"""Thin wrapper for external tools — outputs JSON to stdout."""

import argparse
import json
import sys

from hpcs6500 import HPCS6500, find_hpcs_port


def measure():
    port = find_hpcs_port()
    if not port:
        print('{"error": "HPCS 6500 not found"}', file=sys.stderr)
        sys.exit(1)

    dev = HPCS6500(port)
    try:
        dev.identify()
        reading = dev.take_single_reading()
    finally:
        dev.close()

    if reading is None:
        print('{"error": "measurement failed"}', file=sys.stderr)
        sys.exit(1)

    result = {
        "lumen": round(reading["Phi_lm"], 1),
        "cct": round(reading["CCT_K"]),
    }
    print(json.dumps(result))


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="HPCS 6500 JSON interface")
    parser.add_argument("--measure", action="store_true", help="Take a measurement and output JSON")
    args = parser.parse_args()

    if args.measure:
        measure()
    else:
        parser.print_help()