: currentUserId,
+            cid: cid,
+            messageId: message.id
+        )
+        let currentUserReaction = ChatMessageReaction.mock(
+            id: "current-user-reaction",
+            type: like,
+            updatedAt: Date(timeIntervalSince1970: 200),
+            author: .mock(id: currentUserId, name: "You")
+        )
+        let updatedMessage = ChatMessage.mock(
+            id: message.id,
+            cid: cid,
+            reactionScores: [like: 1, love: 1],
+            reactionCounts: [like: 1, love: 1],
+            currentUserReactions: [currentUserReaction]
+        )
+        messageController.message_mock = updatedMessage
+
+        // When
+        viewModel.messageController(messageController, didChangeMessage: .update(updatedMessage))
+
+        // Then
+        XCTAssertEqual(viewModel.reactions.map(\.id), ["current-user-reaction", "existing"])
+    }
+
+    func test_messageControllerDidChangeMessage_thenCurrentUserReactionIsRemovedImmediately() {
+        // Given
+        let cid = ChannelId.unique
+        let like = MessageReactionType(rawValue: "like")
+        let love = MessageReactionType(rawValue: "love")
+        let message = ChatMessage.mock(cid: cid)
+        let controller = makeReactionListController(messageId: message.id)
+        let currentUserReaction = ChatMessageReaction.mock(
+            id: "current-user-reaction",
+            type: like,
+            updatedAt: Date(timeIntervalSince1970: 200),
+            author: .mock(id: currentUserId, name: "You")
+        )
+        let existingReaction = ChatMessageReaction.mock(
+            id: "existing",
+            type: love,
+            updatedAt: Date(timeIntervalSince1970: 100),
+            author: .mock(id: "other-user")
+        )
+        controller.reactions_simulated = [currentUserReaction, existingReaction]
+
+        let viewModel = ReactionsDetailViewModel(message: message, reactionListController: controller)
+        viewModel.controller(controller, didChangeReactions: [])
+
+        let messageController = ChatMessageControllerSUI_Mock.mock(
+            chatClient: chatClient,
+            currentUserId: currentUserId,
+            cid: cid,
+            messageId: message.id
+        )
+        let updatedMessage = ChatMessage.mock(
+            id: message.id,
+            cid: cid,
+            reactionScores: [love: 1],
+            reactionCounts: [love: 1],
+            currentUserReactions: []
+        )
+        messageController.message_mock = updatedMessage
+
+        // When
+        viewModel.messageController(messageController, didChangeMessage: .update(updatedMessage))
+
+        // Then
+        XCTAssertEqual(viewModel.reactions.map(\.id), ["existing"])
+    }
+
     func test_messageControllerDidChangeReactions_thenReactionsUpdated() {
         // Given
         let cid = ChannelId.unique