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



// 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;
    }
}

// File: @openzeppelin/contracts/math/SafeMath.sol



// 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;
    }
}

// File: @openzeppelin/contracts/proxy/Proxy.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 *
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 *
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 { revert(0, returndatasize()) }
            default { return(0, returndatasize()) }
        }
    }

    /**
     * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal view virtual returns (address);

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback () external payable virtual {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive () external payable virtual {
        _fallback();
    }

    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     *
     * If overriden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {
    }
}

// File: @openzeppelin/contracts/proxy/ProxyAdmin.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../access/Ownable.sol";
import "./TransparentUpgradeableProxy.sol";

/**
 * @dev This is an auxiliary contract meant to be assigned as the admin of a {TransparentUpgradeableProxy}. For an
 * explanation of why you would want to use this see the documentation for {TransparentUpgradeableProxy}.
 */
contract ProxyAdmin is Ownable {

    /**
     * @dev Returns the current implementation of `proxy`.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function getProxyImplementation(TransparentUpgradeableProxy proxy) public view virtual returns (address) {
        // We need to manually run the static call since the getter cannot be flagged as view
        // bytes4(keccak256("implementation()")) == 0x5c60da1b
        (bool success, bytes memory returndata) = address(proxy).staticcall(hex"5c60da1b");
        require(success);
        return abi.decode(returndata, (address));
    }

    /**
     * @dev Returns the current admin of `proxy`.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function getProxyAdmin(TransparentUpgradeableProxy proxy) public view virtual returns (address) {
        // We need to manually run the static call since the getter cannot be flagged as view
        // bytes4(keccak256("admin()")) == 0xf851a440
        (bool success, bytes memory returndata) = address(proxy).staticcall(hex"f851a440");
        require(success);
        return abi.decode(returndata, (address));
    }

    /**
     * @dev Changes the admin of `proxy` to `newAdmin`.
     *
     * Requirements:
     *
     * - This contract must be the current admin of `proxy`.
     */
    function changeProxyAdmin(TransparentUpgradeableProxy proxy, address newAdmin) public virtual onlyOwner {
        proxy.changeAdmin(newAdmin);
    }

    /**
     * @dev Upgrades `proxy` to `implementation`. See {TransparentUpgradeableProxy-upgradeTo}.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function upgrade(TransparentUpgradeableProxy proxy, address implementation) public virtual onlyOwner {
        proxy.upgradeTo(implementation);
    }

    /**
     * @dev Upgrades `proxy` to `implementation` and calls a function on the new implementation. See
     * {TransparentUpgradeableProxy-upgradeToAndCall}.
     *
     * Requirements:
     *
     * - This contract must be the admin of `proxy`.
     */
    function upgradeAndCall(TransparentUpgradeableProxy proxy, address implementation, bytes memory data) public payable virtual onlyOwner {
        proxy.upgradeToAndCall{value: msg.value}(implementation, data);
    }
}

// File: @openzeppelin/contracts/proxy/TransparentUpgradeableProxy.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./UpgradeableProxy.sol";

/**
 * @dev This contract implements a proxy that is upgradeable by an admin.
 *
 * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
 * clashing], which can potentially be used in an attack, this contract uses the
 * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
 * things that go hand in hand:
 *
 * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
 * that call matches one of the admin functions exposed by the proxy itself.
 * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
 * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
 * "admin cannot fallback to proxy target".
 *
 * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
 * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
 * to sudden errors when trying to call a function from the proxy implementation.
 *
 * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
 * you should think of the `ProxyAdmin` instance as the real administrative interface of your proxy.
 */
contract TransparentUpgradeableProxy is UpgradeableProxy {
    /**
     * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
     * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
     */
    constructor(address _logic, address admin_, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
        assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
        _setAdmin(admin_);
    }

    /**
     * @dev Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
     * @dev Storage slot with the admin of the contract.
     * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**
     * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
     */
    modifier ifAdmin() {
        if (msg.sender == _admin()) {
            _;
        } else {
            _fallback();
        }
    }

    /**
     * @dev Returns the current admin.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
     *
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
     */
    function admin() external ifAdmin returns (address admin_) {
        admin_ = _admin();
    }

    /**
     * @dev Returns the current implementation.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
     *
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
     */
    function implementation() external ifAdmin returns (address implementation_) {
        implementation_ = _implementation();
    }

