TempTrack-iOS/TempTrack/Temperature/TemperatureDataTransfer.swift

import Foundation
/*
final class TemperatureDataTransfer {

    private let startDateOfCurrentTransfer: Date
    
    private var interval: TimeInterval {
        TimeInterval(info.measurementInterval) * dilation
    }
    
    private var dataBuffer: Data = Data()
    
    private(set) var currentByteIndex = 0

    private var info: DeviceInfo

    private let dilation: Double
    
    var size: Int {
        info.numberOfRecordedBytes
    }
    
    var blockSize: Int {
        min(50, info.transferBlockSize)
    }
    
    private var numberOfRecordingsInCurrentTransfer: Int {
        measurements.count
    }

    var time: DeviceTime {
        info.time
    }

    var measurements: [TemperatureMeasurement] = []

    /// The last temperatures to calculate relative values
    private var lastRecording: TemperatureMeasurement = .init(sensor0: .notFound, sensor1: .notFound, date: .now)
    
    private var dateOfNextRecording: Date {
        startDateOfCurrentTransfer.addingTimeInterval(TimeInterval(numberOfRecordingsInCurrentTransfer) * interval)
    }
    
    var unprocessedByteCount: Int {
        dataBuffer.count
    }
    
    var remainingBytesToTransfer: Int {
        size - currentByteIndex
    }
    
    init(info: DeviceInfo, previous: DeviceTime?) {
        let (estimatedStart, dilation) = info.estimatedTimeDilation(to: previous)
        log.info("Starting transfer")
        log.info("Estimated start of recording: \(estimatedStart)")
        log.info("Estimated time dilation: \(dilation)")
        self.info = info
        self.dilation = dilation
        self.startDateOfCurrentTransfer = estimatedStart
        log.info("True measurement interval: \(interval)")
    }
    
    func update(info: DeviceInfo) {
        self.info = info
        // Possible bug: Device time updated, but new measurement not transferred
        // Future transfer will calculate wrong time
    }
    
    func nextRequest() -> BluetoothRequest {
        guard remainingBytesToTransfer > 0 else {
            return .clearRecordingBuffer(byteCount: currentByteIndex)
        }
        let chunkSize = min(remainingBytesToTransfer, blockSize)
        return .getRecordingData(offset: currentByteIndex, count: chunkSize)
    }
    
    func add(data: Data, offset: Int, count: Int) -> Bool {
        guard currentByteIndex == offset else {
            log.warning("Transfer: Discarding \(data.count) bytes at offset \(offset), expected \(currentByteIndex)")
            return false
        }
        guard data.count == count else {
            log.warning("Transfer: Expected \(count) bytes, received only \(data.count)")
            return false
        }
        dataBuffer.append(data)
        currentByteIndex += data.count
        log.info("Transfer: \(currentByteIndex) bytes (added \(data.count))")
        return true
    }
    
    private func processBytes() {
        while !dataBuffer.isEmpty {
            let byte = dataBuffer.removeFirst()
            guard (byte == 0xFF) else {
                addRelative(byte: byte)
                continue
            }
            guard dataBuffer.count >= 2 else {
                // Missing data
                return
            }
            let temp0 = TemperatureValue(byte: dataBuffer.removeFirst())
            let temp1 = TemperatureValue(byte: dataBuffer.removeFirst())
            add(sensor0: temp0, sensor1: temp1)
        }
    }
    
    func completeTransfer() -> Bool {
        let emptyIndices = dataBuffer.enumerated().filter { $0.element == 0 }.map { $0.offset }
        processBytes()
        guard dataBuffer.isEmpty else {
            log.warning("\(dataBuffer.count) bytes remaining in transfer buffer")
            return false
        }
        log.info("Transfer complete: \(currentByteIndex) bytes, \(measurements.count) points")
        log.info("Empty bytes: \(emptyIndices)")
        if measurements.count != info.numberOfStoredMeasurements {
            log.warning("Decoded \(measurements.count) points, but only \(info.numberOfStoredMeasurements) recorded")
        }
        return true
    }
    
    private func addRelative(byte: UInt8) {
        add(sensor0: convertTemp(value: (byte >> 4) & 0x0F, relativeTo: lastRecording.sensor0),
            sensor1: convertTemp(value: byte & 0x0F, relativeTo: lastRecording.sensor1))
    }
    
    private func add(sensor0: TemperatureValue, sensor1: TemperatureValue) {
        let measurement = TemperatureMeasurement(
            sensor0: sensor0,
            sensor1: sensor1,
            date: dateOfNextRecording)

        if measurement.sensor0.isValid {
            lastRecording.sensor0 = measurement.sensor0
        }
        if measurement.sensor1.isValid {
            lastRecording.sensor1 = measurement.sensor1
        }
        lastRecording.id = measurement.id
        measurements.append(measurement)
    }
    
    private func convertTemp(value: UInt8, relativeTo previous: TemperatureValue) -> TemperatureValue {
        if value == 0 {
            return .notFound
        }
        let newValue = previous.relativeValue - (Double(value) - 8) * 0.5
        return .value(newValue)
    }
}


private extension TemperatureValue {
    
    var relativeValue: Double {
        if case .value(let double) = self {
            return double
        }
        return 0
    }
}
*/