from typing import List, Optional
from app.models.product import Product
from app.schemas.product import ProductCreate, ProductUpdate

fake_products_db = [
    Product(id=1, name="Laptop", description="High performance laptop", price=999.99, stock=10),
    Product(id=2, name="Mouse", description="Wireless mouse", price=29.99, stock=50),
    Product(id=3, name="Keyboard", description="Mechanical keyboard", price=89.99, stock=25),
]

class ProductService:
    @staticmethod
    def get_all_products() -> List[Product]:
        return fake_products_db

    @staticmethod
    def get_product_by_id(product_id: int) -> Optional[Product]:
        for product in fake_products_db:
            if product.id == product_id:
                return product
        return None

    @staticmethod
    def create_product(product_data: ProductCreate) -> Product:
        new_id = max([p.id for p in fake_products_db]) + 1 if fake_products_db else 1
        new_product = Product(
            id=new_id,
            name=product_data.name,
            description=product_data.description,
            price=product_data.price,
            stock=product_data.stock
        )
        fake_products_db.append(new_product)
        return new_product

    @staticmethod
    def update_product(product_id: int, product_data: ProductUpdate) -> Optional[Product]:
        for i, product in enumerate(fake_products_db):
            if product.id == product_id:
                update_data = product_data.model_dump(exclude_unset=True)
                for field, value in update_data.items():
                    setattr(product, field, value)
                return product
        return None

product_service = ProductService()