pragma solidity ^0.5.2;


interface IGovernance {
    function update(address target, bytes calldata data) external;
}



contract Governable {
    IGovernance public governance;

    constructor(address _governance) public {
        governance = IGovernance(_governance);
    }

    modifier onlyGovernance() {
        _assertGovernance();
        _;
    }

    function _assertGovernance() private view {
        require(
            msg.sender == address(governance),
            "Only governance contract is authorized"
        );
    }
}



contract IWithdrawManager {
    function createExitQueue(address token) external;

    function verifyInclusion(
        bytes calldata data,
        uint8 offset,
        bool verifyTxInclusion
    ) external view returns (uint256 age);

    function addExitToQueue(
        address exitor,
        address childToken,
        address rootToken,
        uint256 exitAmountOrTokenId,
        bytes32 txHash,
        bool isRegularExit,
        uint256 priority
    ) external;

    function addInput(
        uint256 exitId,
        uint256 age,
        address utxoOwner,
        address token
    ) external;

    function challengeExit(
        uint256 exitId,
        uint256 inputId,
        bytes calldata challengeData,
        address adjudicatorPredicate
    ) external;
}




contract Registry is Governable {
    // @todo hardcode constants
    bytes32 private constant WETH_TOKEN = keccak256("wethToken");
    bytes32 private constant DEPOSIT_MANAGER = keccak256("depositManager");
    bytes32 private constant STAKE_MANAGER = keccak256("stakeManager");
    bytes32 private constant VALIDATOR_SHARE = keccak256("validatorShare");
    bytes32 private constant WITHDRAW_MANAGER = keccak256("withdrawManager");
    bytes32 private constant CHILD_CHAIN = keccak256("childChain");
    bytes32 private constant STATE_SENDER = keccak256("stateSender");
    bytes32 private constant SLASHING_MANAGER = keccak256("slashingManager");

    address public erc20Predicate;
    address public erc721Predicate;

    mapping(bytes32 => address) public contractMap;
    mapping(address => address) public rootToChildToken;
    mapping(address => address) public childToRootToken;
    mapping(address => bool) public proofValidatorContracts;
    mapping(address => bool) public isERC721;

    enum Type {Invalid, ERC20, ERC721, Custom}
    struct Predicate {
        Type _type;
    }
    mapping(address => Predicate) public predicates;

    event TokenMapped(address indexed rootToken, address indexed childToken);
    event ProofValidatorAdded(address indexed validator, address indexed from);
    event ProofValidatorRemoved(address indexed validator, address indexed from);
    event PredicateAdded(address indexed predicate, address indexed from);
    event PredicateRemoved(address indexed predicate, address indexed from);
    event ContractMapUpdated(bytes32 indexed key, address indexed previousContract, address indexed newContract);

    constructor(address _governance) public Governable(_governance) {}

    function updateContractMap(bytes32 _key, address _address) external onlyGovernance {
        emit ContractMapUpdated(_key, contractMap[_key], _address);
        contractMap[_key] = _address;
    }

    /**
     * @dev Map root token to child token
     * @param _rootToken Token address on the root chain
     * @param _childToken Token address on the child chain
     * @param _isERC721 Is the token being mapped ERC721
     */
    function mapToken(
        address _rootToken,
        address _childToken,
        bool _isERC721
    ) external onlyGovernance {
        require(_rootToken != address(0x0) && _childToken != address(0x0), "INVALID_TOKEN_ADDRESS");
        rootToChildToken[_rootToken] = _childToken;
        childToRootToken[_childToken] = _rootToken;
        isERC721[_rootToken] = _isERC721;
        IWithdrawManager(contractMap[WITHDRAW_MANAGER]).createExitQueue(_rootToken);
        emit TokenMapped(_rootToken, _childToken);
    }

    function addErc20Predicate(address predicate) public onlyGovernance {
        require(predicate != address(0x0), "Can not add null address as predicate");
        erc20Predicate = predicate;
        addPredicate(predicate, Type.ERC20);
    }

    function addErc721Predicate(address predicate) public onlyGovernance {
        erc721Predicate = predicate;
        addPredicate(predicate, Type.ERC721);
    }

    function addPredicate(address predicate, Type _type) public onlyGovernance {
        require(predicates[predicate]._type == Type.Invalid, "Predicate already added");
        predicates[predicate]._type = _type;
        emit PredicateAdded(predicate, msg.sender);
    }

    function removePredicate(address predicate) public onlyGovernance {
        require(predicates[predicate]._type != Type.Invalid, "Predicate does not exist");
        delete predicates[predicate];
        emit PredicateRemoved(predicate, msg.sender);
    }

    function getValidatorShareAddress() public view returns (address) {
        return contractMap[VALIDATOR_SHARE];
    }

    function getWethTokenAddress() public view returns (address) {
        return contractMap[WETH_TOKEN];
    }

    function getDepositManagerAddress() public view returns (address) {
        return contractMap[DEPOSIT_MANAGER];
    }

    function getStakeManagerAddress() public view returns (address) {
        return contractMap[STAKE_MANAGER];
    }

    function getSlashingManagerAddress() public view returns (address) {
        return contractMap[SLASHING_MANAGER];
    }

    function getWithdrawManagerAddress() public view returns (address) {
        return contractMap[WITHDRAW_MANAGER];
    }

    function getChildChainAndStateSender() public view returns (address, address) {
        return (contractMap[CHILD_CHAIN], contractMap[STATE_SENDER]);
    }

    function isTokenMapped(address _token) public view returns (bool) {
        return rootToChildToken[_token] != address(0x0);
    }

    function isTokenMappedAndIsErc721(address _token) public view returns (bool) {
        require(isTokenMapped(_token), "TOKEN_NOT_MAPPED");
        return isERC721[_token];
    }

    function isTokenMappedAndGetPredicate(address _token) public view returns (address) {
        if (isTokenMappedAndIsErc721(_token)) {
            return erc721Predicate;
        }
        return erc20Predicate;
    }

    function isChildTokenErc721(address childToken) public view returns (bool) {
        address rootToken = childToRootToken[childToken];
        require(rootToken != address(0x0), "Child token is not mapped");
        return isERC721[rootToken];
    }
}


/*
* @author Hamdi Allam [email protected]
* Please reach out with any questions or concerns
*/

library RLPReader {
    uint8 constant STRING_SHORT_START = 0x80;
    uint8 constant STRING_LONG_START  = 0xb8;
    uint8 constant LIST_SHORT_START   = 0xc0;
    uint8 constant LIST_LONG_START    = 0xf8;
    uint8 constant WORD_SIZE = 32;

    struct RLPItem {
        uint len;
        uint memPtr;
    }

    struct Iterator {
        RLPItem item;   // Item that's being iterated over.
        uint nextPtr;   // Position of the next item in the list.
    }

    /*
    * @dev Returns the next element in the iteration. Reverts if it has not next element.
    * @param self The iterator.
    * @return The next element in the iteration.
    */
    function next(Iterator memory self) internal pure returns (RLPItem memory) {
        require(hasNext(self));

        uint ptr = self.nextPtr;
        uint itemLength = _itemLength(ptr);
        self.nextPtr = ptr + itemLength;

        return RLPItem(itemLength, ptr);
    }

    /*
    * @dev Returns true if the iteration has more elements.
    * @param self The iterator.
    * @return true if the iteration has more elements.
    */
    function hasNext(Iterator memory self) internal pure returns (bool) {
        RLPItem memory item = self.item;
        return self.nextPtr < item.memPtr + item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
        uint memPtr;
        assembly {
            memPtr := add(item, 0x20)
        }

        return RLPItem(item.length, memPtr);
    }

    /*
    * @dev Create an iterator. Reverts if item is not a list.
    * @param self The RLP item.
    * @return An 'Iterator' over the item.
    */
    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
        require(isList(self));

        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }

    /*
    * @param item RLP encoded bytes
    */
    function rlpLen(RLPItem memory item) internal pure returns (uint) {
        return item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function payloadLen(RLPItem memory item) internal pure returns (uint) {
        return item.len - _payloadOffset(item.memPtr);
    }

    /*
    * @param item RLP encoded list in bytes
    */
    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
        require(isList(item));

        uint items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);

        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint dataLen;
        for (uint i = 0; i < items; i++) {
            dataLen = _itemLength(memPtr);
            result[i] = RLPItem(dataLen, memPtr); 
            memPtr = memPtr + dataLen;
        }

        return result;
    }

    // @return indicator whether encoded payload is a list. negate this function call for isData.
    function isList(RLPItem memory item) internal pure returns (bool) {
        if (item.len == 0) return false;

        uint8 byte0;
        uint memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < LIST_SHORT_START)
            return false;
        return true;
    }

    /** RLPItem conversions into data types **/

    // @returns raw rlp encoding in bytes
    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
        bytes memory result = new bytes(item.len);
        if (result.length == 0) return result;
        
        uint ptr;
        assembly {
            ptr := add(0x20, result)
        }

        copy(item.memPtr, ptr, item.len);
        return result;
    }

    // any non-zero byte is considered true
    function toBoolean(RLPItem memory item) internal pure returns (bool) {
        require(item.len == 1);
        uint result;
        uint memPtr = item.memPtr;
        assembly {
            result := byte(0, mload(memPtr))
        }

        return result == 0 ? false : true;
    }

    function toAddress(RLPItem memory item) internal pure returns (address) {
        // 1 byte for the length prefix
        require(item.len == 21);

        return address(toUint(item));
    }

    function toUint(RLPItem memory item) internal pure returns (uint) {
        require(item.len > 0 && item.len <= 33);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset;

        uint result;
        uint memPtr = item.memPtr + offset;
        assembly {
            result := mload(memPtr)

            // shfit to the correct location if neccesary
            if lt(len, 32) {
                result := div(result, exp(256, sub(32, len)))
            }
        }

        return result;
    }

    // enforces 32 byte length
    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
        // one byte prefix
        require(item.len == 33);

        uint result;
        uint memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }

        return result;
    }

    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
        require(item.len > 0);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset; // data length
        bytes memory result = new bytes(len);

        uint destPtr;
        assembly {
            destPtr := add(0x20, result)
        }

        copy(item.memPtr + offset, destPtr, len);
        return result;
    }

    /*
    * Private Helpers
    */

    // @return number of payload items inside an encoded list.
    function numItems(RLPItem memory item) private pure returns (uint) {
        if (item.len == 0) return 0;

        uint count = 0;
        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint endPtr = item.memPtr + item.len;
        while (currPtr < endPtr) {
           currPtr = currPtr + _itemLength(currPtr); // skip over an item
           count++;
        }

        return count;
    }

    // @return entire rlp item byte length
    function _itemLength(uint memPtr) private pure returns (uint) {
        uint itemLen;
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START)
            itemLen = 1;
        
        else if (byte0 < STRING_LONG_START)
            itemLen = byte0 - STRING_SHORT_START + 1;

        else if (byte0 < LIST_SHORT_START) {
            assembly {
                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
                memPtr := add(memPtr, 1) // skip over the first byte
                
                /* 32 byte word size */
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        else if (byte0 < LIST_LONG_START) {
            itemLen = byte0 - LIST_SHORT_START + 1;
        } 

        else {
            assembly {
                let byteLen := sub(byte0, 0xf7)
                memPtr := add(memPtr, 1)

                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        return itemLen;
    }

    // @return number of bytes until the data
    function _payloadOffset(uint memPtr) private pure returns (uint) {
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START) 
            return 0;
        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
            return 1;
        else if (byte0 < LIST_SHORT_START)  // being explicit
            return byte0 - (STRING_LONG_START - 1) + 1;
        else
            return byte0 - (LIST_LONG_START - 1) + 1;
    }

    /*
    * @param src Pointer to source
    * @param dest Pointer to destination
    * @param len Amount of memory to copy from the source
    */
    function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;

        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }

            src += WORD_SIZE;
            dest += WORD_SIZE;
        }

        // left over bytes. Mask is used to remove unwanted bytes from the word
        uint mask = 256 ** (WORD_SIZE - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask)) // zero out src
            let destpart := and(mload(dest), mask) // retrieve the bytes
            mstore(dest, or(destpart, srcpart))
        }
    }
}



/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
     * @dev Multiplies two unsigned integers, reverts on overflow.
     */
    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;
    }

    /**
     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two unsigned integers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}



