flat.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.8.0 <0.9.0;


// OpenZeppelin Contracts v4.4.1 (interfaces/IERC20.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 v4.4.1 (interfaces/IERC20Metadata.sol)




// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)





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

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

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







/// @title Gnosis Protocol v2 Order Library
/// @author Gnosis Developers
library GPv2Order {
    /// @dev The complete data for a Gnosis Protocol order. This struct contains
    /// all order parameters that are signed for submitting to GP.
    struct Data {
        IERC20 sellToken;
        IERC20 buyToken;
        address receiver;
        uint256 sellAmount;
        uint256 buyAmount;
        uint32 validTo;
        bytes32 appData;
        uint256 feeAmount;
        bytes32 kind;
        bool partiallyFillable;
        bytes32 sellTokenBalance;
        bytes32 buyTokenBalance;
    }

    /// @dev The order EIP-712 type hash for the [`GPv2Order.Data`] struct.
    ///
    /// This value is pre-computed from the following expression:
    /// ```
    /// keccak256(
    ///     "Order(" +
    ///         "address sellToken," +
    ///         "address buyToken," +
    ///         "address receiver," +
    ///         "uint256 sellAmount," +
    ///         "uint256 buyAmount," +
    ///         "uint32 validTo," +
    ///         "bytes32 appData," +
    ///         "uint256 feeAmount," +
    ///         "string kind," +
    ///         "bool partiallyFillable," +
    ///         "string sellTokenBalance," +
    ///         "string buyTokenBalance" +
    ///     ")"
    /// )
    /// ```
    bytes32 internal constant TYPE_HASH =
        hex"d5a25ba2e97094ad7d83dc28a6572da797d6b3e7fc6663bd93efb789fc17e489";

    /// @dev The marker value for a sell order for computing the order struct
    /// hash. This allows the EIP-712 compatible wallets to display a
    /// descriptive string for the order kind (instead of 0 or 1).
    ///
    /// This value is pre-computed from the following expression:
    /// ```
    /// keccak256("sell")
    /// ```
    bytes32 internal constant KIND_SELL =
        hex"f3b277728b3fee749481eb3e0b3b48980dbbab78658fc419025cb16eee346775";

    /// @dev The OrderKind marker value for a buy order for computing the order
    /// struct hash.
    ///
    /// This value is pre-computed from the following expression:
    /// ```
    /// keccak256("buy")
    /// ```
    bytes32 internal constant KIND_BUY =
        hex"6ed88e868af0a1983e3886d5f3e95a2fafbd6c3450bc229e27342283dc429ccc";

    /// @dev The TokenBalance marker value for using direct ERC20 balances for
    /// computing the order struct hash.
    ///
    /// This value is pre-computed from the following expression:
    /// ```
    /// keccak256("erc20")
    /// ```
    bytes32 internal constant BALANCE_ERC20 =
        hex"5a28e9363bb942b639270062aa6bb295f434bcdfc42c97267bf003f272060dc9";

    /// @dev The TokenBalance marker value for using Balancer Vault external
    /// balances (in order to re-use Vault ERC20 approvals) for computing the
    /// order struct hash.
    ///
    /// This value is pre-computed from the following expression:
    /// ```
    /// keccak256("external")
    /// ```
    bytes32 internal constant BALANCE_EXTERNAL =
        hex"abee3b73373acd583a130924aad6dc38cfdc44ba0555ba94ce2ff63980ea0632";

    /// @dev The TokenBalance marker value for using Balancer Vault internal
    /// balances for computing the order struct hash.
    ///
    /// This value is pre-computed from the following expression:
    /// ```
    /// keccak256("internal")
    /// ```
    bytes32 internal constant BALANCE_INTERNAL =
        hex"4ac99ace14ee0a5ef932dc609df0943ab7ac16b7583634612f8dc35a4289a6ce";

    /// @dev Marker address used to indicate that the receiver of the trade
    /// proceeds should the owner of the order.
    ///
    /// This is chosen to be `address(0)` for gas efficiency as it is expected
    /// to be the most common case.
    address internal constant RECEIVER_SAME_AS_OWNER = address(0);

    /// @dev The byte length of an order unique identifier.
    uint256 internal constant UID_LENGTH = 56;

    /// @dev Returns the actual receiver for an order. This function checks
    /// whether or not the [`receiver`] field uses the marker value to indicate
    /// it is the same as the order owner.
    ///
    /// @return receiver The actual receiver of trade proceeds.
    function actualReceiver(Data memory order, address owner)
        internal
        pure
        returns (address receiver)
    {
        if (order.receiver == RECEIVER_SAME_AS_OWNER) {
            receiver = owner;
        } else {
            receiver = order.receiver;
        }
    }

    /// @dev Return the EIP-712 signing hash for the specified order.
    ///
    /// @param order The order to compute the EIP-712 signing hash for.
    /// @param domainSeparator The EIP-712 domain separator to use.
    /// @return orderDigest The 32 byte EIP-712 struct hash.
    function hash(Data memory order, bytes32 domainSeparator)
        internal
        pure
        returns (bytes32 orderDigest)
    {
        bytes32 structHash;

        // NOTE: Compute the EIP-712 order struct hash in place. As suggested
        // in the EIP proposal, noting that the order struct has 12 fields, and
        // prefixing the type hash `(1 + 12) * 32 = 416` bytes to hash.
        // <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-712.md#rationale-for-encodedata>
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let dataStart := sub(order, 32)
            let temp := mload(dataStart)
            mstore(dataStart, TYPE_HASH)
            structHash := keccak256(dataStart, 416)
            mstore(dataStart, temp)
        }

        // NOTE: Now that we have the struct hash, compute the EIP-712 signing
        // hash using scratch memory past the free memory pointer. The signing
        // hash is computed from `"\x19\x01" || domainSeparator || structHash`.
        // <https://docs.soliditylang.org/en/v0.7.6/internals/layout_in_memory.html#layout-in-memory>
        // <https://github.com/ethereum/EIPs/blob/master/EIPS/eip-712.md#specification>
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let freeMemoryPointer := mload(0x40)
            mstore(freeMemoryPointer, "\x19\x01")
            mstore(add(freeMemoryPointer, 2), domainSeparator)
            mstore(add(freeMemoryPointer, 34), structHash)
            orderDigest := keccak256(freeMemoryPointer, 66)
        }
    }

    /// @dev Packs order UID parameters into the specified memory location. The
    /// result is equivalent to `abi.encodePacked(...)` with the difference that
    /// it allows re-using the memory for packing the order UID.
    ///
    /// This function reverts if the order UID buffer is not the correct size.
    ///
    /// @param orderUid The buffer pack the order UID parameters into.
    /// @param orderDigest The EIP-712 struct digest derived from the order
    /// parameters.
    /// @param owner The address of the user who owns this order.
    /// @param validTo The epoch time at which the order will stop being valid.
    function packOrderUidParams(
        bytes memory orderUid,
        bytes32 orderDigest,
        address owner,
        uint32 validTo
    ) internal pure {
        require(orderUid.length == UID_LENGTH, "GPv2: uid buffer overflow");

        // NOTE: Write the order UID to the allocated memory buffer. The order
        // parameters are written to memory in **reverse order** as memory
        // operations write 32-bytes at a time and we want to use a packed
        // encoding. This means, for example, that after writing the value of
        // `owner` to bytes `20:52`, writing the `orderDigest` to bytes `0:32`
        // will **overwrite** bytes `20:32`. This is desirable as addresses are
        // only 20 bytes and `20:32` should be `0`s:
        //
        //        |           1111111111222222222233333333334444444444555555
        //   byte | 01234567890123456789012345678901234567890123456789012345
        // -------+---------------------------------------------------------
        //  field | [.........orderDigest..........][......owner.......][vT]
        // -------+---------------------------------------------------------
        // mstore |                         [000000000000000000000000000.vT]
        //        |                     [00000000000.......owner.......]
        //        | [.........orderDigest..........]
        //
        // Additionally, since Solidity `bytes memory` are length prefixed,
        // 32 needs to be added to all the offsets.
        //
        // solhint-disable-next-line no-inline-assembly
        assembly {
            mstore(add(orderUid, 56), validTo)
            mstore(add(orderUid, 52), owner)
            mstore(add(orderUid, 32), orderDigest)
        }
    }

    /// @dev Extracts specific order information from the standardized unique
    /// order id of the protocol.
    ///
    /// @param orderUid The unique identifier used to represent an order in
    /// the protocol. This uid is the packed concatenation of the order digest,
    /// the validTo order parameter and the address of the user who created the
    /// order. It is used by the user to interface with the contract directly,
    /// and not by calls that are triggered by the solvers.
    /// @return orderDigest The EIP-712 signing digest derived from the order
    /// parameters.
    /// @return owner The address of the user who owns this order.
    /// @return validTo The epoch time at which the order will stop being valid.
    function extractOrderUidParams(bytes calldata orderUid)
        internal
        pure
        returns (
            bytes32 orderDigest,
            address owner,
            uint32 validTo
        )
    {
        require(orderUid.length == UID_LENGTH, "GPv2: invalid uid");

        // Use assembly to efficiently decode packed calldata.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            orderDigest := calldataload(orderUid.offset)
            owner := shr(96, calldataload(add(orderUid.offset, 32)))
            validTo := shr(224, calldataload(add(orderUid.offset, 52)))
        }
    }
}






// 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)
        }
    }
}


















/**
 * @title Enum - Collection of enums used in Safe contracts.
 * @author Richard Meissner - @rmeissner
 */
abstract contract Enum {
    enum Operation {
        Call,
        DelegateCall
    }
}




/**
 * @title SelfAuthorized - Authorizes current contract to perform actions to itself.
 * @author Richard Meissner - @rmeissner
 */
abstract contract SelfAuthorized {
    function requireSelfCall() private view {
        require(msg.sender == address(this), "GS031");
    }

    modifier authorized() {
        // Modifiers are copied around during compilation. This is a function call as it minimized the bytecode size
        requireSelfCall();
        _;
    }
}





/**
 * @title Executor - A contract that can execute transactions
 * @author Richard Meissner - @rmeissner
 */
abstract contract Executor {
    /**
     * @notice Executes either a delegatecall or a call with provided parameters.
     * @dev This method doesn't perform any sanity check of the transaction, such as:
     *      - if the contract at `to` address has code or not
     *      It is the responsibility of the caller to perform such checks.
     * @param to Destination address.
     * @param value Ether value.
     * @param data Data payload.
     * @param operation Operation type.
     * @return success boolean flag indicating if the call succeeded.
     */
    function execute(
        address to,
        uint256 value,
        bytes memory data,
        Enum.Operation operation,
        uint256 txGas
    ) internal returns (bool success) {
        if (operation == Enum.Operation.DelegateCall) {
            // solhint-disable-next-line no-inline-assembly
            assembly {
                success := delegatecall(txGas, to, add(data, 0x20), mload(data), 0, 0)
            }
        } else {
            // solhint-disable-next-line no-inline-assembly
            assembly {
                success := call(txGas, to, value, add(data, 0x20), mload(data), 0, 0)
            }
        }
    }
}


/**
 * @title Module Manager - A contract managing Safe modules
 * @notice Modules are extensions with unlimited access to a Safe that can be added to a Safe by its owners.
           ⚠️ WARNING: Modules are a security risk since they can execute arbitrary transactions, 
           so only trusted and audited modules should be added to a Safe. A malicious module can
           completely takeover a Safe.
 * @author Stefan George - @Georgi87
 * @author Richard Meissner - @rmeissner
 */
abstract contract ModuleManager is SelfAuthorized, Executor {
    event EnabledModule(address indexed module);
    event DisabledModule(address indexed module);
    event ExecutionFromModuleSuccess(address indexed module);
    event ExecutionFromModuleFailure(address indexed module);

    address internal constant SENTINEL_MODULES = address(0x1);

    mapping(address => address) internal modules;

    /**
     * @notice Setup function sets the initial storage of the contract.
     *         Optionally executes a delegate call to another contract to setup the modules.
     * @param to Optional destination address of call to execute.
     * @param data Optional data of call to execute.
     */
    function setupModules(address to, bytes memory data) internal {
        require(modules[SENTINEL_MODULES] == address(0), "GS100");
        modules[SENTINEL_MODULES] = SENTINEL_MODULES;
        if (to != address(0)) {
            require(isContract(to), "GS002");
            // Setup has to complete successfully or transaction fails.
            require(execute(to, 0, data, Enum.Operation.DelegateCall, type(uint256).max), "GS000");
        }
    }

    /**
     * @notice Enables the module `module` for the Safe.
     * @dev This can only be done via a Safe transaction.
     * @param module Module to be whitelisted.
     */
    function enableModule(address module) public authorized {
        // Module address cannot be null or sentinel.
        require(module != address(0) && module != SENTINEL_MODULES, "GS101");
        // Module cannot be added twice.
        require(modules[module] == address(0), "GS102");
        modules[module] = modules[SENTINEL_MODULES];
        modules[SENTINEL_MODULES] = module;
        emit EnabledModule(module);
    }

    /**
     * @notice Disables the module `module` for the Safe.
     * @dev This can only be done via a Safe transaction.
     * @param prevModule Previous module in the modules linked list.
     * @param module Module to be removed.
     */
    function disableModule(address prevModule, address module) public authorized {
        // Validate module address and check that it corresponds to module index.
        require(module != address(0) && module != SENTINEL_MODULES, "GS101");
        require(modules[prevModule] == module, "GS103");
        modules[prevModule] = modules[module];
        modules[module] = address(0);
        emit DisabledModule(module);
    }

    /**
     * @notice Execute `operation` (0: Call, 1: DelegateCall) to `to` with `value` (Native Token)
     * @dev Function is virtual to allow overriding for L2 singleton to emit an event for indexing.
     * @param to Destination address of module transaction.
     * @param value Ether value of module transaction.
     * @param data Data payload of module transaction.
     * @param operation Operation type of module transaction.
     * @return success Boolean flag indicating if the call succeeded.
     */
    function execTransactionFromModule(
        address to,
        uint256 value,
        bytes memory data,
        Enum.Operation operation
    ) public virtual returns (bool success) {
        // Only whitelisted modules are allowed.
        require(msg.sender != SENTINEL_MODULES && modules[msg.sender] != address(0), "GS104");
        // Execute transaction without further confirmations.
        success = execute(to, value, data, operation, type(uint256).max);
        if (success) emit ExecutionFromModuleSuccess(msg.sender);
        else emit ExecutionFromModuleFailure(msg.sender);
    }

    /**
     * @notice Execute `operation` (0: Call, 1: DelegateCall) to `to` with `value` (Native Token) and return data
     * @param to Destination address of module transaction.
     * @param value Ether value of module transaction.
     * @param data Data payload of module transaction.
     * @param operation Operation type of module transaction.
     * @return success Boolean flag indicating if the call succeeded.
     * @return returnData Data returned by the call.
     */
    function execTransactionFromModuleReturnData(
        address to,
        uint256 value,
        bytes memory data,
        Enum.Operation operation
    ) public returns (bool success, bytes memory returnData) {
        success = execTransactionFromModule(to, value, data, operation);
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Load free memory location
            let ptr := mload(0x40)
            // We allocate memory for the return data by setting the free memory location to
            // current free memory location + data size + 32 bytes for data size value
            mstore(0x40, add(ptr, add(returndatasize(), 0x20)))
            // Store the size
            mstore(ptr, returndatasize())
            // Store the data
            returndatacopy(add(ptr, 0x20), 0, returndatasize())
            // Point the return data to the correct memory location
            returnData := ptr
        }
    }

    /**
     * @notice Returns if an module is enabled
     * @return True if the module is enabled
     */
    function isModuleEnabled(address module) public view returns (bool) {
        return SENTINEL_MODULES != module && modules[module] != address(0);
    }

    /**
     * @notice Returns an array of modules.
     *         If all entries fit into a single page, the next pointer will be 0x1.
     *         If another page is present, next will be the last element of the returned array.
     * @param start Start of the page. Has to be a module or start pointer (0x1 address)
     * @param pageSize Maximum number of modules that should be returned. Has to be > 0
     * @return array Array of modules.
     * @return next Start of the next page.
     */
    function getModulesPaginated(address start, uint256 pageSize) external view returns (address[] memory array, address next) {
        require(start == SENTINEL_MODULES || isModuleEnabled(start), "GS105");
        require(pageSize > 0, "GS106");
        // Init array with max page size
        array = new address[](pageSize);

        // Populate return array
        uint256 moduleCount = 0;
        next = modules[start];
        while (next != address(0) && next != SENTINEL_MODULES && moduleCount < pageSize) {
            array[moduleCount] = next;
            next = modules[next];
            moduleCount++;
        }

        /**
          Because of the argument validation, we can assume that the loop will always iterate over the valid module list values
          and the `next` variable will either be an enabled module or a sentinel address (signalling the end). 
          
