feat(PRT): Add Prt and PrtFeeSplitExtension (#176)

Add `Prt` and `PrtFeeSplitExtension`

Author: pblivin0x

contracts/adapters/FeeSplitExtension.sol

@@ -91,7 +91,7 @@ contract FeeSplitExtension is BaseExtension, TimeLockUpgrade, MutualUpgrade {
      * will automatically be sent to this address so reading the balance of the SetToken in the contract after accrual is
      * sufficient for accounting for all collected fees.
      */
-    function accrueFeesAndDistribute() public {
+    function accrueFeesAndDistribute() public virtual {
         // Emits a FeeActualized event
         streamingFeeModule.accrueFee(setToken);
 
@@ -260,6 +260,7 @@ contract FeeSplitExtension is BaseExtension, TimeLockUpgrade, MutualUpgrade {
      */
     function updateFeeSplit(uint256 _newFeeSplit)
         external
+        virtual
         mutualUpgrade(manager.operator(), manager.methodologist())
     {
         require(_newFeeSplit <= PreciseUnitMath.preciseUnit(), "Fee must be less than 100%");

contracts/adapters/PrtFeeSplitExtension.sol

@@ -0,0 +1,228 @@
+/*
+    Copyright 2024 Index Cooperative
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+    SPDX-License-Identifier: Apache License, Version 2.0
+*/
+
+pragma solidity 0.6.10;
+pragma experimental ABIEncoderV2;
+
+import { Address } from "@openzeppelin/contracts/utils/Address.sol";
+import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
+
+import { FeeSplitExtension } from "./FeeSplitExtension.sol";
+import { IBaseManager } from "../interfaces/IBaseManager.sol";
+import { IIssuanceModule } from "../interfaces/IIssuanceModule.sol";
+import { IPrt } from "../interfaces/IPrt.sol";
+import { IPrtStakingPool } from "../interfaces/IPrtStakingPool.sol";
+import { IStreamingFeeModule } from "../interfaces/IStreamingFeeModule.sol";
+import { PreciseUnitMath } from "../lib/PreciseUnitMath.sol";
+
+/**
+ * @title PrtFeeSplitExtension
+ * @dev Extension that allows for splitting and setting streaming and mint/redeem fees with a 
+ * PRT Staking Pool. The operator can accrue fees from the streaming fee module and distribute
+ * them to the operator and the PRT Staking Pool, snapshotting the PRT Staking Pool. The operator 
+ * can update the PRT staking pool address and the fee split between the operator and the 
+ * PRT staking pool. Includes an optional allow list and timelock on accrue function.
+ */
+contract PrtFeeSplitExtension is FeeSplitExtension {
+    using Address for address;
+    using PreciseUnitMath for uint256;
+    using SafeMath for uint256;
+
+    /* ============ Events ============ */
+
+    event AnyoneAccrueUpdated(bool isAnyoneAllowedToAccrue);
+    event AccruerStatusUpdated(address indexed accruer, bool isAccruerAllowed);
+    event OperatorFeeSplitUpdated(uint256 newFeeSplit);
+    event PrtFeesDistributed(
+        address indexed operatorFeeRecipient,
+        address indexed prtStakingPool,
+        uint256 operatorTake,
+        uint256 prtTake
+    );
+    event PrtStakingPoolUpdated(address newPrtStakingPool);
+
+    /* ============ Immutables ============ */
+
+    IPrt public immutable prt;
+
+    /* ============ State Variables ============ */
+
+    bool public isAnyoneAllowedToAccrue;
+    address[] accrueAllowList;
+    mapping(address => bool) public accrueAllowMap;
+    IPrtStakingPool public prtStakingPool;
+
+    /* ============ Modifiers ============ */
+
+    modifier onlyAllowedAccruer() {
+        require(_isAllowedAccruer(msg.sender), "Not allowed to accrue");
+        _;
+    }
+
+    /* ============ Constructor ============ */
+
+    constructor(
+        IBaseManager _manager,
+        IStreamingFeeModule _streamingFeeModule,
+        IIssuanceModule _issuanceModule,
+        uint256 _operatorFeeSplit,
+        address _operatorFeeRecipient,
+        IPrt _prt
+    )
+        public
+        FeeSplitExtension(
+            _manager,
+            _streamingFeeModule,
+            _issuanceModule,
+            _operatorFeeSplit,
+            _operatorFeeRecipient
+        )
+    {
+        require(_prt.setToken() == address(manager.setToken()), "SetToken mismatch with Prt");
+        prt = _prt;
+    }
+
+    /* ============ External Functions ============ */
+
+    /**
+     * @notice MUTUAL UPGRADE: Updates PRT staking pool. PRT staking pool must have this extension set as the feeSplitExtension.
+     * @param _prtStakingPool Address of the new PRT staking pool
+     */
+    function updatePrtStakingPool(IPrtStakingPool _prtStakingPool) 
+        external 
+        mutualUpgrade(manager.operator(), manager.methodologist()) 
+    {
+        require(address(_prtStakingPool) != address(0), "Zero address not valid");
+        require(_prtStakingPool.distributor() == address(this), "PRT Staking Pool distributor must be this extension");
+        require(_prtStakingPool.stakeToken() == address(prt), "PRT Staking Pool stake token must be PRT");
+        require(_prtStakingPool.rewardToken() == address(manager.setToken()), "PRT Staking Pool reward token must be SetToken");
