Show classifier download progress

Caps/Data/Database.swift

@@ -8,10 +8,27 @@ final class Database: ObservableObject {
     private let imageCompressionQuality: CGFloat = 0.3
 
     @AppStorage("classifier")
-    private(set) var classifierVersion = 0
+    private var storedLocalClassifierVersion = 0 {
+        didSet { localClassifierVersion = storedLocalClassifierVersion }
+    }
 
     @AppStorage("serverClassifier")
+    private var storedServerClassifierVersion = 0 {
+        didSet { serverClassifierVersion = storedServerClassifierVersion }
+    }
+    
+    @Published
+    private(set) var localClassifierVersion = 0
+    
+    @Published
     private(set) var serverClassifierVersion = 0
+    
+    @Published
+    private(set) var classifierDownloadProgress: ClassifierProgress?
+    
+    var hasNewClassifier: Bool {
+        serverClassifierVersion > localClassifierVersion
+    }
 
     let images: ImageCache
 
@@ -146,6 +163,9 @@ final class Database: ObservableObject {
             folder: imageFolder,
             server: server,
             thumbnailSize: CapsApp.thumbnailImageSize)
+        
+        self.localClassifierVersion = storedLocalClassifierVersion
+        self.serverClassifierVersion = storedServerClassifierVersion
 
         ensureFolderExistence(gridStorageFolder)
         loadCaps()
@@ -329,7 +349,7 @@ final class Database: ObservableObject {
     }
 
     @discardableResult
-    func serverHasNewClassifier() async -> Bool {
+    func updateServerClassifierVersion() async -> Bool {
         let data: Data
         let response: URLResponse
         do {
@@ -351,23 +371,29 @@ final class Database: ObservableObject {
             return false
         }
         DispatchQueue.main.async {
-            self.serverClassifierVersion = serverVersion
+            self.storedServerClassifierVersion = serverVersion
         }
-        guard serverVersion > self.classifierVersion else {
-            log("No new classifier available (Local: \(classifierVersion) Server: \(serverVersion))")
-            return false
-        }
-        log("New classifier available (Local: \(classifierVersion) Server: \(serverVersion))")
         return true
     }
 
     @discardableResult
     func downloadClassifier() async -> Bool {
         log("Downloading classifier")
+        
+        let progress = ClassifierProgress()
+        DispatchQueue.main.async {
+            self.classifierDownloadProgress = progress
+        }
+        defer {
+            DispatchQueue.main.async {
+                self.classifierDownloadProgress = nil
+            }
+        }
+        
         let tempUrl: URL
         let response: URLResponse
         do {
-            (tempUrl, response) = try await URLSession.shared.download(from: serverClassifierUrl)
+            (tempUrl, response) = try await URLSession.shared.download(from: serverClassifierUrl, delegate: progress)
         } catch {
             log("Failed to download classifier version: \(error)")
             return false
@@ -386,10 +412,10 @@ final class Database: ObservableObject {
             return false
         }
         DispatchQueue.main.async {
-            self.classifierVersion = self.serverClassifierVersion
+            self.storedLocalClassifierVersion = self.serverClassifierVersion
+            log("Downloaded classifier \(self.localClassifierVersion)")
             self.classifier = nil
         }
-        log("Downloaded classifier \(classifierVersion)")
         return true
     }
     
@@ -987,6 +1013,44 @@ final class Database: ObservableObject {
     }
 }
 
+extension Database {
+    
+    final class ClassifierProgress: NSObject, ObservableObject {
+        
+        @Published
+        var bytesLoaded: Double
+        
+        @Published
+        var total: Double
+        
+        var percentage: Double {
+            guard total > 0 else {
+                return 0.0
+            }
+            return bytesLoaded * 100 / total
+        }
+        
+        init(bytesLoaded: Double = 0, total: Double = 0) {
+            self.bytesLoaded = bytesLoaded
+            self.total = total
+        }
+    }
+}
+
+extension Database.ClassifierProgress: URLSessionDownloadDelegate {
+    
+    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {
+        
+    }
+    
+    func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
+        DispatchQueue.main.async {
+            self.bytesLoaded = Double(totalBytesWritten)
+            self.total = Double(totalBytesExpectedToWrite)
+        }
+    }
+}
+
 extension Database {
 
     static var mock: Database {