wip

ConversationsClassic/AppCore/Middlewares/FileMiddleware.swift

@@ -4,12 +4,21 @@ import UIKit
 
 final class FileMiddleware {
     static let shared = FileMiddleware()
+    private var downloadingMessageIDs = ThreadSafeSet<String>()
 
     func middleware(state _: AppState, action: AppAction) -> AnyPublisher<AppAction, Never> {
         switch action {
         case .conversationAction(.messagesUpdated(let messages)):
-            return Future { promise in
+            return Future { [weak self] promise in
+                guard let wSelf = self else {
+                    promise(.success(.empty))
+                    return
+                }
                 for message in messages where message.attachmentRemotePath != nil && message.attachmentLocalPath == nil {
+                    if wSelf.downloadingMessageIDs.contains(message.id) {
+                        continue
+                    }
+                    wSelf.downloadingMessageIDs.insert(message.id)
                     DispatchQueue.main.async {
                         // swiftlint:disable:next force_unwrapping
                         store.dispatch(.fileAction(.downloadAttachmentFile(id: message.id, attachmentRemotePath: message.attachmentRemotePath!)))
@@ -34,14 +43,19 @@ final class FileMiddleware {
             }.eraseToAnyPublisher()
 
         case .fileAction(.attachmentFileDownloaded(let id, let localUrl)):
-            return Just(.fileAction(.createAttachmentThumbnail(id: id, localUrl: localUrl)))
+            return Future { [weak self] promise in
+                self?.downloadingMessageIDs.remove(id)
+                promise(.success(.fileAction(.createAttachmentThumbnail(id: id, localUrl: localUrl))))
+            }
             .eraseToAnyPublisher()
 
         case .fileAction(.createAttachmentThumbnail(let id, let localUrl)):
-            return Future { promise in
+            return Future { [weak self] promise in
                 if let thumbnailUrl = FileProcessing.shared.createThumbnail(id: id, localUrl: localUrl) {
+                    self?.downloadingMessageIDs.remove(id)
                     promise(.success(.fileAction(.attachmentThumbnailCreated(id: id, thumbnailUrl: thumbnailUrl))))
                 } else {
+                    self?.downloadingMessageIDs.remove(id)
                     promise(.success(.empty))
                 }
             }

ConversationsClassic/Helpers/Set+Extensions.swift

@@ -0,0 +1,26 @@
+import Foundation
+
+class ThreadSafeSet<T: Hashable> {
+    private var set: Set<T> = []
+    private let accessQueue = DispatchQueue(label: "com.example.ThreadSafeSet")
+
+    func insert(_ newElement: T) {
+        _ = accessQueue.sync {
+            set.insert(newElement)
+        }
+    }
+
+    func remove(_ element: T) {
+        _ = accessQueue.sync {
+            set.remove(element)
+        }
+    }
+
+    var elements: Set<T> {
+        accessQueue.sync { set }
+    }
+
+    func contains(_ element: T) -> Bool {
+        accessQueue.sync { set.contains(element) }
+    }
+}

ConversationsClassic/View/Screens/Conversation/ConversationMessageContainer.swift

@@ -70,6 +70,9 @@ private struct AttachmentView: View {
     let message: Message
 
     var body: some View {
+        if message.attachmentDownloadFailed {
+            failed
+        } else {
             switch message.attachmentType {
             case .image:
                 if let thumbnail = thumbnail() {
@@ -95,6 +98,7 @@ private struct AttachmentView: View {
                 placeholder
             }
         }
+    }
 
     @ViewBuilder private var placeholder: some View {
         Rectangle()
@@ -113,6 +117,19 @@ private struct AttachmentView: View {
             }
     }
 
+    @ViewBuilder private var failed: some View {
+        Rectangle()
+            .foregroundColor(.Material.Background.dark)
+            .frame(width: Const.attachmentPreviewSize, height: Const.attachmentPreviewSize)
+            .overlay {
+                ZStack {
+                    Image(systemName: "exclamationmark.triangle")
+                        .font(.body1)
+                        .foregroundColor(.Rainbow.red500)
+                }
+            }
+    }
+
     private func progressImageName(_ type: MessageAttachmentType) -> String {
         switch type {
         case .image: