import time

from serial import Serial
from serial.tools import list_ports

from serial_sync import SerialSync


BAUDRATE = 115200
SERIAL_TIMEOUT = 1.0
CALIBRATION_PERIOD_S = 30.0


def choose_serial_port() -> str:
    ports = list(list_ports.comports())

    if not ports:
        raise RuntimeError("No serial ports found")

    print("Available serial ports:")

    for index, port in enumerate(ports):
        print(f"{index}: {port.device} ({port.description})")

    while True:
        try:
            choice = int(input("Choose a port: "))

            if 0 <= choice < len(ports):
                return ports[choice].device

        except ValueError:
            pass

        print("Invalid choice, try again.")


def main() -> None:
    try:
        port = choose_serial_port()

        print()
        print(f"Opening {port} at {BAUDRATE} baud...")

        with Serial(
            port=port,
            baudrate=BAUDRATE,
            timeout=SERIAL_TIMEOUT,
        ) as serial:
            #
            # Opening the serial port may reset an Arduino,
            # so allow it to boot before calibration.
            #
            print("Waiting for Arduino to start...")
            time.sleep(5)

            sync = SerialSync(serial)

            print()
            print(f"Calibrating for {CALIBRATION_PERIOD_S:.1f} seconds...")

            sync.calibrate_sync(CALIBRATION_PERIOD_S)

            print()
            print("Synchronization complete")
            print("------------------------")
            print(f"Scale:      {sync._scale:.12f}")
            print(f"Offset:     {sync._offset:.0f} ns")
            print(f"Offset:     {sync._offset / 1_000_000:.6f} ms")

    except KeyboardInterrupt:
        print("\nInterrupted.")

    except Exception as exc:
        print(f"\nError: {exc}")


if __name__ == "__main__":
    main()