/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}



contract ProxyStorage is Ownable {
    address internal proxyTo;
}



contract ChainIdMixin {
  bytes constant public networkId = hex"6D";
  uint256 constant public CHAINID = 109;
}





contract RootChainHeader {
    event NewHeaderBlock(
        address indexed proposer,
        uint256 indexed headerBlockId,
        uint256 indexed reward,
        uint256 start,
        uint256 end,
        bytes32 root
    );
    // housekeeping event
    event ResetHeaderBlock(address indexed proposer, uint256 indexed headerBlockId);
    struct HeaderBlock {
        bytes32 root;
        uint256 start;
        uint256 end;
        uint256 createdAt;
        address proposer;
    }
}


contract RootChainStorage is ProxyStorage, RootChainHeader, ChainIdMixin {
    bytes32 public heimdallId;
    uint8 public constant VOTE_TYPE = 2;

    uint16 internal constant MAX_DEPOSITS = 10000;
    uint256 public _nextHeaderBlock = MAX_DEPOSITS;
    uint256 internal _blockDepositId = 1;
    mapping(uint256 => HeaderBlock) public headerBlocks;
    Registry internal registry;
}



contract IStakeManager {
    // validator replacement
    function startAuction(
        uint256 validatorId,
        uint256 amount,
        bool acceptDelegation,
        bytes calldata signerPubkey
    ) external;

    function confirmAuctionBid(uint256 validatorId, uint256 heimdallFee) external;

    function transferFunds(
        uint256 validatorId,
        uint256 amount,
        address delegator
    ) external returns (bool);

    function delegationDeposit(
        uint256 validatorId,
        uint256 amount,
        address delegator
    ) external returns (bool);

    function unstake(uint256 validatorId) external;

    function totalStakedFor(address addr) external view returns (uint256);

    function stakeFor(
        address user,
        uint256 amount,
        uint256 heimdallFee,
        bool acceptDelegation,
        bytes memory signerPubkey
    ) public;

    function checkSignatures(
        uint256 blockInterval,
        bytes32 voteHash,
        bytes32 stateRoot,
        address proposer,
        uint[3][] calldata sigs
    ) external returns (uint256);

    function updateValidatorState(uint256 validatorId, int256 amount) public;

    function ownerOf(uint256 tokenId) public view returns (address);

    function slash(bytes calldata slashingInfoList) external returns (uint256);

    function validatorStake(uint256 validatorId) public view returns (uint256);

    function epoch() public view returns (uint256);

    function getRegistry() public view returns (address);

    function withdrawalDelay() public view returns (uint256);

    function delegatedAmount(uint256 validatorId) public view returns(uint256);

    function decreaseValidatorDelegatedAmount(uint256 validatorId, uint256 amount) public;

    function withdrawDelegatorsReward(uint256 validatorId) public returns(uint256);

    function delegatorsReward(uint256 validatorId) public view returns(uint256);

    function dethroneAndStake(
        address auctionUser,
        uint256 heimdallFee,
        uint256 validatorId,
        uint256 auctionAmount,
        bool acceptDelegation,
        bytes calldata signerPubkey
    ) external;
}




interface IRootChain {
    function slash() external;

    function submitHeaderBlock(bytes calldata data, bytes calldata sigs)
        external;
    
    function submitCheckpoint(bytes calldata data, uint[3][] calldata sigs)
        external;

    function getLastChildBlock() external view returns (uint256);

    function currentHeaderBlock() external view returns (uint256);
}






contract RootChain is RootChainStorage, IRootChain {
    using SafeMath for uint256;
    using RLPReader for bytes;
    using RLPReader for RLPReader.RLPItem;

    modifier onlyDepositManager() {
        require(msg.sender == registry.getDepositManagerAddress(), "UNAUTHORIZED_DEPOSIT_MANAGER_ONLY");
        _;
    }

    function submitHeaderBlock(bytes calldata data, bytes calldata sigs) external {
        revert();
    }

    function submitCheckpoint(bytes calldata data, uint[3][] calldata sigs) external {
        (address proposer, uint256 start, uint256 end, bytes32 rootHash, bytes32 accountHash, uint256 _borChainID) = abi
            .decode(data, (address, uint256, uint256, bytes32, bytes32, uint256));
        require(CHAINID == _borChainID, "Invalid bor chain id");

        require(_buildHeaderBlock(proposer, start, end, rootHash), "INCORRECT_HEADER_DATA");

        // check if it is better to keep it in local storage instead
        IStakeManager stakeManager = IStakeManager(registry.getStakeManagerAddress());
        uint256 _reward = stakeManager.checkSignatures(
            end.sub(start).add(1),
            /**  
                prefix 01 to data 
                01 represents positive vote on data and 00 is negative vote
                malicious validator can try to send 2/3 on negative vote so 01 is appended
             */
            keccak256(abi.encodePacked(bytes(hex"01"), data)),
            accountHash,
            proposer,
            sigs
        );

        require(_reward != 0, "Invalid checkpoint");
        emit NewHeaderBlock(proposer, _nextHeaderBlock, _reward, start, end, rootHash);
        _nextHeaderBlock = _nextHeaderBlock.add(MAX_DEPOSITS);
        _blockDepositId = 1;
    }

    function updateDepositId(uint256 numDeposits) external onlyDepositManager returns (uint256 depositId) {
        depositId = currentHeaderBlock().add(_blockDepositId);
        // deposit ids will be (_blockDepositId, _blockDepositId + 1, .... _blockDepositId + numDeposits - 1)
        _blockDepositId = _blockDepositId.add(numDeposits);
        require(
            // Since _blockDepositId is initialized to 1; only (MAX_DEPOSITS - 1) deposits per header block are allowed
            _blockDepositId <= MAX_DEPOSITS,
            "TOO_MANY_DEPOSITS"
        );
    }

    function getLastChildBlock() external view returns (uint256) {
        return headerBlocks[currentHeaderBlock()].end;
    }

    function slash() external {
        //TODO: future implementation
    }

    function currentHeaderBlock() public view returns (uint256) {
        return _nextHeaderBlock.sub(MAX_DEPOSITS);
    }

    function _buildHeaderBlock(
        address proposer,
        uint256 start,
        uint256 end,
        bytes32 rootHash
    ) private returns (bool) {
        uint256 nextChildBlock;
        /*
    The ID of the 1st header block is MAX_DEPOSITS.
    if _nextHeaderBlock == MAX_DEPOSITS, then the first header block is yet to be submitted, hence nextChildBlock = 0
    */
        if (_nextHeaderBlock > MAX_DEPOSITS) {
            nextChildBlock = headerBlocks[currentHeaderBlock()].end + 1;
        }
        if (nextChildBlock != start) {
            return false;
        }

        HeaderBlock memory headerBlock = HeaderBlock({
            root: rootHash,
            start: nextChildBlock,
            end: end,
            createdAt: now,
            proposer: proposer
        });

        headerBlocks[_nextHeaderBlock] = headerBlock;
        return true;
    }

    // Housekeeping function. @todo remove later
    function setNextHeaderBlock(uint256 _value) public onlyOwner {
        require(_value % MAX_DEPOSITS == 0, "Invalid value");
        for (uint256 i = _value; i < _nextHeaderBlock; i += MAX_DEPOSITS) {
            delete headerBlocks[i];
        }
        _nextHeaderBlock = _value;
        _blockDepositId = 1;
        emit ResetHeaderBlock(msg.sender, _nextHeaderBlock);
    }

    // Housekeeping function. @todo remove later
    function setHeimdallId(string memory _heimdallId) public onlyOwner {
        heimdallId = keccak256(abi.encodePacked(_heimdallId));
    }
}




contract StateSender is Ownable {
    using SafeMath for uint256;

    uint256 public counter;
    mapping(address => address) public registrations;

    event NewRegistration(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event RegistrationUpdated(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event StateSynced(
        uint256 indexed id,
        address indexed contractAddress,
        bytes data
    );

    modifier onlyRegistered(address receiver) {
        require(registrations[receiver] == msg.sender, "Invalid sender");
        _;
    }

    function syncState(address receiver, bytes calldata data)
        external
        onlyRegistered(receiver)
    {
        counter = counter.add(1);
        emit StateSynced(counter, receiver, data);
    }

    // register new contract for state sync
    function register(address sender, address receiver) public {
        require(
            isOwner() || registrations[receiver] == msg.sender,
            "StateSender.register: Not authorized to register"
        );
        registrations[receiver] = sender;
        if (registrations[receiver] == address(0)) {
            emit NewRegistration(msg.sender, sender, receiver);
        } else {
            emit RegistrationUpdated(msg.sender, sender, receiver);
        }
    }
}



contract Lockable {
    bool public locked;

    modifier onlyWhenUnlocked() {
        _assertUnlocked();
        _;
    }

    function _assertUnlocked() private view {
        require(!locked, "locked");
    }

    function lock() public {
        locked = true;
    }

    function unlock() public {
        locked = false;
    }
}




contract GovernanceLockable is Lockable, Governable {
    constructor(address governance) public Governable(governance) {}

    function lock() public onlyGovernance {
        super.lock();
    }

    function unlock() public onlyGovernance {
        super.unlock();
    }
}







contract DepositManagerHeader {
    event NewDepositBlock(address indexed owner, address indexed token, uint256 amountOrNFTId, uint256 depositBlockId);
    event MaxErc20DepositUpdate(uint256 indexed oldLimit, uint256 indexed newLimit);

    struct DepositBlock {
        bytes32 depositHash;
        uint256 createdAt;
    }
}


contract DepositManagerStorage is ProxyStorage, GovernanceLockable, DepositManagerHeader {
    Registry public registry;
    RootChain public rootChain;
    StateSender public stateSender;

    mapping(uint256 => DepositBlock) public deposits;

    address public childChain;
    uint256 public maxErc20Deposit = 100 * (10**18);
}


/*
 * SPDX-License-Identitifer:    MIT
 */


// See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-897.md

interface ERCProxy {
    function proxyType() external pure returns (uint256 proxyTypeId);
    function implementation() external view returns (address codeAddr);
}



contract DelegateProxyForwarder {
    function delegatedFwd(address _dst, bytes memory _calldata) internal {
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let result := delegatecall(
                sub(gas, 10000),
                _dst,
                add(_calldata, 0x20),
                mload(_calldata),
                0,
                0
            )
            let size := returndatasize

            let ptr := mload(0x40)
            returndatacopy(ptr, 0, size)

            // revert instead of invalid() bc if the underlying call failed with invalid() it already wasted gas.
            // if the call returned error data, forward it
            switch result
                case 0 {
                    revert(ptr, size)
                }
                default {
                    return(ptr, size)
                }
        }
    }
    
    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly {
            size := extcodesize(_target)
        }
        return size > 0;
    }
}




contract DelegateProxy is ERCProxy, DelegateProxyForwarder {
    function proxyType() external pure returns (uint256 proxyTypeId) {
        // Upgradeable proxy
        proxyTypeId = 2;
    }

    function implementation() external view returns (address);
}




contract Proxy is ProxyStorage, DelegateProxy {
    event ProxyUpdated(address indexed _new, address indexed _old);
    event OwnerUpdate(address _prevOwner, address _newOwner);

    constructor(address _proxyTo) public {
        updateImplementation(_proxyTo);
    }

    function() external payable {
        // require(currentContract != 0, "If app code has not been set yet, do not call");
        // Todo: filter out some calls or handle in the end fallback
        delegatedFwd(proxyTo, msg.data);
    }

    function implementation() external view returns (address) {
        return proxyTo;
    }

    function updateImplementation(address _newProxyTo) public onlyOwner {
        require(_newProxyTo != address(0x0), "INVALID_PROXY_ADDRESS");
        require(isContract(_newProxyTo), "DESTINATION_ADDRESS_IS_NOT_A_CONTRACT");
        emit ProxyUpdated(_newProxyTo, proxyTo);
        proxyTo = _newProxyTo;
    }