    /**
     * @dev Changes the admin of the proxy.
     *
     * Emits an {AdminChanged} event.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
     */
    function changeAdmin(address newAdmin) external virtual ifAdmin {
        require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
        emit AdminChanged(_admin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
     * @dev Upgrade the implementation of the proxy.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
     */
    function upgradeTo(address newImplementation) external virtual ifAdmin {
        _upgradeTo(newImplementation);
    }

    /**
     * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
     * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
     * proxied contract.
     *
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
     */
    function upgradeToAndCall(address newImplementation, bytes calldata data) external payable virtual ifAdmin {
        _upgradeTo(newImplementation);
        Address.functionDelegateCall(newImplementation, data);
    }

    /**
     * @dev Returns the current admin.
     */
    function _admin() internal view virtual returns (address adm) {
        bytes32 slot = _ADMIN_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            adm := sload(slot)
        }
    }

    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        bytes32 slot = _ADMIN_SLOT;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newAdmin)
        }
    }

    /**
     * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
     */
    function _beforeFallback() internal virtual override {
        require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
        super._beforeFallback();
    }
}

// File: @openzeppelin/contracts/proxy/UpgradeableProxy.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./Proxy.sol";
import "../utils/Address.sol";

/**
 * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
 * implementation address that can be changed. This address is stored in storage in the location specified by
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
 * implementation behind the proxy.
 *
 * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
 * {TransparentUpgradeableProxy}.
 */
contract UpgradeableProxy is Proxy {
    /**
     * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
     *
     * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
     * function call, and allows initializating the storage of the proxy like a Solidity constructor.
     */
    constructor(address _logic, bytes memory _data) public payable {
        assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _setImplementation(_logic);
        if(_data.length > 0) {
            Address.functionDelegateCall(_logic, _data);
        }
    }

    /**
     * @dev Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);

    /**
     * @dev Storage slot with the address of the current implementation.
     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**
     * @dev Returns the current implementation address.
     */
    function _implementation() internal view virtual override returns (address impl) {
        bytes32 slot = _IMPLEMENTATION_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            impl := sload(slot)
        }
    }

    /**
     * @dev Upgrades the proxy to a new implementation.
     *
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal virtual {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");

        bytes32 slot = _IMPLEMENTATION_SLOT;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newImplementation)
        }
    }
}

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



// 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);
}

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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

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



// 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;
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./Context.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

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

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor () internal {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(paused(), "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: contracts/arch/IOneStepProof.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../bridge/interfaces/IBridge.sol";
import "../bridge/interfaces/ISequencerInbox.sol";

interface IOneStepProof {
    // Bridges is sequencer bridge then delayed bridge
    function executeStep(
        address[2] calldata bridges,
        uint256 initialMessagesRead,
        bytes32[2] calldata accs,
        bytes calldata proof,
        bytes calldata bproof
    )
        external
        view
        returns (
            uint64 gas,
            uint256 afterMessagesRead,
            bytes32[4] memory fields
        );

    function executeStepDebug(
        address[2] calldata bridges,
        uint256 initialMessagesRead,
        bytes32[2] calldata accs,
        bytes calldata proof,
        bytes calldata bproof
    ) external view returns (string memory startMachine, string memory afterMachine);
}

// File: contracts/bridge/Messages.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

library Messages {
    function messageHash(
        uint8 kind,
        address sender,
        uint256 blockNumber,
        uint256 timestamp,
        uint256 inboxSeqNum,
        uint256 gasPriceL1,
        bytes32 messageDataHash
    ) internal pure returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(
                    kind,
                    sender,
                    blockNumber,
                    timestamp,
                    inboxSeqNum,
                    gasPriceL1,
                    messageDataHash
                )
            );
    }

    function addMessageToInbox(bytes32 inbox, bytes32 message) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(inbox, message));
    }
}

// File: contracts/bridge/interfaces/IBridge.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface IBridge {
    event MessageDelivered(
        uint256 indexed messageIndex,
        bytes32 indexed beforeInboxAcc,
        address inbox,
        uint8 kind,
        address sender,
        bytes32 messageDataHash
    );

    function deliverMessageToInbox(
        uint8 kind,
        address sender,
        bytes32 messageDataHash
    ) external payable returns (uint256);

    function executeCall(
        address destAddr,
        uint256 amount,
        bytes calldata data
    ) external returns (bool success, bytes memory returnData);

