creation_sourcecode: // SPDX-License-Identifier: UNLICENSED
  pragma solidity 0.8.17;
  
  // OpenZeppelin Contracts (last updated v4.9.2) (utils/cryptography/MerkleProof.sol)
  
  /**
   * @dev 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.
   */
  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 Calldata version of {verify}
       *
       * _Available since v4.7._
       */
      function verifyCalldata(bytes32[] calldata proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
          return processProofCalldata(proof, leaf) == root;
      }
  
      /**
       * @dev Returns the rebuilt hash obtained by traversing a Merkle 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++) {
              computedHash = _hashPair(computedHash, proof[i]);
          }
          return computedHash;
      }
  
      /**
       * @dev Calldata version of {processProof}
       *
       * _Available since v4.7._
       */
      function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
          bytes32 computedHash = leaf;
          for (uint256 i = 0; i < proof.length; i++) {
              computedHash = _hashPair(computedHash, proof[i]);
          }
          return computedHash;
      }
  
      /**
       * @dev Returns true if the `leaves` can be simultaneously proven to be a part of a merkle tree defined by
       * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
       *
       * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
       *
       * _Available since v4.7._
       */
      function multiProofVerify(
          bytes32[] memory proof,
          bool[] memory proofFlags,
          bytes32 root,
          bytes32[] memory leaves
      ) internal pure returns (bool) {
          return processMultiProof(proof, proofFlags, leaves) == root;
      }
  
      /**
       * @dev Calldata version of {multiProofVerify}
       *
       * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
       *
       * _Available since v4.7._
       */
      function multiProofVerifyCalldata(
          bytes32[] calldata proof,
          bool[] calldata proofFlags,
          bytes32 root,
          bytes32[] memory leaves
      ) internal pure returns (bool) {
          return processMultiProofCalldata(proof, proofFlags, leaves) == root;
      }
  
      /**
       * @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
       * proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
       * leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
       * respectively.
       *
       * CAUTION: Not all merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
       * is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
       * tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
       *
       * _Available since v4.7._
       */
      function processMultiProof(
          bytes32[] memory proof,
          bool[] memory proofFlags,
          bytes32[] memory leaves
      ) internal pure returns (bytes32 merkleRoot) {
          // This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
          // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
          // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
          // the merkle tree.
          uint256 leavesLen = leaves.length;
          uint256 proofLen = proof.length;
          uint256 totalHashes = proofFlags.length;
  
          // Check proof validity.
          require(leavesLen + proofLen - 1 == totalHashes, "MerkleProof: invalid multiproof");
  
          // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
          // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
          bytes32[] memory hashes = new bytes32[](totalHashes);
          uint256 leafPos = 0;
          uint256 hashPos = 0;
          uint256 proofPos = 0;
          // At each step, we compute the next hash using two values:
          // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
          //   get the next hash.
          // - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
          //   `proof` array.
          for (uint256 i = 0; i < totalHashes; i++) {
              bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
              bytes32 b = proofFlags[i]
                  ? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
                  : proof[proofPos++];
              hashes[i] = _hashPair(a, b);
          }
  
          if (totalHashes > 0) {
              require(proofPos == proofLen, "MerkleProof: invalid multiproof");
              unchecked {
                  return hashes[totalHashes - 1];
              }
          } else if (leavesLen > 0) {
              return leaves[0];
          } else {
              return proof[0];
          }
      }
  
      /**
       * @dev Calldata version of {processMultiProof}.
       *
       * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
       *
       * _Available since v4.7._
       */
      function processMultiProofCalldata(
          bytes32[] calldata proof,
          bool[] calldata proofFlags,
          bytes32[] memory leaves
      ) internal pure returns (bytes32 merkleRoot) {
          // This function rebuilds the root hash by traversing the tree up from the leaves. The root is rebuilt by
          // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
          // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
          // the merkle tree.
          uint256 leavesLen = leaves.length;
          uint256 proofLen = proof.length;
          uint256 totalHashes = proofFlags.length;
  
          // Check proof validity.
          require(leavesLen + proofLen - 1 == totalHashes, "MerkleProof: invalid multiproof");
  
          // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
          // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
          bytes32[] memory hashes = new bytes32[](totalHashes);
          uint256 leafPos = 0;
          uint256 hashPos = 0;
          uint256 proofPos = 0;
          // At each step, we compute the next hash using two values:
          // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
          //   get the next hash.
          // - depending on the flag, either another value from the "main queue" (merging branches) or an element from the
          //   `proof` array.
          for (uint256 i = 0; i < totalHashes; i++) {
              bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
              bytes32 b = proofFlags[i]
                  ? (leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++])
                  : proof[proofPos++];
              hashes[i] = _hashPair(a, b);
          }
  
          if (totalHashes > 0) {
              require(proofPos == proofLen, "MerkleProof: invalid multiproof");
              unchecked {
                  return hashes[totalHashes - 1];
              }
          } else if (leavesLen > 0) {
              return leaves[0];
          } else {
              return proof[0];
          }
      }
  
      function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
          return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
      }
  
      function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
          /// @solidity memory-safe-assembly
          assembly {
              mstore(0x00, a)
              mstore(0x20, b)
              value := keccak256(0x00, 0x40)
          }
      }
  }
  
  // OpenZeppelin Contracts (last updated v4.9.3) (token/ERC20/utils/SafeERC20.sol)
  
  // OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
  
  /**
   * @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);
  }
  
  // OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)
  
  /**
   * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
   * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
   *
   * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
   * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
   * need to send a transaction, and thus is not required to hold Ether at all.
   */
  interface IERC20Permit {
      /**
       * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
       * given ``owner``'s signed approval.
       *
       * IMPORTANT: The same issues {IERC20-approve} has related to transaction
       * ordering also apply here.
       *
       * Emits an {Approval} event.
       *
       * Requirements:
       *
       * - `spender` cannot be the zero address.
       * - `deadline` must be a timestamp in the future.
       * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
       * over the EIP712-formatted function arguments.
       * - the signature must use ``owner``'s current nonce (see {nonces}).
       *
       * For more information on the signature format, see the
       * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
       * section].
       */
      function permit(
          address owner,
          address spender,
          uint256 value,
          uint256 deadline,
          uint8 v,
          bytes32 r,
          bytes32 s
      ) external;
  
      /**
       * @dev Returns the current nonce for `owner`. This value must be
       * included whenever a signature is generated for {permit}.
       *
       * Every successful call to {permit} increases ``owner``'s nonce by one. This
       * prevents a signature from being used multiple times.
       */
      function nonces(address owner) external view returns (uint256);
  
      /**
       * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
       */
      // solhint-disable-next-line func-name-mixedcase
      function DOMAIN_SEPARATOR() external view returns (bytes32);
  }
  
  // OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
  
  /**
   * @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
       *
       * Furthermore, `isContract` will also return true if the target contract within
       * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
       * which only has an effect at the end of a transaction.
       * ====
       *
       * [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/v0.8.0/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);
          }
      }
  }
  
  /**
   * @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;
  
      /**
       * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
       * non-reverting calls are assumed to be successful.
       */
      function safeTransfer(IERC20 token, address to, uint256 value) internal {
          _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
      }
  
      /**
       * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
       * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
       */
      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));
      }
  
      /**
       * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
       * non-reverting calls are assumed to be successful.
       */
      function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
          uint256 oldAllowance = token.allowance(address(this), spender);
          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
      }
  
      /**
       * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
       * non-reverting calls are assumed to be successful.
       */
      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");
              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
          }
      }
  
      /**
       * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
       * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
       * to be set to zero before setting it to a non-zero value, such as USDT.
       */
      function forceApprove(IERC20 token, address spender, uint256 value) internal {
          bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);
  
          if (!_callOptionalReturnBool(token, approvalCall)) {
              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
              _callOptionalReturn(token, approvalCall);
          }
      }
  
      /**
       * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
       * Revert on invalid signature.
       */
      function safePermit(
          IERC20Permit token,
          address owner,
          address spender,
          uint256 value,
          uint256 deadline,
          uint8 v,
          bytes32 r,
          bytes32 s
      ) internal {
          uint256 nonceBefore = token.nonces(owner);
          token.permit(owner, spender, value, deadline, v, r, s);
          uint256 nonceAfter = token.nonces(owner);
          require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
      }
  
      /**
       * @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");
          require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
      }
  
      /**
       * @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).
       *
       * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
       */
      function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
          // 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 cannot use {Address-functionCall} here since this should return false
          // and not revert is the subcall reverts.
  
