"""Read and decode CAN frames from the CANdapter (candapter.com) USB adapter.

Usage:
    python read_can.py [--bitrate 500000] [--port /dev/cu.usbserial-DNBJV4F5]

Connect the adapter to the CAN bus first, then run this script. It opens the
channel at the given bitrate and prints every frame it receives: timestamp,
arbitration ID (with an 'x' suffix for 29-bit extended IDs), DLC, raw bytes
(hex), and an ASCII preview.

If you don't know the bus's bitrate, common values are 125000, 250000,
500000 (most likely - the adapter is rated for automotive use at 500 kbps),
and 1000000. Wrong bitrate usually means zero frames or garbled data --
try another value.
"""
import argparse
import sys
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[1]))
from adapters.candapter import Candapter  # noqa: E402

DEFAULT_PORT = "/dev/cu.usbserial-DNBJV4F5"
DEFAULT_BITRATE = 500000


def ascii_preview(data: bytes) -> str:
    return "".join(chr(b) if 32 <= b < 127 else "." for b in data)


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--port", default=DEFAULT_PORT, help="Serial device path")
    parser.add_argument("--bitrate", type=int, default=DEFAULT_BITRATE, help="CAN bus bitrate")
    args = parser.parse_args()

    try:
        adapter = Candapter(args.port, args.bitrate, timestamps=True)
    except (OSError, ValueError) as exc:
        print(f"Failed to open adapter on {args.port}: {exc}", file=sys.stderr)
        return 1

    print(f"Listening on {args.port} at {args.bitrate} bps (Ctrl+C to stop)...\n")
    print(f"{'timestamp':>14}  {'id':>10}  {'dlc':>3}  data (hex)              ascii")

    try:
        with adapter:
            while True:
                frame = adapter.read_frame(timeout=None)
                if frame is None:
                    continue
                id_str = f"{frame.arbitration_id:08X}x" if frame.is_extended else f"{frame.arbitration_id:03X}"
                data_hex = " ".join(f"{b:02X}" for b in frame.data)
                ts = frame.timestamp_ms if frame.timestamp_ms is not None else frame.recv_time
                print(
                    f"{ts:14.3f}  {id_str:>10}  {len(frame.data):>3}  "
                    f"{data_hex:<24} {ascii_preview(frame.data)}"
                )
    except KeyboardInterrupt:
        print("\nStopped.")

    return 0


if __name__ == "__main__":
    raise SystemExit(main())