from django.contrib.auth import get_user_model

from rest_framework.permissions import BasePermission

User = get_user_model()


class IsAdmin(BasePermission):
    def has_permission(self, request, view):
        return request.user.is_authenticated and (
            request.user.role == User.ADMIN_ROLE or request.user.is_staff or request.user.is_superuser
        )


class IsTeacherOrAdmin(BasePermission):
    def has_permission(self, request, view):
        return request.user.is_authenticated and (
            request.user.role >= User.TEACHER_ROLE or
            request.user.is_staff or
            request.user.is_superuser
        )


class IsAdminOrIsSelf(BasePermission):
    def has_object_permission(self, request, view, user):
        return request.user.is_authenticated and (
            user == request.user or request.user.is_staff or request.user.is_superuser
        )


class IsAuthorOrAdmin(BasePermission):
    def has_permission(self, request, view):
        return request.user.is_authenticated and (
            request.user.role >= User.AUTHOR_ROLE or
            request.user.is_staff or
            request.user.is_superuser
        )


class IsAuthorObjectOrAdmin(BasePermission):
    def has_object_permission(self, request, view, obj):
        return request.user.is_authenticated and (
            request.user.role == User.ADMIN_ROLE or request.user.is_staff or request.user.is_superuser
        ) or request.user == obj.author