          (bool success, bytes memory returndata) = address(token).call(data);
          return
              success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
      }
  }
  
  // OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)
  
  /**
   * @dev Standard math utilities missing in the Solidity language.
   */
  library Math {
      enum Rounding {
          Down, // Toward negative infinity
          Up, // Toward infinity
          Zero // Toward zero
      }
  
      /**
       * @dev Returns the largest of two numbers.
       */
      function max(uint256 a, uint256 b) internal pure returns (uint256) {
          return a > b ? a : b;
      }
  
      /**
       * @dev Returns the smallest of two numbers.
       */
      function min(uint256 a, uint256 b) internal pure returns (uint256) {
          return a < b ? a : b;
      }
  
      /**
       * @dev Returns the average of two numbers. The result is rounded towards
       * zero.
       */
      function average(uint256 a, uint256 b) internal pure returns (uint256) {
          // (a + b) / 2 can overflow.
          return (a & b) + (a ^ b) / 2;
      }
  
      /**
       * @dev Returns the ceiling of the division of two numbers.
       *
       * This differs from standard division with `/` in that it rounds up instead
       * of rounding down.
       */
      function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
          // (a + b - 1) / b can overflow on addition, so we distribute.
          return a == 0 ? 0 : (a - 1) / b + 1;
      }
  
      /**
       * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
       * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
       * with further edits by Uniswap Labs also under MIT license.
       */
      function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
          unchecked {
              // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
              // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
              // variables such that product = prod1 * 2^256 + prod0.
              uint256 prod0; // Least significant 256 bits of the product
              uint256 prod1; // Most significant 256 bits of the product
              assembly {
                  let mm := mulmod(x, y, not(0))
                  prod0 := mul(x, y)
                  prod1 := sub(sub(mm, prod0), lt(mm, prod0))
              }
  
              // Handle non-overflow cases, 256 by 256 division.
              if (prod1 == 0) {
                  // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                  // The surrounding unchecked block does not change this fact.
                  // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                  return prod0 / denominator;
              }
  
              // Make sure the result is less than 2^256. Also prevents denominator == 0.
              require(denominator > prod1, "Math: mulDiv overflow");
  
              ///////////////////////////////////////////////
              // 512 by 256 division.
              ///////////////////////////////////////////////
  
              // Make division exact by subtracting the remainder from [prod1 prod0].
              uint256 remainder;
              assembly {
                  // Compute remainder using mulmod.
                  remainder := mulmod(x, y, denominator)
  
                  // Subtract 256 bit number from 512 bit number.
                  prod1 := sub(prod1, gt(remainder, prod0))
                  prod0 := sub(prod0, remainder)
              }
  
              // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
              // See https://cs.stackexchange.com/q/138556/92363.
  
              // Does not overflow because the denominator cannot be zero at this stage in the function.
              uint256 twos = denominator & (~denominator + 1);
              assembly {
                  // Divide denominator by twos.
                  denominator := div(denominator, twos)
  
                  // Divide [prod1 prod0] by twos.
                  prod0 := div(prod0, twos)
  
                  // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                  twos := add(div(sub(0, twos), twos), 1)
              }
  
              // Shift in bits from prod1 into prod0.
              prod0 |= prod1 * twos;
  
              // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
              // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
              // four bits. That is, denominator * inv = 1 mod 2^4.
              uint256 inverse = (3 * denominator) ^ 2;
  
              // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
              // in modular arithmetic, doubling the correct bits in each step.
              inverse *= 2 - denominator * inverse; // inverse mod 2^8
              inverse *= 2 - denominator * inverse; // inverse mod 2^16
              inverse *= 2 - denominator * inverse; // inverse mod 2^32
              inverse *= 2 - denominator * inverse; // inverse mod 2^64
              inverse *= 2 - denominator * inverse; // inverse mod 2^128
              inverse *= 2 - denominator * inverse; // inverse mod 2^256
  
              // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
              // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
              // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
              // is no longer required.
              result = prod0 * inverse;
              return result;
          }
      }
  
      /**
       * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
       */
      function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
          uint256 result = mulDiv(x, y, denominator);
          if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
              result += 1;
          }
          return result;
      }
  
      /**
       * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
       *
       * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
       */
      function sqrt(uint256 a) internal pure returns (uint256) {
          if (a == 0) {
              return 0;
          }
  
          // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
          //
          // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
          // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
          //
          // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
          // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
          // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
          //
          // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
          uint256 result = 1 << (log2(a) >> 1);
  
          // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
          // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
          // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
          // into the expected uint128 result.
          unchecked {
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              result = (result + a / result) >> 1;
              return min(result, a / result);
          }
      }
  
      /**
       * @notice Calculates sqrt(a), following the selected rounding direction.
       */
      function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = sqrt(a);
              return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
          }
      }
  
