import CoreBluetooth

var centralManager: CBCentralManager!

extension ViewController: CBCentralManagerDelegate {}

func centralManagerDidUpdateState(_ central: CBCentralManager) {
        switch central.state {
        }

extension ViewController: CBCentralManagerDelegate {
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        switch central.state {
        case .unknown:
            print ("central.state is unknown")
        case .resetting:
            print ("central.state is resetting")
        case .unsupported:
            print ("central.state is unsupported")
        case .unauthorized:
            print ("central.state is unauthorized")
        case .poweredOff:
            print ("central.state is poweredOff")
        case .poweredOn:
            print ("central.state is poweredOn")
        @unknown default:
            break
        }
    }
}

override func viewDidLoad() {
        super.viewDidLoad()
        centralManager = CBCentralManager(delegate: self, queue: nil)
        heartRateLabel.isHidden = true
        bodyLocationLabel.isHidden = true
    }

centralManager.scanForPeripherals(withServices: nil)

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
        print(peripheral)
    }

let heartRateUUID = CBUUID(string: "0x180D")

case .poweredOn:
            print ("central.state is poweredOn")
            centralManager.scanForPeripherals(withServices: [heartRateUUID] )

var heartRatePeripheral: CBPeripheral!

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
        print(peripheral)
        heartRatePeripheral = peripheral
        centralManager.stopScan()
    }

centralManager.connect(heartRatePeripheral, options: nil)

func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
        print("Соединение установлено")
    }

func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
        print("Соединение установлено")
        heartRatePeripheral.discoverServices(nil)
    }

extension ViewController: CBPeripheralDelegate {
    func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
        guard let services = peripheral.services else { return }
        for service in services {
            print(service)
        }
    }
}

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
        print(peripheral)
        heartRatePeripheral = peripheral
        heartRatePeripheral.delegate = self
        centralManager.stopScan()
        centralManager.connect(heartRatePeripheral, options: nil)
    }

heartRatePeripheral.discoverServices([heartRateUUID])

extension ViewController: CBPeripheralDelegate {
    func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
        guard let services = peripheral.services else { return }
        for service in services {
            peripheral.discoverCharacteristics(nil, for: service)
        }
    }
}

func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
        guard let characteristics = service.characteristics else { return }
        for characteristic in characteristics {
            print(characteristic)
        }
    }

let heartRateUUID = CBUUID(string: "0x180D")
let heartRateCharacteristicCBUUID = CBUUID(string: "2A37")
let bodyLocationCharacteristicCBUUID = CBUUID(string: "2A38")

func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
        guard let characteristics = service.characteristics else { return }
        for characteristic in characteristics {
            peripheral.readValue(for: characteristic)
        }
    }

func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic,
                error: Error?) {
  switch characteristic.uuid {
    case bodySensorLocationCharacteristicCBUUID:
      print(characteristic.value ?? "no value")
    default:
      print("Unhandled Characteristic UUID: \(characteristic.uuid)")
  }
}

private func bodyLocation(from characteristic: CBCharacteristic) -> String {
        guard let characteristicData = characteristic.value,
              let byte = characteristicData.first else { return "Error" }
        switch byte {
        case 0: return "Другое"
        case 1: return "Грудь"
        case 2: return "Запястье"
        case 3: return "Палец"
        case 4: return "Ладонь"
        case 5: return "Мочка уха"
        case 6: return "Нога"
        default:
            return "Резерв"
        }
    }

func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic,
                    error: Error?) {
        switch characteristic.uuid {
        case bodyLocationCharacteristicCBUUID:
            let bodySensorLocation = bodyLocation(from: characteristic)
            bodyLocationLabel.text = bodySensorLocation
            bodyLocationLabel.isHidden = false
        default:
          print("Unhandled Characteristic UUID: \(characteristic.uuid)")
      }
    }

func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
        guard let characteristics = service.characteristics else { return }
        for characteristic in characteristics {
            peripheral.readValue(for: characteristic)
            peripheral.setNotifyValue(true, for: characteristic)
        }
    }

private func heartRate(from characteristic: CBCharacteristic) -> Int {
        guard let characteristicData = characteristic.value else { return -1 }
        let byteArray = [UInt8](characteristicData)
        let firstBitValue = byteArray[0] & 0x01
        if firstBitValue == 0 {
            return Int(byteArray[1])
        } else {
            return (Int(byteArray[1]) << 8) + Int(byteArray[2])
        }
    }

func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic,
                    error: Error?) {
        switch characteristic.uuid {
        case bodyLocationCharacteristicCBUUID:
            let bodySensorLocation = bodyLocation(from: characteristic)
            bodyLocationLabel.text = bodySensorLocation
            bodyLocationLabel.isHidden = false
        case heartRateCharacteristicCBUUID:
            let bpm = heartRate(from: characteristic)
            heartRateLabel.text = String(bpm)
            heartRateLabel.isHidden = false
        default:
          print("Unhandled Characteristic UUID: \(characteristic.uuid)")
      }
    }