// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// 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);
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @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);
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/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));
        }
    }

    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");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (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://diligence.consensys.net/posts/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 functionCall(target, data, "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");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(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) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(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) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason 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 {
            // 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);
            }
        }
    }
}

// File: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/cryptography/MerkleProof.sol)

pragma solidity ^0.8.0;

/**
 * @dev These functions deal with verification of Merkle Tree 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.
 *
 * 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.
 */
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 proved to be a part of a Merkle tree defined by
     * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
     *
     * _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}
     *
     * _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 the sibling nodes in `proof`,
     * consuming from one or the other at each step according to the instructions given by
     * `proofFlags`.
     *
     * _Available since v4.7._
     */
    function processMultiProof(
        bytes32[] memory proof,
        bool[] memory proofFlags,
        bytes32[] memory leaves
    ) internal pure returns (bytes32 merkleRoot) {
        // This function rebuild 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 totalHashes = proofFlags.length;

        // Check proof validity.
        require(leavesLen + proof.length - 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 for 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) {
            return hashes[totalHashes - 1];
        } else if (leavesLen > 0) {
            return leaves[0];
        } else {
            return proof[0];
        }
    }

    /**
     * @dev Calldata version of {processMultiProof}
     *
     * _Available since v4.7._
     */
    function processMultiProofCalldata(
        bytes32[] calldata proof,
        bool[] calldata proofFlags,
        bytes32[] memory leaves
    ) internal pure returns (bytes32 merkleRoot) {
        // This function rebuild 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 totalHashes = proofFlags.length;

        // Check proof validity.
        require(leavesLen + proof.length - 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 for 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) {
            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)
        }
    }
}

// File: contracts/claim/TrancheVestingSale_1_3_Distributor.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

import { Distributor } from "./abstract/Distributor.sol";
import { TrancheVesting } from "./abstract/TrancheVesting.sol";
import { MerkleSet } from "./abstract/MerkleSet.sol";
import { ISaleManager_v_1_3 } from "../sale/v1.3/ISaleManager.sol";

abstract contract IERC20WithDecimals is IERC20 {
  function decimals() public view virtual returns (uint8);
}

contract TrancheVestingSale_1_3_Distributor is
  Distributor,
  TrancheVesting,
  ReentrancyGuard
{
  ISaleManager_v_1_3 public immutable saleManager;
  bytes32 public immutable saleId;

  modifier validSaleParticipant(address beneficiary) {
    require(saleManager.getSpent(saleId, beneficiary) != 0, "no purchases found");

    _;
  }

  constructor(
    ISaleManager_v_1_3 _saleManager, // where the purchase occurred
    bytes32 _saleId, // the sale id
    IERC20 _token, // the purchased token to distribute
    Tranche[] memory tranches, // vesting tranches
    uint256 voteWeightBips, // the factor for voting power (e.g. 15000 means users have a 50% voting bonus for unclaimed tokens)
    string memory uri // information on the sale (e.g. merkle proofs)
  )
    TrancheVesting(tranches)
    // initialize the distributor with the total purchased quantity from the sale
    Distributor(_token, _saleManager.spentToBought(_saleId, _saleManager.getTotalSpent(_saleId)), voteWeightBips, uri)
  {
    require(address(_saleManager) != address(0), "TVS_1_3_D: sale is address(0)");
    require(_saleId != bytes32(0), "TVS_1_3_D: sale id is bytes(0)");

    // if the ERC20 token provides decimals, ensure they match 
    int decimals = tryDecimals(_token);
    require(decimals == -1 || decimals == int(_saleManager.getDecimals(_saleId)), "token decimals do not match sale");
    require(_saleManager.isOver(_saleId), "TVS_1_3_D: sale not over");

    saleManager = _saleManager;
    saleId = _saleId;
  }

  function NAME() external override virtual pure returns (string memory) {
    return 'TrancheVestingSale_1_3_Distributor';
  }
  
