from datetime import datetime

from sqlalchemy import Column, BigInteger, String, event, TIMESTAMP, func
from sqlalchemy.ext.declarative import declared_attr

from utils.common import camel_to_snake

from database import Base
from id_generator import options, generator

# https://github.com/yitter/IdGenerator/tree/master/Python
options = options.IdGeneratorOptions(worker_id=23)
idgen = generator.DefaultIdGenerator()
idgen.set_id_generator(options)


# 第一层基类：包含ID
class IdBase(Base):
    __abstract__ = True

    id = Column(BigInteger, primary_key=True, index=True)

    @declared_attr
    def __tablename__(cls):
        # 自动把数据库实体类名驼峰转为数据库表名下划线
        return camel_to_snake(cls.__name__)


# 自动填充id
@event.listens_for(IdBase, 'before_insert', propagate=True)
def before_insert_listener(mapper, connection, target):
    if target.id is None:
        target.id = idgen.next_id()


# 第二层基类：包含ID和审计字段
class AuditBase(IdBase):
    __abstract__ = True

    create_time = Column(TIMESTAMP, nullable=False, default=datetime.now)
    create_by = Column(String(255), nullable=True)
    update_time = Column(TIMESTAMP, nullable=False, default=datetime.now, onupdate=datetime.now)
    update_by = Column(String(255), nullable=True)