          If we haven't reached the end inside the loop, we need to set the next pointer to the last element of the modules array
          because the `next` variable (which is a module by itself) acting as a pointer to the start of the next page is neither 
          included to the current page, nor will it be included in the next one if you pass it as a start.
        */
        if (next != SENTINEL_MODULES) {
            next = array[moduleCount - 1];
        }
        // Set correct size of returned array
        // solhint-disable-next-line no-inline-assembly
        assembly {
            mstore(array, moduleCount)
        }
    }

    /**
     * @notice Returns true if `account` is a contract.
     * @dev This function will return false if invoked during the constructor of a contract,
     *      as the code is not actually created until after the constructor finishes.
     * @param account The address being queried
     */
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
}





/**
 * @title OwnerManager - Manages Safe owners and a threshold to authorize transactions.
 * @dev Uses a linked list to store the owners because the code generate by the solidity compiler
 *      is more efficient than using a dynamic array.
 * @author Stefan George - @Georgi87
 * @author Richard Meissner - @rmeissner
 */
abstract contract OwnerManager is SelfAuthorized {
    event AddedOwner(address indexed owner);
    event RemovedOwner(address indexed owner);
    event ChangedThreshold(uint256 threshold);

    address internal constant SENTINEL_OWNERS = address(0x1);

    mapping(address => address) internal owners;
    uint256 internal ownerCount;
    uint256 internal threshold;

    /**
     * @notice Sets the initial storage of the contract.
     * @param _owners List of Safe owners.
     * @param _threshold Number of required confirmations for a Safe transaction.
     */
    function setupOwners(address[] memory _owners, uint256 _threshold) internal {
        // Threshold can only be 0 at initialization.
        // Check ensures that setup function can only be called once.
        require(threshold == 0, "GS200");
        // Validate that threshold is smaller than number of added owners.
        require(_threshold <= _owners.length, "GS201");
        // There has to be at least one Safe owner.
        require(_threshold >= 1, "GS202");
        // Initializing Safe owners.
        address currentOwner = SENTINEL_OWNERS;
        for (uint256 i = 0; i < _owners.length; i++) {
            // Owner address cannot be null.
            address owner = _owners[i];
            require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this) && currentOwner != owner, "GS203");
            // No duplicate owners allowed.
            require(owners[owner] == address(0), "GS204");
            owners[currentOwner] = owner;
            currentOwner = owner;
        }
        owners[currentOwner] = SENTINEL_OWNERS;
        ownerCount = _owners.length;
        threshold = _threshold;
    }

    /**
     * @notice Adds the owner `owner` to the Safe and updates the threshold to `_threshold`.
     * @dev This can only be done via a Safe transaction.
     * @param owner New owner address.
     * @param _threshold New threshold.
     */
    function addOwnerWithThreshold(address owner, uint256 _threshold) public authorized {
        // Owner address cannot be null, the sentinel or the Safe itself.
        require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this), "GS203");
        // No duplicate owners allowed.
        require(owners[owner] == address(0), "GS204");
        owners[owner] = owners[SENTINEL_OWNERS];
        owners[SENTINEL_OWNERS] = owner;
        ownerCount++;
        emit AddedOwner(owner);
        // Change threshold if threshold was changed.
        if (threshold != _threshold) changeThreshold(_threshold);
    }

    /**
     * @notice Removes the owner `owner` from the Safe and updates the threshold to `_threshold`.
     * @dev This can only be done via a Safe transaction.
     * @param prevOwner Owner that pointed to the owner to be removed in the linked list
     * @param owner Owner address to be removed.
     * @param _threshold New threshold.
     */
    function removeOwner(address prevOwner, address owner, uint256 _threshold) public authorized {
        // Only allow to remove an owner, if threshold can still be reached.
        require(ownerCount - 1 >= _threshold, "GS201");
        // Validate owner address and check that it corresponds to owner index.
        require(owner != address(0) && owner != SENTINEL_OWNERS, "GS203");
        require(owners[prevOwner] == owner, "GS205");
        owners[prevOwner] = owners[owner];
        owners[owner] = address(0);
        ownerCount--;
        emit RemovedOwner(owner);
        // Change threshold if threshold was changed.
        if (threshold != _threshold) changeThreshold(_threshold);
    }

    /**
     * @notice Replaces the owner `oldOwner` in the Safe with `newOwner`.
     * @dev This can only be done via a Safe transaction.
     * @param prevOwner Owner that pointed to the owner to be replaced in the linked list
     * @param oldOwner Owner address to be replaced.
     * @param newOwner New owner address.
     */
    function swapOwner(address prevOwner, address oldOwner, address newOwner) public authorized {
        // Owner address cannot be null, the sentinel or the Safe itself.
        require(newOwner != address(0) && newOwner != SENTINEL_OWNERS && newOwner != address(this), "GS203");
        // No duplicate owners allowed.
        require(owners[newOwner] == address(0), "GS204");
        // Validate oldOwner address and check that it corresponds to owner index.
        require(oldOwner != address(0) && oldOwner != SENTINEL_OWNERS, "GS203");
        require(owners[prevOwner] == oldOwner, "GS205");
        owners[newOwner] = owners[oldOwner];
        owners[prevOwner] = newOwner;
        owners[oldOwner] = address(0);
        emit RemovedOwner(oldOwner);
        emit AddedOwner(newOwner);
    }

    /**
     * @notice Changes the threshold of the Safe to `_threshold`.
     * @dev This can only be done via a Safe transaction.
     * @param _threshold New threshold.
     */
    function changeThreshold(uint256 _threshold) public authorized {
        // Validate that threshold is smaller than number of owners.
        require(_threshold <= ownerCount, "GS201");
        // There has to be at least one Safe owner.
        require(_threshold >= 1, "GS202");
        threshold = _threshold;
        emit ChangedThreshold(threshold);
    }

    /**
     * @notice Returns the number of required confirmations for a Safe transaction aka the threshold.
     * @return Threshold number.
     */
    function getThreshold() public view returns (uint256) {
        return threshold;
    }

    /**
     * @notice Returns if `owner` is an owner of the Safe.
     * @return Boolean if owner is an owner of the Safe.
     */
    function isOwner(address owner) public view returns (bool) {
        return owner != SENTINEL_OWNERS && owners[owner] != address(0);
    }

    /**
     * @notice Returns a list of Safe owners.
     * @return Array of Safe owners.
     */
    function getOwners() public view returns (address[] memory) {
        address[] memory array = new address[](ownerCount);

        // populate return array
        uint256 index = 0;
        address currentOwner = owners[SENTINEL_OWNERS];
        while (currentOwner != SENTINEL_OWNERS) {
            array[index] = currentOwner;
            currentOwner = owners[currentOwner];
            index++;
        }
        return array;
    }
}






/**
 * @title Fallback Manager - A contract managing fallback calls made to this contract
 * @author Richard Meissner - @rmeissner
 */
abstract contract FallbackManager is SelfAuthorized {
    event ChangedFallbackHandler(address indexed handler);

    // keccak256("fallback_manager.handler.address")
    bytes32 internal constant FALLBACK_HANDLER_STORAGE_SLOT = 0x6c9a6c4a39284e37ed1cf53d337577d14212a4870fb976a4366c693b939918d5;

    /**
     *  @notice Internal function to set the fallback handler.
     *  @param handler contract to handle fallback calls.
     */
    function internalSetFallbackHandler(address handler) internal {
        /*
            If a fallback handler is set to self, then the following attack vector is opened:
            Imagine we have a function like this:
            function withdraw() internal authorized {
                withdrawalAddress.call.value(address(this).balance)("");
            }

            If the fallback method is triggered, the fallback handler appends the msg.sender address to the calldata and calls the fallback handler.
            A potential attacker could call a Safe with the 3 bytes signature of a withdraw function. Since 3 bytes do not create a valid signature,
            the call would end in a fallback handler. Since it appends the msg.sender address to the calldata, the attacker could craft an address 
            where the first 3 bytes of the previous calldata + the first byte of the address make up a valid function signature. The subsequent call would result in unsanctioned access to Safe's internal protected methods.
            For some reason, solidity matches the first 4 bytes of the calldata to a function signature, regardless if more data follow these 4 bytes.
        */
        require(handler != address(this), "GS400");

        bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, handler)
        }
    }

    /**
     * @notice Set Fallback Handler to `handler` for the Safe.
     * @dev Only fallback calls without value and with data will be forwarded.
     *      This can only be done via a Safe transaction.
     *      Cannot be set to the Safe itself.
     * @param handler contract to handle fallback calls.
     */
    function setFallbackHandler(address handler) public authorized {
        internalSetFallbackHandler(handler);
        emit ChangedFallbackHandler(handler);
    }

    // @notice Forwards all calls to the fallback handler if set. Returns 0 if no handler is set.
    // @dev Appends the non-padded caller address to the calldata to be optionally used in the handler
    //      The handler can make us of `HandlerContext.sol` to extract the address.
    //      This is done because in the next call frame the `msg.sender` will be FallbackManager's address
    //      and having the original caller address may enable additional verification scenarios.
    // solhint-disable-next-line payable-fallback,no-complex-fallback
    fallback() external {
        bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let handler := sload(slot)
            if iszero(handler) {
                return(0, 0)
            }
            calldatacopy(0, 0, calldatasize())
            // The msg.sender address is shifted to the left by 12 bytes to remove the padding
            // Then the address without padding is stored right after the calldata
            mstore(calldatasize(), shl(96, caller()))
            // Add 20 bytes for the address appended add the end
            let success := call(gas(), handler, 0, 0, add(calldatasize(), 20), 0, 0)
            returndatacopy(0, 0, returndatasize())
            if iszero(success) {
                revert(0, returndatasize())
            }
            return(0, returndatasize())
        }
    }
}









/// @notice More details at https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/introspection/IERC165.sol
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by `interfaceId`.
     * See the corresponding EIP section
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}


interface Guard is IERC165 {
    function checkTransaction(
        address to,
        uint256 value,
        bytes memory data,
        Enum.Operation operation,
        uint256 safeTxGas,
        uint256 baseGas,
        uint256 gasPrice,
        address gasToken,
        address payable refundReceiver,
        bytes memory signatures,
        address msgSender
    ) external;

    function checkAfterExecution(bytes32 txHash, bool success) external;
}

abstract contract BaseGuard is Guard {
    function supportsInterface(bytes4 interfaceId) external view virtual override returns (bool) {
        return
            interfaceId == type(Guard).interfaceId || // 0xe6d7a83a
            interfaceId == type(IERC165).interfaceId; // 0x01ffc9a7
    }
}

/**
 * @title Guard Manager - A contract managing transaction guards which perform pre and post-checks on Safe transactions.
 * @author Richard Meissner - @rmeissner
 */
abstract contract GuardManager is SelfAuthorized {
    event ChangedGuard(address indexed guard);

    // keccak256("guard_manager.guard.address")
    bytes32 internal constant GUARD_STORAGE_SLOT = 0x4a204f620c8c5ccdca3fd54d003badd85ba500436a431f0cbda4f558c93c34c8;

    /**
     * @dev Set a guard that checks transactions before execution
     *      This can only be done via a Safe transaction.
     *      ⚠️ IMPORTANT: Since a guard has full power to block Safe transaction execution,
     *        a broken guard can cause a denial of service for the Safe. Make sure to carefully
     *        audit the guard code and design recovery mechanisms.
     * @notice Set Transaction Guard `guard` for the Safe. Make sure you trust the guard.
     * @param guard The address of the guard to be used or the 0 address to disable the guard
     */
    function setGuard(address guard) external authorized {
        if (guard != address(0)) {
            require(Guard(guard).supportsInterface(type(Guard).interfaceId), "GS300");
        }
        bytes32 slot = GUARD_STORAGE_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, guard)
        }
        emit ChangedGuard(guard);
    }

    /**
     * @dev Internal method to retrieve the current guard
     *      We do not have a public method because we're short on bytecode size limit,
     *      to retrieve the guard address, one can use `getStorageAt` from `StorageAccessible` contract
     *      with the slot `GUARD_STORAGE_SLOT`
     * @return guard The address of the guard
     */
    function getGuard() internal view returns (address guard) {
        bytes32 slot = GUARD_STORAGE_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            guard := sload(slot)
        }
    }
}




/**
 * @title NativeCurrencyPaymentFallback - A contract that has a fallback to accept native currency payments.
 * @author Richard Meissner - @rmeissner
 */
abstract contract NativeCurrencyPaymentFallback {
    event SafeReceived(address indexed sender, uint256 value);

    /**
     * @notice Receive function accepts native currency transactions.
     * @dev Emits an event with sender and received value.
     */
    receive() external payable {
        emit SafeReceived(msg.sender, msg.value);
    }
}




/**
 * @title Singleton - Base for singleton contracts (should always be the first super contract)
 *        This contract is tightly coupled to our proxy contract (see `proxies/SafeProxy.sol`)
 * @author Richard Meissner - @rmeissner
 */
abstract contract Singleton {
    // singleton always has to be the first declared variable to ensure the same location as in the Proxy contract.
    // It should also always be ensured the address is stored alone (uses a full word)
    address private singleton;
}




/**
 * @title SignatureDecoder - Decodes signatures encoded as bytes
 * @author Richard Meissner - @rmeissner
 */
abstract contract SignatureDecoder {
    /**
     * @notice Splits signature bytes into `uint8 v, bytes32 r, bytes32 s`.
     * @dev Make sure to perform a bounds check for @param pos, to avoid out of bounds access on @param signatures
     *      The signature format is a compact form of {bytes32 r}{bytes32 s}{uint8 v}
     *      Compact means uint8 is not padded to 32 bytes.
     * @param pos Which signature to read.
     *            A prior bounds check of this parameter should be performed, to avoid out of bounds access.
     * @param signatures Concatenated {r, s, v} signatures.
     * @return v Recovery ID or Safe signature type.
     * @return r Output value r of the signature.
     * @return s Output value s of the signature.
     */
    function signatureSplit(bytes memory signatures, uint256 pos) internal pure returns (uint8 v, bytes32 r, bytes32 s) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let signaturePos := mul(0x41, pos)
            r := mload(add(signatures, add(signaturePos, 0x20)))
            s := mload(add(signatures, add(signaturePos, 0x40)))
            /**
             * Here we are loading the last 32 bytes, including 31 bytes
             * of 's'. There is no 'mload8' to do this.
             * 'byte' is not working due to the Solidity parser, so lets
             * use the second best option, 'and'
             */
            v := and(mload(add(signatures, add(signaturePos, 0x41))), 0xff)
        }
    }
}




