This repository contains solidity contracts to enable limit orders for LuaSwap.
Typically AMMs only settle orders with market price, which represents a significant limitation compared to orderbook driven exchanges. LuaSwap addresses this critical AMM pain point with the release of the limit order feature.
Contracts in this repo help you submit a limit order with a lower price than what it is now. Later, when the price gets lower enough to meet the requirement of your order, it gets settled.
Limit orders on LuaSwap work in a completely decentralized manner, without the need of any centralized authority. The system consists of two contracts: OrderBook and Settlement.
OrderBook is deployed at 0x9701554EBD790EAF258d5A2131f00ac72525DE42.
OrderBook keeps limit orders that users have submitted. Anyone can call createOrder() to create a limit order with the amount to sell and the minimum price. He/she needs to approve the amount to sell for the Settlement contract.
Settlement is deployed at 0x3fcF522bAA0Ab1D9a1f77EFaC7DC1aC0C5dEBC63.
Settlement is in charge of swapping tokens for orders. Anyone can call fillOrder() to fill the order submitted. We'll call this caller a 'relayer'. Relayers need to call it with proper parameters to meet the minimum price requirement set in the order. If the call is successful, fee will be transferred to the relayer.
The maker of an order can cancel it with cancelOrder() on Settlement.
It is possible to fill only a certain amount of tokens, not all. In most cases, submitted orders will reside on the OrderBook and their amount will be filled by different callers in different blocks.
Settlement is a wrapper contract around UniswapV2Router02. Every function in this contract has a duplicated version in the Settlement with an extra parameter args. If args is not empty, it is used for filling orders; see Settlement.fillOrders() for details.
For every fillOrder() call, 0.4% swap fee of the amount sold is charged.
MIT