chore: async model switching and cleanup

Author: ygivenx

FreeWispr/Sources/FreeWispr/AppState.swift

@@ -20,6 +20,7 @@ class AppState: ObservableObject {
 
     private var isSetUp = false
     private var textCorrector: Any?
+    private var pendingModelSelection: ModelSize?
 
     let hotkeyManager = HotkeyManager()
     let audioRecorder = AudioRecorder()
@@ -51,7 +52,7 @@ class AppState: ObservableObject {
         // Load model
         do {
             let modelPath = modelManager.localModelPath(for: selectedModel)
-            try transcriber.loadModel(at: modelPath)
+            try await transcriber.loadModel(at: modelPath)
             statusMessage = "Ready"
         } catch {
             statusMessage = "Failed to load model: \(error.localizedDescription)"
@@ -153,30 +154,46 @@ class AppState: ObservableObject {
         isTranscribing = false
     }
 
-    func switchModel(to model: ModelSize) async {
-        guard !isSwitchingModel else { return }
+    func switchModel(to targetModel: ModelSize) async {
+        if isSwitchingModel {
+            pendingModelSelection = targetModel
+            return
+        }
+
         isSwitchingModel = true
-        defer { isSwitchingModel = false }
+        let previousModel = selectedModel
+        if previousModel != targetModel {
+            selectedModel = targetModel
+        }
+        defer {
+            isSwitchingModel = false
+            if let pending = pendingModelSelection {
+                pendingModelSelection = nil
+                if pending != selectedModel {
+                    Task { await self.switchModel(to: pending) }
+                }
+            }
+        }
 
         transcriber.unloadModel()
 
-        if !modelManager.isModelDownloaded(model) || !modelManager.isCoreMLDownloaded(model) {
-            statusMessage = "Downloading \(model.displayName)..."
+        if !modelManager.isModelDownloaded(targetModel) || !modelManager.isCoreMLDownloaded(targetModel) {
+            statusMessage = "Downloading \(targetModel.displayName)..."
             do {
-                try await modelManager.downloadModel(model)
+                try await modelManager.downloadModel(targetModel)
             } catch {
                 statusMessage = "Download failed: \(error.localizedDescription)"
-                // Revert UI selection to the model that is still loaded (none now — stay on previous)
+                selectedModel = previousModel
                 return
             }
         }
 
         do {
-            try transcriber.loadModel(at: modelManager.localModelPath(for: model))
-            selectedModel = model   // Commit only after successful load
+            try await transcriber.loadModel(at: modelManager.localModelPath(for: targetModel))
             statusMessage = "Ready"
         } catch {
             statusMessage = "Failed to load model: \(error.localizedDescription)"
+            selectedModel = previousModel
         }
     }
 

FreeWispr/Sources/FreeWispr/FreeWisprApp.swift

@@ -98,7 +98,7 @@ struct MenuBarView: View {
                 Picker("", selection: Binding(
                     get: { appState.selectedModel },
                     set: { newValue in
-                        guard hasAppeared, !appState.isSwitchingModel else { return }
+                        guard hasAppeared else { return }
                         Task { await appState.switchModel(to: newValue) }
                     }
                 )) {
@@ -107,12 +107,6 @@ struct MenuBarView: View {
                     }
                 }
                 .frame(width: 160)
-                .disabled(appState.isSwitchingModel)
-            }
-
-            if appState.modelManager.isDownloading {
-                ProgressView(value: appState.modelManager.downloadProgress)
-                    .progressViewStyle(.linear)
             }
 
             // AI Cleanup (macOS 26+ / Apple Intelligence)

FreeWispr/Sources/FreeWispr/ModelManager.swift

@@ -101,23 +101,28 @@ class ModelManager: ObservableObject {
             }
             let (tempZip, _) = try await URLSession.shared.download(from: coreMLDownloadURL(for: model), delegate: delegate)
 
-            // Unzip the Core ML model into the models directory
             let unzipDir = modelsDirectory
-            let process = Process()
-            process.executableURL = URL(fileURLWithPath: "/usr/bin/unzip")
-            process.arguments = ["-o", tempZip.path, "-d", unzipDir.path]
-            try process.run()
-            process.waitUntilExit()
-            try? FileManager.default.removeItem(at: tempZip)
-
-            if process.terminationStatus != 0 {
-                try? FileManager.default.removeItem(at: localCoreMLPath(for: model))
-                throw ModelDownloadError.unzipFailed(process.terminationStatus)
-            }
+            let coreMLPath = localCoreMLPath(for: model)
+            let tempZipPath = tempZip.path
 
-            guard FileManager.default.fileExists(atPath: localCoreMLPath(for: model).path) else {
-                throw ModelDownloadError.outputMissing(localCoreMLPath(for: model).path)
-            }
+            try await Task.detached(priority: .utility) {
+                let process = Process()
+                process.executableURL = URL(fileURLWithPath: "/usr/bin/unzip")
+                process.arguments = ["-o", tempZipPath, "-d", unzipDir.path]
+                try process.run()
+                process.waitUntilExit()
+
+                try? FileManager.default.removeItem(at: URL(fileURLWithPath: tempZipPath))
+
+                if process.terminationStatus != 0 {
+                    try? FileManager.default.removeItem(at: coreMLPath)
+                    throw ModelDownloadError.unzipFailed(process.terminationStatus)
+                }
+
+                guard FileManager.default.fileExists(atPath: coreMLPath.path) else {
+                    throw ModelDownloadError.outputMissing(coreMLPath.path)
+                }
+            }.value
         }
 
         downloadProgress = 1.0

FreeWispr/Sources/FreeWispr/WhisperTranscriber.swift

@@ -16,15 +16,19 @@ class WhisperTranscriber: ObservableObject {
     private var transcriptionCount = 0
     private let refreshInterval = 50
 
-    func loadModel(at path: URL) throws {
-        let params = WhisperParams(strategy: .greedy)
-        params.language = .english       // Skip auto-detection
-        params.print_progress = false    // Silence progress spam
-        params.print_realtime = false
-        params.print_timestamps = false
-        params.single_segment = true     // Treat as one segment — faster
+    func loadModel(at path: URL) async throws {
+        let newContext = await Task.detached(priority: .userInitiated) { () -> Whisper in
+            let params = WhisperParams(strategy: .greedy)
+            params.language = .english       // Skip auto-detection
+            params.print_progress = false    // Silence progress spam
+            params.print_realtime = false
+            params.print_timestamps = false
+            params.single_segment = true     // Treat as one segment — faster
 
-        whisper = Whisper(fromFileURL: path, withParams: params)
+            return Whisper(fromFileURL: path, withParams: params)
+        }.value
+
+        whisper = newContext
         modelPath = path
         isModelLoaded = true
         transcriptionCount = 0
@@ -55,7 +59,7 @@ class WhisperTranscriber: ObservableObject {
         transcriptionCount += 1
         if transcriptionCount >= refreshInterval, let path = modelPath {
             do {
-                try loadModel(at: path)
+                try await loadModel(at: path)
             } catch {
                 // Reload failed — continue with existing context.
             }

FreeWispr/Tests/BenchmarkTests/PipelineBenchmark.swift

@@ -107,7 +107,7 @@ final class PipelineBenchmark: XCTestCase {
         print()
 
         let transcriber = WhisperTranscriber()
-        try transcriber.loadModel(at: modelPath)
+        try await transcriber.loadModel(at: modelPath)
 
         var correctorAvailable = false
         #if canImport(FoundationModels)