# Copyright (C) 2022 Exaloop Inc. <https://exaloop.io>

@pure
@C
def seq_is_macos() -> bool:
    pass

# <dlfcn.h>
from C import dlerror() -> cobj as c_dlerror
from C import dlopen(cobj, int) -> cobj as c_dlopen
from C import dlsym(cobj, cobj) -> cobj as c_dlsym
from C import dlclose(cobj) -> i32 as c_dlclose

RTLD_NOW = 2
RTLD_GLOBAL = 8 if seq_is_macos() else 256
RTLD_LOCAL = 0 if seq_is_macos() else 256

def dlext() -> str:
    if seq_is_macos():
        return "dylib"
    else:
        return "so"

@pure
def dlerror() -> str:
    return str.from_ptr(c_dlerror())

def dlopen(name: str, flag: int = RTLD_NOW | RTLD_GLOBAL) -> cobj:
    h = c_dlopen(cobj() if name == "" else name.c_str(), flag)
    if h == cobj():
        raise CError(dlerror())
    return h

def dlsym(lib, name: str, Fn: type) -> Fn:
    h = cobj()
    if isinstance(lib, str):
        h = dlopen(lib)
    else:
        h = lib
    fn = c_dlsym(h, name.c_str())
    if fn == cobj():
        raise CError(dlerror())
    return Fn(fn)

def dlclose(handle: cobj):
    if c_dlclose(handle) != i32(0):
        raise CError(dlerror())