    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly {
            size := extcodesize(_target)
        }
        return size > 0;
    }
}







contract DepositManagerProxy is Proxy, DepositManagerStorage {
    constructor(
        address _proxyTo,
        address _registry,
        address _rootChain,
        address _governance
    ) public Proxy(_proxyTo) GovernanceLockable(_governance) {
        registry = Registry(_registry);
        rootChain = RootChain(_rootChain);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
// BoneToken with Governance.
contract BoneToken is ERC20("BONE SHIBASWAP", "BONE"), Ownable {
    /// @notice Creates `_amount` token to `_to`. Must only be called by the owner (TopDog).
    function mint(address _to, uint256 _amount) public onlyOwner {
        _mint(_to, _amount);
        _moveDelegates(address(0), _delegates[_to], _amount);
    }
    function _transfer(address sender, address recipient, uint256 amount) internal override {
        super._transfer(sender, recipient, amount);
        _moveDelegates(_delegates[sender], _delegates[recipient], amount);
    }
    // Copied and modified from YAM code:
    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol
    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol
    // Which is copied and modified from COMPOUND:
    // https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol
    /// @dev A record of each accounts delegate
    mapping (address => address) internal _delegates;
    /// @notice A checkpoint for marking number of votes from a given block
    struct Checkpoint {
        uint32 fromBlock;
        uint256 votes;
    }
    /// @notice A record of votes checkpoints for each account, by index
    mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;
    /// @notice The number of checkpoints for each account
    mapping (address => uint32) public numCheckpoints;
    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");
    /// @notice The EIP-712 typehash for the delegation struct used by the contract
    bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");
    /// @notice A record of states for signing / validating signatures
    mapping (address => uint) public nonces;
      /// @notice An event thats emitted when an account changes its delegate
    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);
    /// @notice An event thats emitted when a delegate account's vote balance changes
    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);
    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegator The address to get delegatee for
     */
    function delegates(address delegator)
        external
        view
        returns (address)
    {
        return _delegates[delegator];
    }
   /**
    * @notice Delegate votes from `msg.sender` to `delegatee`
    * @param delegatee The address to delegate votes to
    */
    function delegate(address delegatee) external {
        return _delegate(msg.sender, delegatee);
    }
    /**
     * @notice Delegates votes from signatory to `delegatee`
     * @param delegatee The address to delegate votes to
     * @param nonce The contract state required to match the signature
     * @param expiry The time at which to expire the signature
     * @param v The recovery byte of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function delegateBySig(
        address delegatee,
        uint nonce,
        uint expiry,
        uint8 v,
        bytes32 r,
        bytes32 s
    )
        external
    {
        bytes32 domainSeparator = keccak256(
            abi.encode(
                DOMAIN_TYPEHASH,
                keccak256(bytes(name())),
                getChainId(),
                address(this)
            )
        );
        bytes32 structHash = keccak256(
            abi.encode(
                DELEGATION_TYPEHASH,
                delegatee,
                nonce,
                expiry
            )
        );
        bytes32 digest = keccak256(
            abi.encodePacked(
                "\\x19\\x01",
                domainSeparator,
                structHash
            )
        );
        address signatory = ecrecover(digest, v, r, s);
        require(signatory != address(0), "BONE::delegateBySig: invalid signature");
        require(nonce == nonces[signatory]++, "BONE::delegateBySig: invalid nonce");
        require(now <= expiry, "BONE::delegateBySig: signature expired");
        return _delegate(signatory, delegatee);
    }
    /**
     * @notice Gets the current votes balance for `account`
     * @param account The address to get votes balance
     * @return The number of current votes for `account`
     */
    function getCurrentVotes(address account)
        external
        view
        returns (uint256)
    {
        uint32 nCheckpoints = numCheckpoints[account];
        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
    }
    /**
     * @notice Determine the prior number of votes for an account as of a block number
     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
     * @param account The address of the account to check
     * @param blockNumber The block number to get the vote balance at
     * @return The number of votes the account had as of the given block
     */
    function getPriorVotes(address account, uint blockNumber)
        external
        view
        returns (uint256)
    {
        require(blockNumber < block.number, "BONE::getPriorVotes: not yet determined");
        uint32 nCheckpoints = numCheckpoints[account];
        if (nCheckpoints == 0) {
            return 0;
        }
        // First check most recent balance
        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
            return checkpoints[account][nCheckpoints - 1].votes;
        }
        // Next check implicit zero balance
        if (checkpoints[account][0].fromBlock > blockNumber) {
            return 0;
        }
        uint32 lower = 0;
        uint32 upper = nCheckpoints - 1;
        while (upper > lower) {
            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
            Checkpoint memory cp = checkpoints[account][center];
            if (cp.fromBlock == blockNumber) {
                return cp.votes;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return checkpoints[account][lower].votes;
    }
    function _delegate(address delegator, address delegatee)
        internal
    {
        address currentDelegate = _delegates[delegator];
        uint256 delegatorBalance = balanceOf(delegator); // balance of underlying BONEs (not scaled);
        _delegates[delegator] = delegatee;
        emit DelegateChanged(delegator, currentDelegate, delegatee);
        _moveDelegates(currentDelegate, delegatee, delegatorBalance);
    }
    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {
        if (srcRep != dstRep && amount > 0) {
            if (srcRep != address(0)) {
                // decrease old representative
                uint32 srcRepNum = numCheckpoints[srcRep];
                uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
                uint256 srcRepNew = srcRepOld.sub(amount);
                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
            }
            if (dstRep != address(0)) {
                // increase new representative
                uint32 dstRepNum = numCheckpoints[dstRep];
                uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
                uint256 dstRepNew = dstRepOld.add(amount);
                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
            }
        }
    }
    function _writeCheckpoint(
        address delegatee,
        uint32 nCheckpoints,
        uint256 oldVotes,
        uint256 newVotes
    )
        internal
    {
        uint32 blockNumber = safe32(block.number, "BONE::_writeCheckpoint: block number exceeds 32 bits");
        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
        } else {
            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
            require(nCheckpoints + 1 > nCheckpoints, "BONE::_writeCheckpoint: new checkpoint exceeds 32 bits");
            numCheckpoints[delegatee] = nCheckpoints + 1;
        }
        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
    }
    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {
        require(n < 2**32, errorMessage);
        return uint32(n);
    }
    function getChainId() internal pure returns (uint) {
        uint256 chainId;
        assembly { chainId := chainid() }
        return chainId;
    }
}// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../../utils/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";
/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 private _totalSupply;
    string private _name;
    string private _symbol;
    uint8 private _decimals;
    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name_, string memory symbol_) public {
        _name = name_;
        _symbol = symbol_;
        _decimals = 18;
    }
    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual returns (string memory) {
        return _name;
    }
    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }
    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual returns (uint8) {
        return _decimals;
    }
    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }
    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }
    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }
    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }
    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }
    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }
    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        _beforeTokenTransfer(sender, recipient, amount);
        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }
    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");
        _beforeTokenTransfer(address(0), account, amount);
        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }
    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");
        _beforeTokenTransfer(account, address(0), amount);
        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }
    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal virtual {
        _decimals = decimals_;
    }
    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../utils/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }
    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }
    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }
    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }
    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);
    /**
     * @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);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }
    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }
    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, 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-contracts/pull/522
        if (a == 0) return (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }
    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }
    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }
    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }
    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        return a - b;
    }
    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }
    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a % b;
    }
}

pragma solidity ^0.5.2;


/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}



/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
     * @dev Multiplies two unsigned integers, reverts on overflow.
     */
    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;
    }

    /**
     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two unsigned integers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}




contract StateSender is Ownable {
    using SafeMath for uint256;

    uint256 public counter;
    mapping(address => address) public registrations;

    event NewRegistration(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event RegistrationUpdated(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event StateSynced(
        uint256 indexed id,
        address indexed contractAddress,
        bytes data
    );

    modifier onlyRegistered(address receiver) {
        require(registrations[receiver] == msg.sender, "Invalid sender");
        _;
    }

    function syncState(address receiver, bytes calldata data)
        external
        onlyRegistered(receiver)
    {
        counter = counter.add(1);
        emit StateSynced(counter, receiver, data);
    }

    // register new contract for state sync
    function register(address sender, address receiver) public {
        require(
            isOwner() || registrations[receiver] == msg.sender,
            "StateSender.register: Not authorized to register"
        );
        registrations[receiver] = sender;
        if (registrations[receiver] == address(0)) {
            emit NewRegistration(msg.sender, sender, receiver);
        } else {
            emit RegistrationUpdated(msg.sender, sender, receiver);
        }
    }
}

pragma solidity ^0.5.2;


/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
contract IERC721Receiver {
    /**
     * @notice Handle the receipt of an NFT
     * @dev The ERC721 smart contract calls this function on the recipient
     * after a `safeTransfer`. This function MUST return the function selector,
     * otherwise the caller will revert the transaction. The selector to be
     * returned can be obtained as `this.onERC721Received.selector`. This
     * function MAY throw to revert and reject the transfer.
     * Note: the ERC721 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 `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
     */
    function onERC721Received(address operator, address from, uint256 tokenId, bytes memory data)
    public returns (bytes4);
}



contract ERC721Holder is IERC721Receiver {
    function onERC721Received(address, address, uint256, bytes memory) public returns (bytes4) {
        return this.onERC721Received.selector;
    }
}



/**
 * @title ERC20 interface
 * @dev see https://eips.ethereum.org/EIPS/eip-20
 */
interface IERC20 {
    function transfer(address to, uint256 value) external returns (bool);

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

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

    function totalSupply() external view returns (uint256);

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

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

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

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



/**
 * @title IERC165
 * @dev https://eips.ethereum.org/EIPS/eip-165
 */
interface IERC165 {
    /**
     * @notice Query if a contract implements an interface
     * @param interfaceId The interface identifier, as specified in ERC-165
     * @dev Interface identification is specified in ERC-165. This function
     * uses less than 30,000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}



/**
 * @title ERC721 Non-Fungible Token Standard basic interface
 * @dev see https://eips.ethereum.org/EIPS/eip-721
 */
contract IERC721 is IERC165 {
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    function balanceOf(address owner) public view returns (uint256 balance);
    function ownerOf(uint256 tokenId) public view returns (address owner);

    function approve(address to, uint256 tokenId) public;
    function getApproved(uint256 tokenId) public view returns (address operator);

    function setApprovalForAll(address operator, bool _approved) public;
    function isApprovedForAll(address owner, address operator) public view returns (bool);

    function transferFrom(address from, address to, uint256 tokenId) public;
    function safeTransferFrom(address from, address to, uint256 tokenId) public;

    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data) public;
}



/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
     * @dev Multiplies two unsigned integers, reverts on overflow.
     */
    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;
    }

    /**
     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two unsigned integers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}



/**
 * Utility library of inline functions on addresses
 */
library Address {
    /**
     * Returns whether the target address 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 address of the account to check
     * @return whether the target address is a contract
     */
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}





/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require((value == 0) || (token.allowance(address(this), spender) == 0));
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must equal true).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.

        require(address(token).isContract());

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success);

        if (returndata.length > 0) { // Return data is optional
            require(abi.decode(returndata, (bool)));
        }
    }
}



interface IGovernance {
    function update(address target, bytes calldata data) external;
}



contract Governable {
    IGovernance public governance;

    constructor(address _governance) public {
        governance = IGovernance(_governance);
    }

    modifier onlyGovernance() {
        _assertGovernance();
        _;
    }

    function _assertGovernance() private view {
        require(
            msg.sender == address(governance),
            "Only governance contract is authorized"
        );
    }
}



contract IWithdrawManager {
    function createExitQueue(address token) external;

    function verifyInclusion(
        bytes calldata data,
        uint8 offset,
        bool verifyTxInclusion
    ) external view returns (uint256 age);

    function addExitToQueue(
        address exitor,
        address childToken,
        address rootToken,
        uint256 exitAmountOrTokenId,
        bytes32 txHash,
        bool isRegularExit,
        uint256 priority
    ) external;

    function addInput(
        uint256 exitId,
        uint256 age,
        address utxoOwner,
        address token
    ) external;

    function challengeExit(
        uint256 exitId,
        uint256 inputId,
        bytes calldata challengeData,
        address adjudicatorPredicate
    ) external;
}




contract Registry is Governable {
    // @todo hardcode constants
    bytes32 private constant WETH_TOKEN = keccak256("wethToken");
    bytes32 private constant DEPOSIT_MANAGER = keccak256("depositManager");
    bytes32 private constant STAKE_MANAGER = keccak256("stakeManager");
    bytes32 private constant VALIDATOR_SHARE = keccak256("validatorShare");
    bytes32 private constant WITHDRAW_MANAGER = keccak256("withdrawManager");
    bytes32 private constant CHILD_CHAIN = keccak256("childChain");
    bytes32 private constant STATE_SENDER = keccak256("stateSender");
    bytes32 private constant SLASHING_MANAGER = keccak256("slashingManager");

    address public erc20Predicate;
    address public erc721Predicate;

    mapping(bytes32 => address) public contractMap;
    mapping(address => address) public rootToChildToken;
    mapping(address => address) public childToRootToken;
    mapping(address => bool) public proofValidatorContracts;
    mapping(address => bool) public isERC721;

    enum Type {Invalid, ERC20, ERC721, Custom}
    struct Predicate {
        Type _type;
    }
    mapping(address => Predicate) public predicates;

    event TokenMapped(address indexed rootToken, address indexed childToken);
    event ProofValidatorAdded(address indexed validator, address indexed from);
    event ProofValidatorRemoved(address indexed validator, address indexed from);
    event PredicateAdded(address indexed predicate, address indexed from);
    event PredicateRemoved(address indexed predicate, address indexed from);
    event ContractMapUpdated(bytes32 indexed key, address indexed previousContract, address indexed newContract);

    constructor(address _governance) public Governable(_governance) {}

    function updateContractMap(bytes32 _key, address _address) external onlyGovernance {
        emit ContractMapUpdated(_key, contractMap[_key], _address);
        contractMap[_key] = _address;
    }

