#!/usr/bin/env python3

import argparse
import tempfile
import os
import socket
import subprocess
import sys

parser = argparse.ArgumentParser(
    description="Check that $HOSTALIASES is working"
)
parser.add_argument(
    "--child",
    action="store_true",
    help="run in child mode, for internal use only",
)
parser.add_argument(
    "-v",
    action="store_true",
    help="verbose mode",
)
args = parser.parse_args()


def dprint(*a):
    if args.v:
        print(*a)


if args.child:
    dprint("child mode, getting hosts")
    lo = socket.gethostbyname("localhost")
    ts = socket.gethostbyname("testserver")
    dprint(ts, lo, ts == lo)
    if ts != lo:
        sys.exit(1)
else:
    dprint("## parent mode")
    # Create the hostaliases file.
    fd = tempfile.NamedTemporaryFile(mode="w+")
    fd.write("testserver localhost\n")
    fd.flush()

    # Re-execute ourselves with --child, to do the check.
    env = dict(os.environ)
    env["HOSTALIASES"] = fd.name
    cargs = [sys.argv[0], "--child"]
    if args.v:
        cargs.append("-v")
    cmd = subprocess.run(
        cargs,
        env=env,
        text=True,
        encoding="ascii",
        stdout=subprocess.PIPE,
        stderr=subprocess.STDOUT,
    )
    dprint("## child output:")
    dprint(cmd.stdout)
    dprint("## child returned", cmd.returncode)
    sys.exit(cmd.returncode)