from app.extensions import db


class Budget(db.Model):
    __tablename__ = 'budgets'
    __table_args__ = (
        db.UniqueConstraint('category_id', 'month', 'year', name='uq_budgets_category_month_year'),
    )

    id = db.Column(db.Integer, primary_key=True)
    month = db.Column(db.Integer, nullable=False)          # 1–12
    year = db.Column(db.Integer, nullable=False)
    amount = db.Column(db.Numeric(10, 2), nullable=False)

    category_id = db.Column(db.Integer, db.ForeignKey('categories.id', ondelete='RESTRICT'), nullable=False)
    category = db.relationship('Category', back_populates='budgets')