cleanup

apps/ios/Shared/Views/Chat/ChatItem/FramedItemView.swift

@@ -12,7 +12,7 @@ import SimpleXChat
 struct FramedItemView: View {
     @EnvironmentObject var m: ChatModel
     @EnvironmentObject var theme: AppTheme
-    @EnvironmentObject var scrollModel: ReverseListScrollModel<ChatItem>
+    @EnvironmentObject var scrollModel: ReverseListScrollModel
     @ObservedObject var chat: Chat
     var chatItem: ChatItem
     var preview: UIImage?

apps/ios/Shared/Views/Chat/ChatItem/FullScreenMediaView.swift

@@ -13,7 +13,7 @@ import AVKit
 
 struct FullScreenMediaView: View {
     @EnvironmentObject var m: ChatModel
-    @EnvironmentObject var scrollModel: ReverseListScrollModel<ChatItem>
+    @EnvironmentObject var scrollModel: ReverseListScrollModel
     @State var chatItem: ChatItem
     @State var image: UIImage?
     @State var player: AVPlayer? = nil

apps/ios/Shared/Views/Chat/ChatView.swift

@@ -22,8 +22,8 @@ struct ChatView: View {
     @Environment(\.presentationMode) var presentationMode
     @Environment(\.scenePhase) var scenePhase
     @State @ObservedObject var chat: Chat
-    @StateObject private var scrollModel = ReverseListScrollModel<ChatItem>()
-    @StateObject private var floatingButtonModel = FloatingButtonModel()
+    @StateObject private var scrollModel = ReverseListScrollModel()
+    @StateObject private var floatingButtonModel: FloatingButtonModel = .shared
     @State private var showChatInfoSheet: Bool = false
     @State private var showAddMembersSheet: Bool = false
     @State private var composeState = ComposeState()
@@ -74,9 +74,12 @@ struct ChatView: View {
                     )
             }
             VStack(spacing: 0) {
-                ZStack(alignment: .bottomTrailing) {
+                ZStack {
                     chatItemsList()
                     floatingButtons(counts: floatingButtonModel.unreadChatItemCounts)
+                        .frame(maxWidth: .infinity, alignment: .trailing)
+                    floatingDate
+                        .frame(maxHeight: .infinity, alignment: .top)
                 }
                 connectingText()
                 if selectedChatItems == nil {
@@ -413,12 +416,6 @@ struct ChatView: View {
                     revealedChatItem: $revealedChatItem,
                     selectedChatItems: $selectedChatItems
                 )
-                .onAppear {
-                    floatingButtonModel.appeared(viewId: ci.viewId)
-                }
-                .onDisappear {
-                    floatingButtonModel.disappeared(viewId: ci.viewId)
-                }
                 .id(ci.id) // Required to trigger `onAppear` on iOS15
             } loadPage: {
                 loadChatItems(cInfo)
@@ -429,9 +426,6 @@ struct ChatView: View {
             .onChange(of: searchText) { _ in
                 Task { await loadChat(chat: chat, search: searchText) }
             }
-            .onChange(of: im.reversedChatItems) { _ in
-                floatingButtonModel.chatItemsChanged()
-            }
             .onChange(of: im.itemAdded) { added in
                 if added {
                     im.itemAdded = false
@@ -458,15 +452,13 @@ struct ChatView: View {
     }
 
     class FloatingButtonModel: ObservableObject {
-        private enum Event {
-            case appeared(String)
-            case disappeared(String)
-            case chatItemsChanged
-        }
+        static let shared = FloatingButtonModel()
 
         @Published var unreadChatItemCounts: UnreadChatItemCounts
+        @Published var date: Date?
+        @Published var isDateVisible: Bool = false
 
-        private let events = PassthroughSubject<Event, Never>()
+        let visibleItems = PassthroughSubject<[String], Never>()
         private var bag = Set<AnyCancellable>()
 
         init() {
@@ -475,34 +467,58 @@ struct ChatView: View {
                 isReallyNearBottom: true,
                 unreadBelow: 0
             )
-            events
+
+            // Unread item counts
+            visibleItems
                 .receive(on: DispatchQueue.global(qos: .background))
-                .scan(Set<String>()) { itemsInView, event in
-                    var updated = itemsInView
-                    switch event {
-                    case let .appeared(viewId): updated.insert(viewId)
-                    case let .disappeared(viewId): updated.remove(viewId)
-                    case .chatItemsChanged: ()
-                    }
-                    return updated
-                }
-                .map { ChatModel.shared.unreadChatItemCounts(itemsInView: $0) }
+                .map { ChatModel.shared.unreadChatItemCounts(itemsInView: Set($0)) }
                 .removeDuplicates()
                 .throttle(for: .seconds(0.2), scheduler: DispatchQueue.main, latest: true)
                 .assign(to: \.unreadChatItemCounts, on: self)
                 .store(in: &bag)
-        }
 
