Display an icon in the room header for rooms with shared history (#5016)

* feat: Display an icon in the room header for rooms with shared history

* fix: Apply suggestions from code review

- Simplifies `isRoomHistoryShared` expressions using type inferrence.
- Adds failure messages to unit test.

Co-authored-by: Doug <6060466+pixlwave@users.noreply.github.com>

* fix: Remove extension method in favour of field on configuration.

* fix: Distinguish between `shared` and `worldReadable` icons.

* refactor: Use `RoomHistorySharingState` enum with extension methods

---------

Co-authored-by: Doug <6060466+pixlwave@users.noreply.github.com>

ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

@@ -7,6 +7,7 @@
 //
 
 import Foundation
+import MatrixRustSDK
 import OrderedCollections
 
 enum RoomScreenViewModelAction: Equatable {
@@ -80,6 +81,9 @@ struct RoomScreenViewState: BindableState {
             (canAcceptKnocks || canDeclineKnocks || canBan)
     }
     
+    /// If `enableKeyShareOnInvite` is set, determines the current history sharing state.
+    var roomHistorySharingState: RoomHistorySharingState?
+    
     var footerDetails: RoomScreenFooterViewDetails?
     
     var bindings = RoomScreenViewStateBindings()

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -67,10 +67,17 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
         self.initialSelectedPinnedEventID = initialSelectedPinnedEventID
         pinnedEventStringBuilder = .pinnedEventStringBuilder(userID: roomProxy.ownUserID)
 
+        let roomHistorySharingState: RoomHistorySharingState? = if appSettings.enableKeyShareOnInvite {
+            roomProxy.infoPublisher.value.historySharingState
+        } else {
+            nil
+        }
+        
         let viewState = RoomScreenViewState(roomTitle: roomProxy.infoPublisher.value.displayName ?? roomProxy.id,
                                             roomAvatar: roomProxy.infoPublisher.value.avatar,
                                             hasOngoingCall: roomProxy.infoPublisher.value.hasRoomCall,
-                                            hasSuccessor: roomProxy.infoPublisher.value.successor != nil)
+                                            hasSuccessor: roomProxy.infoPublisher.value.successor != nil,
+                                            roomHistorySharingState: roomHistorySharingState)
         super.init(initialViewState: appHooks.roomScreenHook.update(viewState),
                    mediaProvider: userSession.mediaProvider)
         
@@ -342,6 +349,14 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
             state.canDeclineKnocks = powerLevels.canOwnUserKick()
             state.canBan = powerLevels.canOwnUserBan()
         }
+        
+        // This causes the UI to become inconsistent with the user's mental model if the user
+        // does not restart the app after disabling the feature flag. We can probably ignore
+        // such cases, since we explicitly ask for an app restart in the caption of the feature
+        // flag switch.
+        if appSettings.enableKeyShareOnInvite {
+            state.roomHistorySharingState = roomInfo.historySharingState
+        }
     }
     
     private func setupPinnedEventsTimelineItemProviderIfNeeded() {

ElementX/Sources/Screens/RoomScreen/View/RoomScreen.swift

@@ -157,6 +157,7 @@ struct RoomScreen: View {
             RoomHeaderView(roomName: context.viewState.roomTitle,
                            roomAvatar: context.viewState.roomAvatar,
                            dmRecipientVerificationState: context.viewState.dmRecipientVerificationState,
+                           roomHistorySharingState: context.viewState.roomHistorySharingState,
                            mediaProvider: context.mediaProvider) {
                 context.send(viewAction: .displayRoomDetails)
             }