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Exchange.sol
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177 lines (147 loc) · 7.1 KB
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// SPDX-License-Identifier: MIT
pragma solidity 0.8.13;
import {IERC721} from "openzeppelin-contracts/contracts/token/ERC721/IERC721.sol";
import {ERC721} from "openzeppelin-contracts/contracts/token/ERC721/ERC721.sol";
import {OrderTypes} from "./libraries/OrderTypes.sol";
/// @title Exchange
/// @notice An MVP for a prediction market made for the polygon hackathon summer 2022
/// @notice The contract is not gas-optimized and NOT audited, so expect some bugs
contract Exchange {
address public deployer;
address public predictionMarketAddress;
mapping(address => uint256) public makerAskCountByFeed;
mapping(address => uint256) public makerAskCountByAccount;
mapping(uint256 => OrderTypes.MakerOrder) public makerAskByTokenId;
mapping(address => mapping(uint256 => OrderTypes.MakerOrder)) public makerAskByFeedAndId;
mapping(address => uint256) public makerAskUpperLimitByFeed;
mapping(address => mapping(uint256 => OrderTypes.MakerOrder)) public makerAskByAccountAndId;
mapping(address => uint256) public makerAskUpperLimitByAccount;
event MakerAsk(
address indexed signer,
uint256 indexed tokenId,
uint256 price,
address priceFeed,
int256 tresholdPrice
);
event TakerBid(address indexed taker, address indexed maker, uint256 indexed tokenId, uint256 price);
constructor() {
deployer = msg.sender;
}
/// @notice Set the address of the prediction market contract
/// @param _predictionMarket The predictionMarket whose tokens are traded on this exchange
function setPredictionMarketAddress(address _predictionMarket) public {
require(msg.sender == deployer, "Only deployer can change the prediction market address");
predictionMarketAddress = _predictionMarket;
}
/// @notice Call this function to list a token on the exchange
/// @param makerAsk An ask to sell something (a listing)
function createMakerAsk(OrderTypes.MakerOrder calldata makerAsk) external {
require(
msg.sender == makerAsk.signer || msg.sender == predictionMarketAddress,
"maker must be the sender"
);
address owner = IERC721(makerAsk.collection).ownerOf(makerAsk.tokenId);
require(
msg.sender == owner || msg.sender == predictionMarketAddress,
"maker must be the owner or the pMarket"
);
if (getMakerAsk(makerAsk.tokenId).signer == address(0)) {
// not just overriding an earlier ask
makerAskCountByFeed[makerAsk.priceFeed]++;
makerAskCountByAccount[makerAsk.signer]++;
}
makerAskByFeedAndId[makerAsk.priceFeed][makerAsk.tokenId] = makerAsk;
makerAskByAccountAndId[makerAsk.signer][makerAsk.tokenId] = makerAsk;
uint256 prevUpperLimitFeed = makerAskUpperLimitByFeed[makerAsk.priceFeed];
if (makerAsk.tokenId > prevUpperLimitFeed) {
makerAskUpperLimitByFeed[makerAsk.priceFeed] = makerAsk.tokenId;
}
uint256 prevUpperLimitAccount = makerAskUpperLimitByAccount[makerAsk.signer];
if (makerAsk.tokenId > prevUpperLimitAccount) {
makerAskUpperLimitByAccount[makerAsk.signer] = makerAsk.tokenId;
}
makerAskByTokenId[makerAsk.tokenId] = makerAsk;
emit MakerAsk(
makerAsk.signer,
makerAsk.tokenId,
makerAsk.price,
makerAsk.priceFeed,
makerAsk.tresholdPrice
);
}
/// @notice Matches an ask with a bid, and exchanges tokens
/// @param takerBid the bid for a particular token
function matchAskWithTakerBid(OrderTypes.TakerOrder calldata takerBid) external payable {
require(msg.sender == takerBid.taker, "Order: Taker must be the sender");
OrderTypes.MakerOrder memory makerAsk = makerAskByTokenId[takerBid.tokenId];
require(makerAsk.signer != address(0), "Order: Token is not listed");
require(makerAsk.signer != takerBid.taker, "Order: Maker and Taker cannot be the same");
require(msg.value == takerBid.price, "Order: Not enough <native currency>");
bool isExecutionValid = canExecuteTakerBid(takerBid, makerAsk);
require(isExecutionValid, "Strategy: Execution invalid");
(bool sent, ) = makerAsk.signer.call{value: msg.value}("");
require(sent, "failed ether transfer");
transferNonFungibleToken(makerAsk.signer, takerBid.taker, takerBid.tokenId, takerBid.collection);
emit TakerBid(takerBid.taker, makerAsk.signer, takerBid.tokenId, takerBid.price);
delete makerAskByTokenId[takerBid.tokenId];
makerAskCountByFeed[makerAsk.priceFeed]--;
delete makerAskByFeedAndId[makerAsk.priceFeed][makerAsk.tokenId];
makerAskCountByAccount[makerAsk.signer]--;
delete makerAskByAccountAndId[makerAsk.signer][makerAsk.tokenId];
}
/// @notice Does elementary validity checks
/// @param takerBid the bid for a particular token
/// @param makerAsk the ask for a particular token
function canExecuteTakerBid(
OrderTypes.TakerOrder calldata takerBid,
OrderTypes.MakerOrder memory makerAsk
) private pure returns (bool) {
return (((makerAsk.price == takerBid.price) && (makerAsk.tokenId == takerBid.tokenId)));
}
function transferNonFungibleToken(
address from,
address to,
uint256 tokenId,
address collection
) internal {
IERC721(collection).safeTransferFrom(from, to, tokenId);
}
function getMakerAsk(uint256 id) public view returns (OrderTypes.MakerOrder memory) {
return makerAskByTokenId[id];
}
function getMakerAsks() public view returns (OrderTypes.MakerOrder memory) {}
function getMakerAsksByFeed(address feed) public view returns (uint256[2][] memory, address[] memory) {
uint256 upperLimit = makerAskUpperLimitByFeed[feed];
uint256 count = makerAskCountByFeed[feed];
uint256[2][] memory makerAsks = new uint256[2][](count);
address[] memory signers = new address[](count);
uint256 i = 0;
uint256 j = 0;
while (i <= upperLimit) {
OrderTypes.MakerOrder memory makerAsk = makerAskByFeedAndId[feed][i];
if (makerAsk.priceFeed != address(0)) {
(makerAsks[j][0], makerAsks[j][1]) = (makerAsk.tokenId, makerAsk.price);
signers[j] = makerAsk.signer;
j++;
}
i++;
}
return (makerAsks, signers);
}
function getMakerAsksByAccount(address account) public view returns (uint256[2][] memory) {
uint256 upperLimit = makerAskUpperLimitByAccount[account];
uint256 count = makerAskCountByAccount[account];
uint256[2][] memory makerAsks = new uint256[2][](count);
uint256 i = 0;
uint256 j = 0;
while (i <= upperLimit) {
OrderTypes.MakerOrder memory makerAsk = makerAskByAccountAndId[account][i];
if (makerAsk.signer != address(0)) {
(makerAsks[j][0], makerAsks[j][1]) = (makerAsk.tokenId, makerAsk.price);
j++;
}
i++;
}
return makerAsks;
}
}