Handle member related events and channel truncated event in LivestreamChannelController (#3775)

* Handle Member Update Events in the Livestream channel controller

* Handle channel truncation updated event in livestream channel controller

* Update demo app livestream UI to show number of members and watchers

* Add test coverage to member related events

* Add test coverage to truncated channel even

* Update CHANGELOG.md

Author: nuno-vieira

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## StreamChat
 ### ✅ Added
+- Handle member-related events in `LivestreamChannelController` [#3775](https://github.com/GetStream/stream-chat-swift/pull/3775)
+- Handle channel truncation events in `LivestreamChannelController` [#3775](https://github.com/GetStream/stream-chat-swift/pull/3775)
 - Add a completion block to `LivestreamChannelController.resume()` to observe possible errors [#3774](https://github.com/GetStream/stream-chat-swift/pull/3774)
 ### 🐞 Fixed
 - Fix pending message being added to `LivestreamChannelController.messages` when in paused state [#3774](https://github.com/GetStream/stream-chat-swift/pull/3774)

DemoApp/Screens/Livestream/DemoLivestreamChatChannelVC.swift

@@ -50,6 +50,35 @@ class DemoLivestreamChatChannelVC: _ViewController,
         .channelAvatarView.init()
         .withoutAutoresizingMaskConstraints
 
+    /// Title label shown in the navigation bar.
+    private lazy var titleLabel: UILabel = {
+        let label = UILabel()
+        label.font = appearance.fonts.subheadlineBold
+        label.textColor = appearance.colorPalette.text
+        label.textAlignment = .center
+        label.setContentHuggingPriority(.required, for: .vertical)
+        return label
+    }()
+
+    /// Subtitle label showing members and online watchers in the navigation bar.
+    private lazy var subtitleLabel: UILabel = {
+        let label = UILabel()
+        label.font = appearance.fonts.footnote
+        label.textColor = appearance.colorPalette.subtitleText
+        label.textAlignment = .center
+        label.setContentCompressionResistancePriority(.required, for: .vertical)
+        return label
+    }()
+
+    /// Stack view containing title and subtitle for the navigation bar.
+    private lazy var titleStackView: UIStackView = {
+        let stack = UIStackView(arrangedSubviews: [titleLabel, subtitleLabel])
+        stack.axis = .vertical
+        stack.alignment = .center
+        stack.spacing = 0
+        return stack
+    }()
+
     /// The message composer bottom constraint used for keyboard animation handling.
     var messageComposerBottomConstraint: NSLayoutConstraint?
 
@@ -124,6 +153,10 @@ class DemoLivestreamChatChannelVC: _ViewController,
         navigationItem.rightBarButtonItem = UIBarButtonItem(customView: channelAvatarView)
         channelAvatarView.content = (livestreamChannelController.channel, client.currentUserId)
 
+        // Set up custom title view with channel name and member/online counts
+        navigationItem.titleView = titleStackView
+        updateNavigationTitle()
+
         // Add pause banner
         view.addSubview(pauseBannerView)
         NSLayoutConstraint.activate([
@@ -313,7 +346,7 @@ class DemoLivestreamChatChannelVC: _ViewController,
         didUpdateChannel channel: ChatChannel
     ) {
         channelAvatarView.content = (livestreamChannelController.channel, client.currentUserId)
-        navigationItem.title = channel.name
+        updateNavigationTitle()
     }
 
     func livestreamChannelController(
@@ -374,6 +407,19 @@ class DemoLivestreamChatChannelVC: _ViewController,
         }
         pauseBannerView.setVisible(show, animated: true)
     }
+
+    /// Updates the navigation title and subtitle with channel name, member count and online watcher count.
+    private func updateNavigationTitle() {
+        let channel = livestreamChannelController.channel
+        titleLabel.text = channel?.name ?? ""
+
+        let memberCount = channel?.memberCount ?? 0
+        let watcherCount = channel?.watcherCount ?? 0
+
+        let membersText = memberCount == 1 ? "1 member" : "\(memberCount) members"
+        let onlineText = watcherCount == 1 ? "1 online" : "\(watcherCount) online"
+        subtitleLabel.text = "\(membersText), \(onlineText)"
+    }
 }
 
 /// A custom composer view controller for livestream channels that uses LivestreamChannelController

Sources/StreamChat/Controllers/ChannelController/LivestreamChannelController.swift

@@ -904,6 +904,24 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
         case let channelUpdatedEvent as ChannelUpdatedEvent:
             handleChannelUpdated(channelUpdatedEvent)
 
