pragma solidity >=0.0; import "../Markets/Market.sol"; import "../Tokens/Token.sol"; import "../Events/Event.sol"; import "../MarketMakers/MarketMaker.sol"; /// @title Market factory contract - Allows to create market contracts /// @author Stefan George - contract StandardMarket is Market { using Math for *; /* * Constants */ uint24 public constant FEE_RANGE = 1000000; // 100% /* * Modifiers */ modifier isCreator () { // Only creator is allowed to proceed require(msg.sender == creator); _; } modifier atStage(Stages _stage) { // Contract has to be in given stage require(stage == _stage); _; } /* * Public functions */ /// @dev Constructor validates and sets market properties /// @param _creator Market creator /// @param _eventContract Event contract /// @param _marketMaker Market maker contract /// @param _fee Market fee constructor(address _creator, Event _eventContract, MarketMaker _marketMaker, uint24 _fee) public { // Validate inputs require(address(_eventContract) != address(0) && address(_marketMaker) != address(0) && _fee < FEE_RANGE); creator = _creator; createdAtBlock = block.number; eventContract = _eventContract; netOutcomeTokensSold = new int[](eventContract.getOutcomeCount()); fee = _fee; marketMaker = _marketMaker; stage = Stages.MarketCreated; } /// @dev Allows to fund the market with collateral tokens converting them into outcome tokens /// @param _funding Funding amount function fund(uint _funding) public override isCreator atStage(Stages.MarketCreated) { // Request collateral tokens and allow event contract to transfer them to buy all outcomes require( eventContract.collateralToken().transferFrom(msg.sender, address(this), _funding) && eventContract.collateralToken().approve(address(eventContract), _funding)); eventContract.buyAllOutcomes(_funding); funding = _funding; stage = Stages.MarketFunded; emit MarketFunding(funding); } /// @dev Allows market creator to close the markets by transferring all remaining outcome tokens to the creator function close() override public isCreator atStage(Stages.MarketFunded) { uint8 outcomeCount = eventContract.getOutcomeCount(); for (uint8 i = 0; i < outcomeCount; i++) require(eventContract.outcomeTokens(i).transfer(creator, eventContract.outcomeTokens(i).balanceOf(address(this)))); stage = Stages.MarketClosed; emit MarketClosing(); } /// @dev Allows market creator to withdraw fees generated by trades /// @return fees Fee amount function withdrawFees() public override isCreator returns (uint fees) { fees = eventContract.collateralToken().balanceOf(address(this)); // Transfer fees require(eventContract.collateralToken().transfer(creator, fees)); emit FeeWithdrawal(fees); } /// @dev Allows to buy outcome tokens from market maker /// @param outcomeTokenIndex Index of the outcome token to buy /// @param outcomeTokenCount Amount of outcome tokens to buy /// @param maxCost The maximum cost in collateral tokens to pay for outcome tokens /// @return cost Cost in collateral tokens function buy(uint8 outcomeTokenIndex, uint outcomeTokenCount, uint maxCost) public override atStage(Stages.MarketFunded) returns (uint cost) { // Calculate cost to buy outcome tokens uint outcomeTokenCost = marketMaker.calcCost(this, outcomeTokenIndex, outcomeTokenCount); // Calculate fees charged by market uint fees = calcMarketFee(outcomeTokenCost); cost = outcomeTokenCost.add(fees); // Check cost doesn't exceed max cost require(cost > 0 && cost <= maxCost); // Transfer tokens to markets contract and buy all outcomes require( eventContract.collateralToken().transferFrom(msg.sender, address(this), cost) && eventContract.collateralToken().approve(address(eventContract), outcomeTokenCost)); // Buy all outcomes eventContract.buyAllOutcomes(outcomeTokenCost); // Transfer outcome tokens to buyer require(eventContract.outcomeTokens(outcomeTokenIndex).transfer(msg.sender, outcomeTokenCount)); // Add outcome token count to market maker net balance require(int(outcomeTokenCount) >= 0); netOutcomeTokensSold[outcomeTokenIndex] = netOutcomeTokensSold[outcomeTokenIndex].add(int(outcomeTokenCount)); emit OutcomeTokenPurchase(msg.sender, outcomeTokenIndex, outcomeTokenCount, cost); } /// @dev Allows to sell outcome tokens to market maker /// @param outcomeTokenIndex Index of the outcome token to sell /// @param outcomeTokenCount Amount of outcome tokens to sell /// @param minProfit The minimum profit in collateral tokens to earn for outcome tokens /// @return profit Profit in collateral tokens function sell(uint8 outcomeTokenIndex, uint outcomeTokenCount, uint minProfit) public override atStage(Stages.MarketFunded) returns (uint profit) { // Calculate profit for selling outcome tokens uint outcomeTokenProfit = marketMaker.calcProfit(this, outcomeTokenIndex, outcomeTokenCount); // Calculate fee charged by market uint fees = calcMarketFee(outcomeTokenProfit); profit = outcomeTokenProfit.sub(fees); // Check profit is not too low require(profit > 0 && profit >= minProfit); // Transfer outcome tokens to markets contract to sell all outcomes require(eventContract.outcomeTokens(outcomeTokenIndex).transferFrom(msg.sender, address(this), outcomeTokenCount)); // Sell all outcomes eventContract.sellAllOutcomes(outcomeTokenProfit); // Transfer profit to seller require(eventContract.collateralToken().transfer(msg.sender, profit)); // Subtract outcome token count from market maker net balance require(int(outcomeTokenCount) >= 0); netOutcomeTokensSold[outcomeTokenIndex] = netOutcomeTokensSold[outcomeTokenIndex].sub(int(outcomeTokenCount)); emit OutcomeTokenSale(msg.sender, outcomeTokenIndex, outcomeTokenCount, profit); } /// @dev Buys all outcomes, then sells all shares of selected outcome which were bought, keeping /// shares of all other outcome tokens. /// @param outcomeTokenIndex Index of the outcome token to short sell /// @param outcomeTokenCount Amount of outcome tokens to short sell /// @param minProfit The minimum profit in collateral tokens to earn for short sold outcome tokens /// @return cost Cost to short sell outcome in collateral tokens function shortSell(uint8 outcomeTokenIndex, uint outcomeTokenCount, uint minProfit) public override returns (uint cost) { // Buy all outcomes require( eventContract.collateralToken().transferFrom(msg.sender, address(this), outcomeTokenCount) && eventContract.collateralToken().approve(address(eventContract), outcomeTokenCount)); eventContract.buyAllOutcomes(outcomeTokenCount); // Short sell selected outcome eventContract.outcomeTokens(outcomeTokenIndex).approve(address(this), outcomeTokenCount); uint profit = this.sell(outcomeTokenIndex, outcomeTokenCount, minProfit); cost = outcomeTokenCount - profit; // Transfer outcome tokens to buyer uint8 outcomeCount = eventContract.getOutcomeCount(); for (uint8 i = 0; i < outcomeCount; i++) if (i != outcomeTokenIndex) require(eventContract.outcomeTokens(i).transfer(msg.sender, outcomeTokenCount)); // Send change back to buyer require(eventContract.collateralToken().transfer(msg.sender, profit)); emit OutcomeTokenShortSale(msg.sender, outcomeTokenIndex, outcomeTokenCount, cost); } /// @dev Calculates fee to be paid to market maker /// @param outcomeTokenCost Cost for buying outcome tokens /// @return Fee for trade function calcMarketFee(uint outcomeTokenCost) public override view returns (uint) { return outcomeTokenCost * fee / FEE_RANGE; } }