Contract Source Code:

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {DistributionTypes} from '../lib/DistributionTypes.sol';

/**
 * @title AaveDistributionManager
 * @notice Accounting contract to manage multiple staking distributions
 * @author Aave
 */
contract AaveDistributionManager {
  struct AssetData {
    uint128 emissionPerSecond;
    uint128 lastUpdateTimestamp;
    uint256 index;
    mapping(address => uint256) users;
  }

  uint256 public immutable DISTRIBUTION_END;

  address public immutable EMISSION_MANAGER;

  uint8 public constant PRECISION = 18;

  mapping(address => AssetData) public assets;

  event AssetConfigUpdated(address indexed asset, uint256 emission);
  event AssetIndexUpdated(address indexed asset, uint256 index);
  event UserIndexUpdated(
    address indexed user,
    address indexed asset,
    uint256 index
  );

  constructor(address emissionManager, uint256 distributionDuration) {
    DISTRIBUTION_END = block.timestamp + distributionDuration;
    EMISSION_MANAGER = emissionManager;
  }

  /**
   * @dev Configures the distribution of rewards for a list of assets
   * @param assetsConfigInput The list of configurations to apply
   */
  function _configureAssets(
    DistributionTypes.AssetConfigInput[] memory assetsConfigInput
  ) internal {
    for (uint256 i = 0; i < assetsConfigInput.length; i++) {
      AssetData storage assetConfig = assets[
        assetsConfigInput[i].underlyingAsset
      ];

      _updateAssetStateInternal(
        assetsConfigInput[i].underlyingAsset,
        assetConfig,
        assetsConfigInput[i].totalStaked
      );

      assetConfig.emissionPerSecond = assetsConfigInput[i].emissionPerSecond;

      emit AssetConfigUpdated(
        assetsConfigInput[i].underlyingAsset,
        assetsConfigInput[i].emissionPerSecond
      );
    }
  }

  /**
   * @dev Updates the state of one distribution, mainly rewards index and timestamp
   * @param underlyingAsset The address used as key in the distribution, for example sAAVE or the aTokens addresses on Aave
   * @param assetConfig Storage pointer to the distribution's config
   * @param totalStaked Current total of staked assets for this distribution
   * @return The new distribution index
   */
  function _updateAssetStateInternal(
    address underlyingAsset,
    AssetData storage assetConfig,
    uint256 totalStaked
  ) internal returns (uint256) {
    uint256 oldIndex = assetConfig.index;
    uint128 lastUpdateTimestamp = assetConfig.lastUpdateTimestamp;

    if (block.timestamp == lastUpdateTimestamp) {
      return oldIndex;
    }

    uint256 newIndex = _getAssetIndex(
      oldIndex,
      assetConfig.emissionPerSecond,
      lastUpdateTimestamp,
      totalStaked
    );

    if (newIndex != oldIndex) {
      assetConfig.index = newIndex;
      emit AssetIndexUpdated(underlyingAsset, newIndex);
    }

    assetConfig.lastUpdateTimestamp = uint128(block.timestamp);

    return newIndex;
  }

  /**
   * @dev Updates the state of an user in a distribution
   * @param user The user's address
   * @param asset The address of the reference asset of the distribution
   * @param stakedByUser Amount of tokens staked by the user in the distribution at the moment
   * @param totalStaked Total tokens staked in the distribution
   * @return The accrued rewards for the user until the moment
   */
  function _updateUserAssetInternal(
    address user,
    address asset,
    uint256 stakedByUser,
    uint256 totalStaked
  ) internal returns (uint256) {
    AssetData storage assetData = assets[asset];
    uint256 userIndex = assetData.users[user];
    uint256 accruedRewards = 0;

    uint256 newIndex = _updateAssetStateInternal(asset, assetData, totalStaked);

    if (userIndex != newIndex) {
      if (stakedByUser != 0) {
        accruedRewards = _getRewards(stakedByUser, newIndex, userIndex);
      }

      assetData.users[user] = newIndex;
      emit UserIndexUpdated(user, asset, newIndex);
    }

    return accruedRewards;
  }

  /**
   * @dev Used by "frontend" stake contracts to update the data of an user when claiming rewards from there
   * @param user The address of the user
   * @param stakes List of structs of the user data related with his stake
   * @return The accrued rewards for the user until the moment
   */
  function _claimRewards(
    address user,
    DistributionTypes.UserStakeInput[] memory stakes
  ) internal returns (uint256) {
    uint256 accruedRewards = 0;

    for (uint256 i = 0; i < stakes.length; i++) {
      accruedRewards =
        accruedRewards +
        _updateUserAssetInternal(
          user,
          stakes[i].underlyingAsset,
          stakes[i].stakedByUser,
          stakes[i].totalStaked
        );
    }

    return accruedRewards;
  }

  /**
   * @dev Return the accrued rewards for an user over a list of distribution
   * @param user The address of the user
   * @param stakes List of structs of the user data related with his stake
   * @return The accrued rewards for the user until the moment
   */
  function _getUnclaimedRewards(
    address user,
    DistributionTypes.UserStakeInput[] memory stakes
  ) internal view returns (uint256) {
    uint256 accruedRewards = 0;

    for (uint256 i = 0; i < stakes.length; i++) {
      AssetData storage assetConfig = assets[stakes[i].underlyingAsset];
      uint256 assetIndex = _getAssetIndex(
        assetConfig.index,
        assetConfig.emissionPerSecond,
        assetConfig.lastUpdateTimestamp,
        stakes[i].totalStaked
      );

      accruedRewards =
        accruedRewards +
        _getRewards(
          stakes[i].stakedByUser,
          assetIndex,
          assetConfig.users[user]
        );
    }
    return accruedRewards;
  }

  /**
   * @dev Internal function for the calculation of user's rewards on a distribution
   * @param principalUserBalance Amount staked by the user on a distribution
   * @param reserveIndex Current index of the distribution
   * @param userIndex Index stored for the user, representation his staking moment
   * @return The rewards
   */
  function _getRewards(
    uint256 principalUserBalance,
    uint256 reserveIndex,
    uint256 userIndex
  ) internal pure returns (uint256) {
    return
      (principalUserBalance * (reserveIndex - userIndex)) /
      (10**uint256(PRECISION));
  }

  /**
   * @dev Calculates the next value of an specific distribution index, with validations
   * @param currentIndex Current index of the distribution
   * @param emissionPerSecond Representing the total rewards distributed per second per asset unit, on the distribution
   * @param lastUpdateTimestamp Last moment this distribution was updated
   * @param totalBalance of tokens considered for the distribution
   * @return The new index.
   */
  function _getAssetIndex(
    uint256 currentIndex,
    uint256 emissionPerSecond,
    uint128 lastUpdateTimestamp,
    uint256 totalBalance
  ) internal view returns (uint256) {
    if (
      emissionPerSecond == 0 ||
      totalBalance == 0 ||
      lastUpdateTimestamp == block.timestamp ||
      lastUpdateTimestamp >= DISTRIBUTION_END
    ) {
      return currentIndex;
    }

    uint256 currentTimestamp = block.timestamp > DISTRIBUTION_END
      ? DISTRIBUTION_END
      : block.timestamp;
    uint256 timeDelta = currentTimestamp - lastUpdateTimestamp;
    return
      ((emissionPerSecond * timeDelta * (10**uint256(PRECISION))) /
        totalBalance) + currentIndex;
  }

  /**
   * @dev Returns the data of an user on a distribution
   * @param user Address of the user
   * @param asset The address of the reference asset of the distribution
   * @return The new index
   */
  function getUserAssetData(address user, address asset)
    public
    view
    returns (uint256)
  {
    return assets[asset].users[user];
  }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {IERC20} from '../interfaces/IERC20.sol';
import {DistributionTypes} from '../lib/DistributionTypes.sol';
import {GovernancePowerDelegationERC20} from '../lib/GovernancePowerDelegationERC20.sol';
import {StakedTokenV3} from './StakedTokenV3.sol';
import {IGhoVariableDebtTokenTransferHook} from '../interfaces/IGhoVariableDebtTokenTransferHook.sol';
import {SafeCast} from '../lib/SafeCast.sol';
import {IStakedAaveV3} from '../interfaces/IStakedAaveV3.sol';
import {IERC20WithPermit} from '../interfaces/IERC20WithPermit.sol';

/**
 * @title StakedAaveV3
 * @notice StakedTokenV3 with AAVE token as staked token
 * @author BGD Labs
 */
contract StakedAaveV3 is StakedTokenV3, IStakedAaveV3 {
  using SafeCast for uint256;

  uint32 internal _exchangeRateSnapshotsCount;
  /// @notice Snapshots of the exchangeRate for a given block
  mapping(uint256 => ExchangeRateSnapshot) internal _exchangeRateSnapshots;

  /// @notice GHO debt token to be used in the _beforeTokenTransfer hook
  IGhoVariableDebtTokenTransferHook public ghoDebtToken;

  function REVISION() public pure virtual override returns (uint256) {
    return 5;
  }

  constructor(
    IERC20 stakedToken,
    IERC20 rewardToken,
    uint256 unstakeWindow,
    address rewardsVault,
    address emissionManager,
    uint128 distributionDuration
  )
    StakedTokenV3(
      stakedToken,
      rewardToken,
      unstakeWindow,
      rewardsVault,
      emissionManager,
      distributionDuration
    )
  {
    // brick initialize
    lastInitializedRevision = REVISION();
  }

  /**
   * @dev Called by the proxy contract
   */
  function initialize(
    address slashingAdmin,
    address cooldownPauseAdmin,
    address claimHelper,
    uint256 maxSlashablePercentage,
    uint256 cooldownSeconds
  ) external override initializer {
    _initialize(
      slashingAdmin,
      cooldownPauseAdmin,
      claimHelper,
      maxSlashablePercentage,
      cooldownSeconds
    );

    // needed to claimRewardsAndStake works without a custom approval each time
    STAKED_TOKEN.approve(address(this), type(uint256).max);
  }

  /// @inheritdoc IStakedAaveV3
  function setGHODebtToken(IGhoVariableDebtTokenTransferHook newGHODebtToken)
    external
  {
    require(msg.sender == 0xEE56e2B3D491590B5b31738cC34d5232F378a8D5); // Short executor
    ghoDebtToken = newGHODebtToken;
    emit GHODebtTokenChanged(address(newGHODebtToken));
  }

  /// @inheritdoc IStakedAaveV3
  function claimRewardsAndStake(address to, uint256 amount)
    external
    override
    returns (uint256)
  {
    return _claimRewardsAndStakeOnBehalf(msg.sender, to, amount);
  }

  /// @inheritdoc IStakedAaveV3
  function claimRewardsAndStakeOnBehalf(
    address from,
    address to,
    uint256 amount
  ) external override onlyClaimHelper returns (uint256) {
    return _claimRewardsAndStakeOnBehalf(from, to, amount);
  }

  /// @inheritdoc IStakedAaveV3
  function stakeWithPermit(
    address from,
    uint256 amount,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external override {
    IERC20WithPermit(address(STAKED_TOKEN)).permit(
      from,
      address(this),
      amount,
      deadline,
      v,
      r,
      s
    );
    _stake(from, from, amount);
  }

  /// @inheritdoc IStakedAaveV3
  function getExchangeRateSnapshotsCount() external view returns (uint32) {
    return _exchangeRateSnapshotsCount;
  }

  /// @inheritdoc IStakedAaveV3
  function getExchangeRateSnapshot(uint32 index)
    external
    view
    returns (ExchangeRateSnapshot memory)
  {
    return _exchangeRateSnapshots[index];
  }