      /**
       * @dev Return the log in base 2, rounded down, of a positive value.
       * Returns 0 if given 0.
       */
      function log2(uint256 value) internal pure returns (uint256) {
          uint256 result = 0;
          unchecked {
              if (value >> 128 > 0) {
                  value >>= 128;
                  result += 128;
              }
              if (value >> 64 > 0) {
                  value >>= 64;
                  result += 64;
              }
              if (value >> 32 > 0) {
                  value >>= 32;
                  result += 32;
              }
              if (value >> 16 > 0) {
                  value >>= 16;
                  result += 16;
              }
              if (value >> 8 > 0) {
                  value >>= 8;
                  result += 8;
              }
              if (value >> 4 > 0) {
                  value >>= 4;
                  result += 4;
              }
              if (value >> 2 > 0) {
                  value >>= 2;
                  result += 2;
              }
              if (value >> 1 > 0) {
                  result += 1;
              }
          }
          return result;
      }
  
      /**
       * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
       * Returns 0 if given 0.
       */
      function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = log2(value);
              return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
          }
      }
  
      /**
       * @dev Return the log in base 10, rounded down, of a positive value.
       * Returns 0 if given 0.
       */
      function log10(uint256 value) internal pure returns (uint256) {
          uint256 result = 0;
          unchecked {
              if (value >= 10 ** 64) {
                  value /= 10 ** 64;
                  result += 64;
              }
              if (value >= 10 ** 32) {
                  value /= 10 ** 32;
                  result += 32;
              }
              if (value >= 10 ** 16) {
                  value /= 10 ** 16;
                  result += 16;
              }
              if (value >= 10 ** 8) {
                  value /= 10 ** 8;
                  result += 8;
              }
              if (value >= 10 ** 4) {
                  value /= 10 ** 4;
                  result += 4;
              }
              if (value >= 10 ** 2) {
                  value /= 10 ** 2;
                  result += 2;
              }
              if (value >= 10 ** 1) {
                  result += 1;
              }
          }
          return result;
      }
  
      /**
       * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
       * Returns 0 if given 0.
       */
      function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = log10(value);
              return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
          }
      }
  
      /**
       * @dev Return the log in base 256, rounded down, of a positive value.
       * Returns 0 if given 0.
       *
       * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
       */
      function log256(uint256 value) internal pure returns (uint256) {
          uint256 result = 0;
          unchecked {
              if (value >> 128 > 0) {
                  value >>= 128;
                  result += 16;
              }
              if (value >> 64 > 0) {
                  value >>= 64;
                  result += 8;
              }
              if (value >> 32 > 0) {
                  value >>= 32;
                  result += 4;
              }
              if (value >> 16 > 0) {
                  value >>= 16;
                  result += 2;
              }
              if (value >> 8 > 0) {
                  result += 1;
              }
          }
          return result;
      }
  
      /**
       * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
       * Returns 0 if given 0.
       */
      function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
          unchecked {
              uint256 result = log256(value);
              return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
          }
      }
  }
  
  // OpenZeppelin Contracts (last updated v4.9.0) (utils/structs/BitMaps.sol)
  
  /**
   * @dev Library for managing uint256 to bool mapping in a compact and efficient way, providing the keys are sequential.
   * Largely inspired by Uniswap's https://github.com/Uniswap/merkle-distributor/blob/master/contracts/MerkleDistributor.sol[merkle-distributor].
   */
  library BitMaps {
      struct BitMap {
          mapping(uint256 => uint256) _data;
      }
  
      /**
       * @dev Returns whether the bit at `index` is set.
       */
      function get(BitMap storage bitmap, uint256 index) internal view returns (bool) {
          uint256 bucket = index >> 8;
          uint256 mask = 1 << (index & 0xff);
          return bitmap._data[bucket] & mask != 0;
      }
  
      /**
       * @dev Sets the bit at `index` to the boolean `value`.
       */
      function setTo(BitMap storage bitmap, uint256 index, bool value) internal {
          if (value) {
              set(bitmap, index);
          } else {
              unset(bitmap, index);
          }
      }
  
      /**
       * @dev Sets the bit at `index`.
       */
      function set(BitMap storage bitmap, uint256 index) internal {
          uint256 bucket = index >> 8;
          uint256 mask = 1 << (index & 0xff);
          bitmap._data[bucket] |= mask;
      }
  