    /**
     * @dev Map root token to child token
     * @param _rootToken Token address on the root chain
     * @param _childToken Token address on the child chain
     * @param _isERC721 Is the token being mapped ERC721
     */
    function mapToken(
        address _rootToken,
        address _childToken,
        bool _isERC721
    ) external onlyGovernance {
        require(_rootToken != address(0x0) && _childToken != address(0x0), "INVALID_TOKEN_ADDRESS");
        rootToChildToken[_rootToken] = _childToken;
        childToRootToken[_childToken] = _rootToken;
        isERC721[_rootToken] = _isERC721;
        IWithdrawManager(contractMap[WITHDRAW_MANAGER]).createExitQueue(_rootToken);
        emit TokenMapped(_rootToken, _childToken);
    }

    function addErc20Predicate(address predicate) public onlyGovernance {
        require(predicate != address(0x0), "Can not add null address as predicate");
        erc20Predicate = predicate;
        addPredicate(predicate, Type.ERC20);
    }

    function addErc721Predicate(address predicate) public onlyGovernance {
        erc721Predicate = predicate;
        addPredicate(predicate, Type.ERC721);
    }

    function addPredicate(address predicate, Type _type) public onlyGovernance {
        require(predicates[predicate]._type == Type.Invalid, "Predicate already added");
        predicates[predicate]._type = _type;
        emit PredicateAdded(predicate, msg.sender);
    }

    function removePredicate(address predicate) public onlyGovernance {
        require(predicates[predicate]._type != Type.Invalid, "Predicate does not exist");
        delete predicates[predicate];
        emit PredicateRemoved(predicate, msg.sender);
    }

    function getValidatorShareAddress() public view returns (address) {
        return contractMap[VALIDATOR_SHARE];
    }

    function getWethTokenAddress() public view returns (address) {
        return contractMap[WETH_TOKEN];
    }

    function getDepositManagerAddress() public view returns (address) {
        return contractMap[DEPOSIT_MANAGER];
    }

    function getStakeManagerAddress() public view returns (address) {
        return contractMap[STAKE_MANAGER];
    }

    function getSlashingManagerAddress() public view returns (address) {
        return contractMap[SLASHING_MANAGER];
    }

    function getWithdrawManagerAddress() public view returns (address) {
        return contractMap[WITHDRAW_MANAGER];
    }

    function getChildChainAndStateSender() public view returns (address, address) {
        return (contractMap[CHILD_CHAIN], contractMap[STATE_SENDER]);
    }

    function isTokenMapped(address _token) public view returns (bool) {
        return rootToChildToken[_token] != address(0x0);
    }

    function isTokenMappedAndIsErc721(address _token) public view returns (bool) {
        require(isTokenMapped(_token), "TOKEN_NOT_MAPPED");
        return isERC721[_token];
    }

    function isTokenMappedAndGetPredicate(address _token) public view returns (address) {
        if (isTokenMappedAndIsErc721(_token)) {
            return erc721Predicate;
        }
        return erc20Predicate;
    }

    function isChildTokenErc721(address childToken) public view returns (bool) {
        address rootToken = childToRootToken[childToken];
        require(rootToken != address(0x0), "Child token is not mapped");
        return isERC721[rootToken];
    }
}




/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://eips.ethereum.org/EIPS/eip-20
 * Originally based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 *
 * This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
 * all accounts just by listening to said events. Note that this isn't required by the specification, and other
 * compliant implementations may not do it.
 */
contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowed;

    uint256 private _totalSupply;

    /**
     * @dev Total number of tokens in existence
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev Gets the balance of the specified address.
     * @param owner The address to query the balance of.
     * @return A uint256 representing the amount owned by the passed address.
     */
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param owner address The address which owns the funds.
     * @param spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    /**
     * @dev Transfer token to a specified address
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     */
    function transfer(address to, uint256 value) public returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     * 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
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     */
    function approve(address spender, uint256 value) public returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another.
     * Note that while this function emits an Approval event, this is not required as per the specification,
     * and other compliant implementations may not emit the event.
     * @param from address The address which you want to send tokens from
     * @param to address The address which you want to transfer to
     * @param value uint256 the amount of tokens to be transferred
     */
    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        _transfer(from, to, value);
        _approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
        return true;
    }

    /**
     * @dev Increase the amount of tokens that an owner allowed to a spender.
     * approve should be called when _allowed[msg.sender][spender] == 0. To increment
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param addedValue The amount of tokens to increase the allowance by.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowed[msg.sender][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Decrease the amount of tokens that an owner allowed to a spender.
     * approve should be called when _allowed[msg.sender][spender] == 0. To decrement
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param subtractedValue The amount of tokens to decrease the allowance by.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowed[msg.sender][spender].sub(subtractedValue));
        return true;
    }

    /**
     * @dev Transfer token for a specified addresses
     * @param from The address to transfer from.
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     */
    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0));

        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

    /**
     * @dev Internal function that mints an amount of the token and assigns it to
     * an account. This encapsulates the modification of balances such that the
     * proper events are emitted.
     * @param account The account that will receive the created tokens.
     * @param value The amount that will be created.
     */
    function _mint(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.add(value);
        _balances[account] = _balances[account].add(value);
        emit Transfer(address(0), account, value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account.
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burn(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    /**
     * @dev Approve an address to spend another addresses' tokens.
     * @param owner The address that owns the tokens.
     * @param spender The address that will spend the tokens.
     * @param value The number of tokens that can be spent.
     */
    function _approve(address owner, address spender, uint256 value) internal {
        require(spender != address(0));
        require(owner != address(0));

        _allowed[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account, deducting from the sender's allowance for said account. Uses the
     * internal burn function.
     * Emits an Approval event (reflecting the reduced allowance).
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burnFrom(address account, uint256 value) internal {
        _burn(account, value);
        _approve(account, msg.sender, _allowed[account][msg.sender].sub(value));
    }
}



contract WETH is ERC20 {
    event Deposit(address indexed dst, uint256 wad);
    event Withdrawal(address indexed src, uint256 wad);

    function deposit() public payable;

    function withdraw(uint256 wad) public;

    function withdraw(uint256 wad, address user) public;
}



interface IDepositManager {
    function depositEther() external payable;
    function transferAssets(
        address _token,
        address _user,
        uint256 _amountOrNFTId
    ) external;
    function depositERC20(address _token, uint256 _amount) external;
    function depositERC721(address _token, uint256 _tokenId) external;
}


/*
* @author Hamdi Allam [email protected]
* Please reach out with any questions or concerns
*/

library RLPReader {
    uint8 constant STRING_SHORT_START = 0x80;
    uint8 constant STRING_LONG_START  = 0xb8;
    uint8 constant LIST_SHORT_START   = 0xc0;
    uint8 constant LIST_LONG_START    = 0xf8;
    uint8 constant WORD_SIZE = 32;

    struct RLPItem {
        uint len;
        uint memPtr;
    }

    struct Iterator {
        RLPItem item;   // Item that's being iterated over.
        uint nextPtr;   // Position of the next item in the list.
    }

    /*
    * @dev Returns the next element in the iteration. Reverts if it has not next element.
    * @param self The iterator.
    * @return The next element in the iteration.
    */
    function next(Iterator memory self) internal pure returns (RLPItem memory) {
        require(hasNext(self));

        uint ptr = self.nextPtr;
        uint itemLength = _itemLength(ptr);
        self.nextPtr = ptr + itemLength;

        return RLPItem(itemLength, ptr);
    }

    /*
    * @dev Returns true if the iteration has more elements.
    * @param self The iterator.
    * @return true if the iteration has more elements.
    */
    function hasNext(Iterator memory self) internal pure returns (bool) {
        RLPItem memory item = self.item;
        return self.nextPtr < item.memPtr + item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
        uint memPtr;
        assembly {
            memPtr := add(item, 0x20)
        }

        return RLPItem(item.length, memPtr);
    }

    /*
    * @dev Create an iterator. Reverts if item is not a list.
    * @param self The RLP item.
    * @return An 'Iterator' over the item.
    */
    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
        require(isList(self));

        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }

    /*
    * @param item RLP encoded bytes
    */
    function rlpLen(RLPItem memory item) internal pure returns (uint) {
        return item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function payloadLen(RLPItem memory item) internal pure returns (uint) {
        return item.len - _payloadOffset(item.memPtr);
    }

    /*
    * @param item RLP encoded list in bytes
    */
    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
        require(isList(item));

        uint items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);

        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint dataLen;
        for (uint i = 0; i < items; i++) {
            dataLen = _itemLength(memPtr);
            result[i] = RLPItem(dataLen, memPtr); 
            memPtr = memPtr + dataLen;
        }

        return result;
    }

    // @return indicator whether encoded payload is a list. negate this function call for isData.
    function isList(RLPItem memory item) internal pure returns (bool) {
        if (item.len == 0) return false;

        uint8 byte0;
        uint memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < LIST_SHORT_START)
            return false;
        return true;
    }

    /** RLPItem conversions into data types **/

    // @returns raw rlp encoding in bytes
    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
        bytes memory result = new bytes(item.len);
        if (result.length == 0) return result;
        
        uint ptr;
        assembly {
            ptr := add(0x20, result)
        }

        copy(item.memPtr, ptr, item.len);
        return result;
    }

    // any non-zero byte is considered true
    function toBoolean(RLPItem memory item) internal pure returns (bool) {
        require(item.len == 1);
        uint result;
        uint memPtr = item.memPtr;
        assembly {
            result := byte(0, mload(memPtr))
        }

        return result == 0 ? false : true;
    }

    function toAddress(RLPItem memory item) internal pure returns (address) {
        // 1 byte for the length prefix
        require(item.len == 21);

        return address(toUint(item));
    }

    function toUint(RLPItem memory item) internal pure returns (uint) {
        require(item.len > 0 && item.len <= 33);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset;

        uint result;
        uint memPtr = item.memPtr + offset;
        assembly {
            result := mload(memPtr)

            // shfit to the correct location if neccesary
            if lt(len, 32) {
                result := div(result, exp(256, sub(32, len)))
            }
        }

        return result;
    }

    // enforces 32 byte length
    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
        // one byte prefix
        require(item.len == 33);

        uint result;
        uint memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }

        return result;
    }

    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
        require(item.len > 0);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset; // data length
        bytes memory result = new bytes(len);

        uint destPtr;
        assembly {
            destPtr := add(0x20, result)
        }

        copy(item.memPtr + offset, destPtr, len);
        return result;
    }

    /*
    * Private Helpers
    */

    // @return number of payload items inside an encoded list.
    function numItems(RLPItem memory item) private pure returns (uint) {
        if (item.len == 0) return 0;

        uint count = 0;
        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint endPtr = item.memPtr + item.len;
        while (currPtr < endPtr) {
           currPtr = currPtr + _itemLength(currPtr); // skip over an item
           count++;
        }

        return count;
    }

    // @return entire rlp item byte length
    function _itemLength(uint memPtr) private pure returns (uint) {
        uint itemLen;
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START)
            itemLen = 1;
        
        else if (byte0 < STRING_LONG_START)
            itemLen = byte0 - STRING_SHORT_START + 1;

        else if (byte0 < LIST_SHORT_START) {
            assembly {
                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
                memPtr := add(memPtr, 1) // skip over the first byte
                
                /* 32 byte word size */
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        else if (byte0 < LIST_LONG_START) {
            itemLen = byte0 - LIST_SHORT_START + 1;
        } 

        else {
            assembly {
                let byteLen := sub(byte0, 0xf7)
                memPtr := add(memPtr, 1)

                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        return itemLen;
    }

    // @return number of bytes until the data
    function _payloadOffset(uint memPtr) private pure returns (uint) {
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START) 
            return 0;
        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
            return 1;
        else if (byte0 < LIST_SHORT_START)  // being explicit
            return byte0 - (STRING_LONG_START - 1) + 1;
        else
            return byte0 - (LIST_LONG_START - 1) + 1;
    }

    /*
    * @param src Pointer to source
    * @param dest Pointer to destination
    * @param len Amount of memory to copy from the source
    */
    function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;

        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }

            src += WORD_SIZE;
            dest += WORD_SIZE;
        }

        // left over bytes. Mask is used to remove unwanted bytes from the word
        uint mask = 256 ** (WORD_SIZE - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask)) // zero out src
            let destpart := and(mload(dest), mask) // retrieve the bytes
            mstore(dest, or(destpart, srcpart))
        }
    }
}



