#!/usr/bin/env python3

import errno
import fcntl
import os
import struct
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


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

    mount = sys.argv[1]

    with tempfile.TemporaryDirectory() as native:
        merge_file = join(mount, "posix-bmap/file")
        native_file = join(native, "posix-bmap/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:
            # FIBMAP often requires CAP_SYS_RAWIO; compare errno parity if denied.
            err = compare_calls(
                "ioctl FIBMAP block0",
                lambda: fibmap(mfd, 0),
                lambda: fibmap(nfd, 0),
                lambda a, b: (a >= 0) == (b >= 0),
            )
            if err:
                # If both denied by privilege checks, compare_calls already passes.
                return fail(err)
        finally:
            os.close(mfd)
            os.close(nfd)

        # EBADF parity on closed fds.
        err = compare_calls(
            "ioctl FIBMAP EBADF",
            lambda: fibmap(mfd, 0),
            lambda: fibmap(nfd, 0),
        )
        if err:
            return fail(err)

    return 0


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