#!/usr/bin/env python3

import ctypes
import errno
import fcntl
import os
import struct
import sys
import tempfile

from posix_parity import cleanup_dir
from posix_parity import compare_calls
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


FIBMAP = 1


def fibmap(fd, block=0):
    buf = struct.pack("i", block)
    out = fcntl.ioctl(fd, FIBMAP, buf)
    return struct.unpack("i", out)[0]


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_file = join(merge_base, "file")
                    native_file = join(native_base, "file")
                    touch(merge_file, b"x" * 8192)
                    touch(native_file, b"x" * 8192)

                    mfd = os.open(merge_file, os.O_RDONLY)
                    nfd = os.open(native_file, os.O_RDONLY)
                    try:
                        err = compare_calls(
                            "ioctl FIBMAP block0",
                            lambda: fibmap(mfd, 0),
                            lambda: fibmap(nfd, 0),
                            lambda a, b: (a >= 0) == (b >= 0),
                        )
                        if err:
                            return fail(err)
                    finally:
                        os.close(mfd)
                        os.close(nfd)

                    err = compare_calls(
                        "ioctl FIBMAP EBADF",
                        lambda: fibmap(mfd, 0),
                        lambda: fibmap(nfd, 0),
                    )
                    if err:
                        return fail(err)

                    return 0
                finally:
                    cleanup_dir(merge_base)
    except RuntimeError as exc:
        print(str(exc), end="")
        return 77


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