/**
 * @title SecuredTokenTransfer - Secure token transfer.
 * @author Richard Meissner - @rmeissner
 */
abstract contract SecuredTokenTransfer {
    /**
     * @notice Transfers a token and returns a boolean if it was a success
     * @dev It checks the return data of the transfer call and returns true if the transfer was successful.
     *      It doesn't check if the `token` address is a contract or not.
     * @param token Token that should be transferred
     * @param receiver Receiver to whom the token should be transferred
     * @param amount The amount of tokens that should be transferred
     * @return transferred Returns true if the transfer was successful
     */
    function transferToken(address token, address receiver, uint256 amount) internal returns (bool transferred) {
        // 0xa9059cbb - keccack("transfer(address,uint256)")
        bytes memory data = abi.encodeWithSelector(0xa9059cbb, receiver, amount);
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // We write the return value to scratch space.
            // See https://docs.soliditylang.org/en/v0.7.6/internals/layout_in_memory.html#layout-in-memory
            let success := call(sub(gas(), 10000), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            switch returndatasize()
            case 0 {
                transferred := success
            }
            case 0x20 {
                transferred := iszero(or(iszero(success), iszero(mload(0))))
            }
            default {
                transferred := 0
            }
        }
    }
}




/**
 * @title StorageAccessible - A generic base contract that allows callers to access all internal storage.
 * @notice See https://github.com/gnosis/util-contracts/blob/bb5fe5fb5df6d8400998094fb1b32a178a47c3a1/contracts/StorageAccessible.sol
 *         It removes a method from the original contract not needed for the Safe contracts.
 * @author Gnosis Developers
 */
abstract contract StorageAccessible {
    /**
     * @notice Reads `length` bytes of storage in the currents contract
     * @param offset - the offset in the current contract's storage in words to start reading from
     * @param length - the number of words (32 bytes) of data to read
     * @return the bytes that were read.
     */
    function getStorageAt(uint256 offset, uint256 length) public view returns (bytes memory) {
        bytes memory result = new bytes(length * 32);
        for (uint256 index = 0; index < length; index++) {
            // solhint-disable-next-line no-inline-assembly
            assembly {
                let word := sload(add(offset, index))
                mstore(add(add(result, 0x20), mul(index, 0x20)), word)
            }
        }
        return result;
    }

    /**
     * @dev Performs a delegatecall on a targetContract in the context of self.
     * Internally reverts execution to avoid side effects (making it static).
     *
     * This method reverts with data equal to `abi.encode(bool(success), bytes(response))`.
     * Specifically, the `returndata` after a call to this method will be:
     * `success:bool || response.length:uint256 || response:bytes`.
     *
     * @param targetContract Address of the contract containing the code to execute.
     * @param calldataPayload Calldata that should be sent to the target contract (encoded method name and arguments).
     */
    function simulateAndRevert(address targetContract, bytes memory calldataPayload) external {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let success := delegatecall(gas(), targetContract, add(calldataPayload, 0x20), mload(calldataPayload), 0, 0)

            mstore(0x00, success)
            mstore(0x20, returndatasize())
            returndatacopy(0x40, 0, returndatasize())
            revert(0, add(returndatasize(), 0x40))
        }
    }
}




contract ISignatureValidatorConstants {
    // bytes4(keccak256("isValidSignature(bytes,bytes)")
    bytes4 internal constant EIP1271_MAGIC_VALUE = 0x20c13b0b;
}

abstract contract ISignatureValidator is ISignatureValidatorConstants {
    /**
     * @notice Legacy EIP1271 method to validate a signature.
     * @param _data Arbitrary length data signed on the behalf of address(this).
     * @param _signature Signature byte array associated with _data.
     *
     * MUST return the bytes4 magic value 0x20c13b0b when function passes.
     * MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
     * MUST allow external calls
     */
    function isValidSignature(bytes memory _data, bytes memory _signature) public view virtual returns (bytes4);
}




/**
 * @title SafeMath
 * @notice Math operations with safety checks that revert on error (overflow/underflow)
 */
library SafeMath {
    /**
     * @notice Multiplies two numbers, reverts on overflow.
     * @param a First number
     * @param b Second number
     * @return Product of a and b
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
     * @notice Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     * @param a First number
     * @param b Second number
     * @return Difference of a and b
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @notice Adds two numbers, reverts on overflow.
     * @param a First number
     * @param b Second number
     * @return Sum of a and b
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @notice Returns the largest of two numbers.
     * @param a First number
     * @param b Second number
     * @return Largest of a and b
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }
}


/**
 * @title Safe - A multisignature wallet with support for confirmations using signed messages based on EIP-712.
 * @dev Most important concepts:
 *      - Threshold: Number of required confirmations for a Safe transaction.
 *      - Owners: List of addresses that control the Safe. They are the only ones that can add/remove owners, change the threshold and
 *        approve transactions. Managed in `OwnerManager`.
 *      - Transaction Hash: Hash of a transaction is calculated using the EIP-712 typed structured data hashing scheme.
 *      - Nonce: Each transaction should have a different nonce to prevent replay attacks.
 *      - Signature: A valid signature of an owner of the Safe for a transaction hash.
 *      - Guard: Guard is a contract that can execute pre- and post- transaction checks. Managed in `GuardManager`.
 *      - Modules: Modules are contracts that can be used to extend the write functionality of a Safe. Managed in `ModuleManager`.
 *      - Fallback: Fallback handler is a contract that can provide additional read-only functional for Safe. Managed in `FallbackManager`.
 *      Note: This version of the implementation contract doesn't emit events for the sake of gas efficiency and therefore requires a tracing node for indexing/
 *      For the events-based implementation see `SafeL2.sol`.
 * @author Stefan George - @Georgi87
 * @author Richard Meissner - @rmeissner
 */
contract Safe is
    Singleton,
    NativeCurrencyPaymentFallback,
    ModuleManager,
    OwnerManager,
    SignatureDecoder,
    SecuredTokenTransfer,
    ISignatureValidatorConstants,
    FallbackManager,
    StorageAccessible,
    GuardManager
{
    using SafeMath for uint256;

    string public constant VERSION = "1.4.1";

    // keccak256(
    //     "EIP712Domain(uint256 chainId,address verifyingContract)"
    // );
    bytes32 private constant DOMAIN_SEPARATOR_TYPEHASH = 0x47e79534a245952e8b16893a336b85a3d9ea9fa8c573f3d803afb92a79469218;

    // keccak256(
    //     "SafeTx(address to,uint256 value,bytes data,uint8 operation,uint256 safeTxGas,uint256 baseGas,uint256 gasPrice,address gasToken,address refundReceiver,uint256 nonce)"
    // );
    bytes32 private constant SAFE_TX_TYPEHASH = 0xbb8310d486368db6bd6f849402fdd73ad53d316b5a4b2644ad6efe0f941286d8;

    event SafeSetup(address indexed initiator, address[] owners, uint256 threshold, address initializer, address fallbackHandler);
    event ApproveHash(bytes32 indexed approvedHash, address indexed owner);
    event SignMsg(bytes32 indexed msgHash);
    event ExecutionFailure(bytes32 indexed txHash, uint256 payment);
    event ExecutionSuccess(bytes32 indexed txHash, uint256 payment);

    uint256 public nonce;
    bytes32 private _deprecatedDomainSeparator;
    // Mapping to keep track of all message hashes that have been approved by ALL REQUIRED owners
    mapping(bytes32 => uint256) public signedMessages;
    // Mapping to keep track of all hashes (message or transaction) that have been approved by ANY owners
    mapping(address => mapping(bytes32 => uint256)) public approvedHashes;

    // This constructor ensures that this contract can only be used as a singleton for Proxy contracts
    constructor() {
        /**
         * By setting the threshold it is not possible to call setup anymore,
         * so we create a Safe with 0 owners and threshold 1.
         * This is an unusable Safe, perfect for the singleton
         */
        threshold = 1;
    }

    /**
     * @notice Sets an initial storage of the Safe contract.
     * @dev This method can only be called once.
     *      If a proxy was created without setting up, anyone can call setup and claim the proxy.
     * @param _owners List of Safe owners.
     * @param _threshold Number of required confirmations for a Safe transaction.
     * @param to Contract address for optional delegate call.
     * @param data Data payload for optional delegate call.
     * @param fallbackHandler Handler for fallback calls to this contract
     * @param paymentToken Token that should be used for the payment (0 is ETH)
     * @param payment Value that should be paid
     * @param paymentReceiver Address that should receive the payment (or 0 if tx.origin)
     */
    function setup(
        address[] calldata _owners,
        uint256 _threshold,
        address to,
        bytes calldata data,
        address fallbackHandler,
        address paymentToken,
        uint256 payment,
        address payable paymentReceiver
    ) external {
        // setupOwners checks if the Threshold is already set, therefore preventing that this method is called twice
        setupOwners(_owners, _threshold);
        if (fallbackHandler != address(0)) internalSetFallbackHandler(fallbackHandler);
        // As setupOwners can only be called if the contract has not been initialized we don't need a check for setupModules
        setupModules(to, data);

        if (payment > 0) {
            // To avoid running into issues with EIP-170 we reuse the handlePayment function (to avoid adjusting code of that has been verified we do not adjust the method itself)
            // baseGas = 0, gasPrice = 1 and gas = payment => amount = (payment + 0) * 1 = payment
            handlePayment(payment, 0, 1, paymentToken, paymentReceiver);
        }
        emit SafeSetup(msg.sender, _owners, _threshold, to, fallbackHandler);
    }

    /** @notice Executes a `operation` {0: Call, 1: DelegateCall}} transaction to `to` with `value` (Native Currency)
     *          and pays `gasPrice` * `gasLimit` in `gasToken` token to `refundReceiver`.
     * @dev The fees are always transferred, even if the user transaction fails.
     *      This method doesn't perform any sanity check of the transaction, such as:
     *      - if the contract at `to` address has code or not
     *      - if the `gasToken` is a contract or not
     *      It is the responsibility of the caller to perform such checks.
     * @param to Destination address of Safe transaction.
     * @param value Ether value of Safe transaction.
     * @param data Data payload of Safe transaction.
     * @param operation Operation type of Safe transaction.
     * @param safeTxGas Gas that should be used for the Safe transaction.
     * @param baseGas Gas costs that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
     * @param gasPrice Gas price that should be used for the payment calculation.
     * @param gasToken Token address (or 0 if ETH) that is used for the payment.
     * @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
     * @param signatures Signature data that should be verified.
     *                   Can be packed ECDSA signature ({bytes32 r}{bytes32 s}{uint8 v}), contract signature (EIP-1271) or approved hash.
     * @return success Boolean indicating transaction's success.
     */
    function execTransaction(
        address to,
        uint256 value,
        bytes calldata data,
        Enum.Operation operation,
        uint256 safeTxGas,
        uint256 baseGas,
        uint256 gasPrice,
        address gasToken,
        address payable refundReceiver,
        bytes memory signatures
    ) public payable virtual returns (bool success) {
        bytes32 txHash;
        // Use scope here to limit variable lifetime and prevent `stack too deep` errors
        {
            bytes memory txHashData = encodeTransactionData(
                // Transaction info
                to,
                value,
                data,
                operation,
                safeTxGas,
                // Payment info
                baseGas,
                gasPrice,
                gasToken,
                refundReceiver,
                // Signature info
                nonce
            );
            // Increase nonce and execute transaction.
            nonce++;
            txHash = keccak256(txHashData);
            checkSignatures(txHash, txHashData, signatures);
        }
        address guard = getGuard();
        {
            if (guard != address(0)) {
                Guard(guard).checkTransaction(
                    // Transaction info
                    to,
                    value,
                    data,
                    operation,
                    safeTxGas,
                    // Payment info
                    baseGas,
                    gasPrice,
                    gasToken,
                    refundReceiver,
                    // Signature info
                    signatures,
                    msg.sender
                );
            }
        }
        // We require some gas to emit the events (at least 2500) after the execution and some to perform code until the execution (500)
        // We also include the 1/64 in the check that is not send along with a call to counteract potential shortings because of EIP-150
        require(gasleft() >= ((safeTxGas * 64) / 63).max(safeTxGas + 2500) + 500, "GS010");
        // Use scope here to limit variable lifetime and prevent `stack too deep` errors
        {
            uint256 gasUsed = gasleft();
            // If the gasPrice is 0 we assume that nearly all available gas can be used (it is always more than safeTxGas)
            // We only substract 2500 (compared to the 3000 before) to ensure that the amount passed is still higher than safeTxGas
            success = execute(to, value, data, operation, gasPrice == 0 ? (gasleft() - 2500) : safeTxGas);
            gasUsed = gasUsed.sub(gasleft());
            // If no safeTxGas and no gasPrice was set (e.g. both are 0), then the internal tx is required to be successful
            // This makes it possible to use `estimateGas` without issues, as it searches for the minimum gas where the tx doesn't revert
            require(success || safeTxGas != 0 || gasPrice != 0, "GS013");
            // We transfer the calculated tx costs to the tx.origin to avoid sending it to intermediate contracts that have made calls
            uint256 payment = 0;
            if (gasPrice > 0) {
                payment = handlePayment(gasUsed, baseGas, gasPrice, gasToken, refundReceiver);
            }
            if (success) emit ExecutionSuccess(txHash, payment);
            else emit ExecutionFailure(txHash, payment);
        }
        {
            if (guard != address(0)) {
                Guard(guard).checkAfterExecution(txHash, success);
            }
        }
    }

    /**
     * @notice Handles the payment for a Safe transaction.
     * @param gasUsed Gas used by the Safe transaction.
     * @param baseGas Gas costs that are independent of the transaction execution (e.g. base transaction fee, signature check, payment of the refund).
     * @param gasPrice Gas price that should be used for the payment calculation.
     * @param gasToken Token address (or 0 if ETH) that is used for the payment.
     * @return payment The amount of payment made in the specified token.
     */
    function handlePayment(
        uint256 gasUsed,
        uint256 baseGas,
        uint256 gasPrice,
        address gasToken,
        address payable refundReceiver
    ) private returns (uint256 payment) {
        // solhint-disable-next-line avoid-tx-origin
        address payable receiver = refundReceiver == address(0) ? payable(tx.origin) : refundReceiver;
        if (gasToken == address(0)) {
            // For ETH we will only adjust the gas price to not be higher than the actual used gas price
            payment = gasUsed.add(baseGas).mul(gasPrice < tx.gasprice ? gasPrice : tx.gasprice);
            require(receiver.send(payment), "GS011");
        } else {
            payment = gasUsed.add(baseGas).mul(gasPrice);
            require(transferToken(gasToken, receiver, payment), "GS012");
        }
    }

    /**
     * @notice Checks whether the signature provided is valid for the provided data and hash. Reverts otherwise.
     * @param dataHash Hash of the data (could be either a message hash or transaction hash)
     * @param data That should be signed (this is passed to an external validator contract)
     * @param signatures Signature data that should be verified.
     *                   Can be packed ECDSA signature ({bytes32 r}{bytes32 s}{uint8 v}), contract signature (EIP-1271) or approved hash.
     */
    function checkSignatures(bytes32 dataHash, bytes memory data, bytes memory signatures) public view {
        // Load threshold to avoid multiple storage loads
        uint256 _threshold = threshold;
        // Check that a threshold is set
        require(_threshold > 0, "GS001");
        checkNSignatures(dataHash, data, signatures, _threshold);
    }