+        prtStakingPool = _prtStakingPool;
+        emit PrtStakingPoolUpdated(address(_prtStakingPool));
+    }
+
+    /**
+     * @notice ONLY ALLOWED ACCRUER: Accrues fees from streaming fee module. Gets resulting balance after fee accrual, calculates fees for
+     * operator and PRT staking pool, and sends to operator fee recipient and PRT Staking Pool respectively. NOTE: mint/redeem fees
+     * will automatically be sent to this address so reading the balance of the SetToken in the contract after accrual is
+     * sufficient for accounting for all collected fees. If the PRT take is greater than 0, the PRT Staking Pool will accrue the fees
+     * and update the snapshot.
+     */
+    function accrueFeesAndDistribute() public override onlyAllowedAccruer {
+        require(address(prtStakingPool) != address(0), "PRT Staking Pool not set");
+
+        // Emits a FeeActualized event
+        streamingFeeModule.accrueFee(setToken);
+
+        uint256 totalFees = setToken.balanceOf(address(this));
+
+        uint256 operatorTake = totalFees.preciseMul(operatorFeeSplit);
+        uint256 prtTake = totalFees.sub(operatorTake);
+
+        if (operatorTake > 0) {
+            setToken.transfer(operatorFeeRecipient, operatorTake);
+        }
+
+        // Accrue PRT Staking Pool rewards and update snapshot
+        if (prtTake > 0) {
+            setToken.approve(address(prtStakingPool), prtTake);
+            prtStakingPool.accrue(prtTake);
+        }
+
+        emit PrtFeesDistributed(operatorFeeRecipient, address(prtStakingPool), operatorTake, prtTake);
+    }
+
+    /**
+     * @notice MUTUAL UPGRADE: Updates fee split between operator and PRT Staking Pool. Split defined in precise units (1% = 10^16).
+     * Does not accrue fees and snapshot PRT Staking Pool.
+     * @param _newFeeSplit Percent of fees in precise units (10^16 = 1%) sent to operator, (rest go to the PRT Staking Pool).
+     */
+    function updateFeeSplit(uint256 _newFeeSplit)
+        external
+        override
+        mutualUpgrade(manager.operator(), manager.methodologist())
+    {
+        require(_newFeeSplit <= PreciseUnitMath.preciseUnit(), "Fee must be less than 100%");
+        operatorFeeSplit = _newFeeSplit;
+        emit OperatorFeeSplitUpdated(_newFeeSplit);
+    }
+
+    /**
+     * @notice ONLY OPERATOR: Toggles the permission status of specified addresses to call the `accrueFeesAndDistribute()` function.
+     * @param _accruers An array of addresses whose accrue permission status is to be toggled.
+     * @param _statuses An array of booleans indicating the new accrue permission status for each corresponding address in `_accruers`.
+     */
+    function setAccruersStatus(
+        address[] memory _accruers,
+        bool[] memory _statuses
+    )
+        external
+        onlyOperator
+    {
+        _accruers.validatePairsWithArray(_statuses);
+        for (uint256 i = 0; i < _accruers.length; i++) {
+            _updateAccrueAllowList(_accruers[i], _statuses[i]);
+            accrueAllowMap[_accruers[i]] = _statuses[i];
+            emit AccruerStatusUpdated(_accruers[i], _statuses[i]);
+        }
+    }
+
+    /**
+     * @notice ONLY OPERATOR: Toggles whether or not anyone is allowed to call the `accrueFeesAndDistribute()` function.
+     * If set to true, it bypasses the accrueAllowList, allowing any address to call the `accrueFeesAndDistribute()` function.
+     * @param _status A boolean indicating if anyone can accrue.
+     */
+    function updateAnyoneAccrue(bool _status)
+        external
+        onlyOperator
+    {
+        isAnyoneAllowedToAccrue = _status;
+        emit AnyoneAccrueUpdated(_status);
+    }
+
+    /**
+     * @notice Determines whether the given address is permitted to `accrueFeesAndDistribute()`.
+     * @param _accruer Address of the accruer.
+     * @return bool True if the given `_accruer` is permitted to accrue, false otherwise.
+     */
+    function isAllowedAccruer(address _accruer) external view returns (bool) {
+        return _isAllowedAccruer(_accruer);
+    }
+
+    /**
+     * @dev Retrieves the list of addresses that are permitted to `accrueFeesAndDistribute()`.
+     * @return address[] Array of addresses representing the allowed accruers.
+     */
+    function getAllowedAccruers() external view returns (address[] memory) {
+        return accrueAllowList;
+    }
+
+
+    /* ============ Internal Functions ============ */
+
+    function _isAllowedAccruer(address _accruer) internal view returns (bool) {
+        return isAnyoneAllowedToAccrue || accrueAllowMap[_accruer];
+    }
+
+    function _updateAccrueAllowList(address _accruer, bool _status) internal {
+        if (_status && !accrueAllowList.contains(_accruer)) {
+            accrueAllowList.push(_accruer);
+        } else if(!_status && accrueAllowList.contains(_accruer)) {
+            accrueAllowList.removeStorage(_accruer);
+        }
+    }
+}

