Fix transfer errors, save raw data

TempTrack/Storage/PersistentStorage.swift

@@ -15,9 +15,6 @@ final class PersistentStorage: ObservableObject {
     @AppStorage("newestDate")
     private var newestMeasurementTime: Int = 0
 
-    @AppStorage("deviceTime")
-    private var lastDeviceTimeData: Data?
-
     /**
      The date of the latest measurement.
 
@@ -71,6 +68,8 @@ final class PersistentStorage: ObservableObject {
         
         ensureExistenceOfFolder()
         //recalculateDailyCounts()
+        updateTransferCount()
+        updateDeviceInfoCount()
     }
     
     private func ensureExistenceOfFolder() {
@@ -121,7 +120,7 @@ final class PersistentStorage: ObservableObject {
     private func updateLastMeasurements(_ measurements: [TemperatureMeasurement]) {
         let startDate = Date().addingTimeInterval(-lastValueInterval).seconds
         recentMeasurements = (measurements + recentMeasurements)
-            .filter { $0.id > startDate }
+            .filter { $0.id > startDate }.sorted().reversed()
         log.info("\(recentMeasurements.count) recent measurements (with \(measurements.count) new entries)")
     }
     
@@ -278,35 +277,78 @@ final class PersistentStorage: ObservableObject {
         }
     }
 
-    // MARK: Device time
+    // MARK: Device info archive
 
-    var lastDeviceTime: DeviceTime? {
-        get {
-            guard let data = lastDeviceTimeData else {
-                return nil
-            }
+    @Published
+    var numberOfStoredDeviceInfos: Int = 0
+
+    private func updateDeviceInfoCount() {
+        let count = countFiles(in: "info")
+        DispatchQueue.main.async {
+            self.numberOfStoredDeviceInfos = count
+        }
+    }
+
+    @Published
+    var numberOfStoredTransfers: Int = 0
+
+    private func updateTransferCount() {
+        let count = countFiles(in: "transfers")
+        DispatchQueue.main.async {
+            self.numberOfStoredTransfers = count
+        }
+    }
+
+    private func countFiles(in folder: String) -> Int {
+        let folder = PersistentStorage.documentDirectory.appendingPathComponent(folder)
+        guard fm.fileExists(atPath: folder.path) else {
+            return 0
+        }
+        do {
+            return try fm.contentsOfDirectory(atPath: folder.path).count
+        } catch {
+            log.error("Failed to count files in '\(folder)': \(error)")
+            return -1
+        }
+    }
+
+    private func save(data: Data, date: Date, in folderName: String) -> Bool {
+        let folder = PersistentStorage.documentDirectory.appendingPathComponent(folderName)
+        if !fm.fileExists(atPath: folder.path) {
             do {
-                let result: DeviceTime = try BinaryDecoder.decode(from: data)
-                return result
+                try fm.createDirectory(at: folder, withIntermediateDirectories: false)
             } catch {
-                log.error("Failed to decode device time: \(error)")
-                lastDeviceTimeData = nil
-                return nil
+                log.error("Failed to create folder '\(folderName)': \(error)")
+                return false
             }
         }
-        set {
-            guard let newValue else {
-                lastDeviceTimeData = nil
-                return
-            }
-            do {
-                let data = try BinaryEncoder.encode(newValue)
-                lastDeviceTimeData = data
-            } catch {
-                log.error("Failed to encode device time: \(error)")
-                lastDeviceTimeData = nil
-            }
+        let url = folder.appendingPathComponent("\(date.seconds)")
+        do {
+            try data.write(to: url)
+        } catch {
+            log.error("Failed to write '\(url.lastPathComponent)' in '\(folder)': \(error)")
+            return false
         }
+        return true
+    }
+
+    @discardableResult
+    func save(deviceInfo: DeviceInfo) -> Bool {
+        defer { updateDeviceInfoCount() }
+        let data: Data
+        do {
+            data = try BinaryEncoder.encode(deviceInfo)
+        } catch {
+            log.error("Failed to encode device info for storage: \(error)")
+            return false
+        }
+        return save(data: data, date: deviceInfo.time.date, in: "info")
+    }
+
+    @discardableResult
+    func saveTransferData(data: Data, date: Date) -> Bool {
+        defer { updateTransferCount() }
+        return save(data: data, date: date, in: "transfers")
     }
 }