    /**
     * @notice Checks whether the signature provided is valid for the provided data and hash. Reverts otherwise.
     * @dev Since the EIP-1271 does an external call, be mindful of reentrancy attacks.
     * @param dataHash Hash of the data (could be either a message hash or transaction hash)
     * @param data That should be signed (this is passed to an external validator contract)
     * @param signatures Signature data that should be verified.
     *                   Can be packed ECDSA signature ({bytes32 r}{bytes32 s}{uint8 v}), contract signature (EIP-1271) or approved hash.
     * @param requiredSignatures Amount of required valid signatures.
     */
    function checkNSignatures(bytes32 dataHash, bytes memory data, bytes memory signatures, uint256 requiredSignatures) public view {
        // Check that the provided signature data is not too short
        require(signatures.length >= requiredSignatures.mul(65), "GS020");
        // There cannot be an owner with address 0.
        address lastOwner = address(0);
        address currentOwner;
        uint8 v;
        bytes32 r;
        bytes32 s;
        uint256 i;
        for (i = 0; i < requiredSignatures; i++) {
            (v, r, s) = signatureSplit(signatures, i);
            if (v == 0) {
                require(keccak256(data) == dataHash, "GS027");
                // If v is 0 then it is a contract signature
                // When handling contract signatures the address of the contract is encoded into r
                currentOwner = address(uint160(uint256(r)));

                // Check that signature data pointer (s) is not pointing inside the static part of the signatures bytes
                // This check is not completely accurate, since it is possible that more signatures than the threshold are send.
                // Here we only check that the pointer is not pointing inside the part that is being processed
                require(uint256(s) >= requiredSignatures.mul(65), "GS021");

                // Check that signature data pointer (s) is in bounds (points to the length of data -> 32 bytes)
                require(uint256(s).add(32) <= signatures.length, "GS022");

                // Check if the contract signature is in bounds: start of data is s + 32 and end is start + signature length
                uint256 contractSignatureLen;
                // solhint-disable-next-line no-inline-assembly
                assembly {
                    contractSignatureLen := mload(add(add(signatures, s), 0x20))
                }
                require(uint256(s).add(32).add(contractSignatureLen) <= signatures.length, "GS023");

                // Check signature
                bytes memory contractSignature;
                // solhint-disable-next-line no-inline-assembly
                assembly {
                    // The signature data for contract signatures is appended to the concatenated signatures and the offset is stored in s
                    contractSignature := add(add(signatures, s), 0x20)
                }
                require(ISignatureValidator(currentOwner).isValidSignature(data, contractSignature) == EIP1271_MAGIC_VALUE, "GS024");
            } else if (v == 1) {
                // If v is 1 then it is an approved hash
                // When handling approved hashes the address of the approver is encoded into r
                currentOwner = address(uint160(uint256(r)));
                // Hashes are automatically approved by the sender of the message or when they have been pre-approved via a separate transaction
                require(msg.sender == currentOwner || approvedHashes[currentOwner][dataHash] != 0, "GS025");
            } else if (v > 30) {
                // If v > 30 then default va (27,28) has been adjusted for eth_sign flow
                // To support eth_sign and similar we adjust v and hash the messageHash with the Ethereum message prefix before applying ecrecover
                currentOwner = ecrecover(keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", dataHash)), v - 4, r, s);
            } else {
                // Default is the ecrecover flow with the provided data hash
                // Use ecrecover with the messageHash for EOA signatures
                currentOwner = ecrecover(dataHash, v, r, s);
            }
            require(currentOwner > lastOwner && owners[currentOwner] != address(0) && currentOwner != SENTINEL_OWNERS, "GS026");
            lastOwner = currentOwner;
        }
    }

    /**
     * @notice Marks hash `hashToApprove` as approved.
     * @dev This can be used with a pre-approved hash transaction signature.
     *      IMPORTANT: The approved hash stays approved forever. There's no revocation mechanism, so it behaves similarly to ECDSA signatures
     * @param hashToApprove The hash to mark as approved for signatures that are verified by this contract.
     */
    function approveHash(bytes32 hashToApprove) external {
        require(owners[msg.sender] != address(0), "GS030");
        approvedHashes[msg.sender][hashToApprove] = 1;
        emit ApproveHash(hashToApprove, msg.sender);
    }

    /**
     * @notice Returns the ID of the chain the contract is currently deployed on.
     * @return The ID of the current chain as a uint256.
     */
    function getChainId() public view returns (uint256) {
        uint256 id;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            id := chainid()
        }
        return id;
    }

    /**
     * @dev Returns the domain separator for this contract, as defined in the EIP-712 standard.
     * @return bytes32 The domain separator hash.
     */
    function domainSeparator() public view returns (bytes32) {
        return keccak256(abi.encode(DOMAIN_SEPARATOR_TYPEHASH, getChainId(), this));
    }

    /**
     * @notice Returns the pre-image of the transaction hash (see getTransactionHash).
     * @param to Destination address.
     * @param value Ether value.
     * @param data Data payload.
     * @param operation Operation type.
     * @param safeTxGas Gas that should be used for the safe transaction.
     * @param baseGas Gas costs for that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
     * @param gasPrice Maximum gas price that should be used for this transaction.
     * @param gasToken Token address (or 0 if ETH) that is used for the payment.
     * @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
     * @param _nonce Transaction nonce.
     * @return Transaction hash bytes.
     */
    function encodeTransactionData(
        address to,
        uint256 value,
        bytes calldata data,
        Enum.Operation operation,
        uint256 safeTxGas,
        uint256 baseGas,
        uint256 gasPrice,
        address gasToken,
        address refundReceiver,
        uint256 _nonce
    ) public view returns (bytes memory) {
        bytes32 safeTxHash = keccak256(
            abi.encode(
                SAFE_TX_TYPEHASH,
                to,
                value,
                keccak256(data),
                operation,
                safeTxGas,
                baseGas,
                gasPrice,
                gasToken,
                refundReceiver,
                _nonce
            )
        );
        return abi.encodePacked(bytes1(0x19), bytes1(0x01), domainSeparator(), safeTxHash);
    }

    /**
     * @notice Returns transaction hash to be signed by owners.
     * @param to Destination address.
     * @param value Ether value.
     * @param data Data payload.
     * @param operation Operation type.
     * @param safeTxGas Fas that should be used for the safe transaction.
     * @param baseGas Gas costs for data used to trigger the safe transaction.
     * @param gasPrice Maximum gas price that should be used for this transaction.
     * @param gasToken Token address (or 0 if ETH) that is used for the payment.
     * @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
     * @param _nonce Transaction nonce.
     * @return Transaction hash.
     */
    function getTransactionHash(
        address to,
        uint256 value,
        bytes calldata data,
        Enum.Operation operation,
        uint256 safeTxGas,
        uint256 baseGas,
        uint256 gasPrice,
        address gasToken,
        address refundReceiver,
        uint256 _nonce
    ) public view returns (bytes32) {
        return keccak256(encodeTransactionData(to, value, data, operation, safeTxGas, baseGas, gasPrice, gasToken, refundReceiver, _nonce));
    }
}




/**
 * @title Handler Context - Allows the fallback handler to extract addition context from the calldata
 * @dev The fallback manager appends the following context to the calldata:
 *      1. Fallback manager caller address (non-padded)
 * based on https://github.com/OpenZeppelin/openzeppelin-contracts/blob/f8cc8b844a9f92f63dc55aa581f7d643a1bc5ac1/contracts/metatx/ERC2771Context.sol
 * @author Richard Meissner - @rmeissner
 */
abstract contract HandlerContext {
    /**
     * @notice Allows fetching the original caller address.
     * @dev This is only reliable in combination with a FallbackManager that supports this (e.g. Safe contract >=1.3.0).
     *      When using this functionality make sure that the linked _manager (aka msg.sender) supports this.
     *      This function does not rely on a trusted forwarder. Use the returned value only to
     *      check information against the calling manager.
     * @return sender Original caller address.
     */
    function _msgSender() internal pure returns (address sender) {
        require(msg.data.length >= 20, "Invalid calldata length");
        // The assembly code is more direct than the Solidity version using `abi.decode`.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            sender := shr(96, calldataload(sub(calldatasize(), 20)))
        }
    }

    /**
     * @notice Returns the FallbackManager address
     * @return Fallback manager address
     */
    function _manager() internal view returns (address) {
        return msg.sender;
    }
}




library MarshalLib {
    /**
     * Encode a method handler into a `bytes32` value
     * @dev The first byte of the `bytes32` value is set to 0x01 if the method is not static (`view`)
     * @dev The last 20 bytes of the `bytes32` value are set to the address of the handler contract
     * @param isStatic Whether the method is static (`view`) or not
     * @param handler The address of the handler contract implementing the `IFallbackMethod` or `IStaticFallbackMethod` interface
     */
    function encode(bool isStatic, address handler) internal pure returns (bytes32 data) {
        data = bytes32(uint256(uint160(handler)) | (isStatic ? 0 : (1 << 248)));
    }

    function encodeWithSelector(bool isStatic, bytes4 selector, address handler) internal pure returns (bytes32 data) {
        data = bytes32(uint256(uint160(handler)) | (isStatic ? 0 : (1 << 248)) | (uint256(uint32(selector)) << 216));
    }

    /**
     * Given a `bytes32` value, decode it into a method handler and return it
     * @param data The packed data to decode
     * @return isStatic Whether the method is static (`view`) or not
     * @return handler The address of the handler contract implementing the `IFallbackMethod` or `IStaticFallbackMethod` interface
     */
    function decode(bytes32 data) internal pure returns (bool isStatic, address handler) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // set isStatic to true if the left-most byte of the data is not 0x00
            isStatic := iszero(shr(248, data))
            handler := shr(96, shl(96, data))
        }
    }

    function decodeWithSelector(bytes32 data) internal pure returns (bool isStatic, bytes4 selector, address handler) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // set isStatic to true if the left-most byte of the data is not 0x00
            isStatic := iszero(shr(248, data))
            handler := shr(96, shl(96, data))
            selector := shl(168, shr(160, data))
        }
    }
}


interface IFallbackMethod {
    function handle(Safe safe, address sender, uint256 value, bytes calldata data) external returns (bytes memory result);
}

interface IStaticFallbackMethod {
    function handle(Safe safe, address sender, uint256 value, bytes calldata data) external view returns (bytes memory result);
}

/**
 * @title Base contract for Extensible Fallback Handlers
 * @dev This contract provides the base for storage and modifiers for extensible fallback handlers
 * @author mfw78 <mfw78@rndlabs.xyz>
 */
abstract contract ExtensibleBase is HandlerContext {
    // --- events ---
    event AddedSafeMethod(Safe indexed safe, bytes4 selector, bytes32 method);
    event ChangedSafeMethod(Safe indexed safe, bytes4 selector, bytes32 oldMethod, bytes32 newMethod);
    event RemovedSafeMethod(Safe indexed safe, bytes4 selector);

    // --- storage ---

    // A mapping of Safe => selector => method
    // The method is a bytes32 that is encoded as follows:
    // - The first byte is 0x00 if the method is static and 0x01 if the method is not static
    // - The last 20 bytes are the address of the handler contract
    // The method is encoded / decoded using the MarshalLib
    mapping(Safe => mapping(bytes4 => bytes32)) public safeMethods;

    // --- modifiers ---
    modifier onlySelf() {
        // Use the `HandlerContext._msgSender()` to get the caller of the fallback function
        // Use the `HandlerContext._manager()` to get the manager, which should be the Safe
        // Require that the caller is the Safe itself
        require(_msgSender() == _manager(), "only safe can call this method");
        _;
    }

    // --- internal ---

    function _setSafeMethod(Safe safe, bytes4 selector, bytes32 newMethod) internal {
        (, address newHandler) = MarshalLib.decode(newMethod);
        bytes32 oldMethod = safeMethods[safe][selector];
        (, address oldHandler) = MarshalLib.decode(oldMethod);

        if (address(newHandler) == address(0) && address(oldHandler) != address(0)) {
            delete safeMethods[safe][selector];
            emit RemovedSafeMethod(safe, selector);
        } else {
            safeMethods[safe][selector] = newMethod;
            if (address(oldHandler) == address(0)) {
                emit AddedSafeMethod(safe, selector, newMethod);
            } else {
                emit ChangedSafeMethod(safe, selector, oldMethod, newMethod);
            }
        }
    }

    /**
     * Dry code to get the Safe and the original `msg.sender` from the FallbackManager
     * @return safe The safe whose FallbackManager is making this call
     * @return sender The original `msg.sender` (as received by the FallbackManager)
     */
    function _getContext() internal view returns (Safe safe, address sender) {
        safe = Safe(payable(_manager()));
        sender = _msgSender();
    }

    /**
     * Get the context and the method handler applicable to the current call
     * @return safe The safe whose FallbackManager is making this call
     * @return sender The original `msg.sender` (as received by the FallbackManager)
     * @return isStatic Whether the method is static (`view`) or not
     * @return handler the address of the handler contract
     */
    function _getContextAndHandler() internal view returns (Safe safe, address sender, bool isStatic, address handler) {
        (safe, sender) = _getContext();
        (isStatic, handler) = MarshalLib.decode(safeMethods[safe][msg.sig]);
    }
}


interface IFallbackHandler {
    function setSafeMethod(bytes4 selector, bytes32 newMethod) external;
}

/**
 * @title FallbackHandler - A fully extensible fallback handler for Safes
 * @dev This contract provides a fallback handler for Safes that can be extended with custom fallback handlers
 *      for specific methods.
 * @author mfw78 <mfw78@rndlabs.xyz>
 */
abstract contract FallbackHandler is ExtensibleBase, IFallbackHandler {
    // --- setters ---

    /**
     * Setter for custom method handlers
     * @param selector The `bytes4` selector of the method to set the handler for
     * @param newMethod A contract that implements the `IFallbackMethod` or `IStaticFallbackMethod` interface
     */
    function setSafeMethod(bytes4 selector, bytes32 newMethod) public override onlySelf {
        _setSafeMethod(Safe(payable(_msgSender())), selector, newMethod);
    }

    // --- fallback ---

    fallback(bytes calldata) external returns (bytes memory result) {
        require(msg.data.length >= 24, "invalid method selector");
        (Safe safe, address sender, bool isStatic, address handler) = _getContextAndHandler();
        require(handler != address(0), "method handler not set");

        if (isStatic) {
            result = IStaticFallbackMethod(handler).handle(safe, sender, 0, msg.data[:msg.data.length - 20]);
        } else {
            result = IFallbackMethod(handler).handle(safe, sender, 0, msg.data[:msg.data.length - 20]);
        }
    }
}







interface ERC1271 {
    function isValidSignature(bytes32 hash, bytes calldata signature) external view returns (bytes4 magicValue);
}

/**
 * @title Safe Signature Verifier Interface
 * @author mfw78 <mfw78@rndlabs.xyz>
 * @notice This interface provides an standard for external contracts that are verifying signatures
 *         for a Safe.
 */
interface ISafeSignatureVerifier {
    /**
     * @dev If called by `SignatureVerifierMuxer`, the following has already been checked:
     *      _hash = h(abi.encodePacked("\x19\x01", domainSeparator, h(typeHash || encodeData)));
     * @param safe The Safe that has delegated the signature verification
     * @param sender The address that originally called the Safe's `isValidSignature` method
     * @param _hash The EIP-712 hash whose signature will be verified
     * @param domainSeparator The EIP-712 domainSeparator
     * @param typeHash The EIP-712 typeHash
     * @param encodeData The EIP-712 encoded data
     * @param payload An arbitrary payload that can be used to pass additional data to the verifier
     * @return magic The magic value that should be returned if the signature is valid (0x1626ba7e)
     */
    function isValidSafeSignature(
        Safe safe,
        address sender,
        bytes32 _hash,
        bytes32 domainSeparator,
        bytes32 typeHash,
        bytes calldata encodeData,
        bytes calldata payload
    ) external view returns (bytes4 magic);
}

interface ISignatureVerifierMuxer {
    function domainVerifiers(Safe safe, bytes32 domainSeparator) external view returns (ISafeSignatureVerifier);

    function setDomainVerifier(bytes32 domainSeparator, ISafeSignatureVerifier verifier) external;
}

