from sqlalchemy import \
    Boolean, Column, DateTime, ForeignKey, Integer, String, Text, UniqueConstraint, \
    text, func, \
    create_engine, inspect, select
from sqlalchemy.engine import Engine
from sqlalchemy.orm import relationship, sessionmaker, Session, class_mapper, joinedload, aliased
from sqlalchemy.orm.attributes import get_history
from sqlalchemy.orm.query import Query
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.sql.expression import CTE
from sqlalchemy.sql.functions import ReturnTypeFromArgs
from sqlalchemy.sql.sqltypes import Numeric
from typing import Any, Optional, List, Tuple

import hra.config as config

Base = declarative_base()
metadata = Base.metadata


_engine: Optional[Engine] = None
_session: Optional[Session] = None
flask_db: Any = None

def get_engine() -> Engine:
    global _engine
    if _engine is None:
        _engine = create_engine(config.SQLALCHEMY_DATABASE_URI, echo=config.SQLALCHEMY_ECHO)
    return _engine

def get_session() -> Session:
    global _session
    if flask_db:
        return flask_db.session
    if _session is None:
        MOSession = sessionmaker(bind=get_engine())
        _session = MOSession()
    return _session



class User(Base):
    __tablename__ = 'users'

    id = Column(Integer, primary_key=True)
    org = Column(Boolean)
    username = Column(String(80), unique=True, nullable=False)
    passwd = Column(String(80), nullable=False)

    def __repr__(self):
        return '<User %r>' % self.username