-        func appeared(viewId: String) {
-            events.send(.appeared(viewId))
+            // Floating date
+            visibleItems
+                .receive(on: DispatchQueue.global(qos: .background))
+                .map { visibleItems -> Date? in
+                    if let viewId = visibleItems.last {
+                        ItemsModel.shared.reversedChatItems
+                            .first { $0.viewId == viewId }
+                            .map { Calendar.current.startOfDay(for: $0.meta.itemTs) }
+                    } else { nil }
+                }
+                .removeDuplicates()
+                .throttle(for: .seconds(0.2), scheduler: DispatchQueue.main, latest: true)
+                .assign(to: \.date, on: self)
+                .store(in: &bag)
+            
+            // Floating date visibility
+            visibleItems
+                .removeDuplicates()
+                .receive(on: DispatchQueue.main)
+                .map { _ in
+                    if !self.isDateVisible {
+                        withAnimation { self.isDateVisible = true }
+                    }
+                }
+                .debounce(for: 1, scheduler: DispatchQueue.main)
+                .sink {
+                    if self.isDateVisible {
+                        withAnimation { self.isDateVisible = false }
+                    }
+                }
+                .store(in: &bag)
         }
+    }
 
-        func disappeared(viewId: String) {
-            events.send(.disappeared(viewId))
-        }
-
-        func chatItemsChanged() {
-            events.send(.chatItemsChanged)
+    @ViewBuilder
+    var floatingDate: some View {
+        if let date = floatingButtonModel.date {
+            DateSeparator(date: date)
+                .padding(.vertical, 4).padding(.horizontal, 8)
+                .background(ToolbarMaterial.material(toolbarMaterial))
+                .clipShape(Capsule())
+                .opacity(floatingButtonModel.isDateVisible ? 1 : 0)
         }
     }
 
@@ -692,6 +708,21 @@ struct ChatView: View {
         VoiceItemState.chatView = [:]
     }
 
+    private struct DateSeparator: View {
+        let date: Date
+
+        var body: some View {
+            Text(String.localizedStringWithFormat(
+                NSLocalizedString("%@, %@", comment: "format for date separator in chat"),
+                date.formatted(.dateTime.weekday(.abbreviated)),
+                date.formatted(.dateTime.day().month(.abbreviated))
+            ))
+            .font(.callout)
+            .fontWeight(.medium)
+            .foregroundStyle(.secondary)
+        }
+    }
+
     private struct ChatItemWithMenu: View {
         @EnvironmentObject var m: ChatModel
         @EnvironmentObject var theme: AppTheme
@@ -763,17 +794,7 @@ struct ChatView: View {
                 } else {
                     VStack(spacing: 0) {
                         chatItemView(chatItem, range, prevItem, timeSeparation)
-                        if let date = timeSeparation.date {
-                            Text(String.localizedStringWithFormat(
-                                NSLocalizedString("%@, %@", comment: "format for date separator in chat"),
-                                date.formatted(.dateTime.weekday(.abbreviated)),
-                                date.formatted(.dateTime.day().month(.abbreviated))
-                            ))
-                            .font(.callout)
-                            .fontWeight(.medium)
-                            .foregroundStyle(.secondary)
-                            .padding(8)
-                        }
+                        if let date = timeSeparation.date { DateSeparator(date: date).padding(8) }
                     }
                     .overlay {
                         if let selected = selectedChatItems, chatItem.canBeDeletedForSelf {

apps/ios/Shared/Views/Chat/ReverseList.swift

@@ -8,15 +8,16 @@
 
 import SwiftUI
 import Combine
+import SimpleXChat
 
 /// A List, which displays it's items in reverse order - from bottom to top
-struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIViewControllerRepresentable {
-    let items: Array<Item>
+struct ReverseList<Content: View>: UIViewControllerRepresentable {
+    let items: Array<ChatItem>
 
-    @Binding var scrollState: ReverseListScrollModel<Item>.State
+    @Binding var scrollState: ReverseListScrollModel.State
 