  /**
   * @dev Writes a snapshot before any operation involving transfer of value: _transfer, _mint and _burn
   * - On _transfer, it writes snapshots for both "from" and "to"
   * - On _mint, only for _to
   * - On _burn, only for _from
   * @param from the from address
   * @param to the to address
   * @param amount the amount to transfer
   */
  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 amount
  ) internal override {
    IGhoVariableDebtTokenTransferHook cachedGhoDebtToken = ghoDebtToken;
    if (address(cachedGhoDebtToken) != address(0)) {
      try
        cachedGhoDebtToken.updateDiscountDistribution(
          from,
          to,
          balanceOf(from),
          balanceOf(to),
          amount
        )
      {} catch (bytes memory) {}
    }
    address votingFromDelegatee = _votingDelegates[from];
    address votingToDelegatee = _votingDelegates[to];

    if (votingFromDelegatee == address(0)) {
      votingFromDelegatee = from;
    }
    if (votingToDelegatee == address(0)) {
      votingToDelegatee = to;
    }

    _moveDelegatesByType(
      votingFromDelegatee,
      votingToDelegatee,
      amount,
      DelegationType.VOTING_POWER
    );

    address propPowerFromDelegatee = _propositionPowerDelegates[from];
    address propPowerToDelegatee = _propositionPowerDelegates[to];

    if (propPowerFromDelegatee == address(0)) {
      propPowerFromDelegatee = from;
    }
    if (propPowerToDelegatee == address(0)) {
      propPowerToDelegatee = to;
    }

    _moveDelegatesByType(
      propPowerFromDelegatee,
      propPowerToDelegatee,
      amount,
      DelegationType.PROPOSITION_POWER
    );
  }

  /// @dev Modified version accounting for exchange rate at block
  /// @inheritdoc GovernancePowerDelegationERC20
  function _searchByBlockNumber(
    mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
    mapping(address => uint256) storage snapshotsCounts,
    address user,
    uint256 blockNumber
  ) internal view override returns (uint256) {
    return
      (super._searchByBlockNumber(
        snapshots,
        snapshotsCounts,
        user,
        blockNumber
      ) * EXCHANGE_RATE_UNIT) /
      _binarySearchExchangeRate(
        _exchangeRateSnapshots,
        _exchangeRateSnapshotsCount,
        blockNumber
      );
  }

  /**
   * @dev Updates the exchangeRate and emits events accordingly
   * @param newExchangeRate the new exchange rate
   */
  function _updateExchangeRate(uint216 newExchangeRate) internal override {
    _exchangeRateSnapshots[_exchangeRateSnapshotsCount] = ExchangeRateSnapshot(
      block.number.toUint40(),
      newExchangeRate
    );
    ++_exchangeRateSnapshotsCount;
    super._updateExchangeRate(newExchangeRate);
  }

  function _binarySearchExchangeRate(
    mapping(uint256 => ExchangeRateSnapshot) storage snapshots,
    uint256 snapshotsCount,
    uint256 blockNumber
  ) internal view returns (uint256) {
    unchecked {
      // First check most recent balance
      if (snapshots[snapshotsCount - 1].blockNumber <= blockNumber) {
        return snapshots[snapshotsCount - 1].value;
      }

      uint256 lower = 0;
      uint256 upper = snapshotsCount - 1;
      while (upper > lower) {
        uint256 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
        ExchangeRateSnapshot memory snapshot = snapshots[center];
        if (snapshot.blockNumber == blockNumber) {
          return snapshot.value;
        } else if (snapshot.blockNumber < blockNumber) {
          lower = center;
        } else {
          upper = center - 1;
        }
      }
      return snapshots[lower].value;
    }
  }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {IERC20} from '../interfaces/IERC20.sol';
import {IStakedTokenV2} from '../interfaces/IStakedTokenV2.sol';

import {ERC20} from '../lib/ERC20.sol';
import {DistributionTypes} from '../lib/DistributionTypes.sol';
import {SafeERC20} from '../lib/SafeERC20.sol';

import {VersionedInitializable} from '../utils/VersionedInitializable.sol';
import {AaveDistributionManager} from './AaveDistributionManager.sol';
import {GovernancePowerWithSnapshot} from '../lib/GovernancePowerWithSnapshot.sol';

/**
 * @title StakedTokenV2
 * @notice Contract to stake Aave token, tokenize the position and get rewards, inheriting from a distribution manager contract
 * @author BGD Labs
 */
abstract contract StakedTokenV2 is
  IStakedTokenV2,
  GovernancePowerWithSnapshot,
  VersionedInitializable,
  AaveDistributionManager
{
  using SafeERC20 for IERC20;

  IERC20 public immutable STAKED_TOKEN;
  IERC20 public immutable REWARD_TOKEN;

  /// @notice Seconds available to redeem once the cooldown period is fulfilled
  uint256 public immutable UNSTAKE_WINDOW;

  /// @notice Address to pull from the rewards, needs to have approved this contract
  address public immutable REWARDS_VAULT;

  mapping(address => uint256) public stakerRewardsToClaim;
  mapping(address => CooldownSnapshot) public stakersCooldowns;

  /// @dev End of Storage layout from StakedToken v1

  /// @dev To see the voting mappings, go to GovernancePowerWithSnapshot.sol
  mapping(address => address) internal _votingDelegates;

  mapping(address => mapping(uint256 => Snapshot))
    internal _propositionPowerSnapshots;
  mapping(address => uint256) internal _propositionPowerSnapshotsCounts;
  mapping(address => address) internal _propositionPowerDelegates;

  bytes32 public DOMAIN_SEPARATOR;
  bytes public constant EIP712_REVISION = bytes('1');
  bytes32 internal constant EIP712_DOMAIN =
    keccak256(
      'EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'
    );
  bytes32 public constant PERMIT_TYPEHASH =
    keccak256(
      'Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)'
    );

  /// @dev owner => next valid nonce to submit with permit()
  mapping(address => uint256) public _nonces;

  constructor(
    IERC20 stakedToken,
    IERC20 rewardToken,
    uint256 unstakeWindow,
    address rewardsVault,
    address emissionManager,
    uint128 distributionDuration
  ) ERC20() AaveDistributionManager(emissionManager, distributionDuration) {
    STAKED_TOKEN = stakedToken;
    REWARD_TOKEN = rewardToken;
    UNSTAKE_WINDOW = unstakeWindow;
    REWARDS_VAULT = rewardsVault;
  }

  /// @inheritdoc IStakedTokenV2
  function stake(address onBehalfOf, uint256 amount) external virtual override;

  /// @inheritdoc IStakedTokenV2
  function redeem(address to, uint256 amount) external virtual override;

  /// @inheritdoc IStakedTokenV2
  function cooldown() external virtual override;

  /// @inheritdoc IStakedTokenV2
  function claimRewards(address to, uint256 amount) external virtual override;

  /// @inheritdoc IStakedTokenV2
  function getTotalRewardsBalance(address staker)
    external
    view
    returns (uint256)
  {
    DistributionTypes.UserStakeInput[]
      memory userStakeInputs = new DistributionTypes.UserStakeInput[](1);
    userStakeInputs[0] = DistributionTypes.UserStakeInput({
      underlyingAsset: address(this),
      stakedByUser: balanceOf(staker),
      totalStaked: totalSupply()
    });
    return
      stakerRewardsToClaim[staker] +
      _getUnclaimedRewards(staker, userStakeInputs);
  }

  /// @inheritdoc IStakedTokenV2
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external {
    require(owner != address(0), 'INVALID_OWNER');
    //solium-disable-next-line
    require(block.timestamp <= deadline, 'INVALID_EXPIRATION');
    uint256 currentValidNonce = _nonces[owner];
    bytes32 digest = keccak256(
      abi.encodePacked(
        '\x19\x01',
        DOMAIN_SEPARATOR,
        keccak256(
          abi.encode(
            PERMIT_TYPEHASH,
            owner,
            spender,
            value,
            currentValidNonce,
            deadline
          )
        )
      )
    );

    require(owner == ecrecover(digest, v, r, s), 'INVALID_SIGNATURE');
    unchecked {
      _nonces[owner] = currentValidNonce + 1;
    }
    _approve(owner, spender, value);
  }

  /**
   * @dev Delegates power from signatory to `delegatee`
   * @param delegatee The address to delegate votes to
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   * @param nonce The contract state required to match the signature
   * @param expiry The time at which to expire the signature
   * @param v The recovery byte of the signature
   * @param r Half of the ECDSA signature pair
   * @param s Half of the ECDSA signature pair
   */
  function delegateByTypeBySig(
    address delegatee,
    DelegationType delegationType,
    uint256 nonce,
    uint256 expiry,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) public {
    bytes32 structHash = keccak256(
      abi.encode(
        DELEGATE_BY_TYPE_TYPEHASH,
        delegatee,
        uint256(delegationType),
        nonce,
        expiry
      )
    );
    bytes32 digest = keccak256(
      abi.encodePacked('\x19\x01', DOMAIN_SEPARATOR, structHash)
    );
    address signatory = ecrecover(digest, v, r, s);
    require(signatory != address(0), 'INVALID_SIGNATURE');
    require(nonce == _nonces[signatory]++, 'INVALID_NONCE');
    require(block.timestamp <= expiry, 'INVALID_EXPIRATION');
    _delegateByType(signatory, delegatee, delegationType);
  }

  /**
   * @dev Delegates power from signatory to `delegatee`
   * @param delegatee The address to delegate votes to
   * @param nonce The contract state required to match the signature
   * @param expiry The time at which to expire the signature
   * @param v The recovery byte of the signature
   * @param r Half of the ECDSA signature pair
   * @param s Half of the ECDSA signature pair
   */
  function delegateBySig(
    address delegatee,
    uint256 nonce,
    uint256 expiry,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) public {
    bytes32 structHash = keccak256(
      abi.encode(DELEGATE_TYPEHASH, delegatee, nonce, expiry)
    );
    bytes32 digest = keccak256(
      abi.encodePacked('\x19\x01', DOMAIN_SEPARATOR, structHash)
    );
    address signatory = ecrecover(digest, v, r, s);
    require(signatory != address(0), 'INVALID_SIGNATURE');
    require(nonce == _nonces[signatory]++, 'INVALID_NONCE');
    require(block.timestamp <= expiry, 'INVALID_EXPIRATION');
    _delegateByType(signatory, delegatee, DelegationType.VOTING_POWER);
    _delegateByType(signatory, delegatee, DelegationType.PROPOSITION_POWER);
  }

  /**
   * @dev Updates the user state related with his accrued rewards
   * @param user Address of the user
   * @param userBalance The current balance of the user
   * @param updateStorage Boolean flag used to update or not the stakerRewardsToClaim of the user
   * @return The unclaimed rewards that were added to the total accrued
   */
  function _updateCurrentUnclaimedRewards(
    address user,
    uint256 userBalance,
    bool updateStorage
  ) internal returns (uint256) {
    uint256 accruedRewards = _updateUserAssetInternal(
      user,
      address(this),
      userBalance,
      totalSupply()
    );
    uint256 unclaimedRewards = stakerRewardsToClaim[user] + accruedRewards;

    if (accruedRewards != 0) {
      if (updateStorage) {
        stakerRewardsToClaim[user] = unclaimedRewards;
      }
      emit RewardsAccrued(user, accruedRewards);
    }

    return unclaimedRewards;
  }

  /**
   * @dev returns relevant storage slots for a DelegationType
   * @param delegationType the requested DelegationType
   * @return the relevant storage
   */
  function _getDelegationDataByType(DelegationType delegationType)
    internal
    view
    override
    returns (
      mapping(address => mapping(uint256 => Snapshot)) storage, //snapshots
      mapping(address => uint256) storage, //snapshots count
      mapping(address => address) storage //delegatees list
    )
  {
    if (delegationType == DelegationType.VOTING_POWER) {
      return (_votingSnapshots, _votingSnapshotsCounts, _votingDelegates);
    } else {
      return (
        _propositionPowerSnapshots,
        _propositionPowerSnapshotsCounts,
        _propositionPowerDelegates
      );
    }
  }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {IERC20} from '../interfaces/IERC20.sol';
import {DistributionTypes} from '../lib/DistributionTypes.sol';
import {SafeERC20} from '../lib/SafeERC20.sol';
import {IAaveDistributionManager} from '../interfaces/IAaveDistributionManager.sol';
import {IERC20Metadata} from '../interfaces/IERC20Metadata.sol';
import {IStakedTokenV2} from '../interfaces/IStakedTokenV2.sol';
import {StakedTokenV2} from './StakedTokenV2.sol';
import {IStakedTokenV3} from '../interfaces/IStakedTokenV3.sol';
import {PercentageMath} from '../lib/PercentageMath.sol';
import {RoleManager} from '../utils/RoleManager.sol';
import {SafeCast} from '../lib/SafeCast.sol';

