pragma solidity ^0.4.11; import "../Oracles/Oracle.sol"; import "../Events/EventFactory.sol"; import "../Markets/MarketFactory.sol"; /// @title Futarchy oracle contract - Allows to create an oracle based on market behaviour /// @author Stefan George - contract FutarchyOracle is Oracle { using Math for *; /* * Events */ event FutarchyFunding(uint funding); event FutarchyClosing(); event OutcomeAssignment(uint winningMarketIndex); /* * Constants */ uint8 public constant LONG = 1; /* * Storage */ address creator; Market[] public markets; CategoricalEvent public categoricalEvent; uint public deadline; uint public winningMarketIndex; bool public isSet; /* * Modifiers */ modifier isCreator () { // Only creator is allowed to proceed require(msg.sender == creator); _; } /* * Public functions */ /// @dev Constructor creates events and markets for futarchy oracle /// @param _creator Oracle creator /// @param eventFactory Event factory contract /// @param collateralToken Tokens used as collateral in exchange for outcome tokens /// @param oracle Oracle contract used to resolve the event /// @param outcomeCount Number of event outcomes /// @param lowerBound Lower bound for event outcome /// @param upperBound Lower bound for event outcome /// @param marketFactory Market factory contract /// @param marketMaker Market maker contract /// @param fee Market fee /// @param _deadline Decision deadline constructor( address _creator, EventFactory eventFactory, Token collateralToken, Oracle oracle, uint8 outcomeCount, int lowerBound, int upperBound, MarketFactory marketFactory, MarketMaker marketMaker, uint24 fee, uint _deadline ) public { // Deadline is in the future require(_deadline > now); // Create decision event categoricalEvent = eventFactory.createCategoricalEvent(collateralToken, this, outcomeCount); // Create outcome events for (uint8 i = 0; i < categoricalEvent.getOutcomeCount(); i++) { ScalarEvent scalarEvent = eventFactory.createScalarEvent( categoricalEvent.outcomeTokens(i), oracle, lowerBound, upperBound ); markets.push(marketFactory.createMarket(scalarEvent, marketMaker, fee)); } creator = _creator; deadline = _deadline; } /// @dev Funds all markets with equal amount of funding /// @param funding Amount of funding function fund(uint funding) public isCreator { // Buy all outcomes require( categoricalEvent.collateralToken().transferFrom(creator, address(this), funding) && categoricalEvent.collateralToken().approve(address(categoricalEvent), funding)); categoricalEvent.buyAllOutcomes(funding); // Fund each market with outcome tokens from categorical event for (uint8 i = 0; i < markets.length; i++) { Market market = markets[i]; // Approve funding for market require(market.eventContract().collateralToken().approve(address(market), funding)); market.fund(funding); } emit FutarchyFunding(funding); } /// @dev Closes market for winning outcome and redeems winnings and sends all collateral tokens to creator function close() public isCreator { // Winning outcome has to be set Market market = markets[uint(getOutcome())]; require(categoricalEvent.isOutcomeSet() && market.eventContract().isOutcomeSet()); // Close market and transfer all outcome tokens from winning outcome to this contract market.close(); market.eventContract().redeemWinnings(); market.withdrawFees(); // Redeem collateral token for winning outcome tokens and transfer collateral tokens to creator categoricalEvent.redeemWinnings(); require(categoricalEvent.collateralToken().transfer(creator, categoricalEvent.collateralToken().balanceOf(address(this)))); emit FutarchyClosing(); } /// @dev Allows to set the oracle outcome based on the market with largest long position function setOutcome() public { // Outcome is not set yet and deadline has passed require(!isSet && deadline <= now); // Find market with highest marginal price for long outcome tokens uint highestMarginalPrice = markets[0].marketMaker().calcMarginalPrice(markets[0], LONG); uint highestIndex = 0; for (uint8 i = 1; i < markets.length; i++) { uint marginalPrice = markets[i].marketMaker().calcMarginalPrice(markets[i], LONG); if (marginalPrice > highestMarginalPrice) { highestMarginalPrice = marginalPrice; highestIndex = i; } } winningMarketIndex = highestIndex; isSet = true; emit OutcomeAssignment(winningMarketIndex); } /// @dev Returns if winning outcome is set /// @return Is outcome set? function isOutcomeSet() public view returns (bool) { return isSet; } /// @dev Returns winning outcome /// @return Outcome function getOutcome() public view returns (int) { return int(winningMarketIndex); } }