/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}



contract ProxyStorage is Ownable {
    address internal proxyTo;
}



contract ChainIdMixin {
  bytes constant public networkId = hex"6D";
  uint256 constant public CHAINID = 109;
}





contract RootChainHeader {
    event NewHeaderBlock(
        address indexed proposer,
        uint256 indexed headerBlockId,
        uint256 indexed reward,
        uint256 start,
        uint256 end,
        bytes32 root
    );
    // housekeeping event
    event ResetHeaderBlock(address indexed proposer, uint256 indexed headerBlockId);
    struct HeaderBlock {
        bytes32 root;
        uint256 start;
        uint256 end;
        uint256 createdAt;
        address proposer;
    }
}


contract RootChainStorage is ProxyStorage, RootChainHeader, ChainIdMixin {
    bytes32 public heimdallId;
    uint8 public constant VOTE_TYPE = 2;

    uint16 internal constant MAX_DEPOSITS = 10000;
    uint256 public _nextHeaderBlock = MAX_DEPOSITS;
    uint256 internal _blockDepositId = 1;
    mapping(uint256 => HeaderBlock) public headerBlocks;
    Registry internal registry;
}



contract IStakeManager {
    // validator replacement
    function startAuction(
        uint256 validatorId,
        uint256 amount,
        bool acceptDelegation,
        bytes calldata signerPubkey
    ) external;

    function confirmAuctionBid(uint256 validatorId, uint256 heimdallFee) external;

    function transferFunds(
        uint256 validatorId,
        uint256 amount,
        address delegator
    ) external returns (bool);

    function delegationDeposit(
        uint256 validatorId,
        uint256 amount,
        address delegator
    ) external returns (bool);

    function unstake(uint256 validatorId) external;

    function totalStakedFor(address addr) external view returns (uint256);

    function stakeFor(
        address user,
        uint256 amount,
        uint256 heimdallFee,
        bool acceptDelegation,
        bytes memory signerPubkey
    ) public;

    function checkSignatures(
        uint256 blockInterval,
        bytes32 voteHash,
        bytes32 stateRoot,
        address proposer,
        uint[3][] calldata sigs
    ) external returns (uint256);

    function updateValidatorState(uint256 validatorId, int256 amount) public;

    function ownerOf(uint256 tokenId) public view returns (address);

    function slash(bytes calldata slashingInfoList) external returns (uint256);

    function validatorStake(uint256 validatorId) public view returns (uint256);

    function epoch() public view returns (uint256);

    function getRegistry() public view returns (address);

    function withdrawalDelay() public view returns (uint256);

    function delegatedAmount(uint256 validatorId) public view returns(uint256);

    function decreaseValidatorDelegatedAmount(uint256 validatorId, uint256 amount) public;

    function withdrawDelegatorsReward(uint256 validatorId) public returns(uint256);

    function delegatorsReward(uint256 validatorId) public view returns(uint256);

    function dethroneAndStake(
        address auctionUser,
        uint256 heimdallFee,
        uint256 validatorId,
        uint256 auctionAmount,
        bool acceptDelegation,
        bytes calldata signerPubkey
    ) external;
}




interface IRootChain {
    function slash() external;

    function submitHeaderBlock(bytes calldata data, bytes calldata sigs)
        external;
    
    function submitCheckpoint(bytes calldata data, uint[3][] calldata sigs)
        external;

    function getLastChildBlock() external view returns (uint256);

    function currentHeaderBlock() external view returns (uint256);
}






contract RootChain is RootChainStorage, IRootChain {
    using SafeMath for uint256;
    using RLPReader for bytes;
    using RLPReader for RLPReader.RLPItem;

    modifier onlyDepositManager() {
        require(msg.sender == registry.getDepositManagerAddress(), "UNAUTHORIZED_DEPOSIT_MANAGER_ONLY");
        _;
    }

    function submitHeaderBlock(bytes calldata data, bytes calldata sigs) external {
        revert();
    }

    function submitCheckpoint(bytes calldata data, uint[3][] calldata sigs) external {
        (address proposer, uint256 start, uint256 end, bytes32 rootHash, bytes32 accountHash, uint256 _borChainID) = abi
            .decode(data, (address, uint256, uint256, bytes32, bytes32, uint256));
        require(CHAINID == _borChainID, "Invalid bor chain id");

        require(_buildHeaderBlock(proposer, start, end, rootHash), "INCORRECT_HEADER_DATA");

        // check if it is better to keep it in local storage instead
        IStakeManager stakeManager = IStakeManager(registry.getStakeManagerAddress());
        uint256 _reward = stakeManager.checkSignatures(
            end.sub(start).add(1),
            /**  
                prefix 01 to data 
                01 represents positive vote on data and 00 is negative vote
                malicious validator can try to send 2/3 on negative vote so 01 is appended
             */
            keccak256(abi.encodePacked(bytes(hex"01"), data)),
            accountHash,
            proposer,
            sigs
        );

        require(_reward != 0, "Invalid checkpoint");
        emit NewHeaderBlock(proposer, _nextHeaderBlock, _reward, start, end, rootHash);
        _nextHeaderBlock = _nextHeaderBlock.add(MAX_DEPOSITS);
        _blockDepositId = 1;
    }

    function updateDepositId(uint256 numDeposits) external onlyDepositManager returns (uint256 depositId) {
        depositId = currentHeaderBlock().add(_blockDepositId);
        // deposit ids will be (_blockDepositId, _blockDepositId + 1, .... _blockDepositId + numDeposits - 1)
        _blockDepositId = _blockDepositId.add(numDeposits);
        require(
            // Since _blockDepositId is initialized to 1; only (MAX_DEPOSITS - 1) deposits per header block are allowed
            _blockDepositId <= MAX_DEPOSITS,
            "TOO_MANY_DEPOSITS"
        );
    }

    function getLastChildBlock() external view returns (uint256) {
        return headerBlocks[currentHeaderBlock()].end;
    }

    function slash() external {
        //TODO: future implementation
    }

    function currentHeaderBlock() public view returns (uint256) {
        return _nextHeaderBlock.sub(MAX_DEPOSITS);
    }

    function _buildHeaderBlock(
        address proposer,
        uint256 start,
        uint256 end,
        bytes32 rootHash
    ) private returns (bool) {
        uint256 nextChildBlock;
        /*
    The ID of the 1st header block is MAX_DEPOSITS.
    if _nextHeaderBlock == MAX_DEPOSITS, then the first header block is yet to be submitted, hence nextChildBlock = 0
    */
        if (_nextHeaderBlock > MAX_DEPOSITS) {
            nextChildBlock = headerBlocks[currentHeaderBlock()].end + 1;
        }
        if (nextChildBlock != start) {
            return false;
        }

        HeaderBlock memory headerBlock = HeaderBlock({
            root: rootHash,
            start: nextChildBlock,
            end: end,
            createdAt: now,
            proposer: proposer
        });

        headerBlocks[_nextHeaderBlock] = headerBlock;
        return true;
    }

    // Housekeeping function. @todo remove later
    function setNextHeaderBlock(uint256 _value) public onlyOwner {
        require(_value % MAX_DEPOSITS == 0, "Invalid value");
        for (uint256 i = _value; i < _nextHeaderBlock; i += MAX_DEPOSITS) {
            delete headerBlocks[i];
        }
        _nextHeaderBlock = _value;
        _blockDepositId = 1;
        emit ResetHeaderBlock(msg.sender, _nextHeaderBlock);
    }

    // Housekeeping function. @todo remove later
    function setHeimdallId(string memory _heimdallId) public onlyOwner {
        heimdallId = keccak256(abi.encodePacked(_heimdallId));
    }
}




contract StateSender is Ownable {
    using SafeMath for uint256;

    uint256 public counter;
    mapping(address => address) public registrations;

    event NewRegistration(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event RegistrationUpdated(
        address indexed user,
        address indexed sender,
        address indexed receiver
    );
    event StateSynced(
        uint256 indexed id,
        address indexed contractAddress,
        bytes data
    );

    modifier onlyRegistered(address receiver) {
        require(registrations[receiver] == msg.sender, "Invalid sender");
        _;
    }

    function syncState(address receiver, bytes calldata data)
        external
        onlyRegistered(receiver)
    {
        counter = counter.add(1);
        emit StateSynced(counter, receiver, data);
    }

    // register new contract for state sync
    function register(address sender, address receiver) public {
        require(
            isOwner() || registrations[receiver] == msg.sender,
            "StateSender.register: Not authorized to register"
        );
        registrations[receiver] = sender;
        if (registrations[receiver] == address(0)) {
            emit NewRegistration(msg.sender, sender, receiver);
        } else {
            emit RegistrationUpdated(msg.sender, sender, receiver);
        }
    }
}



contract Lockable {
    bool public locked;

    modifier onlyWhenUnlocked() {
        _assertUnlocked();
        _;
    }

    function _assertUnlocked() private view {
        require(!locked, "locked");
    }

    function lock() public {
        locked = true;
    }

    function unlock() public {
        locked = false;
    }
}




contract GovernanceLockable is Lockable, Governable {
    constructor(address governance) public Governable(governance) {}

    function lock() public onlyGovernance {
        super.lock();
    }

    function unlock() public onlyGovernance {
        super.unlock();
    }
}







contract DepositManagerHeader {
    event NewDepositBlock(address indexed owner, address indexed token, uint256 amountOrNFTId, uint256 depositBlockId);
    event MaxErc20DepositUpdate(uint256 indexed oldLimit, uint256 indexed newLimit);

    struct DepositBlock {
        bytes32 depositHash;
        uint256 createdAt;
    }
}


contract DepositManagerStorage is ProxyStorage, GovernanceLockable, DepositManagerHeader {
    Registry public registry;
    RootChain public rootChain;
    StateSender public stateSender;

    mapping(uint256 => DepositBlock) public deposits;

    address public childChain;
    uint256 public maxErc20Deposit = 100 * (10**18);
}













contract DepositManager is DepositManagerStorage, IDepositManager, ERC721Holder {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    modifier isTokenMapped(address _token) {
        require(registry.isTokenMapped(_token), "TOKEN_NOT_SUPPORTED");
        _;
    }

    modifier isPredicateAuthorized() {
        require(uint8(registry.predicates(msg.sender)) != 0, "Not a valid predicate");
        _;
    }

    constructor() public GovernanceLockable(address(0x0)) {}

    // deposit ETH by sending to this contract
    function() external payable {
        depositEther();
    }

    function updateMaxErc20Deposit(uint256 maxDepositAmount) public onlyGovernance {
        require(maxDepositAmount != 0);
        emit MaxErc20DepositUpdate(maxErc20Deposit, maxDepositAmount);
        maxErc20Deposit = maxDepositAmount;
    }

    function transferAssets(
        address _token,
        address _user,
        uint256 _amountOrNFTId
    ) external isPredicateAuthorized {
        address wethToken = registry.getWethTokenAddress();
        if (registry.isERC721(_token)) {
            IERC721(_token).transferFrom(address(this), _user, _amountOrNFTId);
        } else if (_token == wethToken) {
            WETH t = WETH(_token);
            t.withdraw(_amountOrNFTId, _user);
        } else {
            require(IERC20(_token).transfer(_user, _amountOrNFTId), "TRANSFER_FAILED");
        }
    }

    function depositERC20(address _token, uint256 _amount) external {
        depositERC20ForUser(_token, msg.sender, _amount);
    }

    function depositERC721(address _token, uint256 _tokenId) external {
        depositERC721ForUser(_token, msg.sender, _tokenId);
    }

    function depositBulk(
        address[] calldata _tokens,
        uint256[] calldata _amountOrTokens,
        address _user
    )
        external
        onlyWhenUnlocked // unlike other deposit functions, depositBulk doesn't invoke _safeCreateDepositBlock
    {
        require(_tokens.length == _amountOrTokens.length, "Invalid Input");
        uint256 depositId = rootChain.updateDepositId(_tokens.length);
        Registry _registry = registry;

        for (uint256 i = 0; i < _tokens.length; i++) {
            // will revert if token is not mapped
            if (_registry.isTokenMappedAndIsErc721(_tokens[i])) {
                _safeTransferERC721(msg.sender, _tokens[i], _amountOrTokens[i]);
            } else {
                IERC20(_tokens[i]).safeTransferFrom(msg.sender, address(this), _amountOrTokens[i]);
            }

            _createDepositBlock(_user, _tokens[i], _amountOrTokens[i], depositId);
            depositId = depositId.add(1);
        }
    }