    // These are only callable by the admin
    function setInbox(address inbox, bool enabled) external;

    function setOutbox(address inbox, bool enabled) external;

    // View functions

    function activeOutbox() external view returns (address);

    function allowedInboxes(address inbox) external view returns (bool);

    function allowedOutboxes(address outbox) external view returns (bool);

    function inboxAccs(uint256 index) external view returns (bytes32);

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

// File: contracts/bridge/interfaces/IMessageProvider.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface IMessageProvider {
    event InboxMessageDelivered(uint256 indexed messageNum, bytes data);

    event InboxMessageDeliveredFromOrigin(uint256 indexed messageNum);
}

// File: contracts/bridge/interfaces/IOutbox.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface IOutbox {
    event OutboxEntryCreated(
        uint256 indexed batchNum,
        uint256 outboxIndex,
        bytes32 outputRoot,
        uint256 numInBatch
    );
    event OutBoxTransactionExecuted(
        address indexed destAddr,
        address indexed l2Sender,
        uint256 indexed outboxIndex,
        uint256 transactionIndex
    );

    function l2ToL1Sender() external view returns (address);

    function l2ToL1Block() external view returns (uint256);

    function l2ToL1EthBlock() external view returns (uint256);

    function l2ToL1Timestamp() external view returns (uint256);

    function processOutgoingMessages(bytes calldata sendsData, uint256[] calldata sendLengths)
        external;
}

// File: contracts/bridge/interfaces/ISequencerInbox.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface ISequencerInbox {
    event SequencerBatchDelivered(
        uint256 indexed firstMessageNum,
        bytes32 indexed beforeAcc,
        uint256 newMessageCount,
        bytes32 afterAcc,
        bytes transactions,
        uint256[] lengths,
        uint256[] sectionsMetadata,
        uint256 seqBatchIndex,
        address sequencer
    );

    event SequencerBatchDeliveredFromOrigin(
        uint256 indexed firstMessageNum,
        bytes32 indexed beforeAcc,
        uint256 newMessageCount,
        bytes32 afterAcc,
        uint256 seqBatchIndex
    );

    event DelayedInboxForced(
        uint256 indexed firstMessageNum,
        bytes32 indexed beforeAcc,
        uint256 newMessageCount,
        uint256 totalDelayedMessagesRead,
        bytes32[2] afterAccAndDelayed,
        uint256 seqBatchIndex
    );

    event SequencerAddressUpdated(address newAddress);

    function setSequencer(address newSequencer) external;

    function messageCount() external view returns (uint256);

    function maxDelayBlocks() external view returns (uint256);

    function maxDelaySeconds() external view returns (uint256);

    function inboxAccs(uint256 index) external view returns (bytes32);

    function proveBatchContainsSequenceNumber(bytes calldata proof, uint256 inboxCount)
        external
        view
        returns (uint256, bytes32);
}

// File: contracts/challenge/ChallengeLib.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../libraries/MerkleLib.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";

library ChallengeLib {
    using SafeMath for uint256;

    function firstSegmentSize(uint256 totalCount, uint256 bisectionCount)
        internal
        pure
        returns (uint256)
    {
        return totalCount / bisectionCount + (totalCount % bisectionCount);
    }

    function otherSegmentSize(uint256 totalCount, uint256 bisectionCount)
        internal
        pure
        returns (uint256)
    {
        return totalCount / bisectionCount;
    }

    function bisectionChunkHash(
        uint256 _segmentStart,
        uint256 _segmentLength,
        bytes32 _startHash,
        bytes32 _endHash
    ) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(_segmentStart, _segmentLength, _startHash, _endHash));
    }

    function inboxDeltaHash(bytes32 _inboxAcc, bytes32 _deltaAcc) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(_inboxAcc, _deltaAcc));
    }

    function assertionHash(uint256 _arbGasUsed, bytes32 _restHash) internal pure returns (bytes32) {
        // Note: make sure this doesn't return Challenge.UNREACHABLE_ASSERTION (currently 0)
        return keccak256(abi.encodePacked(_arbGasUsed, _restHash));
    }

    function assertionRestHash(
        uint256 _totalMessagesRead,
        bytes32 _machineState,
        bytes32 _sendAcc,
        uint256 _sendCount,
        bytes32 _logAcc,
        uint256 _logCount
    ) internal pure returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(
                    _totalMessagesRead,
                    _machineState,
                    _sendAcc,
                    _sendCount,
                    _logAcc,
                    _logCount
                )
            );
    }

