#!/usr/bin/env python3

import errno
import os
import sys
import tempfile

from posix_parity import fail
from posix_parity import join


def open_tmpfile(dirpath):
    return os.open(dirpath, os.O_TMPFILE | os.O_RDWR, 0o600)


def errno_of(call):
    try:
        call()
        return 0
    except OSError as exc:
        return exc.errno


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

    if not hasattr(os, "O_TMPFILE"):
        return 0

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_dir = join(mount, "posix-tmpfile")
        native_dir = join(native, "posix-tmpfile")
        os.makedirs(merge_dir, exist_ok=True)
        os.makedirs(native_dir, exist_ok=True)

        m_err = errno_of(lambda: open_tmpfile(merge_dir))
        n_err = errno_of(lambda: open_tmpfile(native_dir))
        if m_err != n_err:
            return fail(f"O_TMPFILE support mismatch mergerfs_errno={m_err} native_errno={n_err}")

        # If unsupported on both, treat as skip-pass.
        if m_err in (errno.EOPNOTSUPP, errno.EISDIR, errno.EINVAL, errno.ENOSYS):
            return 0

        mfd = open_tmpfile(merge_dir)
        nfd = open_tmpfile(native_dir)
        try:
            mw = os.write(mfd, b"tmpfile-data")
            nw = os.write(nfd, b"tmpfile-data")
            if mw != nw:
                return fail(f"O_TMPFILE write count mismatch mergerfs={mw} native={nw}")
        finally:
            os.close(mfd)
            os.close(nfd)

    return 0


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