Stock Traders

Provides villagers with two different trades: from an item to a currency, and from a currency to the same item, with the exchange rate being dependant on the amount of that item they have available (higher when there's no stock, and lower and lower as they acquire more and more stock).

Requirements

Wishlist ← Summon ← Stock Traders

Advancements:

title	description
Regulated Marketplace	trade materials with a stock trader

Usage

Setting up a Stock Trader

The Stock Traders package does not provide a player-friendly way to set up a stock trader.

This explanation is for stock admins and players in creative mode.

First, place a barrel on the ground for the trader to stand on, and configure its inventory as follows:

B . . . . . . . .
. . . . . . . . .
S . . . . . . . .

Where B is the items the trader will buy, S is the maximum amount of currency the trader will give for it, and . are empty spaces.

Then stand on the barrel and run the following command:

execute summon minecraft:villager run function stock_traders:reset_trader

Price Fluctuation

Stock trader's prices will change in response to how much stock they accumulate; the more stock they have, the less they will pay for more, and the cheaper they'll let their stock go; the actual price depends on the base price defined in the barrel, the stock and a factor of N hardcoded in the datapack (by default 100) in the following way:

price = base / (1 + stock / N)

Roughly this equation behaves as follows:

at stock = 0, the price is equal to base;
at stock = N, the price is base / 2;

If the price of an item reaches zero, the trader will stop buying that item.

Overhead

Adds some advancements:

checks if a player trades with a stock trader; when this happens, the stock trader is tagged for update and the update function is scheduled to run next tick.
- checks every entity in a 6-block radius around each player each second to find stock traders that should be updated.