models.py

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

engine = create_engine('sqlite:///freebies.db')
Session = sessionmaker(bind=engine)
session = Session()

convention = {
    "fk": "fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s",
}
metadata = MetaData(naming_convention=convention)

Base = declarative_base(metadata=metadata)

class Company(Base):
    __tablename__ = 'companies'

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

    def __repr__(self):
        return f'<Company {self.name}>'
    
    def get_freebies(self):
        return self.freebies
    
    def get_devs(self):
        return [freebie.dev for freebie in self.freebies]
    
    def give_freebie(self, dev, item_name, value):
        new_freebie = Freebie(dev=dev, company=self, item_name=item_name, value=value)
        self.get_freebies.append(new_freebie)
        return new_freebie
    
    @classmethod
    def oldest_company(cls):
        return session.query(cls).order_by(cls.founding_year).first()

class Dev(Base):
    __tablename__ = 'devs'

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

    def __repr__(self):
        return f'<Dev {self.name}>'
    
    def get_freebies(self):
        return self.freebies
    
    def get_companies(self):
        return [freebie.company for freebie in self.freebies]
    
    def received_one(self, item_name):
        return any(freebie.item_name == item_name for freebie in self.freebies)
    
    def give_away(self, other_dev, freebie):
        if freebie.dev == self:
            freebie.dev = other_dev



class Freebie(Base):
    __tablename__ = 'freebies'

    id = Column(Integer(), primary_key=True)
    item_name = Column(String)
    value = Column(Integer)
    dev_id = Column(Integer, ForeignKey('devs.id'))
    company_id = Column(Integer, ForeignKey('companies.id'))

    dev = relationship('Dev', backref='freebies')
    company = relationship('Company', backref='freebies')

    def __repr__(self):
        return f'<Freebie {self.name}'
    
    dev = relationship('Dev', backref='freebies')
    company = relationship('Company', backref='freebies')

    def print_details(self):
        return f"{self.dev.name} owns a {self.item_name} from {self.company.name}"