    /**
     * @dev Caches childChain and stateSender (frequently used variables) from registry
     */
    function updateChildChainAndStateSender() public {
        (address _childChain, address _stateSender) = registry.getChildChainAndStateSender();
        require(
            _stateSender != address(stateSender) || _childChain != childChain,
            "Atleast one of stateSender or childChain address should change"
        );
        childChain = _childChain;
        stateSender = StateSender(_stateSender);
    }

    function depositERC20ForUser(
        address _token,
        address _user,
        uint256 _amount
    ) public {
        require(_amount <= maxErc20Deposit, "exceed maximum deposit amount");
        IERC20(_token).safeTransferFrom(msg.sender, address(this), _amount);
        _safeCreateDepositBlock(_user, _token, _amount);
    }

    function depositERC721ForUser(
        address _token,
        address _user,
        uint256 _tokenId
    ) public {
        require(registry.isTokenMappedAndIsErc721(_token), "not erc721");

        _safeTransferERC721(msg.sender, _token, _tokenId);
        _safeCreateDepositBlock(_user, _token, _tokenId);
    }

    // @todo: write depositEtherForUser
    function depositEther() public payable {
        address wethToken = registry.getWethTokenAddress();
        WETH t = WETH(wethToken);
        t.deposit.value(msg.value)();
        _safeCreateDepositBlock(msg.sender, wethToken, msg.value);
    }

    function _safeCreateDepositBlock(
        address _user,
        address _token,
        uint256 _amountOrToken
    ) internal onlyWhenUnlocked isTokenMapped(_token) {
        _createDepositBlock(
            _user,
            _token,
            _amountOrToken,
            rootChain.updateDepositId(1) /* returns _depositId */
        );
    }

    function _createDepositBlock(
        address _user,
        address _token,
        uint256 _amountOrToken,
        uint256 _depositId
    ) internal {
        deposits[_depositId] = DepositBlock(keccak256(abi.encodePacked(_user, _token, _amountOrToken)), now);
        stateSender.syncState(childChain, abi.encode(_user, _token, _amountOrToken, _depositId));
        emit NewDepositBlock(_user, _token, _amountOrToken, _depositId);
    }

    // Housekeeping function. @todo remove later
    function updateRootChain(address _rootChain) public onlyOwner {
        rootChain = RootChain(_rootChain);
    }

    function _safeTransferERC721(address _user, address _token, uint256 _tokenId) private {
        IERC721(_token).safeTransferFrom(_user, address(this), _tokenId);
    }
}

pragma solidity ^0.5.2;


interface IGovernance {
    function update(address target, bytes calldata data) external;
}



contract Governable {
    IGovernance public governance;

    constructor(address _governance) public {
        governance = IGovernance(_governance);
    }

    modifier onlyGovernance() {
        _assertGovernance();
        _;
    }

    function _assertGovernance() private view {
        require(
            msg.sender == address(governance),
            "Only governance contract is authorized"
        );
    }
}



contract IWithdrawManager {
    function createExitQueue(address token) external;

    function verifyInclusion(
        bytes calldata data,
        uint8 offset,
        bool verifyTxInclusion
    ) external view returns (uint256 age);

    function addExitToQueue(
        address exitor,
        address childToken,
        address rootToken,
        uint256 exitAmountOrTokenId,
        bytes32 txHash,
        bool isRegularExit,
        uint256 priority
    ) external;

    function addInput(
        uint256 exitId,
        uint256 age,
        address utxoOwner,
        address token
    ) external;

    function challengeExit(
        uint256 exitId,
        uint256 inputId,
        bytes calldata challengeData,
        address adjudicatorPredicate
    ) external;
}




contract Registry is Governable {
    // @todo hardcode constants
    bytes32 private constant WETH_TOKEN = keccak256("wethToken");
    bytes32 private constant DEPOSIT_MANAGER = keccak256("depositManager");
    bytes32 private constant STAKE_MANAGER = keccak256("stakeManager");
    bytes32 private constant VALIDATOR_SHARE = keccak256("validatorShare");
    bytes32 private constant WITHDRAW_MANAGER = keccak256("withdrawManager");
    bytes32 private constant CHILD_CHAIN = keccak256("childChain");
    bytes32 private constant STATE_SENDER = keccak256("stateSender");
    bytes32 private constant SLASHING_MANAGER = keccak256("slashingManager");

    address public erc20Predicate;
    address public erc721Predicate;

    mapping(bytes32 => address) public contractMap;
    mapping(address => address) public rootToChildToken;
    mapping(address => address) public childToRootToken;
    mapping(address => bool) public proofValidatorContracts;
    mapping(address => bool) public isERC721;

    enum Type {Invalid, ERC20, ERC721, Custom}
    struct Predicate {
        Type _type;
    }
    mapping(address => Predicate) public predicates;

    event TokenMapped(address indexed rootToken, address indexed childToken);
    event ProofValidatorAdded(address indexed validator, address indexed from);
    event ProofValidatorRemoved(address indexed validator, address indexed from);
    event PredicateAdded(address indexed predicate, address indexed from);
    event PredicateRemoved(address indexed predicate, address indexed from);
    event ContractMapUpdated(bytes32 indexed key, address indexed previousContract, address indexed newContract);

    constructor(address _governance) public Governable(_governance) {}

    function updateContractMap(bytes32 _key, address _address) external onlyGovernance {
        emit ContractMapUpdated(_key, contractMap[_key], _address);
        contractMap[_key] = _address;
    }

    /**
     * @dev Map root token to child token
     * @param _rootToken Token address on the root chain
     * @param _childToken Token address on the child chain
     * @param _isERC721 Is the token being mapped ERC721
     */
    function mapToken(
        address _rootToken,
        address _childToken,
        bool _isERC721
    ) external onlyGovernance {
        require(_rootToken != address(0x0) && _childToken != address(0x0), "INVALID_TOKEN_ADDRESS");
        rootToChildToken[_rootToken] = _childToken;
        childToRootToken[_childToken] = _rootToken;
        isERC721[_rootToken] = _isERC721;
        IWithdrawManager(contractMap[WITHDRAW_MANAGER]).createExitQueue(_rootToken);
        emit TokenMapped(_rootToken, _childToken);
    }

    function addErc20Predicate(address predicate) public onlyGovernance {
        require(predicate != address(0x0), "Can not add null address as predicate");
        erc20Predicate = predicate;
        addPredicate(predicate, Type.ERC20);
    }

    function addErc721Predicate(address predicate) public onlyGovernance {
        erc721Predicate = predicate;
        addPredicate(predicate, Type.ERC721);
    }

    function addPredicate(address predicate, Type _type) public onlyGovernance {
        require(predicates[predicate]._type == Type.Invalid, "Predicate already added");
        predicates[predicate]._type = _type;
        emit PredicateAdded(predicate, msg.sender);
    }

    function removePredicate(address predicate) public onlyGovernance {
        require(predicates[predicate]._type != Type.Invalid, "Predicate does not exist");
        delete predicates[predicate];
        emit PredicateRemoved(predicate, msg.sender);
    }

    function getValidatorShareAddress() public view returns (address) {
        return contractMap[VALIDATOR_SHARE];
    }

    function getWethTokenAddress() public view returns (address) {
        return contractMap[WETH_TOKEN];
    }

    function getDepositManagerAddress() public view returns (address) {
        return contractMap[DEPOSIT_MANAGER];
    }

    function getStakeManagerAddress() public view returns (address) {
        return contractMap[STAKE_MANAGER];
    }

    function getSlashingManagerAddress() public view returns (address) {
        return contractMap[SLASHING_MANAGER];
    }

    function getWithdrawManagerAddress() public view returns (address) {
        return contractMap[WITHDRAW_MANAGER];
    }

    function getChildChainAndStateSender() public view returns (address, address) {
        return (contractMap[CHILD_CHAIN], contractMap[STATE_SENDER]);
    }

    function isTokenMapped(address _token) public view returns (bool) {
        return rootToChildToken[_token] != address(0x0);
    }

    function isTokenMappedAndIsErc721(address _token) public view returns (bool) {
        require(isTokenMapped(_token), "TOKEN_NOT_MAPPED");
        return isERC721[_token];
    }

    function isTokenMappedAndGetPredicate(address _token) public view returns (address) {
        if (isTokenMappedAndIsErc721(_token)) {
            return erc721Predicate;
        }
        return erc20Predicate;
    }

    function isChildTokenErc721(address childToken) public view returns (bool) {
        address rootToken = childToRootToken[childToken];
        require(rootToken != address(0x0), "Child token is not mapped");
        return isERC721[rootToken];
    }
}

pragma solidity ^0.5.2;


interface IGovernance {
    function update(address target, bytes calldata data) external;
}



contract Governable {
    IGovernance public governance;

    constructor(address _governance) public {
        governance = IGovernance(_governance);
    }

    modifier onlyGovernance() {
        _assertGovernance();
        _;
    }

    function _assertGovernance() private view {
        require(
            msg.sender == address(governance),
            "Only governance contract is authorized"
        );
    }
}



contract IWithdrawManager {
    function createExitQueue(address token) external;

    function verifyInclusion(
        bytes calldata data,
        uint8 offset,
        bool verifyTxInclusion
    ) external view returns (uint256 age);

    function addExitToQueue(
        address exitor,
        address childToken,
        address rootToken,
        uint256 exitAmountOrTokenId,
        bytes32 txHash,
        bool isRegularExit,
        uint256 priority
    ) external;

    function addInput(
        uint256 exitId,
        uint256 age,
        address utxoOwner,
        address token
    ) external;

    function challengeExit(
        uint256 exitId,
        uint256 inputId,
        bytes calldata challengeData,
        address adjudicatorPredicate
    ) external;
}




contract Registry is Governable {
    // @todo hardcode constants
    bytes32 private constant WETH_TOKEN = keccak256("wethToken");
    bytes32 private constant DEPOSIT_MANAGER = keccak256("depositManager");
    bytes32 private constant STAKE_MANAGER = keccak256("stakeManager");
    bytes32 private constant VALIDATOR_SHARE = keccak256("validatorShare");
    bytes32 private constant WITHDRAW_MANAGER = keccak256("withdrawManager");
    bytes32 private constant CHILD_CHAIN = keccak256("childChain");
    bytes32 private constant STATE_SENDER = keccak256("stateSender");
    bytes32 private constant SLASHING_MANAGER = keccak256("slashingManager");

    address public erc20Predicate;
    address public erc721Predicate;

    mapping(bytes32 => address) public contractMap;
    mapping(address => address) public rootToChildToken;
    mapping(address => address) public childToRootToken;
    mapping(address => bool) public proofValidatorContracts;
    mapping(address => bool) public isERC721;

    enum Type {Invalid, ERC20, ERC721, Custom}
    struct Predicate {
        Type _type;
    }
    mapping(address => Predicate) public predicates;

    event TokenMapped(address indexed rootToken, address indexed childToken);
    event ProofValidatorAdded(address indexed validator, address indexed from);
    event ProofValidatorRemoved(address indexed validator, address indexed from);
    event PredicateAdded(address indexed predicate, address indexed from);
    event PredicateRemoved(address indexed predicate, address indexed from);
    event ContractMapUpdated(bytes32 indexed key, address indexed previousContract, address indexed newContract);

    constructor(address _governance) public Governable(_governance) {}

    function updateContractMap(bytes32 _key, address _address) external onlyGovernance {
        emit ContractMapUpdated(_key, contractMap[_key], _address);
        contractMap[_key] = _address;
    }

