# ========================================================================== #
#                                                                            #
#    KVMD - The main PiKVM daemon.                                           #
#                                                                            #
#    Copyright (C) 2018-2023  Maxim Devaev <mdevaev@gmail.com>               #
#                                                                            #
#    This source file is partially based on python-watchdog module.          #
#                                                                            #
#    This program is free software: you can redistribute it and/or modify    #
#    it under the terms of the GNU General Public License as published by    #
#    the Free Software Foundation, either version 3 of the License, or       #
#    (at your option) any later version.                                     #
#                                                                            #
#    This program is distributed in the hope that it will be useful,         #
#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
#    GNU General Public License for more details.                            #
#                                                                            #
#    You should have received a copy of the GNU General Public License       #
#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
#                                                                            #
# ========================================================================== #


import ctypes
import ctypes.util

from ctypes import c_int
from ctypes import c_uint
from ctypes import c_uint32
from ctypes import c_char_p
from ctypes import c_void_p


# =====
def _load_libc() -> ctypes.CDLL:
    path = ctypes.util.find_library("c")
    if not path:
        raise RuntimeError("Where is libc?")
    assert path
    lib = ctypes.CDLL(path)
    for (name, restype, argtypes) in [
        ("inotify_init", c_int, []),
        ("inotify_add_watch", c_int, [c_int, c_char_p, c_uint32]),
        ("inotify_rm_watch", c_int, [c_int, c_uint32]),
        ("renameat2", c_int, [c_int, c_char_p, c_int, c_char_p, c_uint]),
        ("free", c_int, [c_void_p]),
    ]:
        func = getattr(lib, name)
        if not func:
            raise RuntimeError(f"Where is libc.{name}?")
        setattr(func, "restype", restype)
        setattr(func, "argtypes", argtypes)
    return lib


_libc = _load_libc()


# =====
get_errno = ctypes.get_errno

inotify_init = _libc.inotify_init
inotify_add_watch = _libc.inotify_add_watch
inotify_rm_watch = _libc.inotify_rm_watch
renameat2 = _libc.renameat2
free = _libc.free