from datetime import datetime, timezone, timedelta
from app.extensions import db
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func


class Charge(db.Model):
    __tablename__ = 'charges'

    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
    offer_id = db.Column(db.String(50), nullable=False)
    code = db.Column(db.String(50), nullable=False)
    percent = db.Column(db.Float, default=0.0)
    description = db.Column(db.Text, nullable=True)
    due = db.Column(db.Integer, nullable=False)
    created_at = db.Column(db.DateTime(timezone=True), server_default=func.now())
    updated_at = db.Column(db.DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
    # offer = relationship(
    #     "Offer",
    #     primaryjoin="Charge.offer_id == Offer.id",
    #     foreign_keys=[offer_id],
    #     back_populates="charges",
    # )

    @classmethod
    def add_charges(cls, offer_id, charges):
        """
        Add charges to an offer.

        Args:
            offer_id (int): ID of the offer to associate charges with.
            charges (list): A list of dictionaries with keys:
            code (str), amount (float), percent (float), description (str), due (int)
        """
        if not charges or not isinstance(charges, list):
            raise ValueError("Charges must be a non-empty list of dictionaries")

        if offer_id is None:
            raise ValueError("offer_id cannot be None")

        offer_charges = []
       

        for charge in charges:
            code = charge.get("code")
            percent = charge.get("percent", 0.0)
            description = charge.get("description", "")
            due_days = charge.get("due", 0)

            existing = cls.query.filter_by(offer_id=offer_id, code=code).first()

            if existing:
                continue

            charge_obj = cls(
                offer_id = offer_id,
                code = code,
                percent = percent,
                description = description,
                due = due_days,
                created_at=datetime.now(timezone.utc),
                updated_at=datetime.now(timezone.utc)
            )

            db.session.add(charge_obj)
            offer_charges.append(charge_obj)

        return offer_charges
    
    @classmethod
    def get_offer_charges(cls, offer_id):
        """
        Get all charges for a particular offer as a dictionary

        Args:
            offer_id (str): The offer ID.
        """
        if not offer_id:
            raise ValueError("offer_id not found")

        charges = cls.query.filter_by(offer_id=offer_id).all()
        
        return charges


    def to_dict(self):
        return {
            'id': self.id,
            'offerId': self.offer_id,
            'code': self.code,
            'percent': self.percent,
            'description': self.description,
            'due': self.due
        }

    def __repr__(self):
        return f"<Charge {self.id} - Offer {self.offer_id} - {self.code}>"