#!/usr/bin/env python3

import ctypes
import os
import sys
import tempfile

from posix_parity import fail
from posix_parity import join
from posix_parity import touch


libc = ctypes.CDLL(None, use_errno=True)
libc.opendir.argtypes = [ctypes.c_char_p]
libc.opendir.restype = ctypes.c_void_p
libc.dirfd.argtypes = [ctypes.c_void_p]
libc.dirfd.restype = ctypes.c_int
libc.closedir.argtypes = [ctypes.c_void_p]
libc.closedir.restype = ctypes.c_int


def opendir(path):
    ctypes.set_errno(0)
    dp = libc.opendir(path.encode())
    if not dp:
        err = ctypes.get_errno()
        raise OSError(err, os.strerror(err), path)
    return dp


def close_and_dirfd_errno(path):
    dp = opendir(path)
    fd = libc.dirfd(dp)
    if fd < 0:
        libc.closedir(dp)
        raise OSError(ctypes.get_errno(), "dirfd failed", path)

    rv = libc.closedir(dp)
    if rv != 0:
        raise OSError(ctypes.get_errno(), "closedir failed", path)

    try:
        os.fstat(fd)
        return 0
    except OSError as exc:
        return exc.errno


def main():
    if len(sys.argv) != 2:
        print("usage: TEST_posix_releasedir <mountpoint>", file=sys.stderr)
        return 1

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_dir = join(mount, "posix-releasedir/dir")
        native_dir = join(native, "posix-releasedir/dir")
        touch(join(merge_dir, "a"), b"x")
        touch(join(native_dir, "a"), b"x")

        m_err = close_and_dirfd_errno(merge_dir)
        n_err = close_and_dirfd_errno(native_dir)
        if m_err != n_err:
            return fail(f"releasedir EBADF parity mismatch mergerfs_errno={m_err} native_errno={n_err}")

        return 0


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