from django.contrib.auth.decorators import user_passes_test
from functools import wraps
from django.shortcuts import redirect
from django.core.exceptions import PermissionDenied


def is_in_group(user, group_name):
    return user.groups.filter(name=group_name).exists()


def group_required(group_name):
    return user_passes_test(lambda u: is_in_group(u, group_name))


def custom_permission_required(perm, raise_exception=False):
    def decorator(view_func):
        @wraps(view_func)
        def _wrapped_view(request, *args, **kwargs):
            if request.user.has_perm(perm):
                return view_func(request, *args, **kwargs)
            if raise_exception:
                raise PermissionDenied
            return redirect('error_page')
        return _wrapped_view
    return decorator