    function updatedBisectionRoot(
        bytes32[] memory _chainHashes,
        uint256 _challengedSegmentStart,
        uint256 _challengedSegmentLength
    ) internal pure returns (bytes32) {
        uint256 bisectionCount = _chainHashes.length - 1;
        bytes32[] memory hashes = new bytes32[](bisectionCount);
        uint256 chunkSize = ChallengeLib.firstSegmentSize(_challengedSegmentLength, bisectionCount);
        uint256 segmentStart = _challengedSegmentStart;
        hashes[0] = ChallengeLib.bisectionChunkHash(
            segmentStart,
            chunkSize,
            _chainHashes[0],
            _chainHashes[1]
        );
        segmentStart = segmentStart.add(chunkSize);
        chunkSize = ChallengeLib.otherSegmentSize(_challengedSegmentLength, bisectionCount);
        for (uint256 i = 1; i < bisectionCount; i++) {
            hashes[i] = ChallengeLib.bisectionChunkHash(
                segmentStart,
                chunkSize,
                _chainHashes[i],
                _chainHashes[i + 1]
            );
            segmentStart = segmentStart.add(chunkSize);
        }
        return MerkleLib.generateRoot(hashes);
    }

    function verifySegmentProof(
        bytes32 challengeState,
        bytes32 item,
        bytes32[] calldata _merkleNodes,
        uint256 _merkleRoute
    ) internal pure returns (bool) {
        return challengeState == MerkleLib.calculateRoot(_merkleNodes, _merkleRoute, item);
    }
}

// File: contracts/challenge/IChallenge.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../bridge/interfaces/IBridge.sol";
import "../bridge/interfaces/ISequencerInbox.sol";
import "../arch/IOneStepProof.sol";

interface IChallenge {
    function initializeChallenge(
        IOneStepProof[] calldata _executors,
        address _resultReceiver,
        bytes32 _executionHash,
        uint256 _maxMessageCount,
        address _asserter,
        address _challenger,
        uint256 _asserterTimeLeft,
        uint256 _challengerTimeLeft,
        ISequencerInbox _sequencerBridge,
        IBridge _delayedBridge
    ) external;

    function currentResponderTimeLeft() external view returns (uint256);

    function lastMoveBlock() external view returns (uint256);

    function timeout() external;

    function asserter() external view returns (address);

    function challenger() external view returns (address);

    function clearChallenge() external;
}

// File: contracts/challenge/IChallengeFactory.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../bridge/interfaces/IBridge.sol";
import "../bridge/interfaces/ISequencerInbox.sol";

interface IChallengeFactory {
    function createChallenge(
        address _resultReceiver,
        bytes32 _executionHash,
        uint256 _maxMessageCount,
        address _asserter,
        address _challenger,
        uint256 _asserterTimeLeft,
        uint256 _challengerTimeLeft,
        ISequencerInbox _sequencerBridge,
        IBridge _delayedBridge
    ) external returns (address);
}

// File: contracts/libraries/Cloneable.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2020, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./ICloneable.sol";

contract Cloneable is ICloneable {
    string private constant NOT_CLONE = "NOT_CLONE";

    bool private isMasterCopy;

    constructor() public {
        isMasterCopy = true;
    }

    function isMaster() external view override returns (bool) {
        return isMasterCopy;
    }

    function safeSelfDestruct(address payable dest) internal {
        require(!isMasterCopy, NOT_CLONE);
        selfdestruct(dest);
    }
}

// File: contracts/libraries/ICloneable.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface ICloneable {
    function isMaster() external view returns (bool);
}

// File: contracts/libraries/MerkleLib.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2019-2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

library MerkleLib {
    function generateRoot(bytes32[] memory _hashes) internal pure returns (bytes32) {
        bytes32[] memory prevLayer = _hashes;
        while (prevLayer.length > 1) {
            bytes32[] memory nextLayer = new bytes32[]((prevLayer.length + 1) / 2);
            for (uint256 i = 0; i < nextLayer.length; i++) {
                if (2 * i + 1 < prevLayer.length) {
                    nextLayer[i] = keccak256(
                        abi.encodePacked(prevLayer[2 * i], prevLayer[2 * i + 1])
                    );
                } else {
                    nextLayer[i] = prevLayer[2 * i];
                }
            }
            prevLayer = nextLayer;
        }
        return prevLayer[0];
    }

    function calculateRoot(
        bytes32[] memory nodes,
        uint256 route,
        bytes32 item
    ) internal pure returns (bytes32) {
        uint256 proofItems = nodes.length;
        require(proofItems <= 256);
        bytes32 h = item;
        for (uint256 i = 0; i < proofItems; i++) {
            if (route % 2 == 0) {
                h = keccak256(abi.encodePacked(nodes[i], h));
            } else {
                h = keccak256(abi.encodePacked(h, nodes[i]));
            }
            route /= 2;
        }
        return h;
    }
}

