// File: /home/ubuntu/environment/contracts/contracts/Staking.sol



// SPDX-License-Identifier: UNLICENSED

// Code by zipzinger and cmtzco
// DEFIBOYS
// defiboys.com

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {FxBaseRootTunnel} from "./base/FxBaseRootTunnel.sol";

contract Staking is Ownable, FxBaseRootTunnel {
    IERC20 private _token;

    mapping(address => bool) public staked;
    mapping(address => uint256) public stakedAmount;

    event StakedTokens(address from);
    event UnstakedTokens(address from);
    event StakeTokenChange(IERC20 token);

    constructor(
        IERC20 token,
        address _checkpointManager,
        address _fxRoot
    ) FxBaseRootTunnel(_checkpointManager, _fxRoot) {
        _token = token;
    }

    function setStakeToken(IERC20 token) external onlyOwner {
        _token = token;
        emit StakeTokenChange(_token);
    }

    function getStakeToken() external view returns (IERC20) {
        return _token;
    }

    function getStakedAmount(address _addr) external view returns (uint256) {
        return stakedAmount[_addr];
    }

    function stake(uint256 _amount) external {
        address from = msg.sender;
        require(
            _token.balanceOf(from) >= _amount,
            "You dont own that amount of tokens"
        );

        _token.transferFrom(from, address(this), _amount);

        if (!staked[from]) {
            staked[from] = true;
            stakedAmount[from] = _amount;
        } else {
            stakedAmount[from] = SafeMath.add(stakedAmount[from], _amount);
        }

        _sendMessageToChild(abi.encode(from, true, _amount));

        emit StakedTokens(from);
    }

    function unstake(uint256 _amount) external {
        address from = msg.sender;
        require(
            stakedAmount[from] >= _amount,
            "You dont own that amount of tokens"
        );

        stakedAmount[from] = SafeMath.sub(stakedAmount[from], _amount);
        _token.transfer(from, _amount);

        _sendMessageToChild(abi.encode(from, false, _amount));

        emit UnstakedTokens(from);
    }

    function _processMessageFromChild(bytes memory data) internal override {}

    function updateFxChildTunnel(address _fxChildTunnel) external onlyOwner {
        fxChildTunnel = _fxChildTunnel;
    }
}
// File: @openzeppelin/contracts/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is no longer needed starting with Solidity 0.8. The compiler
 * now has built in overflow checking.
 */
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) {
        unchecked {
            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) {
        unchecked {
            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) {
        unchecked {
            // 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) {
        unchecked {
            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) {
        unchecked {
            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) {
        return a + b;
    }

    /**
     * @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) {
        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) {
        return a * b;
    }

    /**
     * @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.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        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) {
        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) {
        unchecked {
            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.
     *
     * 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).
     *
     * 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) {
        unchecked {
            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) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^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 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) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^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);
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^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 () {
        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;
    }
}

// File: /home/ubuntu/environment/contracts/contracts/base/lib/RLPReader.sol



/*
 * @author Hamdi Allam hamdi.allam97@gmail.com
 * Please reach out with any questions or concerns
 */
pragma solidity ^0.8.0;

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 {
        uint256 len;
        uint256 memPtr;
    }

    struct Iterator {
        RLPItem item; // Item that's being iterated over.
        uint256 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));

        uint256 ptr = self.nextPtr;
        uint256 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)
    {
        uint256 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));

        uint256 ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }

    /*
     * @param item RLP encoded bytes
     */
    function rlpLen(RLPItem memory item) internal pure returns (uint256) {
        return item.len;
    }

    /*
     * @param item RLP encoded bytes
     */
    function payloadLen(RLPItem memory item) internal pure returns (uint256) {
        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));

        uint256 items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);

        uint256 memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint256 dataLen;
        for (uint256 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;
        uint256 memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

