"""
Utility module that defines the tool(s) used by the streaming agent.

The project currently contains a single mock ``get_price`` function.  The
implementation is intentionally tiny – it simply looks up a hard‑coded price
in a dictionary.  In real projects this would be replaced with an API call or
database query.
"""

from langchain.tools import tool

@tool
def get_price(product: str, city: str) -> str:
    """Return a fake price for *product* in *city*.

    Parameters
    ----------
    product : str
        Name of the product (e.g. ``milk``).
    city : str
        City where the price is requested.

    Returns
    -------
    str
        A string describing the price, e.g. ``"89 rubles"``.
    """
    prices = {
        ("milk", "kazan"): "89",
        ("bread", "kazan"): "45",
        ("coffee", "moscow"): "120",
    }
    key = (product.lower(), city.lower())
    price = prices.get(key, "unknown")
    return f"{price} rubles"

# End of tools.py