Add function to clear image cache

Caps/Data/Database.swift

@@ -551,6 +551,20 @@ final class Database: ObservableObject {
         Int(url.lastPathComponent.components(separatedBy: "-").first!)
     }
 
+    private func imageId(from url: URL) -> CapImage? {
+        let parts = url.deletingPathExtension().lastPathComponent.components(separatedBy: "-")
+        guard parts.count == 2 else {
+            log("File \(url.lastPathComponent) is not a cap image")
+            return nil
+        }
+        guard let capId = Int(parts.first!),
+              let version = Int(parts.last!) else {
+            log("File \(url.lastPathComponent) is not a cap image")
+            return nil
+        }
+        return .init(cap: capId, version: version)
+    }
+
     private func uploadAllImages() async {
         guard hasServerAuthentication else {
             log("No server authentication to upload to server")
@@ -929,7 +943,7 @@ final class Database: ObservableObject {
         classifierClasses.count
     }
 
-    func imageCacheSize() async -> Int {
+    func imageCacheSize() -> Int {
         fm.directorySize(images.folder)
     }
 
@@ -940,6 +954,37 @@ final class Database: ObservableObject {
     var classifierSize: Int {
         localClassifierUrl.fileSize
     }
+
+    private var cachedImages: [URL] {
+        do {
+            return try fm.contentsOfDirectory(at: images.folder, includingPropertiesForKeys: nil)
+        } catch {
+            log("Failed to get cached images: \(error)")
+            return []
+        }
+    }
+
+    func clearImageCache() {
+        let allImages = cachedImages
+        let unnecessaryImages = allImages
+            .filter {
+                guard let id = imageId(from: $0) else {
+                    return true
+                }
+                guard let cap = caps[id.cap] else {
+                    return true
+                }
+                return cap.mainImage != id.version
+            }
+        log("Deleting \(unnecessaryImages.count) of \(allImages.count) cached images")
+        for cachedImage in unnecessaryImages {
+            do {
+                try fm.removeItem(at: cachedImage)
+            } catch {
+                log("Failed to delete cached image \(cachedImage.lastPathComponent): \(error)")
+            }
+        }
+    }
 }
 
 extension Database {

Caps/Views/SettingsView.swift

@@ -54,6 +54,12 @@ struct SettingsView: View {
                     SettingsStatisticRow(label: "Image cache", value: byteString(imageCacheSize))
                     SettingsStatisticRow(label: "Database", value: byteString(database.databaseSize))
                     SettingsStatisticRow(label: "Classifier", value: byteString(database.classifierSize))
+                    HStack {
+                        Spacer()
+                        Button("Clear image cache", action: clearImageCache)
+                            .padding()
+                        Spacer()
+                    }
                 }.padding(.horizontal)
                 Spacer()
             }
@@ -64,8 +70,15 @@ struct SettingsView: View {
     }
     
     private func updateImageCacheSize() {
+        imageCacheSize = database.imageCacheSize()
+    }
+
+    private func clearImageCache() {
         Task {
-            imageCacheSize = await database.imageCacheSize()
+            database.clearImageCache()
+            DispatchQueue.main.async {
+                updateImageCacheSize()
+            }
         }
     }