from sqlalchemy import Column, String, Integer, DateTime
from sqlalchemy.sql import func
from app.core.database.db_session import Base

class StockMovement(Base):
    __tablename__ = "stock_movements"

    movement_id = Column(String(26), primary_key=True)
    entity_type = Column(String(20), nullable=False) # 'variant' or 'part'
    entity_id = Column(String(26), nullable=False)   # product variant id or part id
    movement_type = Column(String(30), nullable=False) # Purchase, Sale, Repair, Adjustment, Return, Transfer, Damage
    quantity = Column(Integer, nullable=False) # can be negative (outflow) or positive (inflow)
    reference_type = Column(String(50), nullable=False) # e.g. Order, PurchaseOrder, RepairBooking, ManualAdjustment
    reference_id = Column(String(36), nullable=False)
    created_at = Column(DateTime, server_default=func.now())