#!/usr/bin/env python3
"""Find J1900 by MAC address on local subnet."""
import subprocess, sys

TARGET_MAC = "00:e2:69:34:71:2c"
SUBNET = "192.168.68"

def scan_arp_cache():
    out = subprocess.check_output(["ip", "neigh", "show"], text=True)
    for line in out.strip().split("\n"):
        if TARGET_MAC.lower() in line.lower():
            ip = line.split()[0]
            return ip
    return None

def ping_sweep():
    procs = []
    for i in range(1, 255):
        ip = f"{SUBNET}.{i}"
        p = subprocess.Popen(
            ["ping", "-c", "1", "-W", "0.2", ip],
            stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL
        )
        procs.append(p)
    for p in procs:
        p.wait()

def main():
    ip = scan_arp_cache()
    if ip:
        print(f"{ip}")
        return 0

    print(f"MAC not in ARP cache, scanning {SUBNET}.0/24 ...", file=sys.stderr)
    ping_sweep()

    ip = scan_arp_cache()
    if ip:
        print(f"{ip}")
        return 0

    print(f"NOT FOUND: {TARGET_MAC}", file=sys.stderr)
    return 1

if __name__ == "__main__":
    sys.exit(main())