Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import {LowLevelERC20Transfer} from "@looksrare/contracts-libs/contracts/lowLevelCallers/LowLevelERC20Transfer.sol";
import {OwnableTwoSteps} from "@looksrare/contracts-libs/contracts/OwnableTwoSteps.sol";
import {Pausable} from "@looksrare/contracts-libs/contracts/Pausable.sol";
import {ReentrancyGuard} from "@looksrare/contracts-libs/contracts/ReentrancyGuard.sol";

import {MerkleProof} from "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";

/**
 * @title SeasonRewardsDistributor
 * @notice It distributes LOOKS tokens with rolling Merkle airdrops.
 */
contract SeasonRewardsDistributor is Pausable, ReentrancyGuard, OwnableTwoSteps, LowLevelERC20Transfer {
    uint256 public constant BUFFER_ADMIN_WITHDRAW = 3 days;

    address public immutable looksRareToken;

    // Current reward round (users can only claim pending rewards for the current round)
    uint256 public currentRewardRound;

    // Last paused timestamp
    uint256 public lastPausedTimestamp;

    // Max amount per user in current tree
    uint256 public maximumAmountPerUserInCurrentTree;

    // Total amount claimed by user (in LOOKS)
    mapping(address => uint256) public amountClaimedByUser;

    // Merkle root for a reward round
    mapping(uint256 => bytes32) public merkleRootOfRewardRound;

    // Checks whether a merkle root was used
    mapping(bytes32 => bool) public merkleRootUsed;

    // Keeps track on whether user has claimed at a given reward round
    mapping(uint256 => mapping(address => bool)) public hasUserClaimedForRewardRound;

    event RewardsClaim(address indexed user, uint256 indexed rewardRound, uint256 amount);
    event UpdateSeasonRewards(uint256 indexed rewardRound);
    event TokenWithdrawnOwner(uint256 amount);

    error AlreadyClaimed();
    error AmountHigherThanMax();
    error InvalidProof();
    error MerkleRootAlreadyUsed();
    error TooEarlyToWithdraw();

    /**
     * @notice Constructor
     * @param _looksRareToken address of the LooksRare token
     * @param _owner address of the owner
     */
    constructor(address _looksRareToken, address _owner) OwnableTwoSteps(_owner) {
        looksRareToken = _looksRareToken;
        merkleRootUsed[bytes32(0)] = true;
    }

    /**
     * @notice Claim pending rewards
     * @param amount amount to claim
     * @param merkleProof array containing the merkle proof
     */
    function claim(uint256 amount, bytes32[] calldata merkleProof) external whenNotPaused nonReentrant {
        // Verify the reward round is not claimed already
        if (hasUserClaimedForRewardRound[currentRewardRound][msg.sender]) {
            revert AlreadyClaimed();
        }

        (bool claimStatus, uint256 adjustedAmount) = _canClaim(msg.sender, amount, merkleProof);

        if (!claimStatus) {
            revert InvalidProof();
        }
        if (amount > maximumAmountPerUserInCurrentTree) {
            revert AmountHigherThanMax();
        }

        // Set mapping for user and round as true
        hasUserClaimedForRewardRound[currentRewardRound][msg.sender] = true;

        // Adjust amount claimed
        amountClaimedByUser[msg.sender] += adjustedAmount;

        // Transfer adjusted amount
        _executeERC20DirectTransfer(looksRareToken, msg.sender, adjustedAmount);

        emit RewardsClaim(msg.sender, currentRewardRound, adjustedAmount);
    }

    /**
     * @notice Update season rewards with a new merkle root
     * @dev It automatically increments the currentRewardRound
     * @param merkleRoot root of the computed merkle tree
     */
    function updateSeasonRewards(bytes32 merkleRoot, uint256 newMaximumAmountPerUser) external onlyOwner {
        if (merkleRootUsed[merkleRoot]) {
            revert MerkleRootAlreadyUsed();
        }

        currentRewardRound++;
        merkleRootOfRewardRound[currentRewardRound] = merkleRoot;
        merkleRootUsed[merkleRoot] = true;
        maximumAmountPerUserInCurrentTree = newMaximumAmountPerUser;

        emit UpdateSeasonRewards(currentRewardRound);
    }

    /**
     * @notice Pause distribution
     */
    function pauseDistribution() external onlyOwner whenNotPaused {
        lastPausedTimestamp = block.timestamp;
        _pause();
    }

