import time
import django.utils.timezone as timezone
from django.db import models
from django.db.models import Model
from django.db.models.query import QuerySet
from apps.utils.snowflake import idWorker
from django.db import IntegrityError
from django.db import transaction

# 自定义软删除查询基类


class SoftDeletableQuerySetMixin(object):
    '''
    QuerySet for SoftDeletableModel. Instead of removing instance sets
    its ``is_deleted`` field to True.
    '''

    def delete(self, soft=True):
        '''
        Soft delete objects from queryset (set their ``is_deleted``
        field to True)
        '''
        if soft:
            self.update(is_deleted=True)
        else:
            return super(SoftDeletableQuerySetMixin, self).delete()


class SoftDeletableQuerySet(SoftDeletableQuerySetMixin, QuerySet):
    pass


class SoftDeletableManagerMixin(object):
    '''
    Manager that limits the queryset by default to show only not deleted
    instances of model.
    '''
    _queryset_class = SoftDeletableQuerySet

    def get_queryset(self, all=False):
        '''
        Return queryset limited to not deleted entries.
        '''
        kwargs = {'model': self.model, 'using': self._db}
        if hasattr(self, '_hints'):
            kwargs['hints'] = self._hints
        if all:
            return self._queryset_class(**kwargs)
        return self._queryset_class(**kwargs).filter(is_deleted=False)


class SoftDeletableManager(SoftDeletableManagerMixin, models.Manager):
    pass


class ParentModel(models.Model):
    parent = models.ForeignKey('self', null=True, blank=True,
                               on_delete=models.SET_NULL, verbose_name='父', db_constraint=False)
    parent_link = models.JSONField('父级关联', default=list, blank=True, editable=False)

    def init_parent_link(self):
        link = []
        if self.parent is not None:
            if self.parent == self:
                raise Exception(f'{self.__class__.__name__}-{self.id}-存在循环引用')
            link = [self.parent.id] # 一级
            if self.parent.parent is not None: # 二级
                if self.parent.parent == self:
                    raise Exception(f'{self.__class__.__name__}-{self.id}-存在循环引用')
                link.insert(0, self.parent.parent.id) 
                if self.parent.parent.parent is not None: # 三级
                    if self.parent.parent.parent == self:
                        raise Exception(f'{self.__class__.__name__}-{self.id}-存在循环引用')
                    link.insert(0, self.parent.parent.parent.id)
                    if self.parent.parent.parent.parent is not None:
                        raise Exception(f'{self.__class__.__name__}-{self.id}-最多支持四级')
        return link

    def handle_parent(self):
        if hasattr(self, "parent_link"):
            """
            处理父级关系
            """
            self.parent_link = self.init_parent_link()
            self.save(update_fields=['parent_link'])
            # 处理相关的所有父子关系
            relats = self.__class__.objects.filter(parent_link__contains=[self.id])
            for relat in relats:
                relat.parent_link = relat.init_parent_link()
                relat.save(update_fields=['parent_link'])
                    
    
    class Meta:
        abstract = True

class BaseModel(models.Model):
    """
    基本表
    """
    id = models.CharField(max_length=20, primary_key=True,
                          editable=False, verbose_name='主键ID', help_text='主键ID')
    create_time = models.DateTimeField(
        default=timezone.now, verbose_name='创建时间', help_text='创建时间')
    update_time = models.DateTimeField(
        auto_now=True, verbose_name='修改时间', help_text='修改时间')
    is_deleted = models.BooleanField(
        default=False, verbose_name='删除标记', help_text='删除标记')