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

    /*
     * @dev A cheaper version of keccak256(toRlpBytes(item)) that avoids copying memory.
     * @return keccak256 hash of RLP encoded bytes.
     */
    function rlpBytesKeccak256(RLPItem memory item)
        internal
        pure
        returns (bytes32)
    {
        uint256 ptr = item.memPtr;
        uint256 len = item.len;
        bytes32 result;
        assembly {
            result := keccak256(ptr, len)
        }
        return result;
    }

    function payloadLocation(RLPItem memory item)
        internal
        pure
        returns (uint256, uint256)
    {
        uint256 offset = _payloadOffset(item.memPtr);
        uint256 memPtr = item.memPtr + offset;
        uint256 len = item.len - offset; // data length
        return (memPtr, len);
    }

    /*
     * @dev A cheaper version of keccak256(toBytes(item)) that avoids copying memory.
     * @return keccak256 hash of the item payload.
     */
    function payloadKeccak256(RLPItem memory item)
        internal
        pure
        returns (bytes32)
    {
        (uint256 memPtr, uint256 len) = payloadLocation(item);
        bytes32 result;
        assembly {
            result := keccak256(memPtr, len)
        }
        return result;
    }

    /** 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;

        uint256 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);
        uint256 result;
        uint256 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(uint160(toUint(item)));
    }

    function toUint(RLPItem memory item) internal pure returns (uint256) {
        require(item.len > 0 && item.len <= 33);

        uint256 offset = _payloadOffset(item.memPtr);
        uint256 len = item.len - offset;

        uint256 result;
        uint256 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 (uint256) {
        // one byte prefix
        require(item.len == 33);

        uint256 result;
        uint256 memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }

        return result;
    }

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

        uint256 offset = _payloadOffset(item.memPtr);
        uint256 len = item.len - offset; // data length
        bytes memory result = new bytes(len);

        uint256 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 (uint256) {
        if (item.len == 0) return 0;

        uint256 count = 0;
        uint256 currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint256 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(uint256 memPtr) private pure returns (uint256) {
        uint256 itemLen;
        uint256 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(uint256 memPtr) private pure returns (uint256) {
        uint256 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(
        uint256 src,
        uint256 dest,
        uint256 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
        uint256 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))
        }
    }
}

// File: /home/ubuntu/environment/contracts/contracts/base/lib/MerklePatriciaProof.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

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

library MerklePatriciaProof {
    /*
     * @dev Verifies a merkle patricia proof.
     * @param value The terminating value in the trie.
     * @param encodedPath The path in the trie leading to value.
     * @param rlpParentNodes The rlp encoded stack of nodes.
     * @param root The root hash of the trie.
     * @return The boolean validity of the proof.
     */
    function verify(
        bytes memory value,
        bytes memory encodedPath,
        bytes memory rlpParentNodes,
        bytes32 root
    ) internal pure returns (bool) {
        RLPReader.RLPItem memory item = RLPReader.toRlpItem(rlpParentNodes);
        RLPReader.RLPItem[] memory parentNodes = RLPReader.toList(item);

        bytes memory currentNode;
        RLPReader.RLPItem[] memory currentNodeList;

        bytes32 nodeKey = root;
        uint256 pathPtr = 0;

        bytes memory path = _getNibbleArray(encodedPath);
        if (path.length == 0) {
            return false;
        }

        for (uint256 i = 0; i < parentNodes.length; i++) {
            if (pathPtr > path.length) {
                return false;
            }

            currentNode = RLPReader.toRlpBytes(parentNodes[i]);
            if (nodeKey != keccak256(currentNode)) {
                return false;
            }
            currentNodeList = RLPReader.toList(parentNodes[i]);

            if (currentNodeList.length == 17) {
                if (pathPtr == path.length) {
                    if (
                        keccak256(RLPReader.toBytes(currentNodeList[16])) ==
                        keccak256(value)
                    ) {
                        return true;
                    } else {
                        return false;
                    }
                }