/**
 * @title StakedTokenV3
 * @notice Contract to stake Aave token, tokenize the position and get rewards, inheriting from a distribution manager contract
 * @author BGD Labs
 */
contract StakedTokenV3 is
  StakedTokenV2,
  IStakedTokenV3,
  RoleManager,
  IAaveDistributionManager
{
  using SafeERC20 for IERC20;
  using PercentageMath for uint256;
  using SafeCast for uint256;

  uint256 public constant SLASH_ADMIN_ROLE = 0;
  uint256 public constant COOLDOWN_ADMIN_ROLE = 1;
  uint256 public constant CLAIM_HELPER_ROLE = 2;
  uint216 public constant INITIAL_EXCHANGE_RATE = 1e18;
  uint256 public constant EXCHANGE_RATE_UNIT = 1e18;

  /// @notice lower bound to prevent spam & avoid exchangeRate issues
  // as returnFunds can be called permissionless an attacker could spam returnFunds(1) to produce exchangeRate snapshots making voting expensive
  uint256 public immutable LOWER_BOUND;

  // Reserved storage space to allow for layout changes in the future.
  uint256[8] private ______gap;
  /// @notice Seconds between starting cooldown and being able to withdraw
  uint256 internal _cooldownSeconds;
  /// @notice The maximum amount of funds that can be slashed at any given time
  uint256 internal _maxSlashablePercentage;
  /// @notice Mirror of latest snapshot value for cheaper access
  uint216 internal _currentExchangeRate;
  /// @notice Flag determining if there's an ongoing slashing event that needs to be settled
  bool public inPostSlashingPeriod;

  modifier onlySlashingAdmin() {
    require(
      msg.sender == getAdmin(SLASH_ADMIN_ROLE),
      'CALLER_NOT_SLASHING_ADMIN'
    );
    _;
  }

  modifier onlyCooldownAdmin() {
    require(
      msg.sender == getAdmin(COOLDOWN_ADMIN_ROLE),
      'CALLER_NOT_COOLDOWN_ADMIN'
    );
    _;
  }

  modifier onlyClaimHelper() {
    require(
      msg.sender == getAdmin(CLAIM_HELPER_ROLE),
      'CALLER_NOT_CLAIM_HELPER'
    );
    _;
  }

  constructor(
    IERC20 stakedToken,
    IERC20 rewardToken,
    uint256 unstakeWindow,
    address rewardsVault,
    address emissionManager,
    uint128 distributionDuration
  )
    StakedTokenV2(
      stakedToken,
      rewardToken,
      unstakeWindow,
      rewardsVault,
      emissionManager,
      distributionDuration
    )
  {
    // brick initialize
    lastInitializedRevision = REVISION();
    uint256 decimals = IERC20Metadata(address(stakedToken)).decimals();
    LOWER_BOUND = 10**decimals;
  }

  /**
   * @dev returns the revision of the implementation contract
   * @return The revision
   */
  function REVISION() public pure virtual returns (uint256) {
    return 3;
  }

  /**
   * @dev returns the revision of the implementation contract
   * @return The revision
   */
  function getRevision() internal pure virtual override returns (uint256) {
    return REVISION();
  }

  /**
   * @dev Called by the proxy contract
   */
  function initialize(
    address slashingAdmin,
    address cooldownPauseAdmin,
    address claimHelper,
    uint256 maxSlashablePercentage,
    uint256 cooldownSeconds
  ) external virtual initializer {
    _initialize(
      slashingAdmin,
      cooldownPauseAdmin,
      claimHelper,
      maxSlashablePercentage,
      cooldownSeconds
    );
  }

  function _initialize(
    address slashingAdmin,
    address cooldownPauseAdmin,
    address claimHelper,
    uint256 maxSlashablePercentage,
    uint256 cooldownSeconds
  ) internal {
    InitAdmin[] memory initAdmins = new InitAdmin[](3);
    initAdmins[0] = InitAdmin(SLASH_ADMIN_ROLE, slashingAdmin);
    initAdmins[1] = InitAdmin(COOLDOWN_ADMIN_ROLE, cooldownPauseAdmin);
    initAdmins[2] = InitAdmin(CLAIM_HELPER_ROLE, claimHelper);

    _initAdmins(initAdmins);

    _setMaxSlashablePercentage(maxSlashablePercentage);
    _setCooldownSeconds(cooldownSeconds);
    _updateExchangeRate(INITIAL_EXCHANGE_RATE);
  }

  /// @inheritdoc IAaveDistributionManager
  function configureAssets(
    DistributionTypes.AssetConfigInput[] memory assetsConfigInput
  ) external override {
    require(msg.sender == EMISSION_MANAGER, 'ONLY_EMISSION_MANAGER');

    for (uint256 i = 0; i < assetsConfigInput.length; i++) {
      assetsConfigInput[i].totalStaked = totalSupply();
    }

    _configureAssets(assetsConfigInput);
  }

  /// @inheritdoc IStakedTokenV3
  function previewStake(uint256 assets) public view returns (uint256) {
    return (assets * _currentExchangeRate) / EXCHANGE_RATE_UNIT;
  }

  /// @inheritdoc IStakedTokenV2
  function stake(address to, uint256 amount)
    external
    override(IStakedTokenV2, StakedTokenV2)
  {
    _stake(msg.sender, to, amount);
  }

  /// @inheritdoc IStakedTokenV2
  function cooldown() external override(IStakedTokenV2, StakedTokenV2) {
    _cooldown(msg.sender);
  }

  /// @inheritdoc IStakedTokenV3
  function cooldownOnBehalfOf(address from) external override onlyClaimHelper {
    _cooldown(from);
  }

  function _cooldown(address from) internal {
    uint256 amount = balanceOf(from);
    require(amount != 0, 'INVALID_BALANCE_ON_COOLDOWN');
    stakersCooldowns[from] = CooldownSnapshot({
      timestamp: uint40(block.timestamp),
      amount: uint216(amount)
    });

    emit Cooldown(from, amount);
  }

  /// @inheritdoc IStakedTokenV2
  function redeem(address to, uint256 amount)
    external
    override(IStakedTokenV2, StakedTokenV2)
  {
    _redeem(msg.sender, to, amount);
  }

  /// @inheritdoc IStakedTokenV3
  function redeemOnBehalf(
    address from,
    address to,
    uint256 amount
  ) external override onlyClaimHelper {
    _redeem(from, to, amount);
  }

  /// @inheritdoc IStakedTokenV2
  function claimRewards(address to, uint256 amount)
    external
    override(IStakedTokenV2, StakedTokenV2)
  {
    _claimRewards(msg.sender, to, amount);
  }

  /// @inheritdoc IStakedTokenV3
  function claimRewardsOnBehalf(
    address from,
    address to,
    uint256 amount
  ) external override onlyClaimHelper returns (uint256) {
    return _claimRewards(from, to, amount);
  }

  /// @inheritdoc IStakedTokenV3
  function claimRewardsAndRedeem(
    address to,
    uint256 claimAmount,
    uint256 redeemAmount
  ) external override {
    _claimRewards(msg.sender, to, claimAmount);
    _redeem(msg.sender, to, redeemAmount);
  }

  /// @inheritdoc IStakedTokenV3
  function claimRewardsAndRedeemOnBehalf(
    address from,
    address to,
    uint256 claimAmount,
    uint256 redeemAmount
  ) external override onlyClaimHelper {
    _claimRewards(from, to, claimAmount);
    _redeem(from, to, redeemAmount);
  }

  /// @inheritdoc IStakedTokenV3
  function getExchangeRate() public view override returns (uint216) {
    return _currentExchangeRate;
  }

  /// @inheritdoc IStakedTokenV3
  function previewRedeem(uint256 shares)
    public
    view
    override
    returns (uint256)
  {
    return (EXCHANGE_RATE_UNIT * shares) / _currentExchangeRate;
  }

  /// @inheritdoc IStakedTokenV3
  function slash(address destination, uint256 amount)
    external
    override
    onlySlashingAdmin
    returns (uint256)
  {
    require(!inPostSlashingPeriod, 'PREVIOUS_SLASHING_NOT_SETTLED');
    require(amount > 0, 'ZERO_AMOUNT');
    uint256 currentShares = totalSupply();
    uint256 balance = previewRedeem(currentShares);

    uint256 maxSlashable = balance.percentMul(_maxSlashablePercentage);

    if (amount > maxSlashable) {
      amount = maxSlashable;
    }
    require(balance - amount >= LOWER_BOUND, 'REMAINING_LT_MINIMUM');

    inPostSlashingPeriod = true;
    _updateExchangeRate(_getExchangeRate(balance - amount, currentShares));

    STAKED_TOKEN.safeTransfer(destination, amount);

    emit Slashed(destination, amount);
    return amount;
  }

  /// @inheritdoc IStakedTokenV3
  function returnFunds(uint256 amount) external override {
    require(amount >= LOWER_BOUND, 'AMOUNT_LT_MINIMUM');
    uint256 currentShares = totalSupply();
    require(currentShares >= LOWER_BOUND, 'SHARES_LT_MINIMUM');
    uint256 assets = previewRedeem(currentShares);
    _updateExchangeRate(_getExchangeRate(assets + amount, currentShares));

    STAKED_TOKEN.safeTransferFrom(msg.sender, address(this), amount);
    emit FundsReturned(amount);
  }

  /// @inheritdoc IStakedTokenV3
  function settleSlashing() external override onlySlashingAdmin {
    inPostSlashingPeriod = false;
    emit SlashingSettled();
  }

  /// @inheritdoc IStakedTokenV3
  function setMaxSlashablePercentage(uint256 percentage)
    external
    override
    onlySlashingAdmin
  {
    _setMaxSlashablePercentage(percentage);
  }

  /// @inheritdoc IStakedTokenV3
  function getMaxSlashablePercentage()
    external
    view
    override
    returns (uint256)
  {
    return _maxSlashablePercentage;
  }

  /// @inheritdoc IStakedTokenV3
  function setCooldownSeconds(uint256 cooldownSeconds)
    external
    onlyCooldownAdmin
  {
    _setCooldownSeconds(cooldownSeconds);
  }

  /// @inheritdoc IStakedTokenV3
  function getCooldownSeconds() external view returns (uint256) {
    return _cooldownSeconds;
  }

  /// @inheritdoc IStakedTokenV3
  function COOLDOWN_SECONDS() external view returns (uint256) {
    return _cooldownSeconds;
  }

  /**
   * @dev sets the max slashable percentage
   * @param percentage must be strictly lower 100% as otherwise the exchange rate calculation would result in 0 division
   */
  function _setMaxSlashablePercentage(uint256 percentage) internal {
    require(
      percentage < PercentageMath.PERCENTAGE_FACTOR,
      'INVALID_SLASHING_PERCENTAGE'
    );

    _maxSlashablePercentage = percentage;
    emit MaxSlashablePercentageChanged(percentage);
  }

  /**
   * @dev sets the cooldown seconds
   * @param cooldownSeconds the new amount of cooldown seconds
   */
  function _setCooldownSeconds(uint256 cooldownSeconds) internal {
    _cooldownSeconds = cooldownSeconds;
    emit CooldownSecondsChanged(cooldownSeconds);
  }

  /**
   * @dev claims the rewards for a specified address to a specified address
   * @param from The address of the from from which to claim
   * @param to Address to receive the rewards
   * @param amount Amount to claim
   * @return amount claimed
   */
  function _claimRewards(
    address from,
    address to,
    uint256 amount
  ) internal returns (uint256) {
    require(amount != 0, 'INVALID_ZERO_AMOUNT');
    uint256 newTotalRewards = _updateCurrentUnclaimedRewards(
      from,
      balanceOf(from),
      false
    );

    uint256 amountToClaim = (amount > newTotalRewards)
      ? newTotalRewards
      : amount;
    require(amountToClaim != 0, 'INVALID_ZERO_AMOUNT');

    stakerRewardsToClaim[from] = newTotalRewards - amountToClaim;
    REWARD_TOKEN.safeTransferFrom(REWARDS_VAULT, to, amountToClaim);
    emit RewardsClaimed(from, to, amountToClaim);
    return amountToClaim;
  }