  // File specific version - starts at 1, increments on every solidity diff
  function VERSION() external override virtual pure returns (uint) {
    return 3;
  }

  function tryDecimals(IERC20 _token) internal view returns (int) {
      try IERC20WithDecimals(address(_token)).decimals() returns (uint8 decimals) {
        return int(uint(decimals));
      } catch {
        return -1;
      }
  }

  function getPurchasedAmount(address buyer) public view returns (uint256) {
    /**
    Get the purchased token quantity from the sale
  
    Example: if a user buys $1.11 of a FOO token worth $0.50 each, the purchased amount will be 2.22 FOO
    Returns purchased amount: 2220000 (2.22 with 6 decimals)
    */
    return saleManager.getBought(saleId, buyer);
  }

  function initializeDistributionRecord(
    address beneficiary // the address that will receive tokens
  ) validSaleParticipant(beneficiary) external {
    _initializeDistributionRecord(beneficiary, getPurchasedAmount(beneficiary));
  }

  function claim(
    address beneficiary // the address that will receive tokens
  ) external validSaleParticipant(beneficiary) nonReentrant {
    uint256 amount = getClaimableAmount(beneficiary);

    if (!records[beneficiary].initialized) {
      _initializeDistributionRecord(beneficiary, getPurchasedAmount(beneficiary));
    }

    super._executeClaim(beneficiary, amount);
  }

  function getDistributionRecord(address beneficiary) external override view returns (DistributionRecord memory) {
    DistributionRecord memory record = records[beneficiary];

  // workaround prior to initialization
    if (!record.initialized) {
      record.total = uint120(getPurchasedAmount(beneficiary));
    }
    return record;
  }

  // get the number of tokens currently claimable by a specific user
  function getClaimableAmount(address beneficiary) public override view returns (uint256) {
    if (records[beneficiary].initialized) return super.getClaimableAmount(beneficiary);

    // we can get the claimable amount prior to initialization
    return getPurchasedAmount(beneficiary) * _getVestedBips(beneficiary, block.timestamp) / 10000;
  }
}

// File: contracts/claim/abstract/Distributor.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

import { IVotesLite } from "../interfaces/IVotesLite.sol";

abstract contract Distributor is IVotesLite {
  using SafeERC20 for IERC20;

  event InitializeDistributor(IERC20 indexed token, uint256 total, uint256 weightBips, string uri);
  event InitializeDistributionRecord(address indexed beneficiary, uint256 amount);
  event Claim(address indexed beneficiary, uint256 amount);

  struct DistributionRecord {
    bool initialized; // has the claim record been initialized
    uint120 total; // total token quantity claimable
    uint120 claimed; // token quantity already claimed
  }

  mapping (address => DistributionRecord) internal records; // track distribution records per user
  IERC20 public immutable token; // the token being claimed 
  uint256 public total; // total tokens allocated for claims
  uint256 public claimed; // tokens already claimed
  string public uri; // ipfs link on distributor info
  uint256 private immutable weightBips; // voting weight in basis points (15000 = 1.5x factor)

  // provide context on the contract name and version
  function NAME() external virtual returns (string memory);
  function VERSION() external virtual returns (uint);

  constructor (
    IERC20 _token,
    uint256 _total,
    uint256 _weightBips,
    string memory _uri
  ) {
    require(address(_token) != address(0), "Distributor: token is address(0)");
    require(_total > 0, "Distributor: total is 0");

    token = _token;
    total = _total;
    weightBips = _weightBips;
    uri = _uri;
    emit InitializeDistributor(token, total, weightBips, uri);
  }

  function _initializeDistributionRecord(address beneficiary, uint256 amount) internal {
    // CALLER MUST VERIFY THE BENEFICIARY AND AMOUNT ARE VALID!

