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Merge pull request #9 from revo-market/jophish/multi-reward
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feat(multi-rewards): Add support for multi-reward Ubeswap farms
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@jophish
jophish authored Feb 8, 2022
2 parents 550e4f2 + 343c495 commit e936944
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Showing 2 changed files with 117 additions and 40 deletions.
32 changes: 32 additions & 0 deletions contracts/IMoolaStakingRewards.sol
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Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
// SPDX-License-Identifier: MIT

pragma solidity >=0.4.24;

interface IMoolaStakingRewards {

// Views

function lastTimeRewardApplicable() external view returns (uint256);

function rewardPerToken() external view returns (uint256);

function earned(address account) external view returns (uint256);

function earnedExternal(address account) external returns (uint256[] calldata);

function getRewardForDuration() external view returns (uint256);

function totalSupply() external view returns (uint256);

function balanceOf(address account) external view returns (uint256);

// Mutative

function stake(uint256 amount) external;

function withdraw(uint256 amount) external;

function getReward() external;

function exit() external;
}
125 changes: 85 additions & 40 deletions contracts/farm-bot.sol
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Expand Up @@ -3,19 +3,24 @@ pragma solidity >=0.5.0 <0.9.0;

import "hardhat/console.sol";

import "./ubeswap-farming/contracts/StakingRewards.sol";
import "./ubeswap-farming/contracts/Owned.sol";
import "./IMoolaStakingRewards.sol";
import "./ubeswap/contracts/uniswapv2/interfaces/IUniswapV2Router02.sol";
import "./ubeswap/contracts/uniswapv2/interfaces/IUniswapV2Pair.sol";
import "./ubeswap-farming/contracts/Owned.sol";
import "./FarmbotERC20.sol";
import "./IRevoBounty.sol";


contract FarmBot is Owned, FarmbotERC20 {
uint256 public lpTotalBalance; // total number of LP tokens owned by Farm Bot

StakingRewards public stakingRewards;
IMoolaStakingRewards public stakingRewards;

IERC20 public rewardsToken;
// List of rewards tokens. The first token in this list is assumed to be the primary token;
// the rest correspond to the staking reward contract's external reward tokens. The order of these tokens
// is very important; the first must correspond to the MoolaStakingRewards contract's "native" reward token,
// and the rest must correspond to its "external" tokens, in the same order as they appear in the contract.
IERC20[] public rewardsTokens;

IUniswapV2Pair public stakingToken; // LP that's being staked
IERC20 public stakingToken0; // LP token0
Expand All @@ -24,8 +29,8 @@ contract FarmBot is Owned, FarmbotERC20 {
IUniswapV2Router02 public router; // Router address

// Paths for swapping; can be updated by owner
address[] public path0; // Path to use when swapping rewardsToken to token0. If len < 2, we assume rewardsToken == token0
address[] public path1; // Path to use when swapping rewardsToken to token1. If len < 2, we assume rewardsToken == token1
// Paths to use when swapping rewardsTokens for token0/token1. Each top-level entry represents a pair of paths for each rewardsToken.
address[][2][] public paths;

// Acceptable slippage when swapping/minting LP; can be updated by owner
uint256 public slippageNumerator = 99;
Expand All @@ -46,22 +51,32 @@ contract FarmBot is Owned, FarmbotERC20 {
constructor(
address _owner,
address _stakingRewards,
address _stakingToken,
address _revoBounty,
address _router,
address[] memory _path0,
address[] memory _path1,
address[] memory _rewardsTokens,
address[][2][] memory _paths,
string memory _symbol
) Owned(_owner) {
stakingRewards = StakingRewards(_stakingRewards);
rewardsToken = stakingRewards.rewardsToken();
stakingRewards = IMoolaStakingRewards(_stakingRewards);

for (uint i=0; i<_rewardsTokens.length; i++) {
rewardsTokens.push(IERC20(_rewardsTokens[i]));
}

require(
_paths.length == _rewardsTokens.length,
"Parameters _paths and _rewardsTokens must have equal length"
);
paths = _paths;

revoBounty = IRevoBounty(_revoBounty);

stakingToken = IUniswapV2Pair(address(stakingRewards.stakingToken()));
stakingToken = IUniswapV2Pair(_stakingToken);
stakingToken0 = IERC20(stakingToken.token0());
stakingToken1 = IERC20(stakingToken.token1());

path0 = _path0;
path1 = _path1;

symbol = _symbol;

router = IUniswapV2Router02(_router);
Expand All @@ -71,9 +86,8 @@ contract FarmBot is Owned, FarmbotERC20 {
revoBounty = IRevoBounty(_revoBounty);
}

function updatePaths(address[] calldata _path0, address[] calldata _path1) external onlyOwner {
path0 = _path0;
path1 = _path1;
function updatePaths(address[][2][] memory _paths) external onlyOwner {
paths = _paths;
}

function updateSlippage(uint256 _slippageNumerator, uint256 _slippageDenominator) external onlyOwner {
Expand Down Expand Up @@ -137,11 +151,30 @@ contract FarmBot is Owned, FarmbotERC20 {
}

