from fastapi import FastAPI, HTTPException
from pydantic import BaseModel

app = FastAPI()

products_db: dict = {
    1: {"id": 1, "name": "Laptop", "price": 999.99, "stock": 10},
    2: {"id": 2, "name": "Smartphone", "price": 499.99, "stock": 20},
    3: {"id": 3, "name": "Headphones", "price": 199.99, "stock": 15},
}

class UpdateStockDTO(BaseModel):
    quantity: int

@app.get("/products/{product_id}")
async def get_product(product_id: int):
    product = products_db.get(product_id)
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    return product

@app.put("/products/{product_id}/stock")
async def update_stock(product_id: int, payload: UpdateStockDTO):
    product = products_db.get(product_id)
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    if product["stock"] < payload.quantity:
        raise HTTPException(status_code=400, detail="Insufficient stock")
    product["stock"] -= payload.quantity
    return product

@app.get("/health")
def health():
    return {"status": "ok", "service": "catalog-service"}