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


class Customer(db.Model):
    __tablename__ = 'customers'

    id = db.Column(db.String(50), primary_key=True)
    msisdn = db.Column(db.String(20), unique=True, nullable=False)
    country_code = db.Column(db.String(3), nullable=False)
    created_at = db.Column(db.DateTime, default=datetime.now(timezone.utc))
    updated_at = db.Column(db.DateTime, default=datetime.now(timezone.utc), onupdate=datetime.now(timezone.utc))

    accounts = relationship(
        "Account",
        primaryjoin="Customer.id == Account.customer_id",
        foreign_keys="Account.customer_id",
        back_populates="customer",
    )

    loans = relationship(
        "Loan",
        primaryjoin="Customer.id == Loan.customer_id",
        foreign_keys="Loan.customer_id",
        back_populates="customer",
    )

    @classmethod
    def get_customer(cls, customer_id):
        """
        Get customer by  ID.
        """
        customer = cls.query.filter_by(id=customer_id).first()

        if not customer:
            raise ValueError(f"Customer does not exist")
        return customer

    def __repr__(self):
        return f'<Customer {self.id}>'