from django.contrib.auth.models import Group, Permission
from django.contrib.contenttypes.models import ContentType

from inventory.models import (
    ItemFileModel,
    ItemImageModel,
    ItemLinkModel,
    ItemModel,
    LocationModel,
    MemoFileModel,
    MemoImageModel,
    MemoLinkModel,
    MemoModel,
)


NORMAL_USER_GROUP_NAME = 'normal user'


def get_permissions(*models):
    content_types = []
    for model in models:
        content_types.append(ContentType.objects.get_for_model(model))

    return Permission.objects.filter(content_type__in=content_types)


def get_or_create_normal_user_group():
    """
    Will be called by:
        inventory.signals.post_migrate_callback()
    """
    return Group.objects.get_or_create(name=NORMAL_USER_GROUP_NAME)


def setup_normal_user_permissions(normal_user_group):
    """
    Setup PyInventory "normal user" permissions.
    Will be called by:
        inventory.signals.post_migrate_callback()
    """
    assert normal_user_group.name == NORMAL_USER_GROUP_NAME
    permissions = get_permissions(
        ItemFileModel,
        ItemImageModel,
        ItemLinkModel,
        ItemModel,
        LocationModel,
        MemoFileModel,
        MemoImageModel,
        MemoLinkModel,
        MemoModel,
    )
    existing_permissions = normal_user_group.permissions.all()

    if set(permissions) != set(existing_permissions):
        normal_user_group.permissions.set(permissions)
        return True

    return False