feat: add simple progress remain time estimate

MastodonSDK/Sources/MastodonUI/Scene/ComposeContent/Attachment/AttachmentView.swift

@@ -53,32 +53,58 @@ public struct AttachmentView: View {
             if viewModel.output != nil {
                 VisualEffectView(effect: blurEffect)
                 VStack {
-                    let image: UIImage = {
+                    let actionType: AttachmentView.Action = {
                         if let _ = viewModel.error {
-                            return Asset.Scene.Compose.Attachment.retry.image.withRenderingMode(.alwaysTemplate)
+                            return .retry
                         } else {
-                            return Asset.Scene.Compose.Attachment.stop.image.withRenderingMode(.alwaysTemplate)
+                            return .remove
                         }
                     }()
-                    Image(uiImage: image)
+                    Button {
-                        .foregroundColor(.white)
+                        action(actionType)
-                        .padding()
+                    } label: {
-                        .background(Color(Asset.Scene.Compose.Attachment.indicatorButtonBackground.color))
+                        let image: UIImage = {
-                        .clipShape(Circle())
+                            switch actionType {
-                        .padding()
+                            case .remove:
+                                return Asset.Scene.Compose.Attachment.stop.image.withRenderingMode(.alwaysTemplate)
+                            case .retry:
+                                return Asset.Scene.Compose.Attachment.retry.image.withRenderingMode(.alwaysTemplate)
+                            }
+                        }()
+                        Image(uiImage: image)
+                            .foregroundColor(.white)
+                            .padding()
+                            .background(Color(Asset.Scene.Compose.Attachment.indicatorButtonBackground.color))
+                            .overlay(
+                                CircleProgressView(progress: viewModel.fractionCompleted)
+                                    .animation(.default, value: viewModel.fractionCompleted)
+                            )
+                            .clipShape(Circle())
+                            .padding()
+                    }
+
                     let title: String = {
-                        if let _ = viewModel.error {
+                        switch actionType {
+                        case .remove:
+                            let totalSizeInByte = viewModel.outputSizeInByte
+                            let uploadSizeInByte = Double(totalSizeInByte) * viewModel.progress.fractionCompleted
+                            let total = ByteCountFormatter.string(fromByteCount: Int64(totalSizeInByte), countStyle: .memory)
+                            let upload = ByteCountFormatter.string(fromByteCount: Int64(uploadSizeInByte), countStyle: .memory)
+                            return "\(upload)/\(total)"
+                        case .retry:
                             return "Upload Failed"  // TODO: i18n
-                        } else {
-                            let total = ByteCountFormatter.string(fromByteCount: Int64(viewModel.outputSizeInByte), countStyle: .memory)
-                            return "…/\(total)"
                         }
                     }()
                     let subtitle: String = {
-                        if let error = viewModel.error {
+                        switch actionType {
-                            return error.localizedDescription
+                        case .remove:
-                        } else {
+                            if viewModel.progress.fractionCompleted < 1 {
-                            return "… remaining"
+                                return viewModel.remainTimeLocalizedString ?? ""
+                            } else {
+                                return ""
+                            }
+                        case .retry:
+                            return viewModel.error?.localizedDescription ?? ""
                         }
                     }()
                     Text(title)
@@ -92,10 +118,6 @@ public struct AttachmentView: View {
                 }
             }
         }   // end ZStack
-        .onChange(of: viewModel.progress) { progress in
-            // not works…
-            print(progress.completedUnitCount)
-        }
     }   // end body
     
 }

MastodonSDK/Sources/MastodonUI/Scene/ComposeContent/Attachment/AttachmentViewModel.swift

@@ -32,12 +32,19 @@ final public class AttachmentViewModel: NSObject, ObservableObject, Identifiable
     // output
     @Published public private(set) var output: Output?
     @Published public private(set) var thumbnail: UIImage?      // original size image thumbnail
-    @Published public private(set) var outputSizeInByte: Int = 0
+    @Published public private(set) var outputSizeInByte: Int64 = 0
     
     @Published public var uploadResult: UploadResult?
     @Published var error: Error?
 
     let progress = Progress()       // upload progress
+    @Published var fractionCompleted: Double = 0
+
+    var displayLink: CADisplayLink!
+    private var lastTimestamp: TimeInterval?
+    private var lastUploadSizeInByte: Int64 = 0
+    private var averageUploadSpeedInByte: Int64 = 0
+    @Published var remainTimeLocalizedString: String?
     
     public init(
         api: APIService,
@@ -49,26 +56,34 @@ final public class AttachmentViewModel: NSObject, ObservableObject, Identifiable
         self.input = input
         super.init()
         // end init
+        
+        self.displayLink = CADisplayLink(
+            target: self,
+            selector: #selector(AttachmentViewModel.step(displayLink:))
+        )
+        displayLink.add(to: .current, forMode: .common)
 
         progress
             .observe(\.fractionCompleted, options: [.initial, .new]) { [weak self] progress, _ in
                 guard let self = self else { return }
                 self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): publish progress \(progress.fractionCompleted)")
+                self.fractionCompleted = progress.fractionCompleted
                 DispatchQueue.main.async {
                     self.objectWillChange.send()
                 }
             }
             .store(in: &observations)
         