    /**
     * @notice Unpause distribution
     */
    function unpauseDistribution() external onlyOwner whenPaused {
        _unpause();
    }

    /**
     * @notice Transfer LOOKS tokens back to owner
     * @dev It is for emergency purposes
     * @param amount amount to withdraw
     */
    function withdrawTokenRewards(uint256 amount) external onlyOwner whenPaused {
        if (block.timestamp <= (lastPausedTimestamp + BUFFER_ADMIN_WITHDRAW)) {
            revert TooEarlyToWithdraw();
        }
        _executeERC20DirectTransfer(looksRareToken, msg.sender, amount);

        emit TokenWithdrawnOwner(amount);
    }

    /**
     * @notice Check whether it is possible to claim and how much based on previous distribution
     * @param user address of the user
     * @param amount amount to claim
     * @param merkleProof array with the merkle proof
     */
    function canClaim(
        address user,
        uint256 amount,
        bytes32[] calldata merkleProof
    ) external view returns (bool, uint256) {
        return _canClaim(user, amount, merkleProof);
    }

    /**
     * @notice Check whether it is possible to claim and how much based on previous distribution
     * @param user address of the user
     * @param amount amount to claim
     * @param merkleProof array with the merkle proof
     */
    function _canClaim(
        address user,
        uint256 amount,
        bytes32[] calldata merkleProof
    ) internal view returns (bool, uint256) {
        // Compute the node and verify the merkle proof
        bytes32 node = keccak256(bytes.concat(keccak256(abi.encodePacked(user, amount))));

        bool canUserClaim = MerkleProof.verify(merkleProof, merkleRootOfRewardRound[currentRewardRound], node);

        if ((!canUserClaim) || (hasUserClaimedForRewardRound[currentRewardRound][user])) {
            return (false, 0);
        } else {
            return (true, amount - amountClaimedByUser[user]);
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/**
 * @title Pausable
 * @notice This contract makes it possible to pause the contract.
 *         It is adjusted from OpenZeppelin.
 * @author LooksRare protocol team (👀,💎)
 */
abstract contract Pausable {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    error IsPaused();
    error NotPaused();

    bool private _paused;

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        if (paused()) {
            revert IsPaused();
        }
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        if (!paused()) {
            revert NotPaused();
        }
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(msg.sender);
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(msg.sender);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

// Interfaces
import {IOwnableTwoSteps} from "./interfaces/IOwnableTwoSteps.sol";

/**
 * @title OwnableTwoSteps
 * @notice This contract offers transfer of ownership in two steps with potential owner
 *         having to confirm the transaction to become the owner.
 *         Renouncement of the ownership is also a two-step process since the next potential owner is the address(0).
 * @author LooksRare protocol team (👀,💎)
 */
abstract contract OwnableTwoSteps is IOwnableTwoSteps {
    /**
     * @notice Address of the current owner.
     */
    address public owner;

    /**
     * @notice Address of the potential owner.
     */
    address public potentialOwner;

    /**
     * @notice Ownership status.
     */
    Status public ownershipStatus;

    /**
     * @notice Modifier to wrap functions for contracts that inherit this contract.
     */
    modifier onlyOwner() {
        _onlyOwner();
        _;
    }

    /**
     * @notice Constructor
     * @param _owner The contract's owner
     */
    constructor(address _owner) {
        owner = _owner;
        emit NewOwner(_owner);
    }

    /**
     * @notice This function is used to cancel the ownership transfer.
     * @dev This function can be used for both cancelling a transfer to a new owner and
     *      cancelling the renouncement of the ownership.
     */
    function cancelOwnershipTransfer() external onlyOwner {
        Status _ownershipStatus = ownershipStatus;
        if (_ownershipStatus == Status.NoOngoingTransfer) {
            revert NoOngoingTransferInProgress();
        }

        if (_ownershipStatus == Status.TransferInProgress) {
            delete potentialOwner;
        }

        delete ownershipStatus;

        emit CancelOwnershipTransfer();
    }

    /**
     * @notice This function is used to confirm the ownership renouncement.
     */
    function confirmOwnershipRenouncement() external onlyOwner {
        if (ownershipStatus != Status.RenouncementInProgress) {
            revert RenouncementNotInProgress();
        }

