#!/usr/bin/env python3

import ctypes
import os
import sys
import tempfile

from posix_parity import cleanup_dir
from posix_parity import fail
from posix_parity import join
from posix_parity import mergerfs_mount
from posix_parity import temp_dir
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():
    try:
        with mergerfs_mount() as (mount, _):
            with tempfile.TemporaryDirectory() as native:
                merge_base = temp_dir(mount)
                try:
                    native_base = join(native, os.path.basename(merge_base))
                    os.makedirs(native_base, exist_ok=True)

                    merge_dir = join(merge_base, "dir")
                    native_dir = join(native_base, "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
                finally:
                    cleanup_dir(merge_base)
    except RuntimeError as exc:
        print(str(exc), end="")
        return 77


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