    // Checks
    require(amount <= type(uint120).max, "Distributor: amount > type(uint120).max");
    require(amount > 0, "Distributor: amount == 0");
	  require(!records[beneficiary].initialized, "Distributor: already initialized");

    // Effects
	  records[beneficiary] = DistributionRecord(true, uint120(amount), 0);
    emit InitializeDistributionRecord(beneficiary, amount);
  }

  function _executeClaim(address beneficiary, uint256 _amount) internal {
    // Checks: NONE! THIS FUNCTION DOES NOT CHECK PERMISSIONS: CALLER MUST VERIFY THE CLAIM IS VALID!
    uint120 amount = uint120(_amount);
    require(amount > 0, "Distributor: no more tokens claimable right now");

    // effects
	  records[beneficiary].claimed += amount;
	  claimed += amount;

    // interactions
    token.safeTransfer(beneficiary, amount);
    emit Claim(beneficiary, amount);
  }

  function getVotes(
    address beneficiary
  ) external override view returns (uint256) {
    // Uninitialized claims will not have any votes! (returns 0)

    // The user can vote using tokens that are allocated to them but not yet claimed
    return (records[beneficiary].total - records[beneficiary].claimed) * weightBips / 10000;
  }

  function getVoteWeightBips(address /*beneficiary*/) external view returns (uint256) {
    return weightBips;
  }

  function getDistributionRecord(address beneficiary) external view virtual returns (DistributionRecord memory) {
    return records[beneficiary];
  }

  // Get the fraction of tokens as basis points
  function _getVestedBips(address beneficiary, uint time) public view virtual returns (uint256);

  // get the number of tokens currently claimable by a specific user
  function getClaimableAmount(address beneficiary) public view virtual returns (uint256) {
    require(records[beneficiary].initialized, "Distributor: claim not initialized");

    DistributionRecord memory record = records[beneficiary];

    uint256 claimable = record.total * _getVestedBips(beneficiary, block.timestamp) / 10000;
    return record.claimed >= claimable
      ? 0 // no more tokens to claim
      : claimable - record.claimed; // claim all available tokens
  }
}
// File: contracts/claim/abstract/MerkleSet.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

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

abstract contract MerkleSet {
  event InitializeMerkleSet(address account, uint256 amount);

  bytes32 public immutable merkleRoot;
  constructor(bytes32 _merkleRoot) {
    merkleRoot = _merkleRoot;
  }

  function _testMembership(bytes32 leaf, bytes32[] calldata merkleProof)
    internal
    view returns (bool)
  {
    return MerkleProof.verify(merkleProof, merkleRoot, leaf);
  }

  function _verifyMembership(bytes32 leaf, bytes32[] calldata merkleProof)
    internal
    view
  {
    require(_testMembership(leaf, merkleProof), "invalid proof");
  }

  modifier validMerkleProof(
    uint256 index, // the beneficiary's index in the merkle root
    address beneficiary, // the address that will receive tokens
    uint256 amount, // the total claimable by this beneficiary
    bytes32[] calldata merkleProof
  ) {
    // the merkle leaf encodes the total claimable: the amount claimed in this call is determined by _getVestedFraction()
    bytes32 leaf = keccak256(abi.encodePacked(index, beneficiary, amount));
    _verifyMembership(leaf, merkleProof);

    _;
  }
}
// File: contracts/claim/abstract/TrancheVesting.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.16;

import { Distributor } from "./Distributor.sol";

abstract contract TrancheVesting is Distributor {
  // time and vested fraction must monotonically increase in the tranche array
  struct Tranche {
    uint128 time; // block.timestamp upon which the tranche vests 
    uint128 vestedBips; // fraction of tokens unlockable as basis points (e.g. 100% of vested tokens is 10000)
  }

