from typing import List, Optional

from sqlalchemy.orm import Session

from app.crud.base import CRUDBase
from app.models.item import Item
from app.schemas.item import ItemCreate, ItemUpdate


class CRUDItem(CRUDBase[Item, ItemCreate, ItemUpdate]):
    """
    CRUD operations for Item model.
    """
    def get_by_sku(self, db: Session, *, sku: str) -> Optional[Item]:
        """
        Get an item by SKU.
        """
        return db.query(Item).filter(Item.sku == sku).first()
    
    def get_by_barcode(self, db: Session, *, barcode: str) -> Optional[Item]:
        """
        Get an item by barcode.
        """
        return db.query(Item).filter(Item.barcode == barcode).first()
    
    def get_by_category(
        self, db: Session, *, category_id: int, skip: int = 0, limit: int = 100
    ) -> List[Item]:
        """
        Get items by category.
        """
        return (
            db.query(Item)
            .filter(Item.category_id == category_id)
            .offset(skip)
            .limit(limit)
            .all()
        )
    
    def get_by_supplier(
        self, db: Session, *, supplier_id: int, skip: int = 0, limit: int = 100
    ) -> List[Item]:
        """
        Get items by supplier.
        """
        return (
            db.query(Item)
            .filter(Item.supplier_id == supplier_id)
            .offset(skip)
            .limit(limit)
            .all()
        )
    
    def get_low_stock(
        self, db: Session, *, skip: int = 0, limit: int = 100
    ) -> List[Item]:
        """
        Get items with stock quantity below reorder level.
        """
        return (
            db.query(Item)
            .filter(Item.quantity <= Item.reorder_level)
            .offset(skip)
            .limit(limit)
            .all()
        )


item = CRUDItem(Item)