/**
 * @title ERC-1271 Signature Verifier Multiplexer (Muxer)
 * @author mfw78 <mfw78@rndlabs.xyz>
 * @notice Allows delegating EIP-712 domains to an arbitray `ISafeSignatureVerifier`
 * @dev This multiplexer enforces a strict authorisation per domainSeparator. This is to prevent a malicious
 *     `ISafeSignatureVerifier` from being able to verify signatures for any domainSeparator. This does not prevent
 *      an `ISafeSignatureVerifier` from being able to verify signatures for multiple domainSeparators, however
 *      each domainSeparator requires specific approval by Safe.
 */
abstract contract SignatureVerifierMuxer is ExtensibleBase, ERC1271, ISignatureVerifierMuxer {
    // --- constants ---
    // keccak256("SafeMessage(bytes message)");
    bytes32 private constant SAFE_MSG_TYPEHASH = 0x60b3cbf8b4a223d68d641b3b6ddf9a298e7f33710cf3d3a9d1146b5a6150fbca;
    // keccak256("safeSignature(bytes32,bytes32,bytes,bytes)");
    bytes4 private constant SAFE_SIGNATURE_MAGIC_VALUE = 0x5fd7e97d;

    // --- storage ---
    mapping(Safe => mapping(bytes32 => ISafeSignatureVerifier)) public override domainVerifiers;

    // --- events ---
    event AddedDomainVerifier(Safe indexed safe, bytes32 domainSeparator, ISafeSignatureVerifier verifier);
    event ChangedDomainVerifier(
        Safe indexed safe,
        bytes32 domainSeparator,
        ISafeSignatureVerifier oldVerifier,
        ISafeSignatureVerifier newVerifier
    );
    event RemovedDomainVerifier(Safe indexed safe, bytes32 domainSeparator);

    /**
     * Setter for the signature muxer
     * @param domainSeparator The domainSeparator authorised for the `ISafeSignatureVerifier`
     * @param newVerifier A contract that implements `ISafeSignatureVerifier`
     */
    function setDomainVerifier(bytes32 domainSeparator, ISafeSignatureVerifier newVerifier) public override onlySelf {
        Safe safe = Safe(payable(_msgSender()));
        ISafeSignatureVerifier oldVerifier = domainVerifiers[safe][domainSeparator];
        if (address(newVerifier) == address(0) && address(oldVerifier) != address(0)) {
            delete domainVerifiers[safe][domainSeparator];
            emit RemovedDomainVerifier(safe, domainSeparator);
        } else {
            domainVerifiers[safe][domainSeparator] = newVerifier;
            if (address(oldVerifier) == address(0)) {
                emit AddedDomainVerifier(safe, domainSeparator, newVerifier);
            } else {
                emit ChangedDomainVerifier(safe, domainSeparator, oldVerifier, newVerifier);
            }
        }
    }

    /**
     * @notice Implements ERC1271 interface for smart contract EIP-712 signature validation
     * @dev The signature format is the same as the one used by the Safe contract
     * @param _hash Hash of the data that is signed
     * @param signature The signature to be verified
     * @return magic Standardised ERC1271 return value
     */
    function isValidSignature(bytes32 _hash, bytes calldata signature) external view override returns (bytes4 magic) {
        (Safe safe, address sender) = _getContext();

        // Check if the signature is for an `ISafeSignatureVerifier` and if it is valid for the domain.
        if (signature.length >= 4) {
            bytes4 sigSelector;
            // solhint-disable-next-line no-inline-assembly
            assembly {
                sigSelector := shl(224, shr(224, calldataload(signature.offset)))
            }

            // Guard against short signatures that would cause abi.decode to revert.
            if (sigSelector == SAFE_SIGNATURE_MAGIC_VALUE && signature.length >= 68) {
                // Signature is for an `ISafeSignatureVerifier` - decode the signature.
                // Layout of the `signature`:
                // 0x00 - 0x04: selector
                // 0x04 - 0x36: domainSeparator
                // 0x36 - 0x68: typeHash
                // 0x68 - 0x6C: encodeData length
                // 0x6C - 0x6C + encodeData length: encodeData
                // 0x6C + encodeData length - 0x6C + encodeData length + 0x20: payload length
                // 0x6C + encodeData length + 0x20 - end: payload
                //
                // Get the domainSeparator from the signature.
                (bytes32 domainSeparator, bytes32 typeHash) = abi.decode(signature[4:68], (bytes32, bytes32));

                ISafeSignatureVerifier verifier = domainVerifiers[safe][domainSeparator];
                // Check if there is an `ISafeSignatureVerifier` for the domain.
                if (address(verifier) != address(0)) {
                    (, , bytes memory encodeData, bytes memory payload) = abi.decode(signature[4:], (bytes32, bytes32, bytes, bytes));

                    // Check that the signature is valid for the domain.
                    if (keccak256(EIP712.encodeMessageData(domainSeparator, typeHash, encodeData)) == _hash) {
                        // Preserving the context, call the Safe's authorised `ISafeSignatureVerifier` to verify.
                        return verifier.isValidSafeSignature(safe, sender, _hash, domainSeparator, typeHash, encodeData, payload);
                    }
                }
            }
        }

        // domainVerifier doesn't exist or the signature is invalid for the domain - fall back to the default
        return defaultIsValidSignature(safe, _hash, signature);
    }

    /**
     * Default Safe signature validation (approved hashes / threshold signatures)
     * @param safe The safe being asked to validate the signature
     * @param _hash Hash of the data that is signed
     * @param signature The signature to be verified
     */
    function defaultIsValidSignature(Safe safe, bytes32 _hash, bytes memory signature) internal view returns (bytes4 magic) {
        bytes memory messageData = EIP712.encodeMessageData(
            safe.domainSeparator(),
            SAFE_MSG_TYPEHASH,
            abi.encode(keccak256(abi.encode(_hash)))
        );
        bytes32 messageHash = keccak256(messageData);
        if (signature.length == 0) {
            // approved hashes
            require(safe.signedMessages(messageHash) != 0, "Hash not approved");
        } else {
            // threshold signatures
            safe.checkSignatures(messageHash, messageData, signature);
        }
        magic = ERC1271.isValidSignature.selector;
    }
}

library EIP712 {
    function encodeMessageData(bytes32 domainSeparator, bytes32 typeHash, bytes memory message) internal pure returns (bytes memory) {
        return abi.encodePacked(bytes1(0x19), bytes1(0x01), domainSeparator, keccak256(abi.encodePacked(typeHash, message)));
    }
}







// Note: The ERC-165 identifier for this interface is 0x4e2312e0.
interface ERC1155TokenReceiver {
    /**
     * @notice Handle the receipt of a single ERC1155 token type.
     * @dev An ERC1155-compliant smart contract MUST call this function on the token recipient contract, at the end of a `safeTransferFrom` after the balance has been updated.
     *      This function MUST return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` (i.e. 0xf23a6e61) if it accepts the transfer.
     *      This function MUST revert if it rejects the transfer.
     *      Return of any other value than the prescribed keccak256 generated value MUST result in the transaction being reverted by the caller.
     * @param _operator  The address which initiated the transfer (i.e. msg.sender).
     * @param _from      The address which previously owned the token.
     * @param _id        The ID of the token being transferred.
     * @param _value     The amount of tokens being transferred.
     * @param _data      Additional data with no specified format.
     * @return           `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`.
     */
    function onERC1155Received(
        address _operator,
        address _from,
        uint256 _id,
        uint256 _value,
        bytes calldata _data
    ) external returns (bytes4);

    /**
     * @notice Handle the receipt of multiple ERC1155 token types.
     * @dev An ERC1155-compliant smart contract MUST call this function on the token recipient contract, at the end of a `safeBatchTransferFrom` after the balances have been updated.
     *      This function MUST return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` (i.e. 0xbc197c81) if it accepts the transfer(s).
     *      This function MUST revert if it rejects the transfer(s).
     *      Return of any other value than the prescribed keccak256 generated value MUST result in the transaction being reverted by the caller.
     * @param _operator  The address which initiated the batch transfer (i.e. msg.sender).
     * @param _from      The address which previously owned the token.
     * @param _ids       An array containing ids of each token being transferred (order and length must match _values array).
     * @param _values    An array containing amounts of each token being transferred (order and length must match _ids array).
     * @param _data      Additional data with no specified format.
     * @return           `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`.
     */
    function onERC1155BatchReceived(
        address _operator,
        address _from,
        uint256[] calldata _ids,
        uint256[] calldata _values,
        bytes calldata _data
    ) external returns (bytes4);
}




/// @dev Note: the ERC-165 identifier for this interface is 0x150b7a02.
interface ERC721TokenReceiver {
    /**
     * @notice Handle the receipt of an NFT
     * @dev The ERC721 smart contract calls this function on the recipient
     *  after a `transfer`. This function MAY throw to revert and reject the
     *  transfer. Return of other than the magic value MUST result in the
     *  transaction being reverted.
     *  Note: the contract address is always the message sender.
     * @param _operator The address which called `safeTransferFrom` function.
     * @param _from The address which previously owned the token.
     * @param _tokenId The NFT identifier which is being transferred.
     * @param _data Additional data with no specified format.
     * @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`.
     *  unless throwing
     */
    function onERC721Received(address _operator, address _from, uint256 _tokenId, bytes calldata _data) external returns (bytes4);
}




/**
 * @title TokenCallbacks - ERC1155 and ERC721 token callbacks for Safes
 * @author mfw78 <mfw78@rndlabs.xyz>
 * @notice Refactored from https://github.com/safe-global/safe-contracts/blob/3c3fc80f7f9aef1d39aaae2b53db5f4490051b0d/contracts/handler/TokenCallbackHandler.sol
 */
abstract contract TokenCallbacks is ExtensibleBase, ERC1155TokenReceiver, ERC721TokenReceiver {
    /**
     * @notice Handles ERC1155 Token callback.
     * return Standardized onERC1155Received return value.
     */
    function onERC1155Received(address, address, uint256, uint256, bytes calldata) external pure override returns (bytes4) {
        // Else return the standard value
        return 0xf23a6e61;
    }

    /**
     * @notice Handles ERC1155 Token batch callback.
     * return Standardized onERC1155BatchReceived return value.
     */
    function onERC1155BatchReceived(
        address,
        address,
        uint256[] calldata,
        uint256[] calldata,
        bytes calldata
    ) external pure override returns (bytes4) {
        // Else return the standard value
        return 0xbc197c81;
    }

    /**
     * @notice Handles ERC721 Token callback.
     *  return Standardized onERC721Received return value.
     */
    function onERC721Received(address, address, uint256, bytes calldata) external pure override returns (bytes4) {
        // Else return the standard value
        return 0x150b7a02;
    }
}








interface IERC165Handler {
    function safeInterfaces(Safe safe, bytes4 interfaceId) external view returns (bool);

    function setSupportedInterface(bytes4 interfaceId, bool supported) external;

    function addSupportedInterfaceBatch(bytes4 interfaceId, bytes32[] calldata handlerWithSelectors) external;

    function removeSupportedInterfaceBatch(bytes4 interfaceId, bytes4[] calldata selectors) external;
}

abstract contract ERC165Handler is ExtensibleBase, IERC165Handler {
    // --- events ---

    event AddedInterface(Safe indexed safe, bytes4 interfaceId);
    event RemovedInterface(Safe indexed safe, bytes4 interfaceId);

    // --- storage ---

    mapping(Safe => mapping(bytes4 => bool)) public override safeInterfaces;

    // --- setters ---

    /**
     * Setter to indicate if an interface is supported (and thus reported by ERC165 supportsInterface)
     * @param interfaceId The interface id whose support is to be set
     * @param supported True if the interface is supported, false otherwise
     */
    function setSupportedInterface(bytes4 interfaceId, bool supported) public override onlySelf {
        Safe safe = Safe(payable(_manager()));
        // invalid interface id per ERC165 spec
        require(interfaceId != 0xffffffff, "invalid interface id");
        bool current = safeInterfaces[safe][interfaceId];
        if (supported && !current) {
            safeInterfaces[safe][interfaceId] = true;
            emit AddedInterface(safe, interfaceId);
        } else if (!supported && current) {
            delete safeInterfaces[safe][interfaceId];
            emit RemovedInterface(safe, interfaceId);
        }
    }

    /**
     * Batch add selectors for an interface.
     * @param _interfaceId The interface id to set
     * @param handlerWithSelectors The handlers encoded with the 4-byte selectors of the methods
     */
    function addSupportedInterfaceBatch(bytes4 _interfaceId, bytes32[] calldata handlerWithSelectors) external override onlySelf {
        Safe safe = Safe(payable(_msgSender()));
        bytes4 interfaceId;
        for (uint256 i = 0; i < handlerWithSelectors.length; i++) {
            (bool isStatic, bytes4 selector, address handlerAddress) = MarshalLib.decodeWithSelector(handlerWithSelectors[i]);
            _setSafeMethod(safe, selector, MarshalLib.encode(isStatic, handlerAddress));
            if (i > 0) {
                interfaceId ^= selector;
            } else {
                interfaceId = selector;
            }
        }

        require(interfaceId == _interfaceId, "interface id mismatch");
        setSupportedInterface(_interfaceId, true);
    }

    /**
     * Batch remove selectors for an interface.
     * @param _interfaceId the interface id to remove
     * @param selectors The selectors of the methods to remove
     */
    function removeSupportedInterfaceBatch(bytes4 _interfaceId, bytes4[] calldata selectors) external override onlySelf {
        Safe safe = Safe(payable(_msgSender()));
        bytes4 interfaceId;
        for (uint256 i = 0; i < selectors.length; i++) {
            _setSafeMethod(safe, selectors[i], bytes32(0));
            if (i > 0) {
                interfaceId ^= selectors[i];
            } else {
                interfaceId = selectors[i];
            }
        }

        require(interfaceId == _interfaceId, "interface id mismatch");
        setSupportedInterface(_interfaceId, false);
    }

    /**
     * @notice Implements ERC165 interface detection for the supported interfaces
     * @dev Inheriting contracts should override `_supportsInterface` to add support for additional interfaces
     * @param interfaceId The ERC165 interface id to check
     * @return True if the interface is supported
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool) {
        return
            interfaceId == type(IERC165).interfaceId ||
            interfaceId == type(IERC165Handler).interfaceId ||
            _supportsInterface(interfaceId) ||
            safeInterfaces[Safe(payable(_manager()))][interfaceId];
    }

    // --- internal ---

    /**
     * A stub function to be overridden by inheriting contracts to add support for additional interfaces
     * @param interfaceId The interface id to check support for
     * @return True if the interface is supported
     */
    function _supportsInterface(bytes4 interfaceId) internal view virtual returns (bool);
}


