#!/usr/bin/env python3
"""
Manual CTAPHID INIT probe for a specific hidraw node.

This bypasses python-fido2's device bootstrap so we can see whether the raw HID
transport itself exchanges packets on the expected FIDO interface.
"""

from __future__ import annotations

import argparse
import os
import secrets
import select
import struct
import sys
from pathlib import Path


CTAPHID_INIT = 0x06
TYPE_INIT = 0x80
BROADCAST_CID = 0xFFFFFFFF


def build_init_packet(nonce: bytes) -> bytes:
    frame = struct.pack(">IBH", BROADCAST_CID, TYPE_INIT | CTAPHID_INIT, len(nonce)) + nonce
    return b"\0" + frame.ljust(64, b"\0")


def main() -> int:
    parser = argparse.ArgumentParser(description="Manual CTAPHID INIT probe")
    parser.add_argument("--device-path", default="/dev/hidraw0")
    parser.add_argument("--timeout", type=float, default=3.0)
    args = parser.parse_args()

    path = Path(args.device_path)
    if not path.exists():
        print(f"missing device: {path}", file=sys.stderr)
        return 2

    nonce = secrets.token_bytes(8)
    packet = build_init_packet(nonce)
    print(f"device={path}")
    print(f"nonce={nonce.hex()}")
    print(f"write_len={len(packet)}")
    print(f"write_hex={packet.hex()}")

    fd = os.open(str(path), os.O_RDWR)
    try:
        written = os.write(fd, packet)
        print(f"written={written}")
        poller = select.poll()
        poller.register(fd, select.POLLIN)
        events = poller.poll(int(args.timeout * 1000))
        print(f"events={events}")
        if not events:
            print("timeout_waiting_for_response")
            return 1
        response = os.read(fd, 64)
        print(f"read_len={len(response)}")
        print(f"read_hex={response.hex()}")
        if len(response) >= 24:
            cid, cmd, bc = struct.unpack(">IBH", response[:7])
            print(f"resp_cid=0x{cid:08x}")
            print(f"resp_cmd=0x{cmd:02x}")
            print(f"resp_bc={bc}")
            print(f"resp_payload={response[7:7+bc].hex()}")
        return 0
    finally:
        os.close(fd)


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