  Tranche[] public tranches;

  constructor(
    Tranche[] memory _tranches
  ) {
    require(_tranches.length != 0, "tranches required");

    uint128 lastTime = 0;
    uint128 lastVestedBips = 0;
  
    for (uint i = 0; i < _tranches.length;) {
      require(_tranches[i].vestedBips != 0, "tranche vested fraction == 0");
      require(_tranches[i].time > lastTime, "tranche time must increase");
      require(_tranches[i].vestedBips > lastVestedBips, "tranche vested fraction must increase");
      lastTime = _tranches[i].time;
      lastVestedBips = _tranches[i].vestedBips;
      tranches.push(_tranches[i]);
      unchecked {
        ++i;
      }
    }

    require(lastTime <= 4102444800, "vesting ends after 4102444800 (Jan 1 2100)");
    require(lastVestedBips == 10000, "last tranche must vest all tokens");
  }

  function _getVestedBips(address /*beneficiary*/, uint time) public override view returns (uint256) {
    for (uint i = tranches.length; i != 0;) {
      if (time > tranches[i - 1].time) {
        return tranches[i - 1].vestedBips;
      }
      unchecked {
        --i;
      }
    }
    return 0;
  }
}

// File: contracts/claim/interfaces/IVotesLite.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.16;
interface IVotesLite {
    // an account's current voting power
    function getVotes(address account) external view returns (uint256);
    // a weighting factor used to convert token holdings to voting power (in basis points)
    function getVoteWeightBips(address account) external view returns (uint256);
}

// File: contracts/sale/v1.3/ISaleManager.sol



pragma solidity >=0.8.0 <0.9.0;
// SPDX-License-Identifier: MIT

interface ISaleManager_v_1_3 {
	function getAdmin(bytes32 saleId) external view returns(address);
	function getRecipient(bytes32 saleId) external view returns(address);
	function getMerkleRoot(bytes32 saleId) external view returns(bytes32);
    function getPriceOracle() external view returns(address);
	function getClaimManager(bytes32 saleId) external view returns(address);
	function getSaleBuyLimit(bytes32 saleId) external view returns(uint256);
	function getUserBuyLimit(bytes32 saleId) external view returns(uint256);
	function getPurchaseMinimum(bytes32 saleId) external view returns(uint256);
	function getStartTime(bytes32 saleId) external view returns(uint);
	function getEndTime(bytes32 saleId) external view returns(uint);
	function getUri(bytes32 saleId) external view returns(string memory);
	function getPrice(bytes32 saleId) external view returns(uint);
	function getDecimals(bytes32 saleId) external view returns(uint256);
	function getTotalSpent(bytes32 saleId) external view returns(uint256);
    function getRandomValue(bytes32 saleId) external view returns(uint160);
	function getMaxQueueTime(bytes32 saleId) external view returns(uint256);
	function generateRandomishValue(bytes32 merkleRoot) external view returns(uint160);
	function getFairQueueTime(bytes32 saleId, address buyer) external view returns(uint);
	function spentToBought(bytes32 saleId, uint256 spent) external view returns (uint256);
	function nativeToPaymentToken(uint256 nativeValue) external view returns (uint256);
	function getSpent(bytes32 saleId, address userAddress) external view returns(uint256);
	function getBought(bytes32 saleId, address userAddress) external view returns(uint256);
	function isOpen(bytes32 saleId) external view returns(bool);
	function isOver(bytes32 saleId) external view returns(bool);
	function newSale(address payable recipient, bytes32 merkleRoot, uint256 saleBuyLimit, uint256 userBuyLimit, uint256 purchaseMinimum, uint startTime, uint endTime, uint160 maxQueueTime, string memory uri, uint256 price, uint8 decimals) external returns(bytes32);
	function setStart(bytes32 saleId, uint startTime) external;
	function setEnd(bytes32 saleId, uint endTime) external;
	function setMerkleRoot(bytes32 saleId, bytes32 merkleRoot) external;
	function setMaxQueueTime(bytes32 saleId, uint160 maxQueueTime) external;
	function setUriAndMerkleRoot(bytes32 saleId, bytes32 merkleRoot, string calldata uri) external;
	function buy(bytes32 saleId, uint256 tokenQuantity, bytes32[] calldata proof) external;
	function buy(bytes32 saleId, bytes32[] calldata proof) external payable;
	function registerClaimManager(bytes32 saleId, address claimManager) external;
	function recoverERC20(bytes32 saleId, address tokenAddress, uint256 tokenAmount) external;
}