-        progress
+        // Note: this observation is redundant if .fractionCompleted listener always emit event when reach 1.0 progress
-            .observe(\.isFinished, options: [.initial, .new]) { [weak self] progress, _ in
+        // progress
-                guard let self = self else { return }
+        //     .observe(\.isFinished, options: [.initial, .new]) { [weak self] progress, _ in
-                self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): publish progress \(progress.fractionCompleted)")
+        //         guard let self = self else { return }
-                DispatchQueue.main.async {
+        //         self.logger.log(level: .debug, "\((#file as NSString).lastPathComponent, privacy: .public)[\(#line, privacy: .public)], \(#function, privacy: .public): publish progress \(progress.fractionCompleted)")
-                    self.objectWillChange.send()
+        //         DispatchQueue.main.async {
-                }
+        //             self.objectWillChange.send()
-            }
+        //         }
-            .store(in: &observations)
+        //     }
+        //     .store(in: &observations)
         
         $output
             .map { output -> UIImage? in
@@ -89,7 +104,7 @@ final public class AttachmentViewModel: NSObject, ObservableObject, Identifiable
                 do {
                     let output = try await load(input: input)
                     self.output = output
-                    self.outputSizeInByte = output.asAttachment.sizeInByte ?? 0
+                    self.outputSizeInByte = output.asAttachment.sizeInByte.flatMap { Int64($0) } ?? 0
                     let uploadResult = try await self.upload(context: .init(
                         apiService: self.api,
                         authContext: self.authContext
@@ -103,6 +118,9 @@ final public class AttachmentViewModel: NSObject, ObservableObject, Identifiable
     }
     
     deinit {
+        displayLink.invalidate()
+        displayLink.remove(from: .current, forMode: .common)
+        
         switch output {
         case .image:
             // FIXME:
@@ -115,6 +133,58 @@ final public class AttachmentViewModel: NSObject, ObservableObject, Identifiable
     }
 }
 
+// calculate the upload speed
+// ref: https://stackoverflow.com/a/3841706/3797903
+extension AttachmentViewModel {
+    
+    static var SpeedSmoothingFactor = 0.4
+    static let remainsTimeFormatter: RelativeDateTimeFormatter = {
+        let formatter = RelativeDateTimeFormatter()
+        formatter.unitsStyle = .short
+        return formatter
+    }()
+    
+    @objc private func step(displayLink: CADisplayLink) {
+        guard let lastTimestamp = self.lastTimestamp else {
+            self.lastTimestamp = displayLink.timestamp
+            self.lastUploadSizeInByte = Int64(Double(outputSizeInByte) * progress.fractionCompleted)
+            return
+        }
+
+        let duration = displayLink.timestamp - lastTimestamp
+        guard duration >= 1.0 else { return }       // update every 1 sec
+        
+        let old = self.lastUploadSizeInByte
+        self.lastUploadSizeInByte = Int64(Double(outputSizeInByte) * progress.fractionCompleted)
+        
+        let newSpeed = self.lastUploadSizeInByte - old
+        let lastAverageSpeed = self.averageUploadSpeedInByte
+        let newAverageSpeed = Int64(AttachmentViewModel.SpeedSmoothingFactor * Double(newSpeed) + (1 - AttachmentViewModel.SpeedSmoothingFactor) * Double(lastAverageSpeed))
+        
+        let remainSizeInByte = Double(outputSizeInByte) * (1 - progress.fractionCompleted)
+        
+        let speed = Double(newAverageSpeed)
+        if speed != .zero {
+            // estimate by speed
+            let uploadRemainTimeInSecond = remainSizeInByte / speed
+            // estimate by progress 1s for 10%
+            let remainPercentage = 1 - progress.fractionCompleted
+            let estimateRemainTimeByProgress = remainPercentage / 0.1
+            // max estimate
+            let remainTimeInSecond = max(estimateRemainTimeByProgress, uploadRemainTimeInSecond)
+            
+            let string = AttachmentViewModel.remainsTimeFormatter.localizedString(fromTimeInterval: remainTimeInSecond)
+            remainTimeLocalizedString = string
+            // print("remains: \(remainSizeInByte), speed: \(newAverageSpeed), \(string)")
+        } else {
+            remainTimeLocalizedString = nil
+        }
+        
+        self.lastTimestamp = displayLink.timestamp
+        self.averageUploadSpeedInByte = newAverageSpeed
+    }
+}
+
 extension AttachmentViewModel {
     public enum Input: Hashable {
         case image(UIImage)

MastodonSDK/Sources/MastodonUI/Scene/ComposeContent/ComposeContentViewModel.swift

@@ -278,6 +278,11 @@ extension ComposeContentViewModel {
 // MARK: - UITextViewDelegate
 extension ComposeContentViewModel: UITextViewDelegate {
     public func textViewDidBeginEditing(_ textView: UITextView) {
+        // Note:
+        // Xcode warning:
+        // Publishing changes from within view updates is not allowed, this will cause undefined behavior.
+        //
+        // Just ignore the warning and see what will happen…
         switch textView {
         case contentMetaText?.textView:
             isContentEditing = true

MastodonSDK/Sources/MastodonUI/Vendor/CircleProgressView.swift

@@ -0,0 +1,29 @@
+//
+//  CircleProgressView.swift
+//  
+//
+//  Created by MainasuK on 2022/11/10.
+//
+
+import Foundation
+import SwiftUI
+
+/// https://stackoverflow.com/a/71467536/3797903
+struct CircleProgressView: View {
+
+    let progress: Double
+    
+    var body: some View {
+        let lineWidth: CGFloat = 4
+        let tintColor = Color.white
+        ZStack {
+            Circle()
+                .trim(from: 0.0, to: CGFloat(progress))
+                .stroke(style: StrokeStyle(lineWidth: lineWidth, lineCap: .butt, lineJoin: .bevel))
+                .foregroundColor(tintColor)
+                .rotationEffect(Angle(degrees: 270.0))
+        }
+        .padding(ceil(lineWidth / 2))
+    }
+
+}