import logging

from django.utils.translation import ugettext_lazy as _
from django.db.models import F, TextChoices
from django.db import models

from orgs.mixins.models import OrgModelMixin
from common.utils import lazyproperty
from common.db.models import BaseCreateUpdateModel
from assets.models import Asset, SystemUser, Node, FamilyMixin

from .base import BasePermission


__all__ = [
    'AssetPermission', 'PermNode', 'UserAssetGrantedTreeNodeRelation',
]

# 使用场景
logger = logging.getLogger(__name__)


class AssetPermission(BasePermission):
    assets = models.ManyToManyField('assets.Asset', related_name='granted_by_permissions', blank=True, verbose_name=_("Asset"))
    nodes = models.ManyToManyField('assets.Node', related_name='granted_by_permissions', blank=True, verbose_name=_("Nodes"))
    system_users = models.ManyToManyField('assets.SystemUser', related_name='granted_by_permissions', blank=True, verbose_name=_("System user"))

    class Meta:
        unique_together = [('org_id', 'name')]
        verbose_name = _("Asset permission")
        ordering = ('name',)
        permissions = [
        ]

    @lazyproperty
    def users_amount(self):
        return self.users.count()

    @lazyproperty
    def user_groups_amount(self):
        return self.user_groups.count()

    @lazyproperty
    def assets_amount(self):
        return self.assets.count()

    @lazyproperty
    def nodes_amount(self):
        return self.nodes.count()

    @lazyproperty
    def system_users_amount(self):
        return self.system_users.count()

    @classmethod
    def get_queryset_with_prefetch(cls):
        return cls.objects.all().valid().prefetch_related(
            models.Prefetch('nodes', queryset=Node.objects.all().only('key')),
            models.Prefetch('assets', queryset=Asset.objects.all().only('id')),
            models.Prefetch('system_users', queryset=SystemUser.objects.all().only('id'))
        ).order_by()

    def get_all_assets(self):
        from assets.models import Node
        nodes_keys = self.nodes.all().values_list('key', flat=True)
        asset_ids = set(self.assets.all().values_list('id', flat=True))
        nodes_asset_ids = Node.get_nodes_all_asset_ids_by_keys(nodes_keys)
        asset_ids.update(nodes_asset_ids)
        assets = Asset.objects.filter(id__in=asset_ids)
        return assets

    def users_display(self):
        names = [user.username for user in self.users.all()]
        return names

    def user_groups_display(self):
        names = [group.name for group in self.user_groups.all()]
        return names

    def assets_display(self):
        names = [asset.hostname for asset in self.assets.all()]
        return names

    def system_users_display(self):
        names = [system_user.name for system_user in self.system_users.all()]
        return names

    def nodes_display(self):
        names = [node.full_value for node in self.nodes.all()]
        return names


class UserAssetGrantedTreeNodeRelation(OrgModelMixin, FamilyMixin, BaseCreateUpdateModel):
    class NodeFrom(TextChoices):
        granted = 'granted', 'Direct node granted'
        child = 'child', 'Have children node'
        asset = 'asset', 'Direct asset granted'

    user = models.ForeignKey('users.User', db_constraint=False, on_delete=models.CASCADE)
    node = models.ForeignKey('assets.Node', default=None, on_delete=models.CASCADE,
                             db_constraint=False, null=False, related_name='granted_node_rels')
    node_key = models.CharField(max_length=64, verbose_name=_("Key"), db_index=True)
    node_parent_key = models.CharField(max_length=64, default='', verbose_name=_('Parent key'), db_index=True)
    node_from = models.CharField(choices=NodeFrom.choices, max_length=16, db_index=True)
    node_assets_amount = models.IntegerField(default=0)

    @property
    def key(self):
        return self.node_key

    @property
    def parent_key(self):
        return self.node_parent_key

    @classmethod
    def get_node_granted_status(cls, user, key):
        ancestor_keys = set(cls.get_node_ancestor_keys(key, with_self=True))
        ancestor_rel_nodes = cls.objects.filter(user=user, node_key__in=ancestor_keys)

        for rel_node in ancestor_rel_nodes:
            if rel_node.key == key:
                return rel_node.node_from, rel_node
            if rel_node.node_from == cls.NodeFrom.granted:
                return cls.NodeFrom.granted, None
        return '', None


class PermNode(Node):
    class Meta:
        proxy = True
        ordering = []

    # 特殊节点
    UNGROUPED_NODE_KEY = 'ungrouped'
    UNGROUPED_NODE_VALUE = _('Ungrouped')
    FAVORITE_NODE_KEY = 'favorite'
    FAVORITE_NODE_VALUE = _('Favorite')

    node_from = ''
    granted_assets_amount = 0

    annotate_granted_node_rel_fields = {
        'granted_assets_amount': F('granted_node_rels__node_assets_amount'),
        'node_from': F('granted_node_rels__node_from')
    }

    def use_granted_assets_amount(self):
        self.assets_amount = self.granted_assets_amount

    @classmethod
    def get_ungrouped_node(cls, assets_amount):
        return cls(
            id=cls.UNGROUPED_NODE_KEY,
            key=cls.UNGROUPED_NODE_KEY,
            value=cls.UNGROUPED_NODE_VALUE,
            assets_amount=assets_amount
        )

    @classmethod
    def get_favorite_node(cls, assets_amount):
        node = cls(
            id=cls.FAVORITE_NODE_KEY,
            key=cls.FAVORITE_NODE_KEY,
            value=cls.FAVORITE_NODE_VALUE,
        )
        node.assets_amount = assets_amount
        return node

    def get_granted_status(self, user):
        status, rel_node = UserAssetGrantedTreeNodeRelation.get_node_granted_status(user, self.key)
        self.node_from = status
        if rel_node:
            self.granted_assets_amount = rel_node.node_assets_amount
        return status

    def save(self):
        # 这是个只读 Model
        raise NotImplementedError


class PermedAsset(Asset):
    class Meta:
        proxy = True
        verbose_name = _('Permed asset')
        permissions = [
            ('view_myassets', _('Can view my assets')),
            ('view_userassets', _('Can view user assets')),
            ('view_usergroupassets', _('Can view usergroup assets')),
        ]