#!/usr/bin/env python3

import ctypes
import os
import sys
import tempfile

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


libc = ctypes.CDLL(None, use_errno=True)
libc.syncfs.argtypes = [ctypes.c_int]
libc.syncfs.restype = ctypes.c_int


def syncfs_fd(fd):
    ctypes.set_errno(0)
    rv = libc.syncfs(fd)
    if rv == 0:
        return 0
    err = ctypes.get_errno()
    raise OSError(err, os.strerror(err))


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

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_file = join(mount, "posix-syncfs/file")
        native_file = join(native, "posix-syncfs/file")
        touch(merge_file, b"x")
        touch(native_file, b"x")

        mfd = os.open(merge_file, os.O_RDONLY)
        nfd = os.open(native_file, os.O_RDONLY)
        try:
            err = compare_calls("syncfs success", lambda: syncfs_fd(mfd), lambda: syncfs_fd(nfd))
            if err:
                return fail(err)
        finally:
            os.close(mfd)
            os.close(nfd)

        err = compare_calls("syncfs EBADF", lambda: syncfs_fd(-1), lambda: syncfs_fd(-1))
        if err:
            return fail(err)

        return 0


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