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` and stakes.
   * @param from The address of the from from which to claim
   * @param to Address to stake to
   * @param amount Amount to claim
   * @return amount claimed
   */
  function _claimRewardsAndStakeOnBehalf(
    address from,
    address to,
    uint256 amount
  ) internal returns (uint256) {
    require(REWARD_TOKEN == STAKED_TOKEN, 'REWARD_TOKEN_IS_NOT_STAKED_TOKEN');

    uint256 userUpdatedRewards = _updateCurrentUnclaimedRewards(
      from,
      balanceOf(from),
      true
    );
    uint256 amountToClaim = (amount > userUpdatedRewards)
      ? userUpdatedRewards
      : amount;

    if (amountToClaim != 0) {
      _claimRewards(from, address(this), amountToClaim);
      _stake(address(this), to, amountToClaim);
    }

    return amountToClaim;
  }

  /**
   * @dev Allows staking a specified amount of STAKED_TOKEN
   * @param to The address to receiving the shares
   * @param amount The amount of assets to be staked
   */
  function _stake(
    address from,
    address to,
    uint256 amount
  ) internal {
    require(!inPostSlashingPeriod, 'SLASHING_ONGOING');
    require(amount != 0, 'INVALID_ZERO_AMOUNT');

    uint256 balanceOfTo = balanceOf(to);

    uint256 accruedRewards = _updateUserAssetInternal(
      to,
      address(this),
      balanceOfTo,
      totalSupply()
    );

    if (accruedRewards != 0) {
      stakerRewardsToClaim[to] = stakerRewardsToClaim[to] + accruedRewards;
      emit RewardsAccrued(to, accruedRewards);
    }

    uint256 sharesToMint = previewStake(amount);

    STAKED_TOKEN.safeTransferFrom(from, address(this), amount);

    _mint(to, sharesToMint);

    emit Staked(from, to, amount, sharesToMint);
  }

  /**
   * @dev Redeems staked tokens, and stop earning rewards
   * @param from Address to redeem from
   * @param to Address to redeem to
   * @param amount Amount to redeem
   */
  function _redeem(
    address from,
    address to,
    uint256 amount
  ) internal {
    require(amount != 0, 'INVALID_ZERO_AMOUNT');

    CooldownSnapshot memory cooldownSnapshot = stakersCooldowns[from];
    if (!inPostSlashingPeriod) {
      require(
        (block.timestamp > cooldownSnapshot.timestamp + _cooldownSeconds),
        'INSUFFICIENT_COOLDOWN'
      );
      require(
        (block.timestamp - (cooldownSnapshot.timestamp + _cooldownSeconds) <=
          UNSTAKE_WINDOW),
        'UNSTAKE_WINDOW_FINISHED'
      );
    }

    uint256 balanceOfFrom = balanceOf(from);
    uint256 maxRedeemable = inPostSlashingPeriod
      ? balanceOfFrom
      : cooldownSnapshot.amount;
    require(maxRedeemable != 0, 'INVALID_ZERO_MAX_REDEEMABLE');

    uint256 amountToRedeem = (amount > maxRedeemable) ? maxRedeemable : amount;

    _updateCurrentUnclaimedRewards(from, balanceOfFrom, true);

    uint256 underlyingToRedeem = previewRedeem(amountToRedeem);

    _burn(from, amountToRedeem);

    if (cooldownSnapshot.timestamp != 0) {
      if (cooldownSnapshot.amount - amountToRedeem == 0) {
        delete stakersCooldowns[from];
      } else {
        stakersCooldowns[from].amount =
          stakersCooldowns[from].amount -
          amountToRedeem.toUint184();
      }
    }

    IERC20(STAKED_TOKEN).safeTransfer(to, underlyingToRedeem);

    emit Redeem(from, to, underlyingToRedeem, amountToRedeem);
  }

  /**
   * @dev Updates the exchangeRate and emits events accordingly
   * @param newExchangeRate the new exchange rate
   */
  function _updateExchangeRate(uint216 newExchangeRate) internal virtual {
    require(newExchangeRate != 0, 'ZERO_EXCHANGE_RATE');
    _currentExchangeRate = newExchangeRate;
    emit ExchangeRateChanged(newExchangeRate);
  }

  /**
   * @dev calculates the exchange rate based on totalAssets and totalShares
   * @dev always rounds up to ensure 100% backing of shares by rounding in favor of the contract
   * @param totalAssets The total amount of assets staked
   * @param totalShares The total amount of shares
   * @return exchangeRate as 18 decimal precision uint216
   */
  function _getExchangeRate(uint256 totalAssets, uint256 totalShares)
    internal
    pure
    returns (uint216)
  {
    return
      (((totalShares * EXCHANGE_RATE_UNIT) + totalAssets - 1) / totalAssets)
        .toUint216();
  }

  function _transfer(
    address from,
    address to,
    uint256 amount
  ) internal override {
    uint256 balanceOfFrom = balanceOf(from);
    // Sender
    _updateCurrentUnclaimedRewards(from, balanceOfFrom, true);

    // Recipient
    if (from != to) {
      uint256 balanceOfTo = balanceOf(to);
      _updateCurrentUnclaimedRewards(to, balanceOfTo, true);

      CooldownSnapshot memory previousSenderCooldown = stakersCooldowns[from];
      if (previousSenderCooldown.timestamp != 0) {
        // if cooldown was set and whole balance of sender was transferred - clear cooldown
        if (balanceOfFrom == amount) {
          delete stakersCooldowns[from];
        } else if (balanceOfFrom - amount < previousSenderCooldown.amount) {
          stakersCooldowns[from].amount = uint184(balanceOfFrom - amount);
        }
      }
    }

    super._transfer(from, to, amount);
  }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {DistributionTypes} from '../lib/DistributionTypes.sol';

interface IAaveDistributionManager {
  function configureAssets(
    DistributionTypes.AssetConfigInput[] memory assetsConfigInput
  ) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
  /**
   * @dev Emitted when `value` tokens are moved from one account (`from`) to
   * another (`to`).
   *
   * Note that `value` may be zero.
   */
  event Transfer(address indexed from, address indexed to, uint256 value);

  /**
   * @dev Emitted when the allowance of a `spender` for an `owner` is set by
   * a call to {approve}. `value` is the new allowance.
   */
  event Approval(address indexed owner, address indexed spender, uint256 value);

  /**
   * @dev Returns the amount of tokens in existence.
   */
  function totalSupply() external view returns (uint256);

  /**
   * @dev Returns the amount of tokens owned by `account`.
   */
  function balanceOf(address account) external view returns (uint256);

  /**
   * @dev Moves `amount` tokens from the caller's account to `to`.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a {Transfer} event.
   */
  function transfer(address to, uint256 amount) external returns (bool);

  /**
   * @dev Returns the remaining number of tokens that `spender` will be
   * allowed to spend on behalf of `owner` through {transferFrom}. This is
   * zero by default.
   *
   * This value changes when {approve} or {transferFrom} are called.
   */
  function allowance(address owner, address spender)
    external
    view
    returns (uint256);

  /**
   * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * IMPORTANT: Beware that changing an allowance with this method brings the risk
   * that someone may use both the old and the new allowance by unfortunate
   * transaction ordering. One possible solution to mitigate this race
   * condition is to first reduce the spender's allowance to 0 and set the
   * desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   *
   * Emits an {Approval} event.
   */
  function approve(address spender, uint256 amount) external returns (bool);

  /**
   * @dev Moves `amount` tokens from `from` to `to` using the
   * allowance mechanism. `amount` is then deducted from the caller's
   * allowance.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a {Transfer} event.
   */
  function transferFrom(
    address from,
    address to,
    uint256 amount
  ) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import './IERC20.sol';

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
  /**
   * @dev Returns the name of the token.
   */
  function name() external view returns (string memory);

  /**
   * @dev Returns the symbol of the token.
   */
  function symbol() external view returns (string memory);

  /**
   * @dev Returns the decimals places of the token.
   */
  function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {IERC20} from './IERC20.sol';

interface IERC20WithPermit is IERC20 {
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

interface IGhoVariableDebtTokenTransferHook {
  /**
   * @dev updates the discount when discount token is transferred
   * @dev Only callable by discount token
   * @param sender address of sender
   * @param recipient address of recipient
   * @param senderDiscountTokenBalance sender discount token balance
   * @param recipientDiscountTokenBalance recipient discount token balance
   * @param amount amount of discount token being transferred
   **/
  function updateDiscountDistribution(
    address sender,
    address recipient,
    uint256 senderDiscountTokenBalance,
    uint256 recipientDiscountTokenBalance,
    uint256 amount
  ) external;
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

interface IGovernancePowerDelegationToken {
  enum DelegationType {
    VOTING_POWER,
    PROPOSITION_POWER
  }

  /**
   * @dev emitted when a user delegates to another
   * @param delegator the delegator
   * @param delegatee the delegatee
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   **/
  event DelegateChanged(
    address indexed delegator,
    address indexed delegatee,
    DelegationType delegationType
  );

  /**
   * @dev emitted when an action changes the delegated power of a user
   * @param user the user which delegated power has changed
   * @param amount the amount of delegated power for the user
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   **/
  event DelegatedPowerChanged(
    address indexed user,
    uint256 amount,
    DelegationType delegationType
  );

  /**
   * @dev delegates the specific power to a delegatee
   * @param delegatee the user which delegated power has changed
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   **/
  function delegateByType(address delegatee, DelegationType delegationType)
    external;

  /**
   * @dev delegates all the powers to a specific user
   * @param delegatee the user to which the power will be delegated
   **/
  function delegate(address delegatee) external;

  /**
   * @dev returns the delegatee of an user
   * @param delegator the address of the delegator
   **/
  function getDelegateeByType(address delegator, DelegationType delegationType)
    external
    view
    returns (address);

  /**
   * @dev returns the current delegated power of a user. The current power is the
   * power delegated at the time of the last snapshot
   * @param user the user
   **/
  function getPowerCurrent(address user, DelegationType delegationType)
    external
    view
    returns (uint256);

  /**
   * @dev returns the delegated power of a user at a certain block
   * @param user the user
   **/
  function getPowerAtBlock(
    address user,
    uint256 blockNumber,
    DelegationType delegationType
  ) external view returns (uint256);

  /**
   * @dev returns the total supply at a certain block number
   **/
  function totalSupplyAt(uint256 blockNumber) external view returns (uint256);
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {IStakedTokenV3} from './IStakedTokenV3.sol';
import {IGhoVariableDebtTokenTransferHook} from './IGhoVariableDebtTokenTransferHook.sol';

interface IStakedAaveV3 is IStakedTokenV3 {
  struct ExchangeRateSnapshot {
    uint40 blockNumber;
    uint216 value;
  }

  event GHODebtTokenChanged(address indexed newDebtToken);

  /**
   * @dev Returnes the number of excahngeRate snapshots
   */
  function getExchangeRateSnapshotsCount() external view returns (uint32);

  /**
   * @dev Returns the exchangeRate for a specified index
   * @param index Index of the exchangeRate
   */
  function getExchangeRateSnapshot(uint32 index)
    external
    view
    returns (ExchangeRateSnapshot memory);

  /**
   * @dev Sets the GHO debt token (only callable by SHORT_EXECUTOR)
   * @param newGHODebtToken Address to GHO debt token
   */
  function setGHODebtToken(IGhoVariableDebtTokenTransferHook newGHODebtToken)
    external;

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` and stakes.
   * @param to Address to stake to
   * @param amount Amount to claim
   */
  function claimRewardsAndStake(address to, uint256 amount)
    external
    returns (uint256);