    /**
     * @dev Map root token to child token
     * @param _rootToken Token address on the root chain
     * @param _childToken Token address on the child chain
     * @param _isERC721 Is the token being mapped ERC721
     */
    function mapToken(
        address _rootToken,
        address _childToken,
        bool _isERC721
    ) external onlyGovernance {
        require(_rootToken != address(0x0) && _childToken != address(0x0), "INVALID_TOKEN_ADDRESS");
        rootToChildToken[_rootToken] = _childToken;
        childToRootToken[_childToken] = _rootToken;
        isERC721[_rootToken] = _isERC721;
        IWithdrawManager(contractMap[WITHDRAW_MANAGER]).createExitQueue(_rootToken);
        emit TokenMapped(_rootToken, _childToken);
    }

    function addErc20Predicate(address predicate) public onlyGovernance {
        require(predicate != address(0x0), "Can not add null address as predicate");
        erc20Predicate = predicate;
        addPredicate(predicate, Type.ERC20);
    }

    function addErc721Predicate(address predicate) public onlyGovernance {
        erc721Predicate = predicate;
        addPredicate(predicate, Type.ERC721);
    }

    function addPredicate(address predicate, Type _type) public onlyGovernance {
        require(predicates[predicate]._type == Type.Invalid, "Predicate already added");
        predicates[predicate]._type = _type;
        emit PredicateAdded(predicate, msg.sender);
    }

    function removePredicate(address predicate) public onlyGovernance {
        require(predicates[predicate]._type != Type.Invalid, "Predicate does not exist");
        delete predicates[predicate];
        emit PredicateRemoved(predicate, msg.sender);
    }

    function getValidatorShareAddress() public view returns (address) {
        return contractMap[VALIDATOR_SHARE];
    }

    function getWethTokenAddress() public view returns (address) {
        return contractMap[WETH_TOKEN];
    }

    function getDepositManagerAddress() public view returns (address) {
        return contractMap[DEPOSIT_MANAGER];
    }

    function getStakeManagerAddress() public view returns (address) {
        return contractMap[STAKE_MANAGER];
    }

    function getSlashingManagerAddress() public view returns (address) {
        return contractMap[SLASHING_MANAGER];
    }

    function getWithdrawManagerAddress() public view returns (address) {
        return contractMap[WITHDRAW_MANAGER];
    }

    function getChildChainAndStateSender() public view returns (address, address) {
        return (contractMap[CHILD_CHAIN], contractMap[STATE_SENDER]);
    }

    function isTokenMapped(address _token) public view returns (bool) {
        return rootToChildToken[_token] != address(0x0);
    }

    function isTokenMappedAndIsErc721(address _token) public view returns (bool) {
        require(isTokenMapped(_token), "TOKEN_NOT_MAPPED");
        return isERC721[_token];
    }

    function isTokenMappedAndGetPredicate(address _token) public view returns (address) {
        if (isTokenMappedAndIsErc721(_token)) {
            return erc721Predicate;
        }
        return erc20Predicate;
    }

    function isChildTokenErc721(address childToken) public view returns (bool) {
        address rootToken = childToRootToken[childToken];
        require(rootToken != address(0x0), "Child token is not mapped");
        return isERC721[rootToken];
    }
}



/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}



contract ProxyStorage is Ownable {
    address internal proxyTo;
}



contract ChainIdMixin {
  bytes constant public networkId = hex"6D";
  uint256 constant public CHAINID = 109;
}





contract RootChainHeader {
    event NewHeaderBlock(
        address indexed proposer,
        uint256 indexed headerBlockId,
        uint256 indexed reward,
        uint256 start,
        uint256 end,
        bytes32 root
    );
    // housekeeping event
    event ResetHeaderBlock(address indexed proposer, uint256 indexed headerBlockId);
    struct HeaderBlock {
        bytes32 root;
        uint256 start;
        uint256 end;
        uint256 createdAt;
        address proposer;
    }
}


contract RootChainStorage is ProxyStorage, RootChainHeader, ChainIdMixin {
    bytes32 public heimdallId;
    uint8 public constant VOTE_TYPE = 2;

    uint16 internal constant MAX_DEPOSITS = 10000;
    uint256 public _nextHeaderBlock = MAX_DEPOSITS;
    uint256 internal _blockDepositId = 1;
    mapping(uint256 => HeaderBlock) public headerBlocks;
    Registry internal registry;
}


/*
 * SPDX-License-Identitifer:    MIT
 */


// See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-897.md

interface ERCProxy {
    function proxyType() external pure returns (uint256 proxyTypeId);
    function implementation() external view returns (address codeAddr);
}



contract DelegateProxyForwarder {
    function delegatedFwd(address _dst, bytes memory _calldata) internal {
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let result := delegatecall(
                sub(gas, 10000),
                _dst,
                add(_calldata, 0x20),
                mload(_calldata),
                0,
                0
            )
            let size := returndatasize

            let ptr := mload(0x40)
            returndatacopy(ptr, 0, size)

            // revert instead of invalid() bc if the underlying call failed with invalid() it already wasted gas.
            // if the call returned error data, forward it
            switch result
                case 0 {
                    revert(ptr, size)
                }
                default {
                    return(ptr, size)
                }
        }
    }
    
    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly {
            size := extcodesize(_target)
        }
        return size > 0;
    }
}




contract DelegateProxy is ERCProxy, DelegateProxyForwarder {
    function proxyType() external pure returns (uint256 proxyTypeId) {
        // Upgradeable proxy
        proxyTypeId = 2;
    }

    function implementation() external view returns (address);
}




contract Proxy is ProxyStorage, DelegateProxy {
    event ProxyUpdated(address indexed _new, address indexed _old);
    event OwnerUpdate(address _prevOwner, address _newOwner);

    constructor(address _proxyTo) public {
        updateImplementation(_proxyTo);
    }

    function() external payable {
        // require(currentContract != 0, "If app code has not been set yet, do not call");
        // Todo: filter out some calls or handle in the end fallback
        delegatedFwd(proxyTo, msg.data);
    }

    function implementation() external view returns (address) {
        return proxyTo;
    }

    function updateImplementation(address _newProxyTo) public onlyOwner {
        require(_newProxyTo != address(0x0), "INVALID_PROXY_ADDRESS");
        require(isContract(_newProxyTo), "DESTINATION_ADDRESS_IS_NOT_A_CONTRACT");
        emit ProxyUpdated(_newProxyTo, proxyTo);
        proxyTo = _newProxyTo;
    }

    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly {
            size := extcodesize(_target)
        }
        return size > 0;
    }
}





contract RootChainProxy is Proxy, RootChainStorage {
  constructor(address _proxyTo, address _registry, string memory _heimdallId)
    public
    Proxy(_proxyTo)
  {
    registry = Registry(_registry);
    heimdallId = keccak256(abi.encodePacked(_heimdallId));
  }
}

pragma solidity ^0.5.0;

/*
* @author Hamdi Allam [email protected]
* Please reach out with any questions or concerns
*/

library RLPReader {
    uint8 constant STRING_SHORT_START = 0x80;
    uint8 constant STRING_LONG_START  = 0xb8;
    uint8 constant LIST_SHORT_START   = 0xc0;
    uint8 constant LIST_LONG_START    = 0xf8;
    uint8 constant WORD_SIZE = 32;

    struct RLPItem {
        uint len;
        uint memPtr;
    }

    struct Iterator {
        RLPItem item;   // Item that's being iterated over.
        uint nextPtr;   // Position of the next item in the list.
    }

    /*
    * @dev Returns the next element in the iteration. Reverts if it has not next element.
    * @param self The iterator.
    * @return The next element in the iteration.
    */
    function next(Iterator memory self) internal pure returns (RLPItem memory) {
        require(hasNext(self));

        uint ptr = self.nextPtr;
        uint itemLength = _itemLength(ptr);
        self.nextPtr = ptr + itemLength;

        return RLPItem(itemLength, ptr);
    }

    /*
    * @dev Returns true if the iteration has more elements.
    * @param self The iterator.
    * @return true if the iteration has more elements.
    */
    function hasNext(Iterator memory self) internal pure returns (bool) {
        RLPItem memory item = self.item;
        return self.nextPtr < item.memPtr + item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
        uint memPtr;
        assembly {
            memPtr := add(item, 0x20)
        }

        return RLPItem(item.length, memPtr);
    }

    /*
    * @dev Create an iterator. Reverts if item is not a list.
    * @param self The RLP item.
    * @return An 'Iterator' over the item.
    */
    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
        require(isList(self));

        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }

    /*
    * @param item RLP encoded bytes
    */
    function rlpLen(RLPItem memory item) internal pure returns (uint) {
        return item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function payloadLen(RLPItem memory item) internal pure returns (uint) {
        return item.len - _payloadOffset(item.memPtr);
    }

    /*
    * @param item RLP encoded list in bytes
    */
    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
        require(isList(item));

        uint items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);

        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint dataLen;
        for (uint i = 0; i < items; i++) {
            dataLen = _itemLength(memPtr);
            result[i] = RLPItem(dataLen, memPtr); 
            memPtr = memPtr + dataLen;
        }

        return result;
    }

    // @return indicator whether encoded payload is a list. negate this function call for isData.
    function isList(RLPItem memory item) internal pure returns (bool) {
        if (item.len == 0) return false;

        uint8 byte0;
        uint memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < LIST_SHORT_START)
            return false;
        return true;
    }

    /** RLPItem conversions into data types **/

    // @returns raw rlp encoding in bytes
    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
        bytes memory result = new bytes(item.len);
        if (result.length == 0) return result;
        
        uint ptr;
        assembly {
            ptr := add(0x20, result)
        }

        copy(item.memPtr, ptr, item.len);
        return result;
    }

    // any non-zero byte is considered true
    function toBoolean(RLPItem memory item) internal pure returns (bool) {
        require(item.len == 1);
        uint result;
        uint memPtr = item.memPtr;
        assembly {
            result := byte(0, mload(memPtr))
        }

        return result == 0 ? false : true;
    }

    function toAddress(RLPItem memory item) internal pure returns (address) {
        // 1 byte for the length prefix
        require(item.len == 21);

        return address(toUint(item));
    }

    function toUint(RLPItem memory item) internal pure returns (uint) {
        require(item.len > 0 && item.len <= 33);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset;

        uint result;
        uint memPtr = item.memPtr + offset;
        assembly {
            result := mload(memPtr)

            // shfit to the correct location if neccesary
            if lt(len, 32) {
                result := div(result, exp(256, sub(32, len)))
            }
        }

        return result;
    }

    // enforces 32 byte length
    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
        // one byte prefix
        require(item.len == 33);

        uint result;
        uint memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }

        return result;
    }

    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
        require(item.len > 0);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset; // data length
        bytes memory result = new bytes(len);

        uint destPtr;
        assembly {
            destPtr := add(0x20, result)
        }

        copy(item.memPtr + offset, destPtr, len);
        return result;
    }

    /*
    * Private Helpers
    */

    // @return number of payload items inside an encoded list.
    function numItems(RLPItem memory item) private pure returns (uint) {
        if (item.len == 0) return 0;

        uint count = 0;
        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint endPtr = item.memPtr + item.len;
        while (currPtr < endPtr) {
           currPtr = currPtr + _itemLength(currPtr); // skip over an item
           count++;
        }

        return count;
    }

    // @return entire rlp item byte length
    function _itemLength(uint memPtr) private pure returns (uint) {
        uint itemLen;
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START)
            itemLen = 1;
        
        else if (byte0 < STRING_LONG_START)
            itemLen = byte0 - STRING_SHORT_START + 1;

        else if (byte0 < LIST_SHORT_START) {
            assembly {
                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
                memPtr := add(memPtr, 1) // skip over the first byte
                
                /* 32 byte word size */
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        else if (byte0 < LIST_LONG_START) {
            itemLen = byte0 - LIST_SHORT_START + 1;
        } 

        else {
            assembly {
                let byteLen := sub(byte0, 0xf7)
                memPtr := add(memPtr, 1)

                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        return itemLen;
    }

    // @return number of bytes until the data
    function _payloadOffset(uint memPtr) private pure returns (uint) {
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START) 
            return 0;
        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
            return 1;
        else if (byte0 < LIST_SHORT_START)  // being explicit
            return byte0 - (STRING_LONG_START - 1) + 1;
        else
            return byte0 - (LIST_LONG_START - 1) + 1;
    }

    /*
    * @param src Pointer to source
    * @param dest Pointer to destination
    * @param len Amount of memory to copy from the source
    */
    function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;

        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }

            src += WORD_SIZE;
            dest += WORD_SIZE;
        }

        // left over bytes. Mask is used to remove unwanted bytes from the word
        uint mask = 256 ** (WORD_SIZE - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask)) // zero out src
            let destpart := and(mload(dest), mask) // retrieve the bytes
            mstore(dest, or(destpart, srcpart))
        }
    }
}



/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
     * @dev Multiplies two unsigned integers, reverts on overflow.
     */
    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;
    }