// File: contracts/rollup/INode.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface INode {
    function initialize(
        address _rollup,
        bytes32 _stateHash,
        bytes32 _challengeHash,
        bytes32 _confirmData,
        uint256 _prev,
        uint256 _deadlineBlock
    ) external;

    function destroy() external;

    function addStaker(address staker) external returns (uint256);

    function removeStaker(address staker) external;

    function childCreated(uint256) external;

    function resetChildren() external;

    function newChildConfirmDeadline(uint256 deadline) external;

    function stateHash() external view returns (bytes32);

    function challengeHash() external view returns (bytes32);

    function confirmData() external view returns (bytes32);

    function prev() external view returns (uint256);

    function deadlineBlock() external view returns (uint256);

    function noChildConfirmedBeforeBlock() external view returns (uint256);

    function stakerCount() external view returns (uint256);

    function stakers(address staker) external view returns (bool);

    function firstChildBlock() external view returns (uint256);

    function latestChildNumber() external view returns (uint256);

    function requirePastDeadline() external view;

    function requirePastChildConfirmDeadline() external view;
}

// File: contracts/rollup/INodeFactory.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

interface INodeFactory {
    function createNode(
        bytes32 _stateHash,
        bytes32 _challengeHash,
        bytes32 _confirmData,
        uint256 _prev,
        uint256 _deadlineBlock
    ) external returns (address);
}

// File: contracts/rollup/IRollupCore.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./INode.sol";

interface IRollupCore {
    function _stakerMap(address stakerAddress)
        external
        view
        returns (
            uint256,
            uint256,
            uint256,
            address,
            bool
        );

    function getNode(uint256 nodeNum) external view returns (INode);

    /**
     * @notice Get the address of the staker at the given index
     * @param stakerNum Index of the staker
     * @return Address of the staker
     */
    function getStakerAddress(uint256 stakerNum) external view returns (address);

    /**
     * @notice Check whether the given staker is staked
     * @param staker Staker address to check
     * @return True or False for whether the staker was staked
     */
    function isStaked(address staker) external view returns (bool);

    /**
     * @notice Get the latest staked node of the given staker
     * @param staker Staker address to lookup
     * @return Latest node staked of the staker
     */
    function latestStakedNode(address staker) external view returns (uint256);

    /**
     * @notice Get the current challenge of the given staker
     * @param staker Staker address to lookup
     * @return Current challenge of the staker
     */
    function currentChallenge(address staker) external view returns (address);

    /**
     * @notice Get the amount staked of the given staker
     * @param staker Staker address to lookup
     * @return Amount staked of the staker
     */
    function amountStaked(address staker) external view returns (uint256);

    /**
     * @notice Get the original staker address of the zombie at the given index
     * @param zombieNum Index of the zombie to lookup
     * @return Original staker address of the zombie
     */
    function zombieAddress(uint256 zombieNum) external view returns (address);

    /**
     * @notice Get Latest node that the given zombie at the given index is staked on
     * @param zombieNum Index of the zombie to lookup
     * @return Latest node that the given zombie is staked on
     */
    function zombieLatestStakedNode(uint256 zombieNum) external view returns (uint256);

    /// @return Current number of un-removed zombies
    function zombieCount() external view returns (uint256);

    function isZombie(address staker) external view returns (bool);

    /**
     * @notice Get the amount of funds withdrawable by the given address
     * @param owner Address to check the funds of
     * @return Amount of funds withdrawable by owner
     */
    function withdrawableFunds(address owner) external view returns (uint256);

    /**
     * @return Index of the first unresolved node
     * @dev If all nodes have been resolved, this will be latestNodeCreated + 1
     */
    function firstUnresolvedNode() external view returns (uint256);

    /// @return Index of the latest confirmed node
    function latestConfirmed() external view returns (uint256);

