# -*- coding: utf-8 -*-
#
import threading
from collections import defaultdict
from functools import partial

import django.db.utils
from django.dispatch import receiver
from django.conf import settings
from django.db.utils import ProgrammingError, OperationalError
from django.utils.functional import LazyObject
from django.db.models.signals import post_save, pre_delete, m2m_changed

from orgs.utils import tmp_to_org, set_to_default_org
from orgs.models import Organization
from orgs.hands import set_current_org, Node, get_current_org
from perms.models import AssetPermission
from users.models import UserGroup, User
from common.const.signals import PRE_REMOVE, POST_REMOVE
from common.decorator import on_transaction_commit
from common.signals import django_ready
from common.utils import get_logger
from common.utils.connection import RedisPubSub
from users.signals import post_user_leave_org


logger = get_logger(__file__)


def get_orgs_mapping_for_memory_pub_sub():
    return RedisPubSub('fm.orgs_mapping')


class OrgsMappingForMemoryPubSub(LazyObject):
    def _setup(self):
        self._wrapped = get_orgs_mapping_for_memory_pub_sub()


orgs_mapping_for_memory_pub_sub = OrgsMappingForMemoryPubSub()


def expire_orgs_mapping_for_memory(org_id):
    orgs_mapping_for_memory_pub_sub.publish(str(org_id))


@receiver(django_ready)
def subscribe_orgs_mapping_expire(sender, **kwargs):
    logger.debug("Start subscribe for expire orgs mapping from memory")
    if settings.DEBUG:
        try:
            set_to_default_org()
        except (ProgrammingError, OperationalError):
            pass

    def keep_subscribe_org_mapping():
        orgs_mapping_for_memory_pub_sub.subscribe(
            lambda org_id: Organization.expire_orgs_mapping()
        )

    t = threading.Thread(target=keep_subscribe_org_mapping)
    t.daemon = True
    t.start()


# 创建对应的root
@receiver(post_save, sender=Organization)
def on_org_create_or_update(sender, instance, created=False, **kwargs):
    # 必须放到最开始, 因为下面调用Node.save方法时会获取当前组织的org_id(即instance.org_id), 如果不过期会找不到
    expire_orgs_mapping_for_memory(instance.id)
    old_org = get_current_org()
    set_current_org(instance)
    node_root = Node.org_root()
    if node_root.value != instance.name:
        node_root.value = instance.name
        node_root.save()
    set_current_org(old_org)


@receiver(pre_delete, sender=Organization)
def on_org_delete(sender, instance, **kwargs):
    expire_orgs_mapping_for_memory(instance.id)

    # 删除该组织下所有 节点
    with tmp_to_org(instance):
        root_node = Node.org_root()
        if root_node:
            root_node.delete()


def _remove_users(model, users, org, user_field_name='users'):
    with tmp_to_org(org):
        if not isinstance(users, (tuple, list, set)):
            users = (users, )

        user_field = getattr(model, user_field_name)
        m2m_model = user_field.through
        reverse = user_field.reverse
        if reverse:
            m2m_field_name = user_field.field.m2m_reverse_field_name()
        else:
            m2m_field_name = user_field.field.m2m_field_name()
        relations = m2m_model.objects.filter(**{
            'user__in': users,
            f'{m2m_field_name}__org_id': org.id
        })

        object_id_user_ids_map = defaultdict(set)

        m2m_field_attr_name = f'{m2m_field_name}_id'
        for relation in relations:
            object_id = getattr(relation, m2m_field_attr_name)
            object_id_user_ids_map[object_id].add(relation.user_id)

        objects = model.objects.filter(id__in=object_id_user_ids_map.keys())
        send_m2m_change_signal = partial(
            m2m_changed.send,
            sender=m2m_model, reverse=reverse, model=User, using=model.objects.db
        )

        for obj in objects:
            send_m2m_change_signal(
                instance=obj,
                pk_set=object_id_user_ids_map[obj.id],
                action=PRE_REMOVE
            )

        relations.delete()

        for obj in objects:
            send_m2m_change_signal(
                instance=obj,
                pk_set=object_id_user_ids_map[obj.id],
                action=POST_REMOVE
            )


def _clear_users_from_org(org, users):
    """
    清理用户在该组织下的相关数据
    """
    if not users:
        return

    models = (AssetPermission, UserGroup)

    for m in models:
        _remove_users(m, users, org)

    # _remove_users(CommandFilterRule, users, org, user_field_name='reviewers')


@receiver(post_save, sender=User)
@on_transaction_commit
def on_user_created_set_default_org(sender, instance, created, **kwargs):
    if not instance.id:
        # 用户已被手动删除，instance.orgs 时会使用 id 进行查找报错，所以判断不存在id时不做处理
        return
    if not created:
        return
    if instance.orgs.count() > 0:
        return
    with tmp_to_org(Organization.default()):
        Organization.default().add_member(instance)


@receiver(post_user_leave_org)
def on_user_leave_org(sender, user=None, org=None, **kwargs):
    logger.debug('User leave org signal recv: {} <> {}'.format(user, org))
    _clear_users_from_org(org, [user])