Merge pull request #542 from hats-finance/hatairdrop

Create HATAirdrop

contracts/tge/HATAirdrop.sol

@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.16;
+
+import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
+import "@openzeppelin/contracts-upgradeable/token/ERC20/utils/SafeERC20Upgradeable.sol";
+import "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
+import "@openzeppelin/contracts-upgradeable/utils/cryptography/MerkleProofUpgradeable.sol";
+import "../tokenlock/ITokenLockFactory.sol";
+import "./interfaces/IHATAirdrop.sol";
+
+/*
+An airdrop contract that transfers tokens based on a merkle tree.
+*/
+contract HATAirdrop is IHATAirdrop, Initializable {
+    error CannotRedeemBeforeStartTime();
+    error CannotRedeemAfterDeadline();
+    error LeafAlreadyRedeemed();
+    error InvalidMerkleProof();
+    error CannotRecoverBeforeDeadline();
+    error RedeemerMustBeBeneficiary();
+
+    using SafeERC20Upgradeable for IERC20Upgradeable;
+
+    bytes32 public root;
+    uint256 public startTime;
+    uint256 public deadline;
+    uint256 public lockEndTime;
+    uint256 public periods;
+    IERC20Upgradeable public token;
+    ITokenLockFactory public tokenLockFactory;
+    address public factory;
+
+    mapping (bytes32 => bool) public leafRedeemed;
+
+    event MerkleTreeSet(string _merkleTreeIPFSRef, bytes32 _root, uint256 _startTime, uint256 _deadline);
+    event TokensRedeemed(address indexed _account, address indexed _tokenLock, uint256 _amount);
+
+    constructor () {
+        _disableInitializers();
+    }
+
+    /**
+    * @notice Initialize a HATAirdrop instance
+    * @param _merkleTreeIPFSRef new merkle tree ipfs reference.
+    * @param _root new merkle tree root to use for verifying airdrop data.
+    * @param _startTime start of the redeem period and of the token lock (if exists)
+    * @param _deadline end time to redeem from the contract
+    * @param _lockEndTime end time for the token lock contract. If this date is in the past, the tokens will be transferred directly to the user and no token lock will be created
+    * @param _periods number of periods of the token lock contract (if exists)
+    * @param _token the token to be airdropped
+    * @param _tokenLockFactory the token lock factory to use to deploy the token locks
+    */
+    function initialize(
+        string memory _merkleTreeIPFSRef,
+        bytes32 _root,
+        uint256 _startTime,
+        uint256 _deadline,
+        uint256 _lockEndTime,
+        uint256 _periods,
+        IERC20Upgradeable _token,
+        ITokenLockFactory _tokenLockFactory
+    ) external initializer {
+        root = _root;
+        startTime = _startTime;
+        deadline = _deadline;
+        lockEndTime = _lockEndTime;
+        periods = _periods;
+        token = _token;
+        tokenLockFactory = _tokenLockFactory;
+        factory = msg.sender;
+        emit MerkleTreeSet(_merkleTreeIPFSRef, _root, _startTime, _deadline);
+    }
+
+    function redeem(address _account, uint256 _amount, bytes32[] calldata _proof) external {
+        if (msg.sender != _account && msg.sender != factory) {
+            revert RedeemerMustBeBeneficiary();
+        }
+        // solhint-disable-next-line not-rely-on-time
+        if (block.timestamp < startTime) revert CannotRedeemBeforeStartTime();
+        // solhint-disable-next-line not-rely-on-time
+        if (block.timestamp > deadline) revert CannotRedeemAfterDeadline();
+        bytes32 leaf = _leaf(_account, _amount);
+        if (leafRedeemed[leaf]) revert LeafAlreadyRedeemed();
+        if(!_verify(_proof, leaf)) revert InvalidMerkleProof();
+        leafRedeemed[leaf] = true;
+
+        address _tokenLock = address(0);
+        // solhint-disable-next-line not-rely-on-time
+        if (lockEndTime > block.timestamp) {
+            _tokenLock = tokenLockFactory.createTokenLock(
+                address(token),
+                0x0000000000000000000000000000000000000000,
+                _account,
+                _amount,
+                startTime,
+                lockEndTime,
+                periods,
+                0,
+                0,
+                false,
+                true
+            );
+            token.safeTransferFrom(factory, _tokenLock, _amount);
+        } else {
+            token.safeTransferFrom(factory, _account, _amount);
+        }
+
+        emit TokensRedeemed(_account, _tokenLock, _amount);
+    }
+
+    function _verify(bytes32[] calldata proof, bytes32 leaf) internal view returns (bool) {
+        return MerkleProofUpgradeable.verifyCalldata(proof, root, leaf);
+    }
+
+    function _leaf(address _account, uint256 _amount) internal pure returns (bytes32) {
+        return keccak256(abi.encodePacked(_account, _amount));
+    }
+}

