from sqlalchemy import create_engine, Column, Integer, String, ForeignKey
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

engine = create_engine('sqlite:///:memory')
Base = declarative_base()
Session = sessionmaker(bind=engine)
session = Session()Base = declarative_base()

class Users(Base):
    __tablename__ = "users"

    id = Column(Integer, primary_key=True)
    name = Column(String)
    email = Column(String)

    # digunakan sebagai discriminator
    type = Column(String)

    __mapper_args__ = {
        # jika type pada parent merupakan `user` maka object akan
        # menjadi instance dari class ini
        'polymorphic_identity': 'user',
        'polymorphic_on': type  # Parent model harus mengimplementasi ini
    }

    def __init__(self, name, email, _type='user'):
        self.name = name
        self.email = email
        self.type = _type

    def __repr__(self):
        return "<Users (name='%s', email='%s')>" % (self.name, self.email)

class Employee(Users):
    __tablename__ = "employee"

    id = Column(None, ForeignKey("users.id"), primary_key=True)
    department = Column(String)

    __mapper_args__ = {
        # jika type pada parent merupakan `employee` maka object akan
        # menjadi instance dari class ini
        'polymorphic_identity': 'employee'
    }

    def __init__(self, name, email, department):
        super().__init__(name, email, 'employee')
        self.department = department

    def __repr__(self):
        return "<Employee (name='%s', email='%s', department='%s')>" % (
            self.name, self.email, self.department
        )

class Client(Users):
    __tablename__ = "client"

    id = Column(None, ForeignKey("users.id"), primary_key=True)
    address = Column(String)

    __mapper_args__ = {
        # jika type pada parent merupakan `client` maka object akan
        # menjadi instance dari class ini
        'polymorphic_identity': 'client'
    }

    def __init__(self, name, email, address):
        super().__init__(name, email, "client")
        self.address = address

    def __repr__(self):
        return "<Client (name='%s', email='%s', address='%s')>" % (
            self.name, self.email, self.address
        )

# create table
Base.metadata.create_all(engine)

user = Users("faisalburhanudin", "faisalburhanudin@hotmail.com")
session.add(user)

print(session.query(Users).all())

employee = Employee("gogil", "gogil@mail.com", "hrd")
session.add(employee)

print(session.query(Employee).all())

client = Client("client_name", "client@mail.com", "Klaten")
session.add(client)
session.add(client)

print(session.query(Client).all())