Handle threaded pinned events (#4704)

* implemented focussing a threaded event through the banner tap

* view in timeline implementation for threaded events

* added a test and improved the existing one

* pr suggestions

* put the logic for fetching the event in the view models

ElementX/Sources/Screens/RoomScreen/RoomScreenCoordinator.swift

@@ -47,7 +47,7 @@ enum RoomScreenCoordinatorAction {
     case presentPinnedEventsTimeline
     case presentResolveSendFailure(failure: TimelineItemSendFailure.VerifiedUser, sendHandle: SendHandleProxy)
     case presentKnockRequestsList
-    case presentThread(itemID: TimelineItemIdentifier)
+    case presentThread(threadRootEventID: String, focussedEventID: String?)
     case presentRoom(roomID: String, via: [String])
 }
 
@@ -142,7 +142,10 @@ final class RoomScreenCoordinator: CoordinatorProtocol {
                 case .displayResolveSendFailure(let failure, let sendHandle):
                     actionsSubject.send(.presentResolveSendFailure(failure: failure, sendHandle: sendHandle))
                 case .displayThread(let itemID):
-                    actionsSubject.send(.presentThread(itemID: itemID))
+                    guard let eventID = itemID.eventID else {
+                        fatalError("A thread root has always an eventID")
+                    }
+                    actionsSubject.send(.presentThread(threadRootEventID: eventID, focussedEventID: nil))
                 case .composer(let action):
                     composerViewModel.process(timelineAction: action)
                 case .hasScrolled(direction: let direction):
@@ -184,6 +187,8 @@ final class RoomScreenCoordinator: CoordinatorProtocol {
                     actionsSubject.send(.presentRoom(roomID: roomID, via: via))
                 case .displayMessageForwarding(let forwardingItem):
                     actionsSubject.send(.presentMessageForwarding(forwardingItem: forwardingItem))
+                case .displayThread(let threadRootEventID, let focussedEventID):
+                    actionsSubject.send(.presentThread(threadRootEventID: threadRootEventID, focussedEventID: focussedEventID))
                 }
             }
             .store(in: &cancellables)
@@ -201,6 +206,11 @@ final class RoomScreenCoordinator: CoordinatorProtocol {
         Task { await timelineViewModel.focusOnEvent(eventID: eventID) }
     }
     
+    /// Sets the banner to selection to a specific event ID, even if not visible in the main timeline (like a threaded event).
+    func setSelectedPin(eventID: String) {
+        roomViewModel.setSelectedPinnedEventID(eventID)
+    }
+    
     func shareText(_ string: String) {
         composerViewModel.process(timelineAction: .setMode(mode: .default)) // Make sure we're not e.g. replying.
         composerViewModel.process(timelineAction: .setText(plainText: string, htmlText: nil))

ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

@@ -11,6 +11,7 @@ import OrderedCollections
 
 enum RoomScreenViewModelAction: Equatable {
     case focusEvent(eventID: String)
+    case displayThread(threadRootEventID: String, focussedEventID: String)
     case displayPinnedEventsTimeline
     case displayRoomDetails
     case displayCall

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -85,11 +85,7 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
     override func process(viewAction: RoomScreenViewAction) {
         switch viewAction {
         case .tappedPinnedEventsBanner:
-            analyticsService.trackInteraction(name: .PinnedMessageBannerClick)
-            if let eventID = state.pinnedEventsBannerState.selectedPinnedEventID {
-                actionsSubject.send(.focusEvent(eventID: eventID))
-            }
-            state.pinnedEventsBannerState.previousPin()
+            handleTappedPinnedEventsBanner()
         case .viewAllPins:
             analyticsService.trackInteraction(name: .PinnedMessageBannerViewAllButton)
             actionsSubject.send(.displayPinnedEventsTimeline)
@@ -402,6 +398,27 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
         state.handledEventIDs.subtract(failedIDs)
     }
     
+    private func handleTappedPinnedEventsBanner() {
+        analyticsService.trackInteraction(name: .PinnedMessageBannerClick)
+        if let eventID = state.pinnedEventsBannerState.selectedPinnedEventID {
+            Task {
+                switch await roomProxy.loadOrFetchEventDetails(for: eventID) {
+                case .success(let event):
+                    if appSettings.threadsEnabled,
+                       let threadRootEventID = event.threadRootEventId() {
+                        actionsSubject.send(.focusEvent(eventID: threadRootEventID))
+                        actionsSubject.send(.displayThread(threadRootEventID: threadRootEventID, focussedEventID: eventID))
+                    } else {
+                        actionsSubject.send(.focusEvent(eventID: eventID))
+                    }
+                case .failure:
+                    userIndicatorController.submitIndicator(.init(title: L10n.errorUnknown))
+                }
+            }
+        }
+        state.pinnedEventsBannerState.previousPin()
+    }
+    
     // MARK: Loading indicators
     
     private static let loadingIndicatorIdentifier = "\(RoomScreenViewModel.self)-Loading"