contracts/tge/HATAirdropFactory.sol

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: MIT
+// Disclaimer https://github.com/hats-finance/hats-contracts/blob/main/DISCLAIMER.md
+
+pragma solidity 0.8.16;
+
+import "@openzeppelin/contracts/access/Ownable.sol";
+import "@openzeppelin/contracts/proxy/Clones.sol";
+import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import "./interfaces/IHATAirdrop.sol";
+
+contract HATAirdropFactory is Ownable {
+    error RedeemDataArraysLengthMismatch();
+    error ContractIsNotHATAirdrop();
+    error HATAirdropInitializationFailed();
+
+    using SafeERC20 for IERC20;
+
+    mapping(address => bool) public isAirdrop;
+
+    event TokensWithdrawn(address indexed _owner, uint256 _amount);
+    event HATAirdropCreated(address indexed _hatAirdrop, bytes _initData, IERC20 _token, uint256 _totalAmount);
+
+    function withdrawTokens(IERC20 _token, uint256 _amount) external onlyOwner {
+        address owner = msg.sender;
+        _token.safeTransfer(owner, _amount);
+        emit TokensWithdrawn(owner, _amount);
+    }
+
+    function redeemMultipleAirdrops(IHATAirdrop[] calldata _airdrops, uint256[] calldata _amounts, bytes32[][] calldata _proofs) external {
+        if (_airdrops.length != _amounts.length || _airdrops.length != _proofs.length) {
+            revert RedeemDataArraysLengthMismatch();
+        }
+
+        address caller = msg.sender;
+        for (uint256 i = 0; i < _airdrops.length;) {
+            if (!isAirdrop[address(_airdrops[i])]) {
+                revert ContractIsNotHATAirdrop();
+            }
+
+            _airdrops[i].redeem(caller, _amounts[i], _proofs[i]);
+
+            unchecked {
+                ++i;
+            }
+        }
+    }
+
+    function createHATAirdrop(
+        address _implementation,
+        bytes calldata _initData,
+        IERC20 _token,
+        uint256 _totalAmount
+    ) external onlyOwner returns (address result) {
+        result = Clones.cloneDeterministic(_implementation, keccak256(_initData));
+
+        // solhint-disable-next-line avoid-low-level-calls
+        (bool success,) = result.call(_initData);
+
+        if (!success) {
+            revert HATAirdropInitializationFailed();
+        }
+
+        isAirdrop[result] = true;
+
+        _token.safeApprove(result, _totalAmount);
+
+        emit HATAirdropCreated(result, _initData, _token, _totalAmount);
+    }
+
+    function predictHATAirdropAddress(
+        address _implementation,
+        bytes calldata _initData
+    ) external view returns (address) {
+        return Clones.predictDeterministicAddress(_implementation, keccak256(_initData));
+    }
+}

contracts/tge/interfaces/IHATAirdrop.sol

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: MIT
+// Disclaimer https://github.com/hats-finance/hats-contracts/blob/main/DISCLAIMER.md
+
+pragma solidity 0.8.16;
+
+
+interface IHATAirdrop {
+    function redeem(address _account, uint256 _amount, bytes32[] calldata _proof) external;
+}

docs/dodoc/elin/contracts-upgradeable/utils/cryptography/MerkleProofUpgradeable.md

@@ -0,0 +1,12 @@
+# MerkleProofUpgradeable
+
+
+
+
+
+
+
+*These functions deal with verification of Merkle Tree proofs. The tree and the proofs can be generated using our https://github.com/OpenZeppelin/merkle-tree[JavaScript library]. You will find a quickstart guide in the readme. WARNING: You should avoid using leaf values that are 64 bytes long prior to hashing, or use a hash function other than keccak256 for hashing leaves. This is because the concatenation of a sorted pair of internal nodes in the merkle tree could be reinterpreted as a leaf value. OpenZeppelin's JavaScript library generates merkle trees that are safe against this attack out of the box.*
+
+
+