V0 -> V1 POC review

contracts/DaiBackstopSyndicate.sol → contracts/DaiBackstopSyndicateV0.sol

@@ -36,7 +36,7 @@ interface DaiBackstopSyndicateInterface {
 }
 
 
-contract DaiBackstopSyndicate is DaiBackstopSyndicateInterface, ERC20 {
+contract DaiBackstopSyndicateV0 is DaiBackstopSyndicateInterface, ERC20 {
   using SafeMath for uint256;
 
   // Track the status of the Syndicate.

contracts/DaiBackstopSyndicateV1.sol

@@ -0,0 +1,186 @@
+pragma solidity 0.5.16;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/math/SafeMath.sol";
+
+
+interface DaiBackstopSyndicateInterface {
+  enum Status {
+    ACCEPTING_DEPOSITS,
+    ACTIVATED,
+    DEACTIVATED
+  }
+
+  // Anyone can deposit Dai up until the auctions have started at 1:1
+  function deposit(uint256 daiAmount) external returns (uint256 backstopTokensMinted);
+
+  // Anyone can withdraw at any point (open question how to handle ongoing auctions)
+  function withdraw(uint256 backstopTokenAmount) external returns (uint256 daiRedeemed, uint256 mkrRedeemed);
+
+  // Anyone can activate the contract once auctions have started, stopping deposits and enabling bids
+  function activate() external;
+
+  // Anyone can enter an auction, supplying 50,000 Dai in exchange for 500 MKR
+  function enterAuction(uint256 auctionId) external;
+
+  // (may not be necessary since this is just dent, no tend?)
+  function finalizeAuction(uint256 auctionId) external;
+
+  // Anyone can deactivate the ability to make new bids once auctions finish
+  function deactivate() external;
+
+  function getStatus() external view returns (Status status);
+
+  function getActiveAuctions() external view returns (uint256 activeAuctions);
+}
+
+
+contract DaiBackstopSyndicateV1 is DaiBackstopSyndicateInterface, ERC20 {
+  using SafeMath for uint256;
+
+  // Track the status of the Syndicate.
+  Status internal _status;
+
+  // Track the number of active auctions (TODO: update this as part of withdraw)
+  uint256 internal _activeAuctions;
+
+  // Syndicate can be activated once auctions start (TODO: determine this time!)
+  uint256 internal constant _AUCTION_START_TIME = 1584490000;
+
+  // The backstop price is 100 Dai for 1 MKR.
+  uint256 internal constant _MKR_BACKSTOP_BID_PRICE_DENOMINATED_IN_DAI = 100;
+
+  IERC20 internal constant _DAI = IERC20(
+    0x6B175474E89094C44Da98b954EedeAC495271d0F
+  );
+
+  IERC20 internal constant _MKR = IERC20(
+    0x9f8F72aA9304c8B593d555F12eF6589cC3A579A2
+  );
+
+  constructor() public {
+    _status = Status.ACCEPTING_DEPOSITS;
+  }
+
+  function deposit(
+    uint256 daiAmount
+  ) external returns (uint256 backstopTokensMinted) {
+    require(
+      _status == Status.ACCEPTING_DEPOSITS,
+      "Cannot deposit once auctions are activated."
+    );
+
+    require(
+      _DAI.transferFrom(msg.sender, address(this), daiAmount),
+      "Could not transfer Dai amount from caller."
+    );
+
+    backstopTokensMinted = daiAmount;
+    _mint(msg.sender, backstopTokensMinted);
+  }
+
+  function withdraw(
+    uint256 backstopTokenAmount
+  ) external returns (uint256 daiRedeemed, uint256 mkrRedeemed) {
+    // Determine the % ownership. (scaled up by 1e18)
+    uint256 shareFloat = (backstopTokenAmount.mul(1e18)).div(totalSupply());
+
+    // Burn the tokens.
+    _burn(msg.sender, backstopTokenAmount);
+
+    // TODO: make sure that _activeAuctions is accurate!
+
+    // Determine the Dai currently locked in auctions.
+    uint256 daiLockedInAuctions = _activeAuctions.mul(50000 * 1e18);
+
+    // Determine the Dai currently held by the contract.
+    uint256 daiBalance = _DAI.balanceOf(address(this));
+
+    // Combine Dai locked in auctions with the balance on the contract.
+    uint256 combinedDai = daiLockedInAuctions.add(daiBalance);
+
+    // Determine the Maker currently held by the contract.
+    uint256 makerBalance = _MKR.balanceOf(address(this));
+
+    // Determine the amount of Dai and MKR to redeem based on the share.
+    daiRedeemed = combinedDai.mul(shareFloat) / 1e18;
+    mkrRedeemed = makerBalance.mul(shareFloat) / 1e18;
+
+    // Ensure that sufficient Dai liquidity is currently available to withdraw.
+    require(
+      daiRedeemed <= daiBalance, "Insufficient Dai (in use in auctions)"
+    );
+
+    // Redeem the Dai and MKR.
+    require(_DAI.transfer(msg.sender, daiRedeemed), "Dai redemption failed.");
+    require(_MKR.transfer(msg.sender, mkrRedeemed), "MKR redemption failed.");
+  }
+
+  function activate() external {
+    require(
+      _status == Status.ACCEPTING_DEPOSITS,
+      "Cannot activate again after a prior activation."
+    );
+
+    require(
+      block.timestamp >= _AUCTION_START_TIME,
+      "Cannot activate until MKR auctions have started."
+    );
+
+    // Determine the Dai currently held by the contract.
+    uint256 daiBalance = _DAI.balanceOf(address(this));
+
+    // Jump straight to deactivated if there is not enough dai to make auctions.
+    if (daiBalance < 50000 * 1e18) {
+      _status = Status.DEACTIVATED;
+    } else {
+      // Set the status as active.
+      _status = Status.ACTIVATED;
+    }
+  }
+
+  // Anyone can enter an auction, supplying 50,000 Dai in exchange for 500 MKR
+  function enterAuction(uint256 auctionId) external {
+    // Determine the Dai currently held by the contract.
+    uint256 daiBalance = _DAI.balanceOf(address(this));
+
+    require(
+      daiBalance >= 50000 * 1e18, "Insufficient Dai available for auction."
+    );
+
+    // TODO: ensure that the auction in question has not already been entered?
+
+    // TODO: enter auction
+
+    _activeAuctions = _activeAuctions.add(1);
+  }
+
+  // (may not be necessary since this is just dent, no tend?)
+  function finalizeAuction(uint256 auctionId) external {
+    // TODO: ensure that we are in the auction
+
+    // TODO: finalize auction
+
+    _activeAuctions = _activeAuctions.sub(1);
+  }
+
+  function deactivate() external {
+    require(
+      _status == Status.ACTIVATED,
+      "Cannot deactivate unless currently active."
+    );
+
+    // TODO: determine that MKR auction is over (check the surplus?)
+
+    _status = Status.DEACTIVATED;
+  }
+
+  function getStatus() external view returns (Status status) {
+    status = _status;
+  }
+
+  function getActiveAuctions() external view returns (uint256 activeAuctions) {
+    activeAuctions = _activeAuctions;
+  }
+}