models.py

from sqlalchemy import ForeignKey, Column, Integer, String, MetaData, Table, create_engine
from sqlalchemy.orm import relationship, backref, sessionmaker
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)

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

company_dev = Table(
    'company_dev',
    Base.metadata,
    Column('item_name', String()),
    Column('value', String()),
    Column("dev_id", ForeignKey('devs.id'), primary_key=True),
    Column('company_id', ForeignKey('companies.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())
    
    devs = relationship('Dev', secondary=company_dev, back_populates='companies')
    freebies = relationship('Freebie',backref=backref('company'))

    def __repr__(self):
        return f'<Company {self.name}>'
    
    def give_freebie(self, dev, item_name, value):
        freebie = Freebie(item_name=item_name,value=value, dev_id=dev.id, company_id=self.id)
        session.add(freebie)
        session.commit()
        
        return f"{item_name} given to {dev.name} by {self.name}"
    
    @classmethod
    def oldest_company(cls):
        return session.query(Company).order_by(Company.founding_year).first()
        

class Dev(Base):
    __tablename__ = 'devs'

    id = Column(Integer(), primary_key=True)
    name= Column(String())
    
    companies = relationship('Company', secondary=company_dev, back_populates='devs')
    freebies = relationship('Freebie', backref=backref('dev'))

    def __repr__(self):
        return f'<Dev {self.name}>'
    
    def received_one(self, item_name):
        freebies = session.query(Freebie).filter(Freebie.dev_id==self.id).all()
        return [freebie for freebie in freebies if freebie.item_name == item_name] != []
    
    def give_away(self, dev, freebie):
        freebie_to_update = session.query(Freebie).filter(Freebie.id==freebie.id).first()
        old_dev_id = freebie.dev_id
        
        if freebie_to_update and freebie.dev_id == self.id: 
            freebie.dev_id = dev.id
            session.commit()
            
            print(f"The freebie dev.id updated from {old_dev_id} to {dev.id}")
        else:
            print("The freebie is not owned by the 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'))
    
    
    def __repr__(self):
        return f"Freebie(id={self.id}, item_name={self.item_name}, value={self.value}, dev_id={self.dev_id}, company_id={self.company_id})"

    def print_details(self):
        dev = session.query(Dev).filter_by(id=self.dev_id).first()
        company = session.query(Company).filter_by(id = self.company_id).first()
        return f"{dev.name} owns a {self.item_name} from {company.name}."