Fix pinned status issues

ViewModels/Sources/ViewModels/AccountStatusesViewModel.swift

@@ -28,6 +28,18 @@ public class AccountStatusesViewModel: StatusListViewModel {
             .assign(to: &$accountViewModel)
     }
 
+    public override var collectionItems: AnyPublisher<[[CollectionItem]], Never> {
+        // The pinned key is added to the info of collection items in the first section
+        // so a diffable data source can potentially render it in both sections
+        super.collectionItems
+            .map {
+                $0.enumerated().map {
+                    $0 == 0 ? $1.map { .init(id: $0.id, kind: $0.kind, info: [.pinned: true]) } : $1
+                }
+            }
+            .eraseToAnyPublisher()
+    }
+
     public override var navigationEvents: AnyPublisher<NavigationEvent, Never> {
         $accountViewModel.compactMap { $0 }
             .flatMap(\.events)
@@ -50,10 +62,6 @@ public class AccountStatusesViewModel: StatusListViewModel {
         super.request(maxID: maxID, minID: minID)
     }
 
-    override func isPinned(status: Status) -> Bool {
-        collection == .statuses && items.first?.contains(CollectionItem(id: status.id, kind: .status)) ?? false
-    }
-
     public override var title: AnyPublisher<String?, Never> {
         $accountViewModel.map { $0?.accountName }.eraseToAnyPublisher()
     }

ViewModels/Sources/ViewModels/Entities/CollectionItem.swift

@@ -3,6 +3,13 @@
 public struct CollectionItem: Hashable {
     public let id: String
     public let kind: Kind
+    public let info: [InfoKey: AnyHashable]
+
+    init(id: String, kind: Kind, info: [InfoKey: AnyHashable]? = nil) {
+        self.id = id
+        self.kind = kind
+        self.info = info ?? [InfoKey: AnyHashable]()
+    }
 }
 
 public extension CollectionItem {
@@ -10,4 +17,8 @@ public extension CollectionItem {
         case status
         case account
     }
+
+    enum InfoKey {
+        case pinned
+    }
 }

ViewModels/Sources/ViewModels/StatusListViewModel.swift

@@ -41,6 +41,8 @@ public class StatusListViewModel: ObservableObject {
             .store(in: &cancellables)
     }
 
+    public var collectionItems: AnyPublisher<[[CollectionItem]], Never> { $items.eraseToAnyPublisher() }
+
     public var navigationEvents: AnyPublisher<NavigationEvent, Never> { navigationEventsSubject.eraseToAnyPublisher() }
 
     public var title: AnyPublisher<String?, Never> { Just(statusListService.title).eraseToAnyPublisher() }
@@ -55,13 +57,9 @@ public class StatusListViewModel: ObservableObject {
             .sink { _ in }
             .store(in: &cancellables)
     }
-
-    func isPinned(status: Status) -> Bool { false }
 }
 
 extension StatusListViewModel: CollectionViewModel {
-    public var collectionItems: AnyPublisher<[[CollectionItem]], Never> { $items.eraseToAnyPublisher() }
-
     public var alertItems: AnyPublisher<AlertItem, Never> { $alertItem.compactMap { $0 }.eraseToAnyPublisher() }
 
     public var loading: AnyPublisher<Bool, Never> { loadingSubject.eraseToAnyPublisher() }
@@ -93,7 +91,7 @@ extension StatusListViewModel: CollectionViewModel {
     public func viewModel(item: CollectionItem) -> Any? {
         switch item.kind {
         case .status:
-            return statusViewModel(id: item.id)
+            return statusViewModel(item: item)
         default:
             return nil
         }
@@ -111,8 +109,8 @@ private extension StatusListViewModel {
 
     var contextParentID: String? { statusListService.contextParentID }
 
-    func statusViewModel(id: String) -> StatusViewModel? {
-        guard let status = statuses[id] else { return nil }
+    func statusViewModel(item: CollectionItem) -> StatusViewModel? {
+        guard let status = statuses[item.id] else { return nil }
 
         var statusViewModel: StatusViewModel
 
@@ -136,7 +134,7 @@ private extension StatusListViewModel {
         }
 
         statusViewModel.isContextParent = status.id == statusListService.contextParentID
-        statusViewModel.isPinned = isPinned(status: status)
+        statusViewModel.isPinned = item.info[.pinned] != nil
         statusViewModel.isReplyInContext = isReplyInContext(status: status)
         statusViewModel.hasReplyFollowing = hasReplyFollowing(status: status)