    /// @return Index of the latest rollup node created
    function latestNodeCreated() external view returns (uint256);

    /// @return Ethereum block that the most recent stake was created
    function lastStakeBlock() external view returns (uint256);

    /// @return Number of active stakers currently staked
    function stakerCount() external view returns (uint256);

    /// @return Node hash as of this node number
    function getNodeHash(uint256 index) external view returns (bytes32);
}

// File: contracts/rollup/Rollup.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./RollupCore.sol";
import "@openzeppelin/contracts/utils/Pausable.sol";
import "@openzeppelin/contracts/proxy/ProxyAdmin.sol";
import "./RollupEventBridge.sol";

import "./INode.sol";
import "./INodeFactory.sol";
import "../challenge/IChallenge.sol";
import "../challenge/IChallengeFactory.sol";
import "../bridge/interfaces/IBridge.sol";
import "../bridge/interfaces/IOutbox.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

import "../bridge/Messages.sol";
import "./RollupLib.sol";
import "../libraries/Cloneable.sol";
import "./facets/IRollupFacets.sol";

abstract contract RollupBase is Cloneable, RollupCore, Pausable {
    // Rollup Config
    uint256 public confirmPeriodBlocks;
    uint256 public extraChallengeTimeBlocks;
    uint256 public arbGasSpeedLimitPerBlock;
    uint256 public baseStake;

    // Bridge is an IInbox and IOutbox
    IBridge public delayedBridge;
    ISequencerInbox public sequencerBridge;
    IOutbox public outbox;
    RollupEventBridge public rollupEventBridge;
    IChallengeFactory public challengeFactory;
    INodeFactory public nodeFactory;
    address public owner;
    address public stakeToken;
    uint256 public minimumAssertionPeriod;

    uint256 public sequencerInboxMaxDelayBlocks;
    uint256 public sequencerInboxMaxDelaySeconds;
    uint256 public challengeExecutionBisectionDegree;

    address[] internal facets;

    mapping(address => bool) isValidator;

    event RollupCreated(bytes32 machineHash);

    event NodeCreated(
        uint256 indexed nodeNum,
        bytes32 indexed parentNodeHash,
        bytes32 nodeHash,
        bytes32 executionHash,
        uint256 inboxMaxCount,
        uint256 afterInboxBatchEndCount,
        bytes32 afterInboxBatchAcc,
        bytes32[3][2] assertionBytes32Fields,
        uint256[4][2] assertionIntFields
    );

    event NodeConfirmed(
        uint256 indexed nodeNum,
        bytes32 afterSendAcc,
        uint256 afterSendCount,
        bytes32 afterLogAcc,
        uint256 afterLogCount
    );

    event NodeRejected(uint256 indexed nodeNum);

    event RollupChallengeStarted(
        address indexed challengeContract,
        address asserter,
        address challenger,
        uint256 challengedNode
    );

    event StakerReassigned(address indexed staker, uint256 newNode);
    event NodesDestroyed(uint256 indexed startNode, uint256 indexed endNode);
    event OwnerFunctionCalled(uint256 indexed id);
}

contract Rollup is RollupBase {
    // _rollupParams = [ confirmPeriodBlocks, extraChallengeTimeBlocks, arbGasSpeedLimitPerBlock, baseStake ]
    // connectedContracts = [delayedBridge, sequencerInbox, outbox, rollupEventBridge, challengeFactory, nodeFactory]
    function initialize(
        bytes32 _machineHash,
        uint256[4] calldata _rollupParams,
        address _stakeToken,
        address _owner,
        bytes calldata _extraConfig,
        address[6] calldata connectedContracts,
        address[2] calldata _facets,
        uint256[2] calldata sequencerInboxParams
    ) public {
        require(confirmPeriodBlocks == 0, "ALREADY_INIT");
        require(_rollupParams[0] != 0, "BAD_CONF_PERIOD");

        delayedBridge = IBridge(connectedContracts[0]);
        sequencerBridge = ISequencerInbox(connectedContracts[1]);
        outbox = IOutbox(connectedContracts[2]);
        delayedBridge.setOutbox(connectedContracts[2], true);
        rollupEventBridge = RollupEventBridge(connectedContracts[3]);
        delayedBridge.setInbox(connectedContracts[3], true);

        rollupEventBridge.rollupInitialized(
            _rollupParams[0],
            _rollupParams[2],
            _rollupParams[3],
            _stakeToken,
            _owner,
            _extraConfig
        );

        challengeFactory = IChallengeFactory(connectedContracts[4]);
        nodeFactory = INodeFactory(connectedContracts[5]);