+        case is MemberAddedEvent,
+             is MemberRemovedEvent,
+             is MemberUpdatedEvent,
+             is NotificationAddedToChannelEvent,
+             is NotificationRemovedFromChannelEvent,
+             is NotificationInvitedEvent,
+             is NotificationInviteAcceptedEvent,
+             is NotificationInviteRejectedEvent:
+            updateChannelFromDataStore()
+
+        case let channelTruncatedEvent as ChannelTruncatedEvent:
+            channel = channelTruncatedEvent.channel
+            if let message = channelTruncatedEvent.message {
+                messages = [message]
+            } else {
+                messages = []
+            }
+
         default:
             break
         }
@@ -965,6 +983,15 @@ public class LivestreamChannelController: DataStoreProvider, EventsControllerDel
         channel = event.channel
     }
 
+    // For events that do not have the channel data, and still
+    // go through the middleware, lets fetch it from DB and update it.
+    private func updateChannelFromDataStore() {
+        guard let cid = cid, let updatedChannel = dataStore.channel(cid: cid) else {
+            return
+        }
+        channel = updatedChannel
+    }
+
     private func createNewMessage(
         messageId: MessageId? = nil,
         text: String,

TestTools/StreamChatTestTools/TestData/DummyData/ChannelDetailPayload.swift

@@ -26,6 +26,7 @@ extension ChannelDetailPayload {
         isDisabled: Bool = false,
         isHidden: Bool? = nil,
         members: [MemberPayload] = [],
+        memberCount: Int? = nil,
         team: String? = nil,
         cooldownDuration: Int = 0
     ) -> Self {
@@ -48,7 +49,7 @@ extension ChannelDetailPayload {
             isBlocked: isBlocked,
             isHidden: isHidden,
             members: members,
-            memberCount: members.count,
+            memberCount: memberCount ?? members.count,
             team: team,
             cooldownDuration: cooldownDuration
         )

Tests/StreamChatTests/Controllers/ChannelController/LivestreamChannelController_Tests.swift