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` and stakes. Only the claim helper contract is allowed to call this function
   * @param from The address of the from from which to claim
   * @param to Address to stake to
   * @param amount Amount to claim
   */
  function claimRewardsAndStakeOnBehalf(
    address from,
    address to,
    uint256 amount
  ) external returns (uint256);

  /**
   * @dev Allows staking a certain amount of STAKED_TOKEN with gasless approvals (permit)
   * @param from The address staking the token
   * @param amount The amount to be staked
   * @param deadline The permit execution deadline
   * @param v The v component of the signed message
   * @param r The r component of the signed message
   * @param s The s component of the signed message
   */
  function stakeWithPermit(
    address from,
    uint256 amount,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

interface IStakedTokenV2 {
  struct CooldownSnapshot {
    uint40 timestamp;
    uint216 amount;
  }

  event RewardsAccrued(address user, uint256 amount);
  event RewardsClaimed(
    address indexed from,
    address indexed to,
    uint256 amount
  );
  event Cooldown(address indexed user, uint256 amount);

  /**
   * @dev Allows staking a specified amount of STAKED_TOKEN
   * @param to The address to receiving the shares
   * @param amount The amount of assets to be staked
   */
  function stake(address to, uint256 amount) external;

  /**
   * @dev Redeems shares, and stop earning rewards
   * @param to Address to redeem to
   * @param amount Amount of shares to redeem
   */
  function redeem(address to, uint256 amount) external;

  /**
   * @dev Activates the cooldown period to unstake
   * - It can't be called if the user is not staking
   */
  function cooldown() external;

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` to the address `to`
   * @param to Address to send the claimed rewards
   * @param amount Amount to stake
   */
  function claimRewards(address to, uint256 amount) external;

  /**
   * @dev Return the total rewards pending to claim by an staker
   * @param staker The staker address
   * @return The rewards
   */
  function getTotalRewardsBalance(address staker)
    external
    view
    returns (uint256);

  /**
   * @dev implements the permit function as for https://github.com/ethereum/EIPs/blob/8a34d644aacf0f9f8f00815307fd7dd5da07655f/EIPS/eip-2612.md
   * @param owner the owner of the funds
   * @param spender the spender
   * @param value the amount
   * @param deadline the deadline timestamp, type(uint256).max for no deadline
   * @param v signature param
   * @param s signature param
   * @param r signature param
   */
  function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {IStakedTokenV2} from './IStakedTokenV2.sol';

interface IStakedTokenV3 is IStakedTokenV2 {
  event Staked(
    address indexed from,
    address indexed to,
    uint256 assets,
    uint256 shares
  );
  event Redeem(
    address indexed from,
    address indexed to,
    uint256 assets,
    uint256 shares
  );
  event MaxSlashablePercentageChanged(uint256 newPercentage);
  event Slashed(address indexed destination, uint256 amount);
  event SlashingExitWindowDurationChanged(uint256 windowSeconds);
  event CooldownSecondsChanged(uint256 cooldownSeconds);
  event ExchangeRateChanged(uint216 exchangeRate);
  event FundsReturned(uint256 amount);
  event SlashingSettled();

  /**
   * @dev Returns the current exchange rate
   * @return exchangeRate as 18 decimal precision uint216
   */
  function getExchangeRate() external view returns (uint216);

  /**
   * @dev Executes a slashing of the underlying of a certain amount, transferring the seized funds
   * to destination. Decreasing the amount of underlying will automatically adjust the exchange rate.
   * A call to `slash` will start a slashing event which has to be settled via `settleSlashing`.
   * As long as the slashing event is ongoing, stake and slash are deactivated.
   * - MUST NOT be called when a previous slashing is still ongoing
   * @param destination the address where seized funds will be transferred
   * @param amount the amount to be slashed
   * - if the amount bigger than maximum allowed, the maximum will be slashed instead.
   * @return amount the amount slashed
   */
  function slash(address destination, uint256 amount)
    external
    returns (uint256);

  /**
   * @dev Settles an ongoing slashing event
   */
  function settleSlashing() external;

  /**
   * @dev Pulls STAKE_TOKEN and distributes them amongst current stakers by altering the exchange rate.
   * This method is permissionless and intended to be used after a slashing event to return potential excess funds.
   * @param amount amount of STAKE_TOKEN to pull.
   */
  function returnFunds(uint256 amount) external;

  /**
   * @dev Getter of the cooldown seconds
   * @return cooldownSeconds the amount of seconds between starting the cooldown and being able to redeem
   */
  function getCooldownSeconds() external view returns (uint256);

  /**
   * @dev Getter of the cooldown seconds
   * @return cooldownSeconds the amount of seconds between starting the cooldown and being able to redeem
   */
  function COOLDOWN_SECONDS() external view returns (uint256); // @deprecated

  /**
   * @dev Setter of cooldown seconds
   * Can only be called by the cooldown admin
   * @param cooldownSeconds the new amount of seconds you have to wait between starting the cooldown and being able to redeem
   */
  function setCooldownSeconds(uint256 cooldownSeconds) external;

  /**
   * @dev Getter of the max slashable percentage of the total staked amount.
   * @return percentage the maximum slashable percentage
   */
  function getMaxSlashablePercentage() external view returns (uint256);

  /**
   * @dev Setter of max slashable percentage of the total staked amount.
   * Can only be called by the slashing admin
   * @param percentage the new maximum slashable percentage
   */
  function setMaxSlashablePercentage(uint256 percentage) external;

  /**
   * @dev returns the exact amount of shares that would be received for the provided number of assets
   * @param assets the number of assets to stake
   * @return uint256 shares the number of shares that would be received
   */
  function previewStake(uint256 assets) external view returns (uint256);

  /**
   * @dev Activates the cooldown period to unstake
   * - It can't be called if the user is not staking
   */
  function cooldownOnBehalfOf(address from) external;

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` to the address `to` on behalf of the user. Only the claim helper contract is allowed to call this function
   * @param from The address of the user from to claim
   * @param to Address to send the claimed rewards
   * @param amount Amount to claim
   */
  function claimRewardsOnBehalf(
    address from,
    address to,
    uint256 amount
  ) external returns (uint256);

  /**
   * @dev returns the exact amount of assets that would be redeemed for the provided number of shares
   * @param shares the number of shares to redeem
   * @return uint256 assets the number of assets that would be redeemed
   */
  function previewRedeem(uint256 shares) external view returns (uint256);

  /**
   * @dev Redeems shares for a user. Only the claim helper contract is allowed to call this function
   * @param from Address to redeem from
   * @param to Address to redeem to
   * @param amount Amount of shares to redeem
   */
  function redeemOnBehalf(
    address from,
    address to,
    uint256 amount
  ) external;

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` and redeems to the provided address
   * @param to Address to claim and redeem to
   * @param claimAmount Amount to claim
   * @param redeemAmount Amount to redeem
   */
  function claimRewardsAndRedeem(
    address to,
    uint256 claimAmount,
    uint256 redeemAmount
  ) external;

  /**
   * @dev Claims an `amount` of `REWARD_TOKEN` and redeems the `redeemAmount` to an address. Only the claim helper contract is allowed to call this function
   * @param from The address of the from
   * @param to Address to claim and redeem to
   * @param claimAmount Amount to claim
   * @param redeemAmount Amount to redeem
   */
  function claimRewardsAndRedeemOnBehalf(
    address from,
    address to,
    uint256 claimAmount,
    uint256 redeemAmount
  ) external;
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

interface ITransferHook {
  function onTransfer(
    address from,
    address to,
    uint256 amount
  ) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;
pragma experimental ABIEncoderV2;

library DistributionTypes {
    struct AssetConfigInput {
        uint128 emissionPerSecond;
        uint256 totalStaked;
        address underlyingAsset;
    }

    struct UserStakeInput {
        address underlyingAsset;
        uint256 stakedByUser;
        uint256 totalStaked;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "../interfaces/IERC20.sol";
import "../interfaces/IERC20Metadata.sol";
import "./Context.sol";
/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) internal _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 internal _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals; // @deprecated
    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor() {}

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {ERC20} from './ERC20.sol';
import {
  IGovernancePowerDelegationToken
} from '../interfaces/IGovernancePowerDelegationToken.sol';

/**
 * @notice implementation of the AAVE token contract
 * @author Aave
 */
abstract contract GovernancePowerDelegationERC20 is ERC20, IGovernancePowerDelegationToken {
  /// @notice The EIP-712 typehash for the delegation struct used by the contract
  bytes32 public constant DELEGATE_BY_TYPE_TYPEHASH = keccak256(
    'DelegateByType(address delegatee,uint256 type,uint256 nonce,uint256 expiry)'
  );

  bytes32 public constant DELEGATE_TYPEHASH = keccak256(
    'Delegate(address delegatee,uint256 nonce,uint256 expiry)'
  );

  /// @dev snapshot of a value on a specific block, used for votes
  struct Snapshot {
    uint128 blockNumber;
    uint128 value;
  }

  /**
   * @dev delegates one specific power to a delegatee
   * @param delegatee the user which delegated power has changed
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   **/
  function delegateByType(address delegatee, DelegationType delegationType) external override {
    _delegateByType(msg.sender, delegatee, delegationType);
  }

  /**
   * @dev delegates all the powers to a specific user
   * @param delegatee the user to which the power will be delegated
   **/
  function delegate(address delegatee) external override {
    _delegateByType(msg.sender, delegatee, DelegationType.VOTING_POWER);
    _delegateByType(msg.sender, delegatee, DelegationType.PROPOSITION_POWER);
  }

  /**
   * @dev returns the delegatee of an user
   * @param delegator the address of the delegator
   **/
  function getDelegateeByType(address delegator, DelegationType delegationType)
    external
    override
    view
    returns (address)
  {
    (, , mapping(address => address) storage delegates) = _getDelegationDataByType(delegationType);

    return _getDelegatee(delegator, delegates);
  }

  /**
   * @dev returns the current delegated power of a user. The current power is the
   * power delegated at the time of the last snapshot
   * @param user the user
   **/
  function getPowerCurrent(address user, DelegationType delegationType)
    external
    override
    view
    returns (uint256)
  {
    (
      mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
      mapping(address => uint256) storage snapshotsCounts,

    ) = _getDelegationDataByType(delegationType);

    return _searchByBlockNumber(snapshots, snapshotsCounts, user, block.number);
  }

  /**
   * @dev returns the delegated power of a user at a certain block
   * @param user the user
   **/
  function getPowerAtBlock(
    address user,
    uint256 blockNumber,
    DelegationType delegationType
  ) external override view returns (uint256) {
    (
      mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
      mapping(address => uint256) storage snapshotsCounts,

    ) = _getDelegationDataByType(delegationType);

    return _searchByBlockNumber(snapshots, snapshotsCounts, user, blockNumber);
  }

  /**
   * @dev returns the total supply at a certain block number
   * used by the voting strategy contracts to calculate the total votes needed for threshold/quorum
   * In this initial implementation with no AAVE minting, simply returns the current supply
   * A snapshots mapping will need to be added in case a mint function is added to the AAVE token in the future
   **/
  function totalSupplyAt(uint256) external override view returns (uint256) {
    return super.totalSupply();
  }

  /**
   * @dev delegates the specific power to a delegatee
   * @param delegatee the user which delegated power has changed
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   **/
  function _delegateByType(
    address delegator,
    address delegatee,
    DelegationType delegationType
  ) internal {
    require(delegatee != address(0), 'INVALID_DELEGATEE');

    (, , mapping(address => address) storage delegates) = _getDelegationDataByType(delegationType);

    uint256 delegatorBalance = balanceOf(delegator);

    address previousDelegatee = _getDelegatee(delegator, delegates);

    delegates[delegator] = delegatee;

    _moveDelegatesByType(previousDelegatee, delegatee, delegatorBalance, delegationType);
    emit DelegateChanged(delegator, delegatee, delegationType);
  }

  /**
   * @dev moves delegated power from one user to another
   * @param from the user from which delegated power is moved
   * @param to the user that will receive the delegated power
   * @param amount the amount of delegated power to be moved
   * @param delegationType the type of delegation (VOTING_POWER, PROPOSITION_POWER)
   **/
  function _moveDelegatesByType(
    address from,
    address to,
    uint256 amount,
    DelegationType delegationType
  ) internal {
    if (from == to) {
      return;
    }