/**
 * @title ExtensibleFallbackHandler - A fully extensible fallback handler for Safes
 * @dev Designed to be used with Safe >= 1.3.0.
 * @author mfw78 <mfw78@rndlabs.xyz>
 */
contract ExtensibleFallbackHandler is FallbackHandler, SignatureVerifierMuxer, TokenCallbacks, ERC165Handler {
    /**
     * Specify specific interfaces (ERC721 + ERC1155) that this contract supports.
     * @param interfaceId The interface ID to check for support
     */
    function _supportsInterface(bytes4 interfaceId) internal pure override returns (bool) {
        return
            interfaceId == type(ERC1271).interfaceId ||
            interfaceId == type(ISignatureVerifierMuxer).interfaceId ||
            interfaceId == type(ERC165Handler).interfaceId ||
            interfaceId == type(IFallbackHandler).interfaceId ||
            interfaceId == type(ERC721TokenReceiver).interfaceId ||
            interfaceId == type(ERC1155TokenReceiver).interfaceId;
    }
}









/// @title Gnosis Protocol v2 Interaction Library
/// @author Gnosis Developers
library GPv2Interaction {
    /// @dev Interaction data for performing arbitrary contract interactions.
    /// Submitted to [`GPv2Settlement.settle`] for code execution.
    struct Data {
        address target;
        uint256 value;
        bytes callData;
    }

    /// @dev Execute an arbitrary contract interaction.
    ///
    /// @param interaction Interaction data.
    function execute(Data calldata interaction) internal {
        address target = interaction.target;
        uint256 value = interaction.value;
        bytes calldata callData = interaction.callData;

        // NOTE: Use assembly to call the interaction instead of a low level
        // call for two reasons:
        // - We don't want to copy the return data, since we discard it for
        // interactions.
        // - Solidity will under certain conditions generate code to copy input
        // calldata twice to memory (the second being a "memcopy loop").
        // <https://github.com/gnosis/gp-v2-contracts/pull/417#issuecomment-775091258>
        // solhint-disable-next-line no-inline-assembly
        assembly {
            let freeMemoryPointer := mload(0x40)
            calldatacopy(freeMemoryPointer, callData.offset, callData.length)
            if iszero(
                call(
                    gas(),
                    target,
                    value,
                    freeMemoryPointer,
                    callData.length,
                    0,
                    0
                )
            ) {
                returndatacopy(0, 0, returndatasize())
                revert(0, returndatasize())
            }
        }
    }

    /// @dev Extracts the Solidity ABI selector for the specified interaction.
    ///
    /// @param interaction Interaction data.
    /// @return result The 4 byte function selector of the call encoded in
    /// this interaction.
    function selector(Data calldata interaction)
        internal
        pure
        returns (bytes4 result)
    {
        bytes calldata callData = interaction.callData;
        if (callData.length >= 4) {
            // NOTE: Read the first word of the interaction's calldata. The
            // value does not need to be shifted since `bytesN` values are left
            // aligned, and the value does not need to be masked since masking
            // occurs when the value is accessed and not stored:
            // <https://docs.soliditylang.org/en/v0.7.6/abi-spec.html#encoding-of-indexed-event-parameters>
            // <https://docs.soliditylang.org/en/v0.7.6/assembly.html#access-to-external-variables-functions-and-libraries>
            // solhint-disable-next-line no-inline-assembly
            assembly {
                result := calldataload(callData.offset)
            }
        }
    }
}



/**
 * @title Conditional Order Interface
 * @author CoW Protocol Developers + mfw78 <mfw78@rndlabs.xyz>
 */
interface IConditionalOrder {
    /// @dev This error is returned by the `getTradeableOrder` function if the order condition is not met.
    ///      A parameter of `string` type is included to allow the caller to specify the reason for the failure.
    error OrderNotValid(string);

    // --- errors specific for polling
    // Signal to a watch tower that polling should be attempted again.
    error PollTryNextBlock(string reason);
    // Signal to a watch tower that polling should be attempted again at a specific block number.
    error PollTryAtBlock(uint256 blockNumber, string reason);
    // Signal to a watch tower that polling should be attempted again at a specific epoch (unix timestamp).
    error PollTryAtEpoch(uint256 timestamp, string reason);
    // Signal to a watch tower that the conditional order should not be polled again (delete).
    error PollNever(string reason);

    /**
     * @dev This struct is used to uniquely identify a conditional order for an owner.
     *      H(handler || salt || staticInput) **MUST** be unique for an owner.
     */
    struct ConditionalOrderParams {
        IConditionalOrder handler;
        bytes32 salt;
        bytes staticInput;
    }

    /**
     * Verify if a given discrete order is valid.
     * @dev Used in combination with `isValidSafeSignature` to verify that the order is signed by the Safe.
     *      **MUST** revert if the order condition is not met.
     * @dev The `order` parameter is ignored / not validated by the `IConditionalOrderGenerator` implementation.
     *      This parameter is included to allow more granular control over the order verification logic, and to
     *      allow a watch tower / user to propose a discrete order without it being generated by on-chain logic.
     * @param owner the contract who is the owner of the order
     * @param sender the `msg.sender` of the transaction
     * @param _hash the hash of the order
     * @param domainSeparator the domain separator used to sign the order
     * @param ctx the context key of the order (bytes32(0) if a merkle tree is used, otherwise H(params)) with which to lookup the cabinet
     * @param staticInput the static input for all discrete orders cut from this conditional order
     * @param offchainInput dynamic off-chain input for a discrete order cut from this conditional order
     * @param order `GPv2Order.Data` of a discrete order to be verified (if *not* an `IConditionalOrderGenerator`).
     */
    function verify(
        address owner,
        address sender,
        bytes32 _hash,
        bytes32 domainSeparator,
        bytes32 ctx,
        bytes calldata staticInput,
        bytes calldata offchainInput,
        GPv2Order.Data calldata order
    ) external view;

    /**
     * A helper function for SDK users to verify if a given conditional order's data is valid.
     * @param data The ABI-encoded concrete order type's `Data` struct to be validated.
     * @dev Throws if the data is invalid.
     */
    function validateData(bytes memory data) external view;
}

/**
 * @title Conditional Order Generator Interface
 * @author mfw78 <mfw78@rndlabs.xyz>
 */
interface IConditionalOrderGenerator is IConditionalOrder, IERC165 {
    /**
     * @dev This event is emitted when a new conditional order is created.
     * @param owner the address that has created the conditional order
     * @param params the address / salt / data of the conditional order
     */
    event ConditionalOrderCreated(address indexed owner, IConditionalOrder.ConditionalOrderParams params);

    /**
     * @dev Get a tradeable order that can be posted to the CoW Protocol API and would pass signature validation.
     *      **MUST** revert if the order condition is not met.
     * @param owner the contract who is the owner of the order
     * @param sender the `msg.sender` of the parent `isValidSignature` call
     * @param ctx the context of the order (bytes32(0) if merkle tree is used, otherwise the H(params))
     * @param staticInput the static input for all discrete orders cut from this conditional order
     * @param offchainInput dynamic off-chain input for a discrete order cut from this conditional order
     * @return the tradeable order for submission to the CoW Protocol API
     */
    function getTradeableOrder(
        address owner,
        address sender,
        bytes32 ctx,
        bytes calldata staticInput,
        bytes calldata offchainInput
    ) external view returns (GPv2Order.Data memory);
}









/**
 * @title SwapGuard Interface - Restrict CoW Protocol settlement for an account using `ComposableCoW`.
 * @author mfw78 <mfw78@rndlabs.xyz>
 */
interface ISwapGuard is IERC165 {
    /**
     * @notice Verify that the order is allowed to be settled via CoW Protocol.
     * @param order The order to verify.
     * @param ctx The context of the order (bytes32(0) if a merkle tree is used, otherwise H(params))
     * @param params The conditional order parameters (handler, salt, staticInput).
     * @param offchainInput Any offchain input to verify.
     * @return True if the order is allowed to be settled via CoW Protocol.
     */
    function verify(
        GPv2Order.Data calldata order,
        bytes32 ctx,
        IConditionalOrder.ConditionalOrderParams calldata params,
        bytes calldata offchainInput
    ) external view returns (bool);
}




/**
 * @title IValueFactory - An interface for on-chain value determination
 * @author mfw78 <mfw78@rndlabs.xyz>
 * @dev Designed to be used with Safe + ExtensibleFallbackHandler + ComposableCoW
 */
interface IValueFactory {
    /**
     * Return a value at the time of the call
     * @param data Implementation specific off-chain data
     * @return value The value at the time of the call
     */
    function getValue(bytes calldata data) external view returns (bytes32 value);
}




interface CoWSettlement {
    function domainSeparator() external view returns (bytes32);
}


/**
 * @title ComposableCoW - A contract that allows users to create multiple conditional orders
 * @author mfw78 <mfw78@rndlabs.xyz>
 * @dev Designed to be used with Safe + ExtensibleFallbackHandler
 */
contract ComposableCoW is ISafeSignatureVerifier {
    // --- errors
    error ProofNotAuthed();
    error SingleOrderNotAuthed();
    error SwapGuardRestricted();
    error InvalidHandler();
    error InvalidFallbackHandler();
    error InterfaceNotSupported();

    // --- types

    // A struct to encapsulate order parameters / offchain input
    struct PayloadStruct {
        bytes32[] proof;
        IConditionalOrder.ConditionalOrderParams params;
        bytes offchainInput;
    }

    // A struct representing where to find the proofs
    struct Proof {
        uint256 location;
        bytes data;
    }

    // --- events

    // An event emitted when a user sets their merkle root
    event MerkleRootSet(address indexed owner, bytes32 root, Proof proof);
    event ConditionalOrderCreated(address indexed owner, IConditionalOrder.ConditionalOrderParams params);
    event SwapGuardSet(address indexed owner, ISwapGuard swapGuard);

    // --- state
    // Domain separator is only used for generating signatures
    bytes32 public immutable domainSeparator;
    /// @dev Mapping of owner's merkle roots
    mapping(address => bytes32) public roots;
    /// @dev Mapping of owner's single orders
    mapping(address => mapping(bytes32 => bool)) public singleOrders;
    // @dev Mapping of owner's swap guard
    mapping(address => ISwapGuard) public swapGuards;
    // @dev Mapping of owner's on-chain storage slots
    mapping(address => mapping(bytes32 => bytes32)) public cabinet;

    // --- constructor

    /**
     * @param _settlement The GPv2 settlement contract
     */
    constructor(address _settlement) {
        domainSeparator = CoWSettlement(_settlement).domainSeparator();
    }

    // --- setters

    /**
     * Set the merkle root of the user's conditional orders
     * @notice Set the merkle root of the user's conditional orders
     * @param root The merkle root of the user's conditional orders
     * @param proof Where to find the proofs
     */
    function setRoot(bytes32 root, Proof calldata proof) public {
        roots[msg.sender] = root;
        emit MerkleRootSet(msg.sender, root, proof);
    }

    /**
     * Set the merkle root of the user's conditional orders and store a value from on-chain in the cabinet
     * @param root The merkle root of the user's conditional orders
     * @param proof Where to find the proofs
     * @param factory A factory from which to get a value to store in the cabinet related to the merkle root
     * @param data Implementation specific off-chain data
     */
    function setRootWithContext(bytes32 root, Proof calldata proof, IValueFactory factory, bytes calldata data)
        external
    {
        setRoot(root, proof);

        // Default to the zero slot for a merkle root as this is the most common use case
        // and should save gas on calldata when reading the cabinet.

        // Set the cabinet slot
        cabinet[msg.sender][bytes32(0)] = factory.getValue(data);
    }

    /**
     * Authorise a single conditional order
     * @param params The parameters of the conditional order
     * @param dispatch Whether to dispatch the `ConditionalOrderCreated` event
     */
    function create(IConditionalOrder.ConditionalOrderParams calldata params, bool dispatch) public {
        if (!(address(params.handler) != address(0))) {
            revert InvalidHandler();
        }

        singleOrders[msg.sender][hash(params)] = true;
        if (dispatch) {
            emit ConditionalOrderCreated(msg.sender, params);
        }
    }

    /**
     * Authorise a single conditional order and store a value from on-chain in the cabinet
     * @param params The parameters of the conditional order
     * @param factory A factory from which to get a value to store in the cabinet
     * @param data Implementation specific off-chain data
     * @param dispatch Whether to dispatch the `ConditionalOrderCreated` event
     */
    function createWithContext(
        IConditionalOrder.ConditionalOrderParams calldata params,
        IValueFactory factory,
        bytes calldata data,
        bool dispatch
    ) external {
        create(params, dispatch);

        // When setting the slot, an opinionated direction is taken to tie the return value of
        // the slot to the conditional order, such that there is a guarantee or data integrity

        // Set the cabinet slot
        cabinet[msg.sender][hash(params)] = factory.getValue(data);
    }

    /**
     * Remove the authorisation of a single conditional order
     * @param singleOrderHash The hash of the single conditional order to remove
     */
    function remove(bytes32 singleOrderHash) external {
        singleOrders[msg.sender][singleOrderHash] = false;
        cabinet[msg.sender][singleOrderHash] = bytes32(0);
    }

    /**
     * Set the swap guard of the user's conditional orders
     * @param swapGuard The address of the swap guard
     */
    function setSwapGuard(ISwapGuard swapGuard) external {
        swapGuards[msg.sender] = swapGuard;
        emit SwapGuardSet(msg.sender, swapGuard);
    }

    // --- ISafeSignatureVerifier

    /**
     * @inheritdoc ISafeSignatureVerifier
     * @dev This function does not make use of the `typeHash` parameter as CoW Protocol does not
     *      have more than one type.
     * @param encodeData Is the abi encoded `GPv2Order.Data`
     * @param payload Is the abi encoded `PayloadStruct`
     */
    function isValidSafeSignature(
        Safe safe,
        address sender,
        bytes32 _hash,
        bytes32 _domainSeparator,
        bytes32, // typeHash
        bytes calldata encodeData,
        bytes calldata payload
    ) external view override returns (bytes4 magic) {
        // First decode the payload
        PayloadStruct memory _payload = abi.decode(payload, (PayloadStruct));

        // Check if the order is authorised
        bytes32 ctx = _auth(address(safe), _payload.params, _payload.proof);

        // It's an authorised order, validate it.
        GPv2Order.Data memory order = abi.decode(encodeData, (GPv2Order.Data));

        // Check with the swap guard if the order is restricted or not
        if (!(_guardCheck(address(safe), ctx, _payload.params, _payload.offchainInput, order))) {
            revert SwapGuardRestricted();
        }

        // Proof is valid, guard (if any) is valid, now check the handler
        _payload.params.handler.verify(
            address(safe),
            sender,
            _hash,
            _domainSeparator,
            ctx,
            _payload.params.staticInput,
            _payload.offchainInput,
            order
        );

        return ERC1271.isValidSignature.selector;
    }

    // --- getters

    /**
     * Get the `GPv2Order.Data` and signature for submitting to CoW Protocol API
     * @param owner of the order
     * @param params `ConditionalOrderParams` for the order
     * @param offchainInput any dynamic off-chain input for generating the discrete order
     * @param proof if using merkle-roots that H(handler || salt || staticInput) is in the merkle tree
     * @return order discrete order for submitting to CoW Protocol API
     * @return signature for submitting to CoW Protocol API
     */
    function getTradeableOrderWithSignature(
        address owner,
        IConditionalOrder.ConditionalOrderParams calldata params,
        bytes calldata offchainInput,
        bytes32[] calldata proof
    ) external view returns (GPv2Order.Data memory order, bytes memory signature) {
        // Check if the order is authorised and in doing so, get the context
        bytes32 ctx = _auth(owner, params, proof);