      /**
       * @dev Unsets the bit at `index`.
       */
      function unset(BitMap storage bitmap, uint256 index) internal {
          uint256 bucket = index >> 8;
          uint256 mask = 1 << (index & 0xff);
          bitmap._data[bucket] &= ~mask;
      }
  }
  
  contract Vesting {
      using BitMaps for BitMaps.BitMap;
      using SafeERC20 for IERC20;
  
      address public immutable token;
      bytes32 public immutable merkleRoot;
      uint256 public constant MAX_PERCENTAGE = 1e4;
  
      address public owner;
  
      mapping(uint256 => uint256) public claimed;
      BitMaps.BitMap private _revokedBitmap;
  
      error InvalidProof();
      error NothingToClaim();
      error InvalidDates();
      error EmptyMerkleRoot();
      error OnlyOwner();
      error AlreadyRevoked();
      error ZeroAddress();
      error CantRevokeEndedVesting();
      error UnrevocableVesting();
      error ClaimAmountGtClaimable();
      error Revoked();
  
      event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
      event Claim(address indexed account, uint256 amount);
      event VestingRevoked(address indexed account, uint256 amountUnvested);
  
      constructor(
          address _token,
          bytes32 _merkleRoot,
          address _owner
      ) {
          if (_merkleRoot == "") revert EmptyMerkleRoot();
  
          token = _token;
          merkleRoot = _merkleRoot;
  
          owner = _owner;
      }
  
      modifier onlyOwner() {
          if (msg.sender != owner) revert OnlyOwner();
          _;
      }
  
      function claim(
          uint256 index,
          address account,
          uint256 amount,
          bool revocable,
          uint256 start,
          uint256 end,
          uint256 cadence,
          uint256 percentageOnStart,
          bytes32[] calldata merkleProof,
          uint256 claimAmount
      ) public {
          bytes32 node = keccak256(
              abi.encodePacked(index, account, amount, revocable, start, end, cadence, percentageOnStart)
          );
          if (!MerkleProof.verify(merkleProof, merkleRoot, node)) revert InvalidProof();
  
          if (getRevoked(index)) revert Revoked();
  
          uint256 claimable = getClaimable(index, amount, start, end, cadence, percentageOnStart);
  
          if (claimable == 0) revert NothingToClaim();
          if (claimAmount > claimable) revert ClaimAmountGtClaimable();
  
          claimed[index] += claimAmount;
  
          IERC20(token).safeTransfer(account, claimAmount);
  
          emit Claim(account, claimAmount);
      }
  
      function stopVesting(
          uint256 index,
          address account,
          uint256 amount,
          bool revocable,
          uint256 start,
          uint256 end,
          uint256 cadence,
          uint256 percentageOnStart,
          bytes32[] calldata merkleProof
      ) external onlyOwner {
          bytes32 node = keccak256(
              abi.encodePacked(index, account, amount, revocable, start, end, cadence, percentageOnStart)
          );
          if (!MerkleProof.verify(merkleProof, merkleRoot, node)) revert InvalidProof();
  
          if (!revocable) revert UnrevocableVesting();
  
          if (getRevoked(index)) revert AlreadyRevoked();
  
          if (block.timestamp >= end) revert CantRevokeEndedVesting();
  
          uint256 claimable = getClaimable(index, amount, start, end, cadence, percentageOnStart);
  
          setRevoked(index);
  
          if (claimable != 0) {
              IERC20(token).safeTransfer(account, claimable);
              emit Claim(account, claimable);
          }
  
          uint256 rest = amount - (claimable + claimed[index]);
  
          IERC20(token).safeTransfer(owner, rest);
  
          emit VestingRevoked(account, rest);
      }
  
      function getClaimable(
          uint256 index,
          uint256 amount,
          uint256 start,
          uint256 end,
          uint256 cadence,
          uint256 percentageOnStart
      ) public view returns (uint256) {
          if (block.timestamp < start) return 0;
          if (block.timestamp > end) return amount - claimed[index];
  
          uint256 elapsed = ((block.timestamp - start) / cadence) * cadence;
  
          if (percentageOnStart != 0) {
              uint256 claimableOnStart = (percentageOnStart * amount) / MAX_PERCENTAGE;
              uint256 claimableRest = (elapsed * (amount - claimableOnStart)) / (end - start);
  
              return claimableRest + claimableOnStart - claimed[index];
          }
  
          return (elapsed * amount) / (end - start) - claimed[index];
      }
  
      function transferOwnership(address newOwner) public virtual onlyOwner {
          if (newOwner == address(0)) revert ZeroAddress();
          owner = newOwner;
      }
  
      function getRevoked(uint256 index) public view returns (bool) {
          return _revokedBitmap.get(index);
      }
  
      function setRevoked(uint256 index) internal {
          _revokedBitmap.set(index);
      }
  }