    (
      mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
      mapping(address => uint256) storage snapshotsCounts,

    ) = _getDelegationDataByType(delegationType);

    if (from != address(0)) {
      uint256 previous = 0;
      uint256 fromSnapshotsCount = snapshotsCounts[from];

      if (fromSnapshotsCount != 0) {
        previous = snapshots[from][fromSnapshotsCount - 1].value;
      } else {
        previous = balanceOf(from);
      }

      _writeSnapshot(
        snapshots,
        snapshotsCounts,
        from,
        uint128(previous),
        uint128(previous - amount)
      );

      emit DelegatedPowerChanged(from, previous - amount, delegationType);
    }
    if (to != address(0)) {
      uint256 previous = 0;
      uint256 toSnapshotsCount = snapshotsCounts[to];
      if (toSnapshotsCount != 0) {
        previous = snapshots[to][toSnapshotsCount - 1].value;
      } else {
        previous = balanceOf(to);
      }

      _writeSnapshot(
        snapshots,
        snapshotsCounts,
        to,
        uint128(previous),
        uint128(previous + amount)
      );

      emit DelegatedPowerChanged(to, previous + amount, delegationType);
    }
  }

  /**
   * @dev searches a snapshot by block number. Uses binary search.
   * @param snapshots the snapshots mapping
   * @param snapshotsCounts the number of snapshots
   * @param user the user for which the snapshot is being searched
   * @param blockNumber the block number being searched
   **/
  function _searchByBlockNumber(
    mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
    mapping(address => uint256) storage snapshotsCounts,
    address user,
    uint256 blockNumber
  ) internal virtual view returns (uint256) {
    require(blockNumber <= block.number, 'INVALID_BLOCK_NUMBER');

    uint256 snapshotsCount = snapshotsCounts[user];

    if (snapshotsCount == 0) {
      return balanceOf(user);
    }

    // Check implicit zero balance
    if (snapshots[user][0].blockNumber > blockNumber) {
      return 0;
    }

    return _binarySearch(snapshots[user], snapshotsCount, blockNumber);
  }

  function _binarySearch(mapping(uint256 => Snapshot) storage snapshots, uint256 snapshotsCount, uint256 blockNumber) internal view returns (uint256) {
    unchecked {
      // First check most recent balance
      if (snapshots[snapshotsCount - 1].blockNumber <= blockNumber) {
        return snapshots[snapshotsCount - 1].value;
      }

      uint256 lower = 0;
      uint256 upper = snapshotsCount - 1;
      while (upper > lower) {
        uint256 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
        Snapshot memory snapshot = snapshots[center];
        if (snapshot.blockNumber == blockNumber) {
          return snapshot.value;
        } else if (snapshot.blockNumber < blockNumber) {
          lower = center;
        } else {
          upper = center - 1;
        }
      }
      return snapshots[lower].value;
    }
  }

  /**
   * @dev returns the delegation data (snapshot, snapshotsCount, list of delegates) by delegation type
   * NOTE: Ideal implementation would have mapped this in a struct by delegation type. Unfortunately,
   * the AAVE token and StakeToken already include a mapping for the snapshots, so we require contracts
   * who inherit from this to provide access to the delegation data by overriding this method.
   * @param delegationType the type of delegation
   **/
  function _getDelegationDataByType(DelegationType delegationType)
    internal
    virtual
    view
    returns (
      mapping(address => mapping(uint256 => Snapshot)) storage, //snapshots
      mapping(address => uint256) storage, //snapshots count
      mapping(address => address) storage //delegatees list
    );

  /**
   * @dev Writes a snapshot for an owner of tokens
   * @param owner The owner of the tokens
   * @param oldValue The value before the operation that is gonna be executed after the snapshot
   * @param newValue The value after the operation
   */
  function _writeSnapshot(
    mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
    mapping(address => uint256) storage snapshotsCounts,
    address owner,
    uint128 oldValue,
    uint128 newValue
  ) internal {
    uint128 currentBlock = uint128(block.number);

    uint256 ownerSnapshotsCount = snapshotsCounts[owner];
    mapping(uint256 => Snapshot) storage snapshotsOwner = snapshots[owner];

    // Doing multiple operations in the same block
    if (
      ownerSnapshotsCount != 0 &&
      snapshotsOwner[ownerSnapshotsCount - 1].blockNumber == currentBlock
    ) {
      snapshotsOwner[ownerSnapshotsCount - 1].value = newValue;
    } else {
      snapshotsOwner[ownerSnapshotsCount] = Snapshot(currentBlock, newValue);
      snapshotsCounts[owner] = ownerSnapshotsCount + 1;
    }
  }

  /**
   * @dev returns the user delegatee. If a user never performed any delegation,
   * his delegated address will be 0x0. In that case we simply return the user itself
   * @param delegator the address of the user for which return the delegatee
   * @param delegates the array of delegates for a particular type of delegation
   **/
  function _getDelegatee(address delegator, mapping(address => address) storage delegates)
    internal
    view
    returns (address)
  {
    address previousDelegatee = delegates[delegator];

    if (previousDelegatee == address(0)) {
      return delegator;
    }

    return previousDelegatee;
  }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

import {ERC20} from '../lib/ERC20.sol';
import {ITransferHook} from '../interfaces/ITransferHook.sol';
import {
  GovernancePowerDelegationERC20
} from './GovernancePowerDelegationERC20.sol';

/**
 * @title ERC20WithSnapshot
 * @notice ERC20 including snapshots of balances on transfer-related actions
 * @author Aave
 **/
abstract contract GovernancePowerWithSnapshot is GovernancePowerDelegationERC20 {
  /**
   * @dev The following storage layout points to the prior StakedToken.sol implementation:
   * _snapshots => _votingSnapshots
   * _snapshotsCounts =>  _votingSnapshotsCounts
   * _aaveGovernance => _aaveGovernance
   */
  mapping(address => mapping(uint256 => Snapshot)) public _votingSnapshots;
  mapping(address => uint256) public _votingSnapshotsCounts;

  /// @dev reference to the Aave governance contract to call (if initialized) on _beforeTokenTransfer
  /// !!! IMPORTANT The Aave governance is considered a trustable contract, being its responsibility
  /// to control all potential reentrancies by calling back the this contract
  /// @dev DEPRECATED
  ITransferHook public _aaveGovernance;
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

/**
 * @title PercentageMath library
 * @author Aave
 * @notice Provides functions to perform percentage calculations
 * @dev Percentages are defined by default with 2 decimals of precision (100.00). The precision is indicated by PERCENTAGE_FACTOR
 * @dev Operations are rounded half up
 **/

library PercentageMath {
    uint256 constant PERCENTAGE_FACTOR = 1e4; //percentage plus two decimals
    uint256 constant HALF_PERCENT = PERCENTAGE_FACTOR / 2;

    /**
     * @dev Executes a percentage multiplication
     * @param value The value of which the percentage needs to be calculated
     * @param percentage The percentage of the value to be calculated
     * @return The percentage of value
     **/
    function percentMul(uint256 value, uint256 percentage)
        internal
        pure
        returns (uint256)
    {
        if (value == 0 || percentage == 0) {
            return 0;
        }

        require(
            value <= (type(uint256).max) / percentage,
            "MATH_MULTIPLICATION_OVERFLOW"
        );

        return (value * percentage) / PERCENTAGE_FACTOR;
    }

    /**
     * @dev Executes a percentage division
     * @param value The value of which the percentage needs to be calculated
     * @param percentage The percentage of the value to be calculated
     * @return The value divided the percentage
     **/
    function percentDiv(uint256 value, uint256 percentage)
        internal
        pure
        returns (uint256)
    {
        require(percentage != 0, "MATH_DIVISION_BY_ZERO");

        require(
            value <= type(uint256).max / PERCENTAGE_FACTOR,
            "MATH_MULTIPLICATION_OVERFLOW"
        );

        return (value * PERCENTAGE_FACTOR) / percentage;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SafeCast.sol)
// This file was procedurally generated from scripts/generate/templates/SafeCast.js.

pragma solidity ^0.8.0;

/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such an operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {
    /**
     * @dev Returns the downcasted uint248 from uint256, reverting on
     * overflow (when the input is greater than largest uint248).
     *
     * Counterpart to Solidity's `uint248` operator.
     *
     * Requirements:
     *
     * - input must fit into 248 bits
     *
     * _Available since v4.7._
     */
    function toUint248(uint256 value) internal pure returns (uint248) {
        require(value <= type(uint248).max, "SafeCast: value doesn't fit in 248 bits");
        return uint248(value);
    }

    /**
     * @dev Returns the downcasted uint240 from uint256, reverting on
     * overflow (when the input is greater than largest uint240).
     *
     * Counterpart to Solidity's `uint240` operator.
     *
     * Requirements:
     *
     * - input must fit into 240 bits
     *
     * _Available since v4.7._
     */
    function toUint240(uint256 value) internal pure returns (uint240) {
        require(value <= type(uint240).max, "SafeCast: value doesn't fit in 240 bits");
        return uint240(value);
    }

    /**
     * @dev Returns the downcasted uint232 from uint256, reverting on
     * overflow (when the input is greater than largest uint232).
     *
     * Counterpart to Solidity's `uint232` operator.
     *
     * Requirements:
     *
     * - input must fit into 232 bits
     *
     * _Available since v4.7._
     */
    function toUint232(uint256 value) internal pure returns (uint232) {
        require(value <= type(uint232).max, "SafeCast: value doesn't fit in 232 bits");
        return uint232(value);
    }

    /**
     * @dev Returns the downcasted uint224 from uint256, reverting on
     * overflow (when the input is greater than largest uint224).
     *
     * Counterpart to Solidity's `uint224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     *
     * _Available since v4.2._
     */
    function toUint224(uint256 value) internal pure returns (uint224) {
        require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
        return uint224(value);
    }

    /**
     * @dev Returns the downcasted uint216 from uint256, reverting on
     * overflow (when the input is greater than largest uint216).
     *
     * Counterpart to Solidity's `uint216` operator.
     *
     * Requirements:
     *
     * - input must fit into 216 bits
     *
     * _Available since v4.7._
     */
    function toUint216(uint256 value) internal pure returns (uint216) {
        require(value <= type(uint216).max, "SafeCast: value doesn't fit in 216 bits");
        return uint216(value);
    }

    /**
     * @dev Returns the downcasted uint208 from uint256, reverting on
     * overflow (when the input is greater than largest uint208).
     *
     * Counterpart to Solidity's `uint208` operator.
     *
     * Requirements:
     *
     * - input must fit into 208 bits
     *
     * _Available since v4.7._
     */
    function toUint208(uint256 value) internal pure returns (uint208) {
        require(value <= type(uint208).max, "SafeCast: value doesn't fit in 208 bits");
        return uint208(value);
    }

    /**
     * @dev Returns the downcasted uint200 from uint256, reverting on
     * overflow (when the input is greater than largest uint200).
     *
     * Counterpart to Solidity's `uint200` operator.
     *
     * Requirements:
     *
     * - input must fit into 200 bits
     *
     * _Available since v4.7._
     */
    function toUint200(uint256 value) internal pure returns (uint200) {
        require(value <= type(uint200).max, "SafeCast: value doesn't fit in 200 bits");
        return uint200(value);
    }

    /**
     * @dev Returns the downcasted uint192 from uint256, reverting on
     * overflow (when the input is greater than largest uint192).
     *
     * Counterpart to Solidity's `uint192` operator.
     *
     * Requirements:
     *
     * - input must fit into 192 bits
     *
     * _Available since v4.7._
     */
    function toUint192(uint256 value) internal pure returns (uint192) {
        require(value <= type(uint192).max, "SafeCast: value doesn't fit in 192 bits");
        return uint192(value);
    }

