models.py

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

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

Base = declarative_base(metadata=metadata)

company_dev = Table(
    'company_devs',
    Base.metadata,
    Column('company_id', ForeignKey('companies.id'), primary_key=True),
    Column('dev_id', ForeignKey('devs.id'), primary_key=True),
    extend_existing=True,
)

class Company(Base):
    __tablename__ = 'companies'

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

    freebies = relationship('Freebie', backref=backref('company'))

    devs = relationship('Dev', secondary=company_dev, back_populates='companies')


    def give_freebie(self, dev, item_name, value):
        freebie = Freebie(item_name=item_name, value=value, dev_id=dev.id, company_id=self.id)
        return freebie

    @classmethod
    def oldest_company(cls, session):
        return session.query(cls).order_by(cls.founding_year).first()

    def __repr__(self):
        return f'<Company {self.name}>'
    
    

class Freebie(Base):
    __tablename__ = 'freebies'

    id = Column(Integer(), primary_key=True)
    item_name = Column(String())
    value= Column(Integer())

    company_id = Column(Integer(), ForeignKey('companies.id'))

    dev_id = Column(Integer(), ForeignKey('devs.id'))

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

    def __repr__(self):
        return f'Freebie(id={self.id},' + \
            f'item_name={self.item_name}, ' + \
            f'company_id={self.company_id})'


class Dev(Base):
    __tablename__ = 'devs'

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

    freebies = relationship('Freebie', backref=backref('dev'))

    companies = relationship ('Company', secondary = company_dev, back_populates = 'devs')

    def received_one(self, item_name):
        return any(freebie.item_name == item_name for freebie in self.freebies)

    def give_away(self, dev, freebie):
        if freebie in self.freebies:
            freebie.dev_id = dev.id
            return True
        return False

    def __repr__(self):
        return f'<Dev {self.name}>'