                uint8 nextPathNibble = uint8(path[pathPtr]);
                if (nextPathNibble > 16) {
                    return false;
                }
                nodeKey = bytes32(
                    RLPReader.toUintStrict(currentNodeList[nextPathNibble])
                );
                pathPtr += 1;
            } else if (currentNodeList.length == 2) {
                uint256 traversed = _nibblesToTraverse(
                    RLPReader.toBytes(currentNodeList[0]),
                    path,
                    pathPtr
                );
                if (pathPtr + traversed == path.length) {
                    //leaf node
                    if (
                        keccak256(RLPReader.toBytes(currentNodeList[1])) ==
                        keccak256(value)
                    ) {
                        return true;
                    } else {
                        return false;
                    }
                }

                //extension node
                if (traversed == 0) {
                    return false;
                }

                pathPtr += traversed;
                nodeKey = bytes32(RLPReader.toUintStrict(currentNodeList[1]));
            } else {
                return false;
            }
        }
    }

    function _nibblesToTraverse(
        bytes memory encodedPartialPath,
        bytes memory path,
        uint256 pathPtr
    ) private pure returns (uint256) {
        uint256 len = 0;
        // encodedPartialPath has elements that are each two hex characters (1 byte), but partialPath
        // and slicedPath have elements that are each one hex character (1 nibble)
        bytes memory partialPath = _getNibbleArray(encodedPartialPath);
        bytes memory slicedPath = new bytes(partialPath.length);

        // pathPtr counts nibbles in path
        // partialPath.length is a number of nibbles
        for (uint256 i = pathPtr; i < pathPtr + partialPath.length; i++) {
            bytes1 pathNibble = path[i];
            slicedPath[i - pathPtr] = pathNibble;
        }

        if (keccak256(partialPath) == keccak256(slicedPath)) {
            len = partialPath.length;
        } else {
            len = 0;
        }
        return len;
    }

    // bytes b must be hp encoded
    function _getNibbleArray(bytes memory b)
        internal
        pure
        returns (bytes memory)
    {
        bytes memory nibbles = "";
        if (b.length > 0) {
            uint8 offset;
            uint8 hpNibble = uint8(_getNthNibbleOfBytes(0, b));
            if (hpNibble == 1 || hpNibble == 3) {
                nibbles = new bytes(b.length * 2 - 1);
                bytes1 oddNibble = _getNthNibbleOfBytes(1, b);
                nibbles[0] = oddNibble;
                offset = 1;
            } else {
                nibbles = new bytes(b.length * 2 - 2);
                offset = 0;
            }

            for (uint256 i = offset; i < nibbles.length; i++) {
                nibbles[i] = _getNthNibbleOfBytes(i - offset + 2, b);
            }
        }
        return nibbles;
    }

    function _getNthNibbleOfBytes(uint256 n, bytes memory str)
        private
        pure
        returns (bytes1)
    {
        return
            bytes1(
                n % 2 == 0 ? uint8(str[n / 2]) / 0x10 : uint8(str[n / 2]) % 0x10
            );
    }
}

// File: /home/ubuntu/environment/contracts/contracts/base/lib/Merkle.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

library Merkle {
    function checkMembership(
        bytes32 leaf,
        uint256 index,
        bytes32 rootHash,
        bytes memory proof
    ) internal pure returns (bool) {
        require(proof.length % 32 == 0, "Invalid proof length");
        uint256 proofHeight = proof.length / 32;
        // Proof of size n means, height of the tree is n+1.
        // In a tree of height n+1, max #leafs possible is 2 ^ n
        require(index < 2**proofHeight, "Leaf index is too big");

        bytes32 proofElement;
        bytes32 computedHash = leaf;
        for (uint256 i = 32; i <= proof.length; i += 32) {
            assembly {
                proofElement := mload(add(proof, i))
            }