    /**
     * @dev Returns the downcasted uint184 from uint256, reverting on
     * overflow (when the input is greater than largest uint184).
     *
     * Counterpart to Solidity's `uint184` operator.
     *
     * Requirements:
     *
     * - input must fit into 184 bits
     *
     * _Available since v4.7._
     */
    function toUint184(uint256 value) internal pure returns (uint184) {
        require(value <= type(uint184).max, "SafeCast: value doesn't fit in 184 bits");
        return uint184(value);
    }

    /**
     * @dev Returns the downcasted uint176 from uint256, reverting on
     * overflow (when the input is greater than largest uint176).
     *
     * Counterpart to Solidity's `uint176` operator.
     *
     * Requirements:
     *
     * - input must fit into 176 bits
     *
     * _Available since v4.7._
     */
    function toUint176(uint256 value) internal pure returns (uint176) {
        require(value <= type(uint176).max, "SafeCast: value doesn't fit in 176 bits");
        return uint176(value);
    }

    /**
     * @dev Returns the downcasted uint168 from uint256, reverting on
     * overflow (when the input is greater than largest uint168).
     *
     * Counterpart to Solidity's `uint168` operator.
     *
     * Requirements:
     *
     * - input must fit into 168 bits
     *
     * _Available since v4.7._
     */
    function toUint168(uint256 value) internal pure returns (uint168) {
        require(value <= type(uint168).max, "SafeCast: value doesn't fit in 168 bits");
        return uint168(value);
    }

    /**
     * @dev Returns the downcasted uint160 from uint256, reverting on
     * overflow (when the input is greater than largest uint160).
     *
     * Counterpart to Solidity's `uint160` operator.
     *
     * Requirements:
     *
     * - input must fit into 160 bits
     *
     * _Available since v4.7._
     */
    function toUint160(uint256 value) internal pure returns (uint160) {
        require(value <= type(uint160).max, "SafeCast: value doesn't fit in 160 bits");
        return uint160(value);
    }

    /**
     * @dev Returns the downcasted uint152 from uint256, reverting on
     * overflow (when the input is greater than largest uint152).
     *
     * Counterpart to Solidity's `uint152` operator.
     *
     * Requirements:
     *
     * - input must fit into 152 bits
     *
     * _Available since v4.7._
     */
    function toUint152(uint256 value) internal pure returns (uint152) {
        require(value <= type(uint152).max, "SafeCast: value doesn't fit in 152 bits");
        return uint152(value);
    }

    /**
     * @dev Returns the downcasted uint144 from uint256, reverting on
     * overflow (when the input is greater than largest uint144).
     *
     * Counterpart to Solidity's `uint144` operator.
     *
     * Requirements:
     *
     * - input must fit into 144 bits
     *
     * _Available since v4.7._
     */
    function toUint144(uint256 value) internal pure returns (uint144) {
        require(value <= type(uint144).max, "SafeCast: value doesn't fit in 144 bits");
        return uint144(value);
    }

    /**
     * @dev Returns the downcasted uint136 from uint256, reverting on
     * overflow (when the input is greater than largest uint136).
     *
     * Counterpart to Solidity's `uint136` operator.
     *
     * Requirements:
     *
     * - input must fit into 136 bits
     *
     * _Available since v4.7._
     */
    function toUint136(uint256 value) internal pure returns (uint136) {
        require(value <= type(uint136).max, "SafeCast: value doesn't fit in 136 bits");
        return uint136(value);
    }

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v2.5._
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint120 from uint256, reverting on
     * overflow (when the input is greater than largest uint120).
     *
     * Counterpart to Solidity's `uint120` operator.
     *
     * Requirements:
     *
     * - input must fit into 120 bits
     *
     * _Available since v4.7._
     */
    function toUint120(uint256 value) internal pure returns (uint120) {
        require(value <= type(uint120).max, "SafeCast: value doesn't fit in 120 bits");
        return uint120(value);
    }

    /**
     * @dev Returns the downcasted uint112 from uint256, reverting on
     * overflow (when the input is greater than largest uint112).
     *
     * Counterpart to Solidity's `uint112` operator.
     *
     * Requirements:
     *
     * - input must fit into 112 bits
     *
     * _Available since v4.7._
     */
    function toUint112(uint256 value) internal pure returns (uint112) {
        require(value <= type(uint112).max, "SafeCast: value doesn't fit in 112 bits");
        return uint112(value);
    }

    /**
     * @dev Returns the downcasted uint104 from uint256, reverting on
     * overflow (when the input is greater than largest uint104).
     *
     * Counterpart to Solidity's `uint104` operator.
     *
     * Requirements:
     *
     * - input must fit into 104 bits
     *
     * _Available since v4.7._
     */
    function toUint104(uint256 value) internal pure returns (uint104) {
        require(value <= type(uint104).max, "SafeCast: value doesn't fit in 104 bits");
        return uint104(value);
    }

    /**
     * @dev Returns the downcasted uint96 from uint256, reverting on
     * overflow (when the input is greater than largest uint96).
     *
     * Counterpart to Solidity's `uint96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     *
     * _Available since v4.2._
     */
    function toUint96(uint256 value) internal pure returns (uint96) {
        require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
        return uint96(value);
    }

    /**
     * @dev Returns the downcasted uint88 from uint256, reverting on
     * overflow (when the input is greater than largest uint88).
     *
     * Counterpart to Solidity's `uint88` operator.
     *
     * Requirements:
     *
     * - input must fit into 88 bits
     *
     * _Available since v4.7._
     */
    function toUint88(uint256 value) internal pure returns (uint88) {
        require(value <= type(uint88).max, "SafeCast: value doesn't fit in 88 bits");
        return uint88(value);
    }

    /**
     * @dev Returns the downcasted uint80 from uint256, reverting on
     * overflow (when the input is greater than largest uint80).
     *
     * Counterpart to Solidity's `uint80` operator.
     *
     * Requirements:
     *
     * - input must fit into 80 bits
     *
     * _Available since v4.7._
     */
    function toUint80(uint256 value) internal pure returns (uint80) {
        require(value <= type(uint80).max, "SafeCast: value doesn't fit in 80 bits");
        return uint80(value);
    }

    /**
     * @dev Returns the downcasted uint72 from uint256, reverting on
     * overflow (when the input is greater than largest uint72).
     *
     * Counterpart to Solidity's `uint72` operator.
     *
     * Requirements:
     *
     * - input must fit into 72 bits
     *
     * _Available since v4.7._
     */
    function toUint72(uint256 value) internal pure returns (uint72) {
        require(value <= type(uint72).max, "SafeCast: value doesn't fit in 72 bits");
        return uint72(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v2.5._
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint56 from uint256, reverting on
     * overflow (when the input is greater than largest uint56).
     *
     * Counterpart to Solidity's `uint56` operator.
     *
     * Requirements:
     *
     * - input must fit into 56 bits
     *
     * _Available since v4.7._
     */
    function toUint56(uint256 value) internal pure returns (uint56) {
        require(value <= type(uint56).max, "SafeCast: value doesn't fit in 56 bits");
        return uint56(value);
    }

    /**
     * @dev Returns the downcasted uint48 from uint256, reverting on
     * overflow (when the input is greater than largest uint48).
     *
     * Counterpart to Solidity's `uint48` operator.
     *
     * Requirements:
     *
     * - input must fit into 48 bits
     *
     * _Available since v4.7._
     */
    function toUint48(uint256 value) internal pure returns (uint48) {
        require(value <= type(uint48).max, "SafeCast: value doesn't fit in 48 bits");
        return uint48(value);
    }

    /**
     * @dev Returns the downcasted uint40 from uint256, reverting on
     * overflow (when the input is greater than largest uint40).
     *
     * Counterpart to Solidity's `uint40` operator.
     *
     * Requirements:
     *
     * - input must fit into 40 bits
     *
     * _Available since v4.7._
     */
    function toUint40(uint256 value) internal pure returns (uint40) {
        require(value <= type(uint40).max, "SafeCast: value doesn't fit in 40 bits");
        return uint40(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v2.5._
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint24 from uint256, reverting on
     * overflow (when the input is greater than largest uint24).
     *
     * Counterpart to Solidity's `uint24` operator.
     *
     * Requirements:
     *
     * - input must fit into 24 bits
     *
     * _Available since v4.7._
     */
    function toUint24(uint256 value) internal pure returns (uint24) {
        require(value <= type(uint24).max, "SafeCast: value doesn't fit in 24 bits");
        return uint24(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v2.5._
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits
     *
     * _Available since v2.5._
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     *
     * _Available since v3.0._
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int248 from int256, reverting on
     * overflow (when the input is less than smallest int248 or
     * greater than largest int248).
     *
     * Counterpart to Solidity's `int248` operator.
     *
     * Requirements:
     *
     * - input must fit into 248 bits
     *
     * _Available since v4.7._
     */
    function toInt248(int256 value) internal pure returns (int248 downcasted) {
        downcasted = int248(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 248 bits");
    }

    /**
     * @dev Returns the downcasted int240 from int256, reverting on
     * overflow (when the input is less than smallest int240 or
     * greater than largest int240).
     *
     * Counterpart to Solidity's `int240` operator.
     *
     * Requirements:
     *
     * - input must fit into 240 bits
     *
     * _Available since v4.7._
     */
    function toInt240(int256 value) internal pure returns (int240 downcasted) {
        downcasted = int240(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 240 bits");
    }

    /**
     * @dev Returns the downcasted int232 from int256, reverting on
     * overflow (when the input is less than smallest int232 or
     * greater than largest int232).
     *
     * Counterpart to Solidity's `int232` operator.
     *
     * Requirements:
     *
     * - input must fit into 232 bits
     *
     * _Available since v4.7._
     */
    function toInt232(int256 value) internal pure returns (int232 downcasted) {
        downcasted = int232(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 232 bits");
    }

    /**
     * @dev Returns the downcasted int224 from int256, reverting on
     * overflow (when the input is less than smallest int224 or
     * greater than largest int224).
     *
     * Counterpart to Solidity's `int224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     *
     * _Available since v4.7._
     */
    function toInt224(int256 value) internal pure returns (int224 downcasted) {
        downcasted = int224(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 224 bits");
    }

    /**
     * @dev Returns the downcasted int216 from int256, reverting on
     * overflow (when the input is less than smallest int216 or
     * greater than largest int216).
     *
     * Counterpart to Solidity's `int216` operator.
     *
     * Requirements:
     *
     * - input must fit into 216 bits
     *
     * _Available since v4.7._
     */
    function toInt216(int256 value) internal pure returns (int216 downcasted) {
        downcasted = int216(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 216 bits");
    }

    /**
     * @dev Returns the downcasted int208 from int256, reverting on
     * overflow (when the input is less than smallest int208 or
     * greater than largest int208).
     *
     * Counterpart to Solidity's `int208` operator.
     *
     * Requirements:
     *
     * - input must fit into 208 bits
     *
     * _Available since v4.7._
     */
    function toInt208(int256 value) internal pure returns (int208 downcasted) {
        downcasted = int208(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 208 bits");
    }

    /**
     * @dev Returns the downcasted int200 from int256, reverting on
     * overflow (when the input is less than smallest int200 or
     * greater than largest int200).
     *
     * Counterpart to Solidity's `int200` operator.
     *
     * Requirements:
     *
     * - input must fit into 200 bits
     *
     * _Available since v4.7._
     */
    function toInt200(int256 value) internal pure returns (int200 downcasted) {
        downcasted = int200(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 200 bits");
    }

    /**
     * @dev Returns the downcasted int192 from int256, reverting on
     * overflow (when the input is less than smallest int192 or
     * greater than largest int192).
     *
     * Counterpart to Solidity's `int192` operator.
     *
     * Requirements:
     *
     * - input must fit into 192 bits
     *
     * _Available since v4.7._
     */
    function toInt192(int256 value) internal pure returns (int192 downcasted) {
        downcasted = int192(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 192 bits");
    }

    /**
     * @dev Returns the downcasted int184 from int256, reverting on
     * overflow (when the input is less than smallest int184 or
     * greater than largest int184).
     *
     * Counterpart to Solidity's `int184` operator.
     *
     * Requirements:
     *
     * - input must fit into 184 bits
     *
     * _Available since v4.7._
     */
    function toInt184(int256 value) internal pure returns (int184 downcasted) {
        downcasted = int184(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 184 bits");
    }