contracts/interfaces/IPrt.sol

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: Apache License, Version 2.0
+pragma solidity 0.6.10;
+
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+interface IPrt is IERC20 {
+    function setToken() external view returns (address);
+}

contracts/interfaces/IPrtStakingPool.sol

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: Apache License, Version 2.0
+pragma solidity ^0.6.10;
+
+interface IPrtStakingPool {
+    function accrue(uint256 _amount) external;
+    function distributor() external view returns (address);
+    function stakeToken() external view returns (address);
+    function rewardToken() external view returns (address);
+}

contracts/mocks/PrtStakingPoolMock.sol

@@ -0,0 +1,38 @@
+/*
+    Copyright 2024 Index Cooperative
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+    SPDX-License-Identifier: Apache License, Version 2.0
+*/
+
+pragma solidity ^0.6.10;
+pragma experimental ABIEncoderV2;
+
+import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+
+contract PrtStakingPoolMock {
+    IERC20 public immutable rewardToken;
+    IERC20 public immutable stakeToken;
+    address public distributor;
+
+    constructor(IERC20 _rewardToken, IERC20 _stakeToken, address _distributor) public {
+        rewardToken = _rewardToken;
+        stakeToken = _stakeToken;
+        distributor = _distributor;
+    }
+
+    function accrue(uint256 _amount) external {
+        rewardToken.transferFrom(msg.sender, address(this), _amount);
+    }
+}

contracts/token/Prt.sol

@@ -0,0 +1,53 @@
+/*
+    Copyright 2024 Index Cooperative
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+
+    SPDX-License-Identifier: Apache License, Version 2.0
+*/
+
+pragma solidity 0.6.10;
+
+import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+
+/**
+ * @title Prt
+ * @author Index Cooperative
+ * @notice Standard ERC20 token with a fixed supply allocated to a distributor. Associated with a SetToken.
+ */
+contract Prt is ERC20 {
+    /// @notice Address of the SetToken associated with this Prt token.
+    address public immutable setToken;
+    
+    /**
+     * @notice Constructor for the Prt token.
+     * @dev Mints the total supply of tokens and assigns them to the distributor.
+     * @param _name The name of the Prt token.
+     * @param _symbol The symbol of the Prt token.
+     * @param _setToken The address of the SetToken associated with this Prt token.
+     * @param _distributor The address that will receive and distribute the total supply of Prt tokens.
+     * @param _totalSupply The total supply of Prt tokens to be minted and distributed.
+     */
+    constructor(
+        string memory _name,
+        string memory _symbol,
+        address _setToken,
+        address _distributor,
+        uint256 _totalSupply
+    ) public
+        ERC20(_name, _symbol)
+    {
+        setToken = _setToken;
+        _mint(_distributor, _totalSupply);
+    }
+}