     /// Closure, that returns user interface for a given item
-    let content: (Item) -> Content
+    let content: (ChatItem) -> Content
 
     let loadPage: () -> Void
 
@@ -25,6 +26,7 @@ struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIV
     }
 
     func updateUIViewController(_ controller: Controller, context: Context) {
+        controller.representer = self
         if case let .scrollingTo(destination) = scrollState, !items.isEmpty {
             switch destination {
             case .nextPage:
@@ -42,8 +44,8 @@ struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIV
     /// Controller, which hosts SwiftUI cells
     class Controller: UITableViewController {
         private enum Section { case main }
-        private let representer: ReverseList
-        private var dataSource: UITableViewDiffableDataSource<Section, Item>!
+        var representer: ReverseList
+        private var dataSource: UITableViewDiffableDataSource<Section, ChatItem>!
         private var itemCount: Int = 0
         private var bag = Set<AnyCancellable>()
 
@@ -71,7 +73,7 @@ struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIV
             }
 
             // 3. Configure data source
-            self.dataSource = UITableViewDiffableDataSource<Section, Item>(
+            self.dataSource = UITableViewDiffableDataSource<Section, ChatItem>(
                 tableView: tableView
             ) { (tableView, indexPath, item) -> UITableViewCell? in
                 if indexPath.item > self.itemCount - 8, self.itemCount > 8 {
@@ -171,8 +173,8 @@ struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIV
             Task { representer.scrollState = .atDestination }
         }
 
-        func update(items: Array<Item>) {
-            var snapshot = NSDiffableDataSourceSnapshot<Section, Item>()
+        func update(items: [ChatItem]) {
+            var snapshot = NSDiffableDataSourceSnapshot<Section, ChatItem>()
             snapshot.appendSections([.main])
             snapshot.appendItems(items)
             dataSource.defaultRowAnimation = .none
@@ -188,6 +190,30 @@ struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIV
                 )
             }
             itemCount = items.count
+            updateVisibleItems()
+        }
+
+        override func scrollViewDidScroll(_ scrollView: UIScrollView) {
+            updateVisibleItems()
+        }
+
+        private func updateVisibleItems() {
+            ChatView.FloatingButtonModel.shared.visibleItems.send(
+                (tableView.indexPathsForVisibleRows ?? [])
+                    .compactMap { indexPath -> String? in
+                        let relativeFrame = tableView.superview!.convert(
+                            tableView.rectForRow(at: indexPath),
+                            from: tableView
+                        )
+                        // Checks that the cell is visible accounting for the added insets
+                        let isVisible =
+                            relativeFrame.maxY > InvertedTableView.inset &&
+                            relativeFrame.minY < tableView.frame.height - InvertedTableView.inset
+                        return indexPath.item < representer.items.count && isVisible
+                        ? representer.items[indexPath.item].viewId
+                        : nil
+                    }
+            )
         }
     }
 
@@ -232,12 +258,12 @@ struct ReverseList<Item: Identifiable & Hashable & Sendable, Content: View>: UIV
 }
 
 /// Manages ``ReverseList`` scrolling
-class ReverseListScrollModel<Item: Identifiable>: ObservableObject {
+class ReverseListScrollModel: ObservableObject {
     /// Represents Scroll State of ``ReverseList``
     enum State: Equatable {
         enum Destination: Equatable {
             case nextPage
-            case item(Item.ID)
+            case item(ChatItem.ID)
             case bottom
         }
 
@@ -255,7 +281,7 @@ class ReverseListScrollModel<Item: Identifiable>: ObservableObject {
         state = .scrollingTo(.bottom)
     }
 
-    func scrollToItem(id: Item.ID) {
+    func scrollToItem(id: ChatItem.ID) {
         state = .scrollingTo(.item(id))
     }
 }

apps/ios/Shared/Views/ChatList/ChatPreviewView.swift

@@ -324,12 +324,12 @@ struct ChatPreviewView: View {
         case let .image(_, image):
             smallContentPreview(size: dynamicMediaSize) {
                 CIImageView(chatItem: ci, preview: UIImage(base64Encoded: image), maxWidth: dynamicMediaSize, smallView: true, showFullScreenImage: $showFullscreenGallery)
-                    .environmentObject(ReverseListScrollModel<ChatItem>())
+                    .environmentObject(ReverseListScrollModel())
             }
         case let .video(_,image, duration):
             smallContentPreview(size: dynamicMediaSize) {
                 CIVideoView(chatItem: ci, preview: UIImage(base64Encoded: image), duration: duration, maxWidth: dynamicMediaSize, videoWidth: nil, smallView: true, showFullscreenPlayer: $showFullscreenGallery)
-                    .environmentObject(ReverseListScrollModel<ChatItem>())
+                    .environmentObject(ReverseListScrollModel())
             }
         case let .voice(_, duration):
             smallContentPreviewVoice(size: dynamicMediaSize) {