@@ -1226,10 +1226,231 @@ extension LivestreamChannelController_Tests {
             ),
             didReceiveEvent: event
         )
-        
+
         // Then
         XCTAssertEqual(controller.channel?.name, "Updated Name")
     }
+
+    // MARK: - Member Update Events Tests
+
+    func test_didReceiveEvent_memberRelatedEvents_updateChannelFromDataStore() {
+        let cid = controller.cid!
+
+        // Test data for all member-related events
+        let memberEvents: [(event: Event, description: String)] = [
+            (
+                MemberAddedEvent(
+                    user: .mock(id: .unique),
+                    cid: cid,
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "MemberAddedEvent"
+            ),
+            (
+                MemberRemovedEvent(
+                    user: .mock(id: .unique),
+                    cid: cid,
+                    createdAt: .unique
+                ),
+                "MemberRemovedEvent"
+            ),
+            (
+                MemberUpdatedEvent(
+                    user: .mock(id: .unique),
+                    cid: cid,
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "MemberUpdatedEvent"
+            ),
+            (
+                NotificationAddedToChannelEvent(
+                    channel: .mock(cid: cid),
+                    unreadCount: nil,
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "NotificationAddedToChannelEvent"
+            ),
+            (
+                NotificationRemovedFromChannelEvent(
+                    user: .mock(id: .unique),
+                    cid: cid,
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "NotificationRemovedFromChannelEvent"
+            ),
+            (
+                NotificationInvitedEvent(
+                    user: .mock(id: .unique),
+                    cid: cid,
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "NotificationInvitedEvent"
+            ),
+            (
+                NotificationInviteAcceptedEvent(
+                    user: .mock(id: .unique),
+                    channel: .mock(cid: cid),
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "NotificationInviteAcceptedEvent"
+            ),
+            (
+                NotificationInviteRejectedEvent(
+                    user: .mock(id: .unique),
+                    channel: .mock(cid: cid),
+                    member: .mock(id: .unique),
+                    createdAt: .unique
+                ),
+                "NotificationInviteRejectedEvent"
+            )
+        ]
+
+        // Test each member-related event
+        for (index, (event, description)) in memberEvents.enumerated() {
+            let initialMemberCount = 10 + index
+            let updatedMemberCount = 20 + index
+
+            // Given - Set up initial channel in database
+            let initialChannelPayload = ChannelPayload.dummy(
+                channel: .dummy(cid: cid, memberCount: initialMemberCount)
+            )
+            try! client.databaseContainer.writeSynchronously { session in
+                try session.saveChannel(payload: initialChannelPayload)
+            }
+
+            // Load initial data
+            let exp = expectation(description: "sync completes")
+            controller.synchronize { _ in
+                exp.fulfill()
+            }
+            client.mockAPIClient.test_simulateResponse(.success(initialChannelPayload))
+
+            waitForExpectations(timeout: defaultTimeout)
+            XCTAssertEqual(controller.channel?.memberCount, initialMemberCount, "Initial setup failed for \(description)")
+
+            // Update channel in database with new member count
+            let updatedChannelPayload = ChannelPayload.dummy(
+                channel: .dummy(cid: cid, memberCount: updatedMemberCount)
+            )
+            try! client.databaseContainer.writeSynchronously { session in
+                try session.saveChannel(payload: updatedChannelPayload)
+            }
+
+            // When
+            controller.eventsController(
+                EventsController(notificationCenter: client.eventNotificationCenter),
+                didReceiveEvent: event
+            )
+
+            // Then
+            XCTAssertEqual(
+                controller.channel?.memberCount,
+                updatedMemberCount,
+                "\(description) should update channel from data store"
+            )
+        }
+    }
+    
+    func test_didReceiveEvent_channelTruncatedEvent_updatesChannelAndMessages() {
+        // Given - Set up initial channel with messages
+        let cid = controller.cid!
+        let initialMessage1 = ChatMessage.mock(id: "message1", cid: cid, text: "Message 1")
+        let initialMessage2 = ChatMessage.mock(id: "message2", cid: cid, text: "Message 2")
+        
+        // Load initial messages
+        controller.eventsController(
+            EventsController(notificationCenter: client.eventNotificationCenter),
+            didReceiveEvent: MessageNewEvent(
+                user: .mock(id: .unique),
+                message: initialMessage1,
+                channel: .mock(cid: cid),
+                createdAt: .unique,
+                watcherCount: nil,
+                unreadCount: nil
+            )
+        )
+        controller.eventsController(
+            EventsController(notificationCenter: client.eventNotificationCenter),
+            didReceiveEvent: MessageNewEvent(
+                user: .mock(id: .unique),
+                message: initialMessage2,
+                channel: .mock(cid: cid),
+                createdAt: .unique,
+                watcherCount: nil,
+                unreadCount: nil
+            )
+        )
+        XCTAssertEqual(controller.messages.count, 2)
+        
+        // Create truncated channel and truncation message
+        let truncatedChannel = ChatChannel.mock(cid: cid, name: "Truncated Channel")
+        let truncationMessage = ChatMessage.mock(id: "truncation", cid: cid, text: "Channel was truncated")
+        
+        let event = ChannelTruncatedEvent(
+            channel: truncatedChannel,
+            user: .mock(id: .unique),
+            message: truncationMessage,
+            createdAt: .unique
+        )
+        
+        // When
+        controller.eventsController(
+            EventsController(notificationCenter: client.eventNotificationCenter),
+            didReceiveEvent: event
+        )
+        
+        // Then
+        XCTAssertEqual(controller.channel?.name, "Truncated Channel")
+        XCTAssertEqual(controller.messages.count, 1)
+        XCTAssertEqual(controller.messages.first?.id, "truncation")
+        XCTAssertEqual(controller.messages.first?.text, "Channel was truncated")
+    }
+    
+    func test_didReceiveEvent_channelTruncatedEventWithoutMessage_clearsMessages() {
+        // Given - Set up initial channel with messages
+        let cid = controller.cid!
+        let initialMessage = ChatMessage.mock(id: "message1", cid: cid, text: "Message 1")
+        
+        // Load initial message
+        controller.eventsController(
+            EventsController(notificationCenter: client.eventNotificationCenter),
+            didReceiveEvent: MessageNewEvent(
+                user: .mock(id: .unique),
+                message: initialMessage,
+                channel: .mock(cid: cid),
+                createdAt: .unique,
+                watcherCount: nil,
+                unreadCount: nil
+            )
+        )
+        XCTAssertEqual(controller.messages.count, 1)
+        
+        // Create truncated channel without truncation message
+        let truncatedChannel = ChatChannel.mock(cid: cid, name: "Truncated Channel")
+        
+        let event = ChannelTruncatedEvent(
+            channel: truncatedChannel,
+            user: .mock(id: .unique),
+            message: nil, // No truncation message
+            createdAt: .unique
+        )
+        
+        // When
+        controller.eventsController(
+            EventsController(notificationCenter: client.eventNotificationCenter),
+            didReceiveEvent: event
+        )
+        
+        // Then
+        XCTAssertEqual(controller.channel?.name, "Truncated Channel")
+        XCTAssertTrue(controller.messages.isEmpty)
+    }
 
     func test_didReceiveEvent_differentChannelEvent_isIgnored() {
         let otherChannelId = ChannelId.unique