    /**
     * @dev Returns the downcasted int176 from int256, reverting on
     * overflow (when the input is less than smallest int176 or
     * greater than largest int176).
     *
     * Counterpart to Solidity's `int176` operator.
     *
     * Requirements:
     *
     * - input must fit into 176 bits
     *
     * _Available since v4.7._
     */
    function toInt176(int256 value) internal pure returns (int176 downcasted) {
        downcasted = int176(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 176 bits");
    }

    /**
     * @dev Returns the downcasted int168 from int256, reverting on
     * overflow (when the input is less than smallest int168 or
     * greater than largest int168).
     *
     * Counterpart to Solidity's `int168` operator.
     *
     * Requirements:
     *
     * - input must fit into 168 bits
     *
     * _Available since v4.7._
     */
    function toInt168(int256 value) internal pure returns (int168 downcasted) {
        downcasted = int168(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 168 bits");
    }

    /**
     * @dev Returns the downcasted int160 from int256, reverting on
     * overflow (when the input is less than smallest int160 or
     * greater than largest int160).
     *
     * Counterpart to Solidity's `int160` operator.
     *
     * Requirements:
     *
     * - input must fit into 160 bits
     *
     * _Available since v4.7._
     */
    function toInt160(int256 value) internal pure returns (int160 downcasted) {
        downcasted = int160(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 160 bits");
    }

    /**
     * @dev Returns the downcasted int152 from int256, reverting on
     * overflow (when the input is less than smallest int152 or
     * greater than largest int152).
     *
     * Counterpart to Solidity's `int152` operator.
     *
     * Requirements:
     *
     * - input must fit into 152 bits
     *
     * _Available since v4.7._
     */
    function toInt152(int256 value) internal pure returns (int152 downcasted) {
        downcasted = int152(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 152 bits");
    }

    /**
     * @dev Returns the downcasted int144 from int256, reverting on
     * overflow (when the input is less than smallest int144 or
     * greater than largest int144).
     *
     * Counterpart to Solidity's `int144` operator.
     *
     * Requirements:
     *
     * - input must fit into 144 bits
     *
     * _Available since v4.7._
     */
    function toInt144(int256 value) internal pure returns (int144 downcasted) {
        downcasted = int144(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 144 bits");
    }

    /**
     * @dev Returns the downcasted int136 from int256, reverting on
     * overflow (when the input is less than smallest int136 or
     * greater than largest int136).
     *
     * Counterpart to Solidity's `int136` operator.
     *
     * Requirements:
     *
     * - input must fit into 136 bits
     *
     * _Available since v4.7._
     */
    function toInt136(int256 value) internal pure returns (int136 downcasted) {
        downcasted = int136(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 136 bits");
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128 downcasted) {
        downcasted = int128(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 128 bits");
    }

    /**
     * @dev Returns the downcasted int120 from int256, reverting on
     * overflow (when the input is less than smallest int120 or
     * greater than largest int120).
     *
     * Counterpart to Solidity's `int120` operator.
     *
     * Requirements:
     *
     * - input must fit into 120 bits
     *
     * _Available since v4.7._
     */
    function toInt120(int256 value) internal pure returns (int120 downcasted) {
        downcasted = int120(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 120 bits");
    }

    /**
     * @dev Returns the downcasted int112 from int256, reverting on
     * overflow (when the input is less than smallest int112 or
     * greater than largest int112).
     *
     * Counterpart to Solidity's `int112` operator.
     *
     * Requirements:
     *
     * - input must fit into 112 bits
     *
     * _Available since v4.7._
     */
    function toInt112(int256 value) internal pure returns (int112 downcasted) {
        downcasted = int112(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 112 bits");
    }

    /**
     * @dev Returns the downcasted int104 from int256, reverting on
     * overflow (when the input is less than smallest int104 or
     * greater than largest int104).
     *
     * Counterpart to Solidity's `int104` operator.
     *
     * Requirements:
     *
     * - input must fit into 104 bits
     *
     * _Available since v4.7._
     */
    function toInt104(int256 value) internal pure returns (int104 downcasted) {
        downcasted = int104(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 104 bits");
    }

    /**
     * @dev Returns the downcasted int96 from int256, reverting on
     * overflow (when the input is less than smallest int96 or
     * greater than largest int96).
     *
     * Counterpart to Solidity's `int96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     *
     * _Available since v4.7._
     */
    function toInt96(int256 value) internal pure returns (int96 downcasted) {
        downcasted = int96(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 96 bits");
    }

    /**
     * @dev Returns the downcasted int88 from int256, reverting on
     * overflow (when the input is less than smallest int88 or
     * greater than largest int88).
     *
     * Counterpart to Solidity's `int88` operator.
     *
     * Requirements:
     *
     * - input must fit into 88 bits
     *
     * _Available since v4.7._
     */
    function toInt88(int256 value) internal pure returns (int88 downcasted) {
        downcasted = int88(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 88 bits");
    }

    /**
     * @dev Returns the downcasted int80 from int256, reverting on
     * overflow (when the input is less than smallest int80 or
     * greater than largest int80).
     *
     * Counterpart to Solidity's `int80` operator.
     *
     * Requirements:
     *
     * - input must fit into 80 bits
     *
     * _Available since v4.7._
     */
    function toInt80(int256 value) internal pure returns (int80 downcasted) {
        downcasted = int80(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 80 bits");
    }

    /**
     * @dev Returns the downcasted int72 from int256, reverting on
     * overflow (when the input is less than smallest int72 or
     * greater than largest int72).
     *
     * Counterpart to Solidity's `int72` operator.
     *
     * Requirements:
     *
     * - input must fit into 72 bits
     *
     * _Available since v4.7._
     */
    function toInt72(int256 value) internal pure returns (int72 downcasted) {
        downcasted = int72(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 72 bits");
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64 downcasted) {
        downcasted = int64(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 64 bits");
    }

    /**
     * @dev Returns the downcasted int56 from int256, reverting on
     * overflow (when the input is less than smallest int56 or
     * greater than largest int56).
     *
     * Counterpart to Solidity's `int56` operator.
     *
     * Requirements:
     *
     * - input must fit into 56 bits
     *
     * _Available since v4.7._
     */
    function toInt56(int256 value) internal pure returns (int56 downcasted) {
        downcasted = int56(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 56 bits");
    }

    /**
     * @dev Returns the downcasted int48 from int256, reverting on
     * overflow (when the input is less than smallest int48 or
     * greater than largest int48).
     *
     * Counterpart to Solidity's `int48` operator.
     *
     * Requirements:
     *
     * - input must fit into 48 bits
     *
     * _Available since v4.7._
     */
    function toInt48(int256 value) internal pure returns (int48 downcasted) {
        downcasted = int48(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 48 bits");
    }

    /**
     * @dev Returns the downcasted int40 from int256, reverting on
     * overflow (when the input is less than smallest int40 or
     * greater than largest int40).
     *
     * Counterpart to Solidity's `int40` operator.
     *
     * Requirements:
     *
     * - input must fit into 40 bits
     *
     * _Available since v4.7._
     */
    function toInt40(int256 value) internal pure returns (int40 downcasted) {
        downcasted = int40(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 40 bits");
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32 downcasted) {
        downcasted = int32(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 32 bits");
    }

    /**
     * @dev Returns the downcasted int24 from int256, reverting on
     * overflow (when the input is less than smallest int24 or
     * greater than largest int24).
     *
     * Counterpart to Solidity's `int24` operator.
     *
     * Requirements:
     *
     * - input must fit into 24 bits
     *
     * _Available since v4.7._
     */
    function toInt24(int256 value) internal pure returns (int24 downcasted) {
        downcasted = int24(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 24 bits");
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16 downcasted) {
        downcasted = int16(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 16 bits");
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8 downcasted) {
        downcasted = int8(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 8 bits");
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     *
     * _Available since v3.0._
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        // Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
        require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../interfaces/IERC20.sol";
import "./Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(token.transfer.selector, to, value)
        );
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(token.transferFrom.selector, from, to, value)
        );
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(token.approve.selector, spender, value)
        );
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(
                token.approve.selector,
                spender,
                newAllowance
            )
        );
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(
                oldAllowance >= value,
                "SafeERC20: decreased allowance below zero"
            );
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(
                token,
                abi.encodeWithSelector(
                    token.approve.selector,
                    spender,
                    newAllowance
                )
            );
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(
            data,
            "SafeERC20: low-level call failed"
        );
        if (returndata.length > 0) {
            // Return data is optional
            require(
                abi.decode(returndata, (bool)),
                "SafeERC20: ERC20 operation did not succeed"
            );
        }
    }
}

pragma solidity ^0.8.0;

/**
 * @title RoleManager
 * @notice Generic role manager to manage slashing and cooldown admin in StakedAaveV3.
 *         It implements a claim admin role pattern to safely migrate between different admin addresses
 * @author Aave
 **/
contract RoleManager {
  struct InitAdmin {
    uint256 role;
    address admin;
  }

  mapping(uint256 => address) private _admins;
  mapping(uint256 => address) private _pendingAdmins;

  event PendingAdminChanged(address indexed newPendingAdmin, uint256 role);
  event RoleClaimed(address indexed newAdmin, uint256 role);

  modifier onlyRoleAdmin(uint256 role) {
    require(_admins[role] == msg.sender, 'CALLER_NOT_ROLE_ADMIN');
    _;
  }

  modifier onlyPendingRoleAdmin(uint256 role) {
    require(
      _pendingAdmins[role] == msg.sender,
      'CALLER_NOT_PENDING_ROLE_ADMIN'
    );
    _;
  }

  /**
   * @dev returns the admin associated with the specific role
   * @param role the role associated with the admin being returned
   **/
  function getAdmin(uint256 role) public view returns (address) {
    return _admins[role];
  }

  /**
   * @dev returns the pending admin associated with the specific role
   * @param role the role associated with the pending admin being returned
   **/
  function getPendingAdmin(uint256 role) public view returns (address) {
    return _pendingAdmins[role];
  }

  /**
   * @dev sets the pending admin for a specific role
   * @param role the role associated with the new pending admin being set
   * @param newPendingAdmin the address of the new pending admin
   **/
  function setPendingAdmin(uint256 role, address newPendingAdmin)
    public
    onlyRoleAdmin(role)
  {
    _pendingAdmins[role] = newPendingAdmin;
    emit PendingAdminChanged(newPendingAdmin, role);
  }

  /**
   * @dev allows the caller to become a specific role admin
   * @param role the role associated with the admin claiming the new role
   **/
  function claimRoleAdmin(uint256 role) external onlyPendingRoleAdmin(role) {
    _admins[role] = msg.sender;
    _pendingAdmins[role] = address(0);
    emit RoleClaimed(msg.sender, role);
  }

  function _initAdmins(InitAdmin[] memory initAdmins) internal {
    for (uint256 i = 0; i < initAdmins.length; i++) {
      require(
        _admins[initAdmins[i].role] == address(0) &&
          initAdmins[i].admin != address(0),
        'ADMIN_CANNOT_BE_INITIALIZED'
      );
      _admins[initAdmins[i].role] = initAdmins[i].admin;
      emit RoleClaimed(initAdmins[i].admin, initAdmins[i].role);
    }
  }
}

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.8.0;

/**
 * @title VersionedInitializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 *
 * @author Aave, inspired by the OpenZeppelin Initializable contract
 */
abstract contract VersionedInitializable {
  /**
   * @dev Indicates that the contract has been initialized.
   */
  uint256 internal lastInitializedRevision = 0;

  /**
   * @dev Modifier to use in the initializer function of a contract.
   */
  modifier initializer() {
    uint256 revision = getRevision();
    require(
      revision > lastInitializedRevision,
      'Contract instance has already been initialized'
    );

    lastInitializedRevision = revision;

    _;
  }

  /// @dev returns the revision number of the contract.
  /// Needs to be defined in the inherited class as a constant.
  function getRevision() internal pure virtual returns (uint256);

  // Reserved storage space to allow for layout changes in the future.
  uint256[50] private ______gap;
}