adds TrueFi adapter

adapters/truefi/ITrueFarm.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.6.10;
+
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+interface ITrueFarm {
+    // writes
+    function stakingToken() external view returns (IERC20);
+    function trustToken() external view returns (IERC20);
+    function trueDistributor() external view returns (ITrueDistributor);
+    function name() external view returns (string memory);
+    function totalStaked() external view returns (uint256);
+    function stake(uint256 amount) external;
+    function unstake(uint256 amount) external;
+    function claim() external;
+    function exit(uint256 amount) external;
+    function staked(uint256 address) external returns (uint265);
+}

adapters/truefi/TrueFiAdapter.sol

@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity 0.6.12;
+
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "../../interfaces/IUniswapV2Pair.sol";
+import "../../interfaces/IUniswapV2Factory.sol";
+import "../../interfaces/IUniswapV2Router02.sol";
+import "../../libraries/UniswapV2Library.sol";
+import "../../IVampireAdapter.sol";
+import "../../IDrainController.sol";
+import "./ITrueFarm.sol";
+
+contract TruefiAdapter is IVampireAdapter {
+  IDrainController constant drainController = IDrainController(0x2e813f2e524dB699d279E631B0F2117856eb902C);
+  ITrueFarm constant trueFarm = ITrueFarm(0xED45Cf4895C110f464cE857eBE5f270949eC2ff4);
+  IUniswapV2Router02 constant router = IUniswapV2Router02(0x1d5C6F1607A171Ad52EFB270121331b3039dD83e);
+  IERC20 constant tru = IERC20(0x4C19596f5aAfF459fA38B0f7eD92F11AE6543784);
+  IERC20 constant weth = IERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
+  IUniswapV2Pair constant truWethPair = IUniswapV2Pair(0xeC6a6b7dB761A5c9910bA8fcaB98116d384b1B85);
+
+  constructor() public {}
+
+  // Victim info
+  function rewardToken() external view override returns (IERC20) {
+    return tru;
+  }
+
+  function poolCount() external view override returns (uint256) { 
+    return trueFarm.totalStaked();
+  }
+
+  function sellableRewardAmount() external view override returns (uint256) {
+    return uint256(-1);
+  }
+
+  // Victim actions, requires impersonation via delegatecall
+  function sellRewardForWeth(address, uint256 rewardAmount, address to) external override returns(uint256) {
+    require(drainController.priceIsUnderRejectionTreshold(), "Possible price manipulation, drain rejected");
+    address[] memory path = new address[](2);
+    path[0] = address(tru);
+    path[1] = address(weth);
+    uint[] memory amounts = router.getAmountsOut(rewardAmount, path);
+    tru.approve(address(router), uint256(-1));
+    amounts = router.swapExactTokensForTokens(rewardAmount, amounts[amounts.length - 1], path, to, block.timestamp );
+    return amounts[amounts.length - 1];
+  }
+
+  // Pool info
+  function lockableToken(uint256 poolId) external view override returns (IERC20) {
+    return trueFarm.stakingToken();
+  }
+
+  function lockedAmount(address user, uint256 poolId) external view override returns (uint256) {
+    return trueFarm.staked(user);
+  }
+
+  // Pool actions, requires impersonation via delegatecall
+  function deposit(address _adapter, uint256 poolId, uint256 amount) external override {
+    IVampireAdapter adapter = IVampireAdapter(_adapter);
+    adapter.lockableToken(poolId).approve(address(trueFarm), uint256(-1));
+    trueFarm.deposit(amount);
+  }
+
+  function withdraw(address, uint256 poolId, uint256 amount) external override {
+    trueFarm.unstake(amount);
+  }
+
+  function claimReward(address, uint256 poolId) external override {
+    trueFarm.claim();
+  }
+
+  function emergencyWithdraw(address, uint256 poolId) external override {
+    require(false, "not implemented");
+  }
+
+  // Service methods
+  function poolAddress(uint256) external view override returns (address) {
+    return address(trueFarm);
+  }
+
+  function rewardToWethPool() external view override returns (address) {
+    return address(truWethPair);
+  }
+
+  function lockedValue(address, uint256) external override view returns (uint256) {
+    require(false, "not implemented");
+  }    
+
+  function totalLockedValue(uint256) external override view returns (uint256) {
+    require(false, "not implemented");
+  }
+
+  function normalizedAPY(uint256) external override view returns (uint256) {
+    require(false, "not implemented");
+  }
+}