        delete owner;
        delete ownershipStatus;

        emit NewOwner(address(0));
    }

    /**
     * @notice This function is used to confirm the ownership transfer.
     * @dev This function can only be called by the current potential owner.
     */
    function confirmOwnershipTransfer() external {
        if (ownershipStatus != Status.TransferInProgress) {
            revert TransferNotInProgress();
        }

        if (msg.sender != potentialOwner) {
            revert WrongPotentialOwner();
        }

        owner = msg.sender;
        delete ownershipStatus;
        delete potentialOwner;

        emit NewOwner(msg.sender);
    }

    /**
     * @notice This function is used to initiate the transfer of ownership to a new owner.
     * @param newPotentialOwner New potential owner address
     */
    function initiateOwnershipTransfer(address newPotentialOwner) external onlyOwner {
        if (ownershipStatus != Status.NoOngoingTransfer) {
            revert TransferAlreadyInProgress();
        }

        ownershipStatus = Status.TransferInProgress;
        potentialOwner = newPotentialOwner;

        /**
         * @dev This function can only be called by the owner, so msg.sender is the owner.
         *      We don't have to SLOAD the owner again.
         */
        emit InitiateOwnershipTransfer(msg.sender, newPotentialOwner);
    }

    /**
     * @notice This function is used to initiate the ownership renouncement.
     */
    function initiateOwnershipRenouncement() external onlyOwner {
        if (ownershipStatus != Status.NoOngoingTransfer) {
            revert TransferAlreadyInProgress();
        }

        ownershipStatus = Status.RenouncementInProgress;

        emit InitiateOwnershipRenouncement();
    }

    function _onlyOwner() private view {
        if (msg.sender != owner) revert NotOwner();
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

// Interfaces
import {IReentrancyGuard} from "./interfaces/IReentrancyGuard.sol";

/**
 * @title ReentrancyGuard
 * @notice This contract protects against reentrancy attacks.
 *         It is adjusted from OpenZeppelin.
 * @author LooksRare protocol team (👀,💎)
 */
abstract contract ReentrancyGuard is IReentrancyGuard {
    uint256 private _status;

    /**
     * @notice Modifier to wrap functions to prevent reentrancy calls.
     */
    modifier nonReentrant() {
        if (_status == 2) {
            revert ReentrancyFail();
        }

        _status = 2;
        _;
        _status = 1;
    }

    constructor() {
        _status = 1;
    }
}

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

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Trees proofs.
 *
 * The proofs can be generated using the JavaScript library
 * https://github.com/miguelmota/merkletreejs[merkletreejs].
 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
 *
 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.
 */
library MerkleProof {
    /**
     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
     * defined by `root`. For this, a `proof` must be provided, containing
     * sibling hashes on the branch from the leaf to the root of the tree. Each
     * pair of leaves and each pair of pre-images are assumed to be sorted.
     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    /**
     * @dev Returns the rebuilt hash obtained by traversing a Merklee tree up
     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
     * hash matches the root of the tree. When processing the proof, the pairs
     * of leafs & pre-images are assumed to be sorted.
     *
     * _Available since v4.4._
     */
    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            bytes32 proofElement = proof[i];
            if (computedHash <= proofElement) {
                // Hash(current computed hash + current element of the proof)
                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
            } else {
                // Hash(current element of the proof + current computed hash)
                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
            }
        }
        return computedHash;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/**
 * @notice It is emitted if the call recipient is not a contract.
 */
error NotAContract();

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/**
 * @notice It is emitted if the ETH transfer fails.
 */
error ETHTransferFail();

/**
 * @notice It is emitted if the ERC20 approval fails.
 */
error ERC20ApprovalFail();

/**
 * @notice It is emitted if the ERC20 transfer fails.
 */
error ERC20TransferFail();

/**
 * @notice It is emitted if the ERC20 transferFrom fails.
 */
error ERC20TransferFromFail();

/**
 * @notice It is emitted if the ERC721 transferFrom fails.
 */
error ERC721TransferFromFail();

/**
 * @notice It is emitted if the ERC1155 safeTransferFrom fails.
 */
error ERC1155SafeTransferFromFail();