    /**
     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two unsigned integers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}



interface IGovernance {
    function update(address target, bytes calldata data) external;
}



contract Governable {
    IGovernance public governance;

    constructor(address _governance) public {
        governance = IGovernance(_governance);
    }

    modifier onlyGovernance() {
        _assertGovernance();
        _;
    }

    function _assertGovernance() private view {
        require(
            msg.sender == address(governance),
            "Only governance contract is authorized"
        );
    }
}



contract IWithdrawManager {
    function createExitQueue(address token) external;

    function verifyInclusion(
        bytes calldata data,
        uint8 offset,
        bool verifyTxInclusion
    ) external view returns (uint256 age);

    function addExitToQueue(
        address exitor,
        address childToken,
        address rootToken,
        uint256 exitAmountOrTokenId,
        bytes32 txHash,
        bool isRegularExit,
        uint256 priority
    ) external;

    function addInput(
        uint256 exitId,
        uint256 age,
        address utxoOwner,
        address token
    ) external;

    function challengeExit(
        uint256 exitId,
        uint256 inputId,
        bytes calldata challengeData,
        address adjudicatorPredicate
    ) external;
}




contract Registry is Governable {
    // @todo hardcode constants
    bytes32 private constant WETH_TOKEN = keccak256("wethToken");
    bytes32 private constant DEPOSIT_MANAGER = keccak256("depositManager");
    bytes32 private constant STAKE_MANAGER = keccak256("stakeManager");
    bytes32 private constant VALIDATOR_SHARE = keccak256("validatorShare");
    bytes32 private constant WITHDRAW_MANAGER = keccak256("withdrawManager");
    bytes32 private constant CHILD_CHAIN = keccak256("childChain");
    bytes32 private constant STATE_SENDER = keccak256("stateSender");
    bytes32 private constant SLASHING_MANAGER = keccak256("slashingManager");

    address public erc20Predicate;
    address public erc721Predicate;

    mapping(bytes32 => address) public contractMap;
    mapping(address => address) public rootToChildToken;
    mapping(address => address) public childToRootToken;
    mapping(address => bool) public proofValidatorContracts;
    mapping(address => bool) public isERC721;

    enum Type {Invalid, ERC20, ERC721, Custom}
    struct Predicate {
        Type _type;
    }
    mapping(address => Predicate) public predicates;

    event TokenMapped(address indexed rootToken, address indexed childToken);
    event ProofValidatorAdded(address indexed validator, address indexed from);
    event ProofValidatorRemoved(address indexed validator, address indexed from);
    event PredicateAdded(address indexed predicate, address indexed from);
    event PredicateRemoved(address indexed predicate, address indexed from);
    event ContractMapUpdated(bytes32 indexed key, address indexed previousContract, address indexed newContract);

    constructor(address _governance) public Governable(_governance) {}

    function updateContractMap(bytes32 _key, address _address) external onlyGovernance {
        emit ContractMapUpdated(_key, contractMap[_key], _address);
        contractMap[_key] = _address;
    }

    /**
     * @dev Map root token to child token
     * @param _rootToken Token address on the root chain
     * @param _childToken Token address on the child chain
     * @param _isERC721 Is the token being mapped ERC721
     */
    function mapToken(
        address _rootToken,
        address _childToken,
        bool _isERC721
    ) external onlyGovernance {
        require(_rootToken != address(0x0) && _childToken != address(0x0), "INVALID_TOKEN_ADDRESS");
        rootToChildToken[_rootToken] = _childToken;
        childToRootToken[_childToken] = _rootToken;
        isERC721[_rootToken] = _isERC721;
        IWithdrawManager(contractMap[WITHDRAW_MANAGER]).createExitQueue(_rootToken);
        emit TokenMapped(_rootToken, _childToken);
    }

    function addErc20Predicate(address predicate) public onlyGovernance {
        require(predicate != address(0x0), "Can not add null address as predicate");
        erc20Predicate = predicate;
        addPredicate(predicate, Type.ERC20);
    }

    function addErc721Predicate(address predicate) public onlyGovernance {
        erc721Predicate = predicate;
        addPredicate(predicate, Type.ERC721);
    }

    function addPredicate(address predicate, Type _type) public onlyGovernance {
        require(predicates[predicate]._type == Type.Invalid, "Predicate already added");
        predicates[predicate]._type = _type;
        emit PredicateAdded(predicate, msg.sender);
    }

    function removePredicate(address predicate) public onlyGovernance {
        require(predicates[predicate]._type != Type.Invalid, "Predicate does not exist");
        delete predicates[predicate];
        emit PredicateRemoved(predicate, msg.sender);
    }

    function getValidatorShareAddress() public view returns (address) {
        return contractMap[VALIDATOR_SHARE];
    }

    function getWethTokenAddress() public view returns (address) {
        return contractMap[WETH_TOKEN];
    }

    function getDepositManagerAddress() public view returns (address) {
        return contractMap[DEPOSIT_MANAGER];
    }

    function getStakeManagerAddress() public view returns (address) {
        return contractMap[STAKE_MANAGER];
    }

    function getSlashingManagerAddress() public view returns (address) {
        return contractMap[SLASHING_MANAGER];
    }

    function getWithdrawManagerAddress() public view returns (address) {
        return contractMap[WITHDRAW_MANAGER];
    }

    function getChildChainAndStateSender() public view returns (address, address) {
        return (contractMap[CHILD_CHAIN], contractMap[STATE_SENDER]);
    }

    function isTokenMapped(address _token) public view returns (bool) {
        return rootToChildToken[_token] != address(0x0);
    }

    function isTokenMappedAndIsErc721(address _token) public view returns (bool) {
        require(isTokenMapped(_token), "TOKEN_NOT_MAPPED");
        return isERC721[_token];
    }

    function isTokenMappedAndGetPredicate(address _token) public view returns (address) {
        if (isTokenMappedAndIsErc721(_token)) {
            return erc721Predicate;
        }
        return erc20Predicate;
    }

    function isChildTokenErc721(address childToken) public view returns (bool) {
        address rootToken = childToRootToken[childToken];
        require(rootToken != address(0x0), "Child token is not mapped");
        return isERC721[rootToken];
    }
}



/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}



contract ProxyStorage is Ownable {
    address internal proxyTo;
}



contract ChainIdMixin {
  bytes constant public networkId = hex"6D";
  uint256 constant public CHAINID = 109;
}





contract RootChainHeader {
    event NewHeaderBlock(
        address indexed proposer,
        uint256 indexed headerBlockId,
        uint256 indexed reward,
        uint256 start,
        uint256 end,
        bytes32 root
    );
    // housekeeping event
    event ResetHeaderBlock(address indexed proposer, uint256 indexed headerBlockId);
    struct HeaderBlock {
        bytes32 root;
        uint256 start;
        uint256 end;
        uint256 createdAt;
        address proposer;
    }
}


contract RootChainStorage is ProxyStorage, RootChainHeader, ChainIdMixin {
    bytes32 public heimdallId;
    uint8 public constant VOTE_TYPE = 2;

    uint16 internal constant MAX_DEPOSITS = 10000;
    uint256 public _nextHeaderBlock = MAX_DEPOSITS;
    uint256 internal _blockDepositId = 1;
    mapping(uint256 => HeaderBlock) public headerBlocks;
    Registry internal registry;
}



contract IStakeManager {
    // validator replacement
    function startAuction(
        uint256 validatorId,
        uint256 amount,
        bool acceptDelegation,
        bytes calldata signerPubkey
    ) external;

    function confirmAuctionBid(uint256 validatorId, uint256 heimdallFee) external;

    function transferFunds(
        uint256 validatorId,
        uint256 amount,
        address delegator
    ) external returns (bool);

    function delegationDeposit(
        uint256 validatorId,
        uint256 amount,
        address delegator
    ) external returns (bool);

    function unstake(uint256 validatorId) external;

    function totalStakedFor(address addr) external view returns (uint256);

    function stakeFor(
        address user,
        uint256 amount,
        uint256 heimdallFee,
        bool acceptDelegation,
        bytes memory signerPubkey
    ) public;

    function checkSignatures(
        uint256 blockInterval,
        bytes32 voteHash,
        bytes32 stateRoot,
        address proposer,
        uint[3][] calldata sigs
    ) external returns (uint256);

    function updateValidatorState(uint256 validatorId, int256 amount) public;

    function ownerOf(uint256 tokenId) public view returns (address);

    function slash(bytes calldata slashingInfoList) external returns (uint256);

    function validatorStake(uint256 validatorId) public view returns (uint256);

    function epoch() public view returns (uint256);

    function getRegistry() public view returns (address);

    function withdrawalDelay() public view returns (uint256);

    function delegatedAmount(uint256 validatorId) public view returns(uint256);

    function decreaseValidatorDelegatedAmount(uint256 validatorId, uint256 amount) public;

    function withdrawDelegatorsReward(uint256 validatorId) public returns(uint256);

    function delegatorsReward(uint256 validatorId) public view returns(uint256);

    function dethroneAndStake(
        address auctionUser,
        uint256 heimdallFee,
        uint256 validatorId,
        uint256 auctionAmount,
        bool acceptDelegation,
        bytes calldata signerPubkey
    ) external;
}




interface IRootChain {
    function slash() external;

    function submitHeaderBlock(bytes calldata data, bytes calldata sigs)
        external;
    
    function submitCheckpoint(bytes calldata data, uint[3][] calldata sigs)
        external;

    function getLastChildBlock() external view returns (uint256);

    function currentHeaderBlock() external view returns (uint256);
}






contract RootChain is RootChainStorage, IRootChain {
    using SafeMath for uint256;
    using RLPReader for bytes;
    using RLPReader for RLPReader.RLPItem;

    modifier onlyDepositManager() {
        require(msg.sender == registry.getDepositManagerAddress(), "UNAUTHORIZED_DEPOSIT_MANAGER_ONLY");
        _;
    }

    function submitHeaderBlock(bytes calldata data, bytes calldata sigs) external {
        revert();
    }

    function submitCheckpoint(bytes calldata data, uint[3][] calldata sigs) external {
        (address proposer, uint256 start, uint256 end, bytes32 rootHash, bytes32 accountHash, uint256 _borChainID) = abi
            .decode(data, (address, uint256, uint256, bytes32, bytes32, uint256));
        require(CHAINID == _borChainID, "Invalid bor chain id");

        require(_buildHeaderBlock(proposer, start, end, rootHash), "INCORRECT_HEADER_DATA");

        // check if it is better to keep it in local storage instead
        IStakeManager stakeManager = IStakeManager(registry.getStakeManagerAddress());
        uint256 _reward = stakeManager.checkSignatures(
            end.sub(start).add(1),
            /**  
                prefix 01 to data 
                01 represents positive vote on data and 00 is negative vote
                malicious validator can try to send 2/3 on negative vote so 01 is appended
             */
            keccak256(abi.encodePacked(bytes(hex"01"), data)),
            accountHash,
            proposer,
            sigs
        );

        require(_reward != 0, "Invalid checkpoint");
        emit NewHeaderBlock(proposer, _nextHeaderBlock, _reward, start, end, rootHash);
        _nextHeaderBlock = _nextHeaderBlock.add(MAX_DEPOSITS);
        _blockDepositId = 1;
    }

    function updateDepositId(uint256 numDeposits) external onlyDepositManager returns (uint256 depositId) {
        depositId = currentHeaderBlock().add(_blockDepositId);
        // deposit ids will be (_blockDepositId, _blockDepositId + 1, .... _blockDepositId + numDeposits - 1)
        _blockDepositId = _blockDepositId.add(numDeposits);
        require(
            // Since _blockDepositId is initialized to 1; only (MAX_DEPOSITS - 1) deposits per header block are allowed
            _blockDepositId <= MAX_DEPOSITS,
            "TOO_MANY_DEPOSITS"
        );
    }

    function getLastChildBlock() external view returns (uint256) {
        return headerBlocks[currentHeaderBlock()].end;
    }

    function slash() external {
        //TODO: future implementation
    }

    function currentHeaderBlock() public view returns (uint256) {
        return _nextHeaderBlock.sub(MAX_DEPOSITS);
    }

    function _buildHeaderBlock(
        address proposer,
        uint256 start,
        uint256 end,
        bytes32 rootHash
    ) private returns (bool) {
        uint256 nextChildBlock;
        /*
    The ID of the 1st header block is MAX_DEPOSITS.
    if _nextHeaderBlock == MAX_DEPOSITS, then the first header block is yet to be submitted, hence nextChildBlock = 0
    */
        if (_nextHeaderBlock > MAX_DEPOSITS) {
            nextChildBlock = headerBlocks[currentHeaderBlock()].end + 1;
        }
        if (nextChildBlock != start) {
            return false;
        }

        HeaderBlock memory headerBlock = HeaderBlock({
            root: rootHash,
            start: nextChildBlock,
            end: end,
            createdAt: now,
            proposer: proposer
        });

        headerBlocks[_nextHeaderBlock] = headerBlock;
        return true;
    }

    // Housekeeping function. @todo remove later
    function setNextHeaderBlock(uint256 _value) public onlyOwner {
        require(_value % MAX_DEPOSITS == 0, "Invalid value");
        for (uint256 i = _value; i < _nextHeaderBlock; i += MAX_DEPOSITS) {
            delete headerBlocks[i];
        }
        _nextHeaderBlock = _value;
        _blockDepositId = 1;
        emit ResetHeaderBlock(msg.sender, _nextHeaderBlock);
    }

    // Housekeeping function. @todo remove later
    function setHeimdallId(string memory _heimdallId) public onlyOwner {
        heimdallId = keccak256(abi.encodePacked(_heimdallId));
    }
}