from math import inf

class BuyerMarketplace:
    def __init__(self, datastore: Datastore):
        self.ds = datastore

    def buy_items(self, buyer_name: str, wants: dict[str, int]) -> dict[str, Item]:
        listings = self.ds.get_all()

        # cheapest unsold listing per item_name
        cheapest: dict[str, Item] = {}
        cheapest_price: dict[str, float] = {}

        for it in listings:
            if it.buyer_name:   # skip sold
                continue
            p = it.price
            name = it.item_name
            if name not in cheapest_price or p < cheapest_price[name]:
                cheapest_price[name] = p
                cheapest[name] = it

        result: dict[str, Item] = {}

        for name, max_price in wants.items():
            if name in cheapest and cheapest_price[name] <= max_price:
                it = cheapest[name]
                trade = Item(it.seller_name, buyer_name, name, cheapest_price[name])
                self.ds.put(trade)          # persist sale
                result[name] = trade

        return result