            if (index % 2 == 0) {
                computedHash = keccak256(
                    abi.encodePacked(computedHash, proofElement)
                );
            } else {
                computedHash = keccak256(
                    abi.encodePacked(proofElement, computedHash)
                );
            }

            index = index / 2;
        }
        return computedHash == rootHash;
    }
}

// File: /home/ubuntu/environment/contracts/contracts/base/FxBaseRootTunnel.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import {RLPReader} from "./lib/RLPReader.sol";
import {MerklePatriciaProof} from "./lib/MerklePatriciaProof.sol";
import {Merkle} from "./lib/Merkle.sol";

interface IFxStateSender {
    function sendMessageToChild(address _receiver, bytes calldata _data)
        external;
}

contract ICheckpointManager {
    struct HeaderBlock {
        bytes32 root;
        uint256 start;
        uint256 end;
        uint256 createdAt;
        address proposer;
    }

    /**
     * @notice mapping of checkpoint header numbers to block details
     * @dev These checkpoints are submited by plasma contracts
     */
    mapping(uint256 => HeaderBlock) public headerBlocks;
}

abstract contract FxBaseRootTunnel {
    using RLPReader for bytes;
    using RLPReader for RLPReader.RLPItem;
    using Merkle for bytes32;

    // keccak256(MessageSent(bytes))
    bytes32 public constant SEND_MESSAGE_EVENT_SIG =
        0x8c5261668696ce22758910d05bab8f186d6eb247ceac2af2e82c7dc17669b036;

    // state sender contract
    IFxStateSender public fxRoot;
    // root chain manager
    ICheckpointManager public checkpointManager;
    // child tunnel contract which receives and sends messages
    address public fxChildTunnel;

    // storage to avoid duplicate exits
    mapping(bytes32 => bool) public processedExits;

    constructor(address _checkpointManager, address _fxRoot) {
        checkpointManager = ICheckpointManager(_checkpointManager);
        fxRoot = IFxStateSender(_fxRoot);
    }

    // set fxChildTunnel if not set already
    function setFxChildTunnel(address _fxChildTunnel) public {
        require(
            fxChildTunnel == address(0x0),
            "FxBaseRootTunnel: CHILD_TUNNEL_ALREADY_SET"
        );
        fxChildTunnel = _fxChildTunnel;
    }

    /**
     * @notice Send bytes message to Child Tunnel
     * @param message bytes message that will be sent to Child Tunnel
     * some message examples -
     *   abi.encode(tokenId);
     *   abi.encode(tokenId, tokenMetadata);
     *   abi.encode(messageType, messageData);
     */
    function _sendMessageToChild(bytes memory message) internal {
        fxRoot.sendMessageToChild(fxChildTunnel, message);
    }

    function _validateAndExtractMessage(bytes memory inputData)
        internal
        returns (bytes memory)
    {
        RLPReader.RLPItem[] memory inputDataRLPList = inputData
            .toRlpItem()
            .toList();

        // checking if exit has already been processed
        // unique exit is identified using hash of (blockNumber, branchMask, receiptLogIndex)
        bytes32 exitHash = keccak256(
            abi.encodePacked(
                inputDataRLPList[2].toUint(), // blockNumber
                // first 2 nibbles are dropped while generating nibble array
                // this allows branch masks that are valid but bypass exitHash check (changing first 2 nibbles only)
                // so converting to nibble array and then hashing it
                MerklePatriciaProof._getNibbleArray(
                    inputDataRLPList[8].toBytes()
                ), // branchMask
                inputDataRLPList[9].toUint() // receiptLogIndex
            )
        );
        require(
            processedExits[exitHash] == false,
            "FxRootTunnel: EXIT_ALREADY_PROCESSED"
        );
        processedExits[exitHash] = true;

        RLPReader.RLPItem[] memory receiptRLPList = inputDataRLPList[6]
            .toBytes()
            .toRlpItem()
            .toList();
        RLPReader.RLPItem memory logRLP = receiptRLPList[3].toList()[
            inputDataRLPList[9].toUint() // receiptLogIndex
        ];