        // Make sure the handler supports `IConditionalOrderGenerator`
        try IConditionalOrderGenerator(address(params.handler)).supportsInterface(
            type(IConditionalOrderGenerator).interfaceId
        ) returns (bool supported) {
            if (!supported) {
                revert InterfaceNotSupported();
            }
        } catch {
            revert InterfaceNotSupported();
        }

        order = IConditionalOrderGenerator(address(params.handler)).getTradeableOrder(
            owner, msg.sender, ctx, params.staticInput, offchainInput
        );

        // Check with the swap guard if the order is restricted or not
        if (!(_guardCheck(owner, ctx, params, offchainInput, order))) {
            revert SwapGuardRestricted();
        }

        try ExtensibleFallbackHandler(owner).supportsInterface(type(ISignatureVerifierMuxer).interfaceId) returns (
            bool supported
        ) {
            if (!supported) {
                revert InvalidFallbackHandler();
            }
            signature = abi.encodeWithSignature(
                "safeSignature(bytes32,bytes32,bytes,bytes)",
                domainSeparator,
                GPv2Order.TYPE_HASH,
                abi.encode(order),
                abi.encode(PayloadStruct({params: params, offchainInput: offchainInput, proof: proof}))
            );
        } catch {
            // Assume that this is the EIP-1271 Forwarder (which does not have a `NAME` function)
            // The default signature is the abi.encode of the tuple (order, payload)
            signature = abi.encode(order, PayloadStruct({params: params, offchainInput: offchainInput, proof: proof}));
        }
    }

    // --- helper viewer functions

    /**
     * Return the hash of the conditional order parameters
     * @param params `ConditionalOrderParams` for the order
     * @return hash of the conditional order parameters
     */
    function hash(IConditionalOrder.ConditionalOrderParams memory params) public pure returns (bytes32) {
        return keccak256(abi.encode(params));
    }

    // --- internal functions

    /**
     * Check if the order has been authorised by the owner
     * @dev If `proof.length == 0`, then we use the single order auth
     * @param owner of the order whose authorisation is being checked
     * @param params that uniquely identify the order
     * @param proof to assert that H(params) is in the merkle tree (optional)
     */
    function _auth(address owner, IConditionalOrder.ConditionalOrderParams memory params, bytes32[] memory proof)
        internal
        view
        returns (bytes32 ctx)
    {
        if (proof.length != 0) {
            /// @dev Computing proof using leaf double hashing
            bytes32 leaf = keccak256(bytes.concat(hash(params)));

            // Check if the proof is valid
            if (!MerkleProof.verify(proof, roots[owner], leaf)) {
                revert ProofNotAuthed();
            }
        } else {
            // Check if the order is authorised
            ctx = hash(params);
            if (!singleOrders[owner][ctx]) {
                revert SingleOrderNotAuthed();
            }
        }
    }

    /**
     * Check the swap guard if the order is restricted or not
     * @param owner who's swap guard to check
     * @param ctx of the order (bytes32(0) if a merkle tree is used, otherwise H(params))
     * @param params that uniquely identify the order
     * @param offchainInput that has been proposed by `sender`
     * @param order GPv2Order.Data that has been proposed by `sender`
     */
    function _guardCheck(
        address owner,
        bytes32 ctx,
        IConditionalOrder.ConditionalOrderParams memory params,
        bytes memory offchainInput,
        GPv2Order.Data memory order
    ) internal view returns (bool) {
        ISwapGuard guard = swapGuards[owner];
        if (address(guard) != address(0)) {
            return guard.verify(order, ctx, params, offchainInput);
        }
        return true;
    }
}








// --- error strings
/// @dev This error is returned by the `verify` function if the *generated* order hash does not match
///      the hash passed as a parameter.
string constant INVALID_HASH = "invalid hash";

/**
 * @title Base logic for conditional orders.
 * @dev Enforces the order verification logic for conditional orders, allowing developers
 *      to focus on the logic for generating the tradeable order.
 * @author mfw78 <mfw78@rndlabs.xyz>
 */
abstract contract BaseConditionalOrder is IConditionalOrderGenerator {
    /**
     * @inheritdoc IConditionalOrder
     * @dev As an order generator, the `GPv2Order.Data` passed as a parameter is ignored / not validated.
     */
    function verify(
        address owner,
        address sender,
        bytes32 _hash,
        bytes32 domainSeparator,
        bytes32 ctx,
        bytes calldata staticInput,
        bytes calldata offchainInput,
        GPv2Order.Data calldata
    ) external view override {
        GPv2Order.Data memory generatedOrder = getTradeableOrder(owner, sender, ctx, staticInput, offchainInput);

        /// @dev Verify that the *generated* order is valid and matches the payload.
        if (!(_hash == GPv2Order.hash(generatedOrder, domainSeparator))) {
            revert IConditionalOrder.OrderNotValid(INVALID_HASH);
        }
    }

    /**
     * @dev Set the visibility of this function to `public` to allow `verify` to call it.
     * @inheritdoc IConditionalOrderGenerator
     */
    function getTradeableOrder(
        address owner,
        address sender,
        bytes32 ctx,
        bytes calldata staticInput,
        bytes calldata offchainInput
    ) public view virtual override returns (GPv2Order.Data memory);

    /**
     * @inheritdoc IERC165
     */
    function supportsInterface(bytes4 interfaceId) external view virtual override returns (bool) {
        return interfaceId == type(IConditionalOrderGenerator).interfaceId || interfaceId == type(IERC165).interfaceId;
    }

    function validateData(bytes memory data) external view virtual override {
        // --- no-op
    }
}




interface IAggregatorV3Interface {
    function decimals() external view returns (uint8);

    function description() external view returns (string memory);

    function version() external view returns (uint256);

    function getRoundData(uint80 _roundId)
        external
        view
        returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);

    function latestRoundData()
        external
        view
        returns (uint80 roundId, int256 answer, uint256 startedAt, uint256 updatedAt, uint80 answeredInRound);
}





interface IAgaveOracle {

  /// @notice Gets a list of prices from a list of assets addresses
  /// @param assets The list of assets addresses
  function getAssetsPrices(address[] calldata assets) external view returns (uint256[] memory);

	function getAssetPrice(address asset) external view returns (uint256);

}






/**
 * @title LendingPoolAddressesProvider contract
 * @dev Main registry of addresses part of or connected to the protocol, including permissioned roles
 * - Acting also as factory of proxies and admin of those, so with right to change its implementations
 * - Owned by the Aave Governance
 * @author Aave
 **/
interface ILendingPoolAddressesProvider {
  event MarketIdSet(string newMarketId);
  event LendingPoolUpdated(address indexed newAddress);
  event ConfigurationAdminUpdated(address indexed newAddress);
  event EmergencyAdminUpdated(address indexed newAddress);
  event LendingPoolConfiguratorUpdated(address indexed newAddress);
  event LendingPoolCollateralManagerUpdated(address indexed newAddress);
  event PriceOracleUpdated(address indexed newAddress);
  event LendingRateOracleUpdated(address indexed newAddress);
  event ProxyCreated(bytes32 id, address indexed newAddress);
  event AddressSet(bytes32 id, address indexed newAddress, bool hasProxy);

  function getMarketId() external view returns (string memory);

  function setMarketId(string calldata marketId) external;

  function setAddress(bytes32 id, address newAddress) external;

  function setAddressAsProxy(bytes32 id, address impl) external;

  function getAddress(bytes32 id) external view returns (address);

  function getLendingPool() external view returns (address);

  function setLendingPoolImpl(address pool) external;

  function getLendingPoolConfigurator() external view returns (address);

  function setLendingPoolConfiguratorImpl(address configurator) external;

  function getLendingPoolCollateralManager() external view returns (address);

  function setLendingPoolCollateralManager(address manager) external;

  function getPoolAdmin() external view returns (address);

  function setPoolAdmin(address admin) external;

  function getEmergencyAdmin() external view returns (address);

  function setEmergencyAdmin(address admin) external;

  function getPriceOracle() external view returns (address);

  function setPriceOracle(address priceOracle) external;

  function getLendingRateOracle() external view returns (address);

  function setLendingRateOracle(address lendingRateOracle) external;
}




library DataTypes {
    // refer to the whitepaper, section 1.1 basic concepts for a formal description of these properties.
    struct ReserveData {
    //stores the reserve configuration
        ReserveConfigurationMap configuration;
        //the liquidity index. Expressed in ray
        uint128 liquidityIndex;
        //variable borrow index. Expressed in ray
        uint128 variableBorrowIndex;
        //the current supply rate. Expressed in ray
        uint128 currentLiquidityRate;
        //the current variable borrow rate. Expressed in ray
        uint128 currentVariableBorrowRate;
        //the current stable borrow rate. Expressed in ray
        uint128 currentStableBorrowRate;
        uint40 lastUpdateTimestamp;
        //tokens addresses
        address aTokenAddress;
        address stableDebtTokenAddress;
        address variableDebtTokenAddress;
        //address of the interest rate strategy
        address interestRateStrategyAddress;
        //the id of the reserve. Represents the position in the list of the active reserves
        uint8 id;
    }

    struct ReserveConfigurationMap {
    //bit 0-15: LTV
    //bit 16-31: Liq. threshold
    //bit 32-47: Liq. bonus
    //bit 48-55: Decimals
    //bit 56: Reserve is active
    //bit 57: reserve is frozen
    //bit 58: borrowing is enabled
    //bit 59: stable rate borrowing enabled
    //bit 60-63: reserved
    //bit 64-79: reserve factor
        uint256 data;
    }

    struct UserConfigurationMap {
        uint256 data;
    }

    enum InterestRateMode {
        NONE,
        STABLE,
        VARIABLE
    }
}


interface ILendingPool {
  /**
   * @dev Emitted on deposit()
   * @param reserve The address of the underlying asset of the reserve
   * @param user The address initiating the deposit
   * @param onBehalfOf The beneficiary of the deposit, receiving the aTokens
   * @param amount The amount deposited
   * @param referral The referral code used
   **/
  event Deposit(
    address indexed reserve,
    address user,
    address indexed onBehalfOf,
    uint256 amount,
    uint16 indexed referral
  );

  /**
   * @dev Emitted on withdraw()
   * @param reserve The address of the underlyng asset being withdrawn
   * @param user The address initiating the withdrawal, owner of aTokens
   * @param to Address that will receive the underlying
   * @param amount The amount to be withdrawn
   **/
  event Withdraw(address indexed reserve, address indexed user, address indexed to, uint256 amount);

  /**
   * @dev Emitted on borrow() and flashLoan() when debt needs to be opened
   * @param reserve The address of the underlying asset being borrowed
   * @param user The address of the user initiating the borrow(), receiving the funds on borrow() or just
   * initiator of the transaction on flashLoan()
   * @param onBehalfOf The address that will be getting the debt
   * @param amount The amount borrowed out
   * @param borrowRateMode The rate mode: 1 for Stable, 2 for Variable
   * @param borrowRate The numeric rate at which the user has borrowed
   * @param referral The referral code used
   **/
  event Borrow(
    address indexed reserve,
    address user,
    address indexed onBehalfOf,
    uint256 amount,
    uint256 borrowRateMode,
    uint256 borrowRate,
    uint16 indexed referral
  );

  /**
   * @dev Emitted on repay()
   * @param reserve The address of the underlying asset of the reserve
   * @param user The beneficiary of the repayment, getting his debt reduced
   * @param repayer The address of the user initiating the repay(), providing the funds
   * @param amount The amount repaid
   **/
  event Repay(
    address indexed reserve,
    address indexed user,
    address indexed repayer,
    uint256 amount
  );

  /**
   * @dev Emitted on swapBorrowRateMode()
   * @param reserve The address of the underlying asset of the reserve
   * @param user The address of the user swapping his rate mode
   * @param rateMode The rate mode that the user wants to swap to
   **/
  event Swap(address indexed reserve, address indexed user, uint256 rateMode);

  /**
   * @dev Emitted on setUserUseReserveAsCollateral()
   * @param reserve The address of the underlying asset of the reserve
   * @param user The address of the user enabling the usage as collateral
   **/
  event ReserveUsedAsCollateralEnabled(address indexed reserve, address indexed user);

  /**
   * @dev Emitted on setUserUseReserveAsCollateral()
   * @param reserve The address of the underlying asset of the reserve
   * @param user The address of the user enabling the usage as collateral
   **/
  event ReserveUsedAsCollateralDisabled(address indexed reserve, address indexed user);

  /**
   * @dev Emitted on rebalanceStableBorrowRate()
   * @param reserve The address of the underlying asset of the reserve
   * @param user The address of the user for which the rebalance has been executed
   **/
  event RebalanceStableBorrowRate(address indexed reserve, address indexed user);

  /**
   * @dev Emitted on flashLoan()
   * @param target The address of the flash loan receiver contract
   * @param initiator The address initiating the flash loan
   * @param asset The address of the asset being flash borrowed
   * @param amount The amount flash borrowed
   * @param premium The fee flash borrowed
   * @param referralCode The referral code used
   **/
  event FlashLoan(
    address indexed target,
    address indexed initiator,
    address indexed asset,
    uint256 amount,
    uint256 premium,
    uint16 referralCode
  );

  /**
   * @dev Emitted when the pause is triggered.
   */
  event Paused();

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

  /**
   * @dev Emitted when a borrower is liquidated. This event is emitted by the LendingPool via
   * LendingPoolCollateral manager using a DELEGATECALL
   * This allows to have the events in the generated ABI for LendingPool.
   * @param collateralAsset The address of the underlying asset used as collateral, to receive as result of the liquidation
   * @param debtAsset The address of the underlying borrowed asset to be repaid with the liquidation
   * @param user The address of the borrower getting liquidated
   * @param debtToCover The debt amount of borrowed `asset` the liquidator wants to cover
   * @param liquidatedCollateralAmount The amount of collateral received by the liiquidator
   * @param liquidator The address of the liquidator
   * @param receiveAToken `true` if the liquidators wants to receive the collateral aTokens, `false` if he wants
   * to receive the underlying collateral asset directly
   **/
  event LiquidationCall(
    address indexed collateralAsset,
    address indexed debtAsset,
    address indexed user,
    uint256 debtToCover,
    uint256 liquidatedCollateralAmount,
    address liquidator,
    bool receiveAToken
  );

  /**
   * @dev Emitted when the state of a reserve is updated. NOTE: This event is actually declared
   * in the ReserveLogic library and emitted in the updateInterestRates() function. Since the function is internal,
   * the event will actually be fired by the LendingPool contract. The event is therefore replicated here so it
   * gets added to the LendingPool ABI
   * @param reserve The address of the underlying asset of the reserve
   * @param liquidityRate The new liquidity rate
   * @param stableBorrowRate The new stable borrow rate
   * @param variableBorrowRate The new variable borrow rate
   * @param liquidityIndex The new liquidity index
   * @param variableBorrowIndex The new variable borrow index
   **/
  event ReserveDataUpdated(
    address indexed reserve,
    uint256 liquidityRate,
    uint256 stableBorrowRate,
    uint256 variableBorrowRate,
    uint256 liquidityIndex,
    uint256 variableBorrowIndex
  );

  /**
   * @dev Deposits an `amount` of underlying asset into the reserve, receiving in return overlying aTokens.
   * - E.g. User deposits 100 USDC and gets in return 100 aUSDC
   * @param asset The address of the underlying asset to deposit
   * @param amount The amount to be deposited
   * @param onBehalfOf The address that will receive the aTokens, same as msg.sender if the user
   *   wants to receive them on his own wallet, or a different address if the beneficiary of aTokens
   *   is a different wallet
   * @param referralCode Code used to register the integrator originating the operation, for potential rewards.
   *   0 if the action is executed directly by the user, without any middle-man
   **/
  function deposit(
    address asset,
    uint256 amount,
    address onBehalfOf,
    uint16 referralCode
  ) external;

