from sqlalchemy import Column, Integer, String, Float, DateTime, ForeignKey
from sqlalchemy.orm import relationship
from datetime import datetime
from core.database import Base

class Invoice(Base):
    __tablename__ = "invoices"

    # Auto-incrementing ID
    id = Column(Integer, primary_key=True, index=True, autoincrement=True)
    
    # User selected date (defaults to now)
    date = Column(DateTime, default=datetime.utcnow)
    invoice_no = Column(String, nullable=True)
    doctor_name = Column(String)
    clinic_name = Column(String)
    total_amount = Column(Float)
    received_amount = Column(Float)
    remaining_balance = Column(Float)
    notes = Column(String, nullable=True)
    items = relationship("InvoiceItem", back_populates="invoice", cascade="all, delete-orphan")

    # This MUST be indented inside the class
    @property
    def invoice_number(self):
        return f"INV-{self.id:04d}"
    

class InvoiceItem(Base):
    __tablename__ = "invoice_items"
    
    id = Column(Integer, primary_key=True, index=True, autoincrement=True)
    invoice_id = Column(Integer, ForeignKey("invoices.id"))
    patient_name = Column(String)
    shade = Column(String)
    description = Column(String)
    quantity = Column(Integer)
    price_per_unit = Column(Float)
    total_price = Column(Float)

    invoice = relationship("Invoice", back_populates="items")