    class Meta:
        abstract = True

    def handle_parent(self, is_create):
        pass

    def save(self, *args, **kwargs) -> None:
        # 出现了雪花ID重复,不知道怎么处理，先这样异常处理一下;已经修改了snowflake, 以防万一, 这里依然保留
        is_create = False
        if not self.id:
            is_create = True
            self.id = idWorker.get_id()
        with transaction.atomic():
            old_parent = None
            need_handle_parent = False
            if hasattr(self, "parent"):
                try:
                    old_parent = self.__class__.objects.get(id=self.id).parent
                except Exception:
                    self.parent = None
                    need_handle_parent = True
                if self.parent != old_parent:
                    need_handle_parent = True
            try:
                ins = super().save(*args, **kwargs)
            except IntegrityError as e:
                if is_create:
                    time.sleep(0.01)
                    self.id = idWorker.get_id()
                    ins = super().save(*args, **kwargs)
                raise e
            # 处理父级
            if need_handle_parent:
                self.handle_parent()
            return ins


class SoftModel(BaseModel):
    """
    软删除基本表
    """
    class Meta:
        abstract = True

    objects = SoftDeletableManager()

    def delete(self, using=None, soft=True, update_by=None, *args, **kwargs):
        '''
        这里需要真删除的话soft=False即可
        '''
        if soft:
            self.is_deleted = True
            self.update_by = update_by
            self.save(using=using)
        else:

            return super(SoftModel, self).delete(using=using, *args, **kwargs)


class CommonAModel(SoftModel):
    """
    业务用基本表A,包含create_by, update_by字段
    """
    create_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='创建人', related_name='%(class)s_create_by')
    update_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='最后编辑人', related_name='%(class)s_update_by')
    # delete_by = models.ForeignKey(
    #     'system.user', null=True, blank=True, on_delete=models.SET_NULL,
    #     verbose_name='删除人', related_name='%(class)s_delete_by')

    class Meta:
        abstract = True


class CommonBModel(SoftModel):
    """
    业务用基本表B,包含create_by, update_by, belong_dept字段
    """
    create_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='创建人', related_name='%(class)s_create_by')
    update_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='最后编辑人', related_name='%(class)s_update_by')
    # delete_by = models.ForeignKey(
    #     'system.user', null=True, blank=True, on_delete=models.SET_NULL,
    #     verbose_name='删除人', related_name='%(class)s_delete_by')
    belong_dept = models.ForeignKey(
        'system.dept', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='所属部门', related_name='%(class)s_belong_dept')

    class Meta:
        abstract = True


class CommonADModel(BaseModel):
    """
    业务用基本表A, 物理删除, 包含create_by, update_by字段
    """
    create_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='创建人', related_name='%(class)s_create_by')
    update_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='最后编辑人', related_name='%(class)s_update_by')
    # delete_by = models.ForeignKey(
    #     'system.user', null=True, blank=True, on_delete=models.SET_NULL,
    #     verbose_name='删除人', related_name='%(class)s_delete_by')

    class Meta:
        abstract = True


class CommonBDModel(BaseModel):
    """
    业务用基本表B, 物理删除, 包含create_by, update_by, belong_dept字段
    """
    create_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='创建人', related_name='%(class)s_create_by')
    update_by = models.ForeignKey(
        'system.user', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='最后编辑人', related_name='%(class)s_update_by')
    # delete_by = models.ForeignKey(
    #     'system.user', null=True, blank=True, on_delete=models.SET_NULL,
    #     verbose_name='删除人', related_name='%(class)s_delete_by')
    belong_dept = models.ForeignKey(
        'system.dept', null=True, blank=True, on_delete=models.SET_NULL,
        verbose_name='所属部门', related_name='%(class)s_belong_dept')

    class Meta:
        abstract = True


def get_model_info(cls_or_instance):
    """
    返回类似 system.dept 的字符
    """
    if isinstance(cls_or_instance, Model):
        # 是一个模型实例
        app_label = cls_or_instance._meta.app_label
        model_name = cls_or_instance._meta.model_name
    else:
        # 假定是一个模型类
        app_label = cls_or_instance._meta.app_label
        model_name = cls_or_instance._meta.model_name

    return f'{app_label}.{model_name}'