  /**
   * @dev Withdraws an `amount` of underlying asset from the reserve, burning the equivalent aTokens owned
   * E.g. User has 100 aUSDC, calls withdraw() and receives 100 USDC, burning the 100 aUSDC
   * @param asset The address of the underlying asset to withdraw
   * @param amount The underlying amount to be withdrawn
   *   - Send the value type(uint256).max in order to withdraw the whole aToken balance
   * @param to Address that will receive the underlying, same as msg.sender if the user
   *   wants to receive it on his own wallet, or a different address if the beneficiary is a
   *   different wallet
   * @return The final amount withdrawn
   **/
  function withdraw(
    address asset,
    uint256 amount,
    address to
  ) external returns (uint256);

  /**
   * @dev Allows users to borrow a specific `amount` of the reserve underlying asset, provided that the borrower
   * already deposited enough collateral, or he was given enough allowance by a credit delegator on the
   * corresponding debt token (StableDebtToken or VariableDebtToken)
   * - E.g. User borrows 100 USDC passing as `onBehalfOf` his own address, receiving the 100 USDC in his wallet
   *   and 100 stable/variable debt tokens, depending on the `interestRateMode`
   * @param asset The address of the underlying asset to borrow
   * @param amount The amount to be borrowed
   * @param interestRateMode The interest rate mode at which the user wants to borrow: 1 for Stable, 2 for Variable
   * @param referralCode Code used to register the integrator originating the operation, for potential rewards.
   *   0 if the action is executed directly by the user, without any middle-man
   * @param onBehalfOf Address of the user who will receive the debt. Should be the address of the borrower itself
   * calling the function if he wants to borrow against his own collateral, or the address of the credit delegator
   * if he has been given credit delegation allowance
   **/
  function borrow(
    address asset,
    uint256 amount,
    uint256 interestRateMode,
    uint16 referralCode,
    address onBehalfOf
  ) external;

  /**
   * @notice Repays a borrowed `amount` on a specific reserve, burning the equivalent debt tokens owned
   * - E.g. User repays 100 USDC, burning 100 variable/stable debt tokens of the `onBehalfOf` address
   * @param asset The address of the borrowed underlying asset previously borrowed
   * @param amount The amount to repay
   * - Send the value type(uint256).max in order to repay the whole debt for `asset` on the specific `debtMode`
   * @param rateMode The interest rate mode at of the debt the user wants to repay: 1 for Stable, 2 for Variable
   * @param onBehalfOf Address of the user who will get his debt reduced/removed. Should be the address of the
   * user calling the function if he wants to reduce/remove his own debt, or the address of any other
   * other borrower whose debt should be removed
   * @return The final amount repaid
   **/
  function repay(
    address asset,
    uint256 amount,
    uint256 rateMode,
    address onBehalfOf
  ) external returns (uint256);

    /**
   * @notice Repays a borrowed `amount` on a specific reserve, burning the equivalent debt tokens owned using deposited balance of the same asset
   * - E.g. User repays 100 agUSDC, burning 100 variable/stable debt tokens of the `onBehalfOf` address
   * @param asset The address of the borrowed underlying asset previously borrowed
   * @param amount The amount to repay
   * - Send the value type(uint256).max in order to repay the whole debt for `asset` on the specific `debtMode`
   * @param rateMode The interest rate mode at of the debt the user wants to repay: 1 for Stable, 2 for Variable
   * @param onBehalfOf Address of the user who will get his debt reduced/removed. Should be the address of the
   * user calling the function if he wants to reduce/remove his own debt, or the address of any other
   * other borrower whose debt should be removed
   * @return The final amount repaid
   **/
  function repayUsingAgToken(
    address asset,
    uint256 amount,
    uint256 rateMode,
    address onBehalfOf
  ) external returns (uint256);

  /**
   * @dev Allows a borrower to swap his debt between stable and variable mode, or viceversa
   * @param asset The address of the underlying asset borrowed
   * @param rateMode The rate mode that the user wants to swap to
   **/
  function swapBorrowRateMode(address asset, uint256 rateMode) external;

  /**
   * @dev Rebalances the stable interest rate of a user to the current stable rate defined on the reserve.
   * - Users can be rebalanced if the following conditions are satisfied:
   *     1. Usage ratio is above 95%
   *     2. the current deposit APY is below REBALANCE_UP_THRESHOLD * maxVariableBorrowRate, which means that too much has been
   *        borrowed at a stable rate and depositors are not earning enough
   * @param asset The address of the underlying asset borrowed
   * @param user The address of the user to be rebalanced
   **/
  function rebalanceStableBorrowRate(address asset, address user) external;

  /**
   * @dev Allows depositors to enable/disable a specific deposited asset as collateral
   * @param asset The address of the underlying asset deposited
   * @param useAsCollateral `true` if the user wants to use the deposit as collateral, `false` otherwise
   **/
  function setUserUseReserveAsCollateral(address asset, bool useAsCollateral) external;

  /**
   * @dev Function to liquidate a non-healthy position collateral-wise, with Health Factor below 1
   * - The caller (liquidator) covers `debtToCover` amount of debt of the user getting liquidated, and receives
   *   a proportionally amount of the `collateralAsset` plus a bonus to cover market risk
   * @param collateralAsset The address of the underlying asset used as collateral, to receive as result of the liquidation
   * @param debtAsset The address of the underlying borrowed asset to be repaid with the liquidation
   * @param user The address of the borrower getting liquidated
   * @param debtToCover The debt amount of borrowed `asset` the liquidator wants to cover
   * @param receiveAToken `true` if the liquidators wants to receive the collateral aTokens, `false` if he wants
   * to receive the underlying collateral asset directly
   **/
  function liquidationCall(
    address collateralAsset,
    address debtAsset,
    address user,
    uint256 debtToCover,
    bool receiveAToken
  ) external;

	function liquidationCallUsingAgToken(
    address collateralAsset,
    address debtAsset,
    address user,
    uint256 debtToCover,
    bool receiveAToken
  ) external;


  /**
   * @dev Allows smartcontracts to access the liquidity of the pool within one transaction,
   * as long as the amount taken plus a fee is returned.
   * IMPORTANT There are security concerns for developers of flashloan receiver contracts that must be kept into consideration.
   * For further details please visit https://developers.aave.com
   * @param receiverAddress The address of the contract receiving the funds, implementing the IFlashLoanReceiver interface
   * @param assets The addresses of the assets being flash-borrowed
   * @param amounts The amounts amounts being flash-borrowed
   * @param modes Types of the debt to open if the flash loan is not returned:
   *   0 -> Don't open any debt, just revert if funds can't be transferred from the receiver
   *   1 -> Open debt at stable rate for the value of the amount flash-borrowed to the `onBehalfOf` address
   *   2 -> Open debt at variable rate for the value of the amount flash-borrowed to the `onBehalfOf` address
   * @param onBehalfOf The address  that will receive the debt in the case of using on `modes` 1 or 2
   * @param params Variadic packed params to pass to the receiver as extra information
   * @param referralCode Code used to register the integrator originating the operation, for potential rewards.
   *   0 if the action is executed directly by the user, without any middle-man
   **/
  function flashLoan(
    address receiverAddress,
    address[] calldata assets,
    uint256[] calldata amounts,
    uint256[] calldata modes,
    address onBehalfOf,
    bytes calldata params,
    uint16 referralCode
  ) external;

  /**
   * @dev Returns the user account data across all the reserves
   * @param user The address of the user
   * @return totalCollateralETH the total collateral in ETH of the user
   * @return totalDebtETH the total debt in ETH of the user
   * @return availableBorrowsETH the borrowing power left of the user
   * @return currentLiquidationThreshold the liquidation threshold of the user
   * @return ltv the loan to value of the user
   * @return healthFactor the current health factor of the user
   **/
  function getUserAccountData(address user)
    external
    view
    returns (
      uint256 totalCollateralETH,
      uint256 totalDebtETH,
      uint256 availableBorrowsETH,
      uint256 currentLiquidationThreshold,
      uint256 ltv,
      uint256 healthFactor
    );

  function initReserve(
    address reserve,
    address aTokenAddress,
    address stableDebtAddress,
    address variableDebtAddress,
    address interestRateStrategyAddress
  ) external;

  function setReserveInterestRateStrategyAddress(address reserve, address rateStrategyAddress)
    external;

  function setConfiguration(address reserve, uint256 configuration) external;

  /**
   * @dev Returns the configuration of the reserve
   * @param asset The address of the underlying asset of the reserve
   * @return The configuration of the reserve
   **/
  function getConfiguration(address asset)
    external
    view
    returns (DataTypes.ReserveConfigurationMap memory);

  /**
   * @dev Returns the configuration of the user across all the reserves
   * @param user The user address
   * @return The configuration of the user
   **/
  function getUserConfiguration(address user)
    external
    view
    returns (DataTypes.UserConfigurationMap memory);

  /**
   * @dev Returns the normalized income normalized income of the reserve
   * @param asset The address of the underlying asset of the reserve
   * @return The reserve's normalized income
   */
  function getReserveNormalizedIncome(address asset) external view returns (uint256);

  /**
   * @dev Returns the normalized variable debt per unit of asset
   * @param asset The address of the underlying asset of the reserve
   * @return The reserve normalized variable debt
   */
  function getReserveNormalizedVariableDebt(address asset) external view returns (uint256);

  /**
   * @dev Returns the state and configuration of the reserve
   * @param asset The address of the underlying asset of the reserve
   * @return The state of the reserve
   **/
  function getReserveData(address asset) external view returns (DataTypes.ReserveData memory);

  function finalizeTransfer(
    address asset,
    address from,
    address to,
    uint256 amount,
    uint256 balanceFromAfter,
    uint256 balanceToBefore
  ) external;

  function getReservesList() external view returns (address[] memory);

  function getAddressesProvider() external view returns (ILendingPoolAddressesProvider);

  function setPause(bool val) external;

  function paused() external view returns (bool);
}


// --- error strings
/// @dev can't buy and sell the same token
string constant ERR_SAME_TOKENS = "same tokens";
/// @dev sell amount must be greater than zero
string constant ERR_MIN_SELL_AMOUNT = "sellAmount must be gt 0";

/**
 * @title Buy asset when market price below oracle price.
 * @author CoW Protocol Developers
 * @author Pogo (changes specific to )
 */
contract CornArb is BaseConditionalOrder {
    /// @dev `staticInput` data struct for buying
    struct Data {
        IERC20 sellToken;
        IERC20 buyToken;
        //address receiver;
        //uint256 sellAmount;
        bytes32 appData;
    }

    /// @dev need to know where to find ComposableCoW as this has the cabinet!
    ComposableCoW public immutable composableCow;

		ILendingPool pool = ILendingPool(0x5E15d5E33d318dCEd84Bfe3F4EACe07909bE6d9c);
		IAgaveOracle oracle = IAgaveOracle(0x062B9D1D3F5357Ef399948067E93B81F4B85db7a);
		address WBTC = 0x8e5bBbb09Ed1ebdE8674Cda39A0c169401db4252;
		address variableDebtWTBC = 0x110C5A1494F0AB6C851abB72AA2efa3dA738aB72;
		// address AGVE = 0x3a97704a1b25F08aa230ae53B352e2e72ef52843;
		// address GNO  = 0x9C58BAcC331c9aa871AFD802DB6379a98e80CEdb;
		address agaveDao = 0xb4c575308221CAA398e0DD2cDEB6B2f10d7b000A;
		address owner = 0x90AA4056945B9f4D8A9A301A6CAD95b0A7AfAfBa;

		uint immutable maxSwapWBTC;
		uint curSwapWBTC;

    constructor(ComposableCoW _composableCow) {
        composableCow = _composableCow;
				IERC20(WBTC).approve(address(pool), 1000000000000000000000 ether);
				maxSwapWBTC = 220000000;
    }

		function depositOnBehalfOfAgaveDAO() external {
				uint balance = IERC20(WBTC).balanceOf(owner);
				IERC20(WBTC).transferFrom(owner, address(this), balance);
				if (IERC20(variableDebtWTBC).balanceOf(agaveDao) >= balance){
						pool.repay(WBTC, balance, 2, agaveDao);
				} else {
						pool.deposit(WBTC, balance, agaveDao, 0x00);
				}
				curSwapWBTC += balance;
		}

		// if anything gets stuck here
		function emergencyWithdraw(address asset) external {
				require(msg.sender == owner);

				IERC20(asset).transfer(msg.sender, IERC20(asset).balanceOf(address(this)));
		}

		function transferOwnership(address newOwner) external {
				require(msg.sender == owner);

				owner = newOwner;
		}

    /**
     * If the conditions are satisfied, return the order that can be filled.
     * @param staticInput The ABI encoded `Data` struct.
     * @return order The GPv2Order.Data struct that can be filled.
     */
    function getTradeableOrder(address, address, bytes32, bytes calldata staticInput, bytes calldata)
        public
        view
        override
        returns (GPv2Order.Data memory order)
    {
        Data memory data = abi.decode(staticInput, (Data));
        _validateData(data);

				if (curSwapWBTC >= maxSwapWBTC) {
						revert("all done");
				}

				uint oracleSellTokenPrice = oracle.getAssetPrice(address(data.sellToken));
				uint sellAmount = 1 ether * 20 ether / oracleSellTokenPrice;

				if (IERC20(data.sellToken).balanceOf(owner) < sellAmount){
						revert("no balance");
				}

				uint oracleBuyTokenPrice = oracle.getAssetPrice(address(data.buyToken));

				uint decimalsBuyToken = 10**IERC20Metadata(address(data.buyToken)).decimals();
				uint decimalsSellToken = 10**IERC20Metadata(address(data.sellToken)).decimals();

				uint oracleBuyAmount = oracleSellTokenPrice  * sellAmount * decimalsBuyToken / (oracleBuyTokenPrice * decimalsSellToken);
				uint marketBuyAmount = oracleBuyAmount + oracleBuyAmount * 3 / 1000; // we want a price at least 0.3% better than oracle price, if available

        order = GPv2Order.Data(
            data.sellToken,
            data.buyToken,
            owner,
            sellAmount,
            marketBuyAmount,
            validToBucket(180), // expiry
            data.appData,
            0, // use zero fee for limit orders
            GPv2Order.KIND_SELL, // only sell order support for now
            false, // partially fillable orders are not supported
            GPv2Order.BALANCE_ERC20,
            GPv2Order.BALANCE_ERC20
        );

    }

		/**
     * Given the width of the validity bucket, return the timestamp of the *end* of the bucket.
     * @param validity The width of the validity bucket in seconds.
     */
    function validToBucket(uint32 validity) internal view returns (uint32 validTo) {
        validTo = ((uint32(block.timestamp) / validity) * validity) + validity;
    }

    /**
     * @dev External function for validating the ABI encoded data struct. Help debuggers!
     * @param data `Data` struct containing the order parameters
     * @dev Throws if the order provided is not valid.
     */
    function validateData(bytes memory data) external pure override {
        _validateData(abi.decode(data, (Data)));
    }

    /**
     * Internal method for validating the ABI encoded data struct.
     * @dev This is a gas optimisation method as it allows us to avoid ABI decoding the data struct twice.
     * @param data `Data` struct containing the order parameters
     * @dev Throws if the order provided is not valid.
     */
    function _validateData(Data memory data) internal pure {
        if (data.sellToken == data.buyToken) revert OrderNotValid(ERR_SAME_TOKENS);
    }
}