        RLPReader.RLPItem[] memory logRLPList = logRLP.toList();

        // check child tunnel
        require(
            fxChildTunnel == RLPReader.toAddress(logRLPList[0]),
            "FxRootTunnel: INVALID_FX_CHILD_TUNNEL"
        );

        // verify receipt inclusion
        require(
            MerklePatriciaProof.verify(
                inputDataRLPList[6].toBytes(), // receipt
                inputDataRLPList[8].toBytes(), // branchMask
                inputDataRLPList[7].toBytes(), // receiptProof
                bytes32(inputDataRLPList[5].toUint()) // receiptRoot
            ),
            "FxRootTunnel: INVALID_RECEIPT_PROOF"
        );

        // verify checkpoint inclusion
        _checkBlockMembershipInCheckpoint(
            inputDataRLPList[2].toUint(), // blockNumber
            inputDataRLPList[3].toUint(), // blockTime
            bytes32(inputDataRLPList[4].toUint()), // txRoot
            bytes32(inputDataRLPList[5].toUint()), // receiptRoot
            inputDataRLPList[0].toUint(), // headerNumber
            inputDataRLPList[1].toBytes() // blockProof
        );

        RLPReader.RLPItem[] memory logTopicRLPList = logRLPList[1].toList(); // topics

        require(
            bytes32(logTopicRLPList[0].toUint()) == SEND_MESSAGE_EVENT_SIG, // topic0 is event sig
            "FxRootTunnel: INVALID_SIGNATURE"
        );

        // received message data
        bytes memory receivedData = logRLPList[2].toBytes();
        bytes memory message = abi.decode(receivedData, (bytes)); // event decodes params again, so decoding bytes to get message
        return message;
    }

    function _checkBlockMembershipInCheckpoint(
        uint256 blockNumber,
        uint256 blockTime,
        bytes32 txRoot,
        bytes32 receiptRoot,
        uint256 headerNumber,
        bytes memory blockProof
    ) private view returns (uint256) {
        (
            bytes32 headerRoot,
            uint256 startBlock,
            ,
            uint256 createdAt,

        ) = checkpointManager.headerBlocks(headerNumber);

        require(
            keccak256(
                abi.encodePacked(blockNumber, blockTime, txRoot, receiptRoot)
            ).checkMembership(blockNumber - startBlock, headerRoot, blockProof),
            "FxRootTunnel: INVALID_HEADER"
        );
        return createdAt;
    }

    /**
     * @notice receive message from  L2 to L1, validated by proof
     * @dev This function verifies if the transaction actually happened on child chain
     *
     * @param inputData RLP encoded data of the reference tx containing following list of fields
     *  0 - headerNumber - Checkpoint header block number containing the reference tx
     *  1 - blockProof - Proof that the block header (in the child chain) is a leaf in the submitted merkle root
     *  2 - blockNumber - Block number containing the reference tx on child chain
     *  3 - blockTime - Reference tx block time
     *  4 - txRoot - Transactions root of block
     *  5 - receiptRoot - Receipts root of block
     *  6 - receipt - Receipt of the reference transaction
     *  7 - receiptProof - Merkle proof of the reference receipt
     *  8 - branchMask - 32 bits denoting the path of receipt in merkle tree
     *  9 - receiptLogIndex - Log Index to read from the receipt
     */
    function receiveMessage(bytes memory inputData) public virtual {
        bytes memory message = _validateAndExtractMessage(inputData);
        _processMessageFromChild(message);
    }

    /**
     * @notice Process message received from Child Tunnel
     * @dev function needs to be implemented to handle message as per requirement
     * This is called by onStateReceive function.
     * Since it is called via a system call, any event will not be emitted during its execution.
     * @param message bytes message that was sent from Child Tunnel
     */
    function _processMessageFromChild(bytes memory message) internal virtual;
}