/**
 * @notice It is emitted if the ERC1155 safeBatchTransferFrom fails.
 */
error ERC1155SafeBatchTransferFromFail();

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

interface IERC20 {
    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);

    function totalSupply() external view returns (uint256);

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

    function transfer(address to, uint256 amount) external returns (bool);

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/**
 * @title IOwnableTwoSteps
 * @author LooksRare protocol team (👀,💎)
 */
interface IOwnableTwoSteps {
    /**
     * @notice This enum keeps track of the ownership status.
     * @param NoOngoingTransfer The default status when the owner is set
     * @param TransferInProgress The status when a transfer to a new owner is initialized
     * @param RenouncementInProgress The status when a transfer to address(0) is initialized
     */
    enum Status {
        NoOngoingTransfer,
        TransferInProgress,
        RenouncementInProgress
    }

    /**
     * @notice This is returned when there is no transfer of ownership in progress.
     */
    error NoOngoingTransferInProgress();

    /**
     * @notice This is returned when the caller is not the owner.
     */
    error NotOwner();

    /**
     * @notice This is returned when there is no renouncement in progress but
     *         the owner tries to validate the ownership renouncement.
     */
    error RenouncementNotInProgress();

    /**
     * @notice This is returned when the transfer is already in progress but the owner tries
     *         initiate a new ownership transfer.
     */
    error TransferAlreadyInProgress();

    /**
     * @notice This is returned when there is no ownership transfer in progress but the
     *         ownership change tries to be approved.
     */
    error TransferNotInProgress();

    /**
     * @notice This is returned when the ownership transfer is attempted to be validated by the
     *         a caller that is not the potential owner.
     */
    error WrongPotentialOwner();

    /**
     * @notice This is emitted if the ownership transfer is cancelled.
     */
    event CancelOwnershipTransfer();

    /**
     * @notice This is emitted if the ownership renouncement is initiated.
     */
    event InitiateOwnershipRenouncement();

    /**
     * @notice This is emitted if the ownership transfer is initiated.
     * @param previousOwner Previous/current owner
     * @param potentialOwner Potential/future owner
     */
    event InitiateOwnershipTransfer(address previousOwner, address potentialOwner);

    /**
     * @notice This is emitted when there is a new owner.
     */
    event NewOwner(address newOwner);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

/**
 * @title IReentrancyGuard
 * @author LooksRare protocol team (👀,💎)
 */
interface IReentrancyGuard {
    /**
     * @notice This is returned when there is a reentrant call.
     */
    error ReentrancyFail();
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

// Interfaces
import {IERC20} from "../interfaces/generic/IERC20.sol";

// Errors
import {ERC20TransferFail, ERC20TransferFromFail} from "../errors/LowLevelErrors.sol";
import {NotAContract} from "../errors/GenericErrors.sol";

/**
 * @title LowLevelERC20Transfer
 * @notice This contract contains low-level calls to transfer ERC20 tokens.
 * @author LooksRare protocol team (👀,💎)
 */
contract LowLevelERC20Transfer {
    /**
     * @notice Execute ERC20 transferFrom
     * @param currency Currency address
     * @param from Sender address
     * @param to Recipient address
     * @param amount Amount to transfer
     */
    function _executeERC20TransferFrom(address currency, address from, address to, uint256 amount) internal {
        if (currency.code.length == 0) {
            revert NotAContract();
        }

        (bool status, bytes memory data) = currency.call(abi.encodeCall(IERC20.transferFrom, (from, to, amount)));

        if (!status) {
            revert ERC20TransferFromFail();
        }

        if (data.length > 0) {
            if (!abi.decode(data, (bool))) {
                revert ERC20TransferFromFail();
            }
        }
    }

    /**
     * @notice Execute ERC20 (direct) transfer
     * @param currency Currency address
     * @param to Recipient address
     * @param amount Amount to transfer
     */
    function _executeERC20DirectTransfer(address currency, address to, uint256 amount) internal {
        if (currency.code.length == 0) {
            revert NotAContract();
        }

        (bool status, bytes memory data) = currency.call(abi.encodeCall(IERC20.transfer, (to, amount)));

        if (!status) {
            revert ERC20TransferFail();
        }

        if (data.length > 0) {
            if (!abi.decode(data, (bool))) {
                revert ERC20TransferFail();
            }
        }
    }
}