// convenience method for anyone considering calling claimRewards (who may want to compare bounty to gas cost)
function previewBounty() external view returns (TokenAmount[] memory) {
uint _leftoverBalance = rewardsToken.balanceOf(address(this));
uint _interestEarned = stakingRewards.earned(address(this));
TokenAmount[] memory _rewardsTokenBalances = new TokenAmount[](1);
_rewardsTokenBalances[0] = TokenAmount(rewardsToken, _interestEarned + _leftoverBalance);
// Annoyingly, the MoolaStakingRewards.earnedExternal method is not declared as a view, so we cannot declare this
// method as a view itself.
function previewBounty() external returns (TokenAmount[] memory) {
uint[] memory _leftoverBalances = new uint[](rewardsTokens.length);
for (uint i=0; i < rewardsTokens.length; i++) {
_leftoverBalances[i] = rewardsTokens[i].balanceOf(address(this));
}

// The MoolaStakingRewards contract treats the "native" reward token as fundamentally
// different than the "external" ones, so we have to query the earned balance separately
uint[] memory _interestEarned = new uint[](rewardsTokens.length);
_interestEarned[0] = stakingRewards.earned(address(this));

uint[] memory _externalEarned = stakingRewards.earnedExternal(address(this));
require(_externalEarned.length == rewardsTokens.length - 1, "Incorrect amount of external rewards tokens");
for (uint i=0; i < _externalEarned.length; i++) {
_interestEarned[i+1] = _externalEarned[i];
}

TokenAmount[] memory _rewardsTokenBalances = new TokenAmount[](rewardsTokens.length);
for (uint i=0; i < rewardsTokens.length; i++) {
_rewardsTokenBalances[i] = TokenAmount(rewardsTokens[i], _interestEarned[i] + _leftoverBalances[i]);
}

return revoBounty.calculateFeeBounty(_rewardsTokenBalances);
}

Expand All @@ -168,37 +201,47 @@ contract FarmBot is Owned, FarmbotERC20 {
stakingRewards.getReward();

// compute bounty for the caller
uint256 _tokenBalance = rewardsToken.balanceOf(address(this));
if (_tokenBalance == 0) {
return;
}
uint256 _bountyAmount;
uint256[] memory _tokenBalances = new uint256[](rewardsTokens.length);
TokenAmount[] memory _interestAccrued = new TokenAmount[](rewardsTokens.length);

for (uint i=0; i< rewardsTokens.length; i++) {
_tokenBalances[i] = rewardsTokens[i].balanceOf(address(this));
_interestAccrued[i] = TokenAmount(rewardsTokens[i], _tokenBalances[i]);
}

uint256[] memory _bountyAmounts = new uint256[](rewardsTokens.length);
{ // block is to prevent 'stack too deep' compilation error.
TokenAmount[] memory _interestAccrued = new TokenAmount[](1);
_interestAccrued[0] = TokenAmount(rewardsToken, _tokenBalance);
_bountyAmount = revoBounty.calculateFeeBounty(_interestAccrued)[0].amount;
TokenAmount[] memory _feeBounties = revoBounty.calculateFeeBounty(_interestAccrued);
for (uint i=0; i < _feeBounties.length; i++) {
_bountyAmounts[i] = _feeBounties[i].amount;
require(_bountyAmounts[i] <= maxFeeNumerator * _tokenBalances[i] / maxFeeDenominator, "Bounty amount too high");
}
}
assert(_bountyAmount <= maxFeeNumerator * _tokenBalance / maxFeeDenominator);
uint256 _halfTokens = (_tokenBalance - _bountyAmount) / 2;

uint256 amountToken0 = swapForTokenInPool(path0, _halfTokens, rewardsToken, deadline);
uint256 amountToken1 = swapForTokenInPool(path1, _halfTokens, rewardsToken, deadline);
uint256 _totalAmountToken0 = 0;
uint256 _totalAmountToken1 = 0;
for (uint i=0; i < _bountyAmounts.length; i++) {
uint256 _halfTokens = (_tokenBalances[i] - _bountyAmounts[i]) / 2;
_totalAmountToken0 += swapForTokenInPool(paths[i][0], _halfTokens, rewardsTokens[i], deadline);
_totalAmountToken1 += swapForTokenInPool(paths[i][1], _halfTokens, rewardsTokens[i], deadline);
}

// Approve the router to spend the bot's token0/token1
stakingToken0.approve(address(router), amountToken0);
stakingToken1.approve(address(router), amountToken1);
stakingToken0.approve(address(router), _totalAmountToken0);
stakingToken1.approve(address(router), _totalAmountToken1);
// Actually add liquidity
router.addLiquidity(
address(stakingToken0),
address(stakingToken1),
amountToken0,
amountToken1,
amountToken0 * slippageNumerator / slippageDenominator,
amountToken1 * slippageNumerator / slippageDenominator,
_totalAmountToken0,
_totalAmountToken1,
_totalAmountToken0 * slippageNumerator / slippageDenominator,
_totalAmountToken1 * slippageNumerator / slippageDenominator,
address(this),
deadline
);


// How much LP we have to re-invest
uint256 lpBalance = stakingToken.balanceOf(address(this));
stakingToken.approve(address(stakingRewards), lpBalance);
Expand All @@ -208,7 +251,9 @@ contract FarmBot is Owned, FarmbotERC20 {
lpTotalBalance += lpBalance;

// Send bounty to caller
rewardsToken.transfer(msg.sender, _bountyAmount);
for (uint i=0; i < rewardsTokens.length; i++) {
rewardsTokens[i].transfer(msg.sender, _bountyAmounts[i]);
}
revoBounty.issueAdditionalBounty(msg.sender);
}
}

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