        INode node = createInitialNode(_machineHash);
        initializeCore(node);

        confirmPeriodBlocks = _rollupParams[0];
        extraChallengeTimeBlocks = _rollupParams[1];
        arbGasSpeedLimitPerBlock = _rollupParams[2];
        baseStake = _rollupParams[3];
        owner = _owner;
        // A little over 15 minutes
        minimumAssertionPeriod = 75;
        challengeExecutionBisectionDegree = 400;

        sequencerInboxMaxDelayBlocks = sequencerInboxParams[0];
        sequencerInboxMaxDelaySeconds = sequencerInboxParams[1];

        // facets[0] == admin, facets[1] == user
        facets = _facets;

        (bool success, ) =
            _facets[1].delegatecall(
                abi.encodeWithSelector(IRollupUser.initialize.selector, _stakeToken)
            );
        require(success, "FAIL_INIT_FACET");

        emit RollupCreated(_machineHash);
    }

    function createInitialNode(bytes32 _machineHash) private returns (INode) {
        bytes32 state =
            RollupLib.stateHash(
                RollupLib.ExecutionState(
                    0, // total gas used
                    _machineHash,
                    0, // inbox count
                    0, // send count
                    0, // log count
                    0, // send acc
                    0, // log acc
                    block.number, // block proposed
                    1 // Initialization message already in inbox
                )
            );
        return
            INode(
                nodeFactory.createNode(
                    state,
                    0, // challenge hash (not challengeable)
                    0, // confirm data
                    0, // prev node
                    block.number // deadline block (not challengeable)
                )
            );
    }

    /**
     * Fallback and delegate functions from OZ
     * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/proxy/TransparentUpgradeableProxy.sol
     * And dispatch pattern from EIP-2535: Diamonds
     */

    function getFacets() public view returns (address, address) {
        return (getAdminFacet(), getUserFacet());
    }

    function getAdminFacet() public view returns (address) {
        return facets[0];
    }

    function getUserFacet() public view returns (address) {
        return facets[1];
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback() external payable {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive() external payable {
        _fallback();
    }

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        require(msg.data.length >= 4, "NO_FUNC_SIG");
        address rollupOwner = owner;
        // if there is an owner and it is the sender, delegate to admin facet
        address target =
            rollupOwner != address(0) && rollupOwner == msg.sender
                ? getAdminFacet()
                : getUserFacet();
        _delegate(target);
    }

    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
                // delegatecall returns 0 on error.
                case 0 {
                    revert(0, returndatasize())
                }
                default {
                    return(0, returndatasize())
                }
        }
    }
}

// File: contracts/rollup/RollupCore.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./INode.sol";
import "./IRollupCore.sol";
import "./RollupLib.sol";

import "@openzeppelin/contracts/math/SafeMath.sol";

contract RollupCore is IRollupCore {
    using SafeMath for uint256;

    struct Zombie {
        address stakerAddress;
        uint256 latestStakedNode;
    }

    struct Staker {
        uint256 index;
        uint256 latestStakedNode;
        uint256 amountStaked;
        // currentChallenge is 0 if staker is not in a challenge
        address currentChallenge;
        bool isStaked;
    }

    uint256 private _latestConfirmed;
    uint256 private _firstUnresolvedNode;
    uint256 private _latestNodeCreated;
    uint256 private _lastStakeBlock;
    mapping(uint256 => INode) private _nodes;
    mapping(uint256 => bytes32) private _nodeHashes;

    address payable[] private _stakerList;
    mapping(address => Staker) public override _stakerMap;

    Zombie[] private _zombies;

    mapping(address => uint256) private _withdrawableFunds;

    /**
     * @notice Get the address of the Node contract for the given node
     * @param nodeNum Index of the node
     * @return Address of the Node contract
     */
    function getNode(uint256 nodeNum) public view override returns (INode) {
        return _nodes[nodeNum];
    }

    /**
     * @notice Get the address of the staker at the given index
     * @param stakerNum Index of the staker
     * @return Address of the staker
     */
    function getStakerAddress(uint256 stakerNum) public view override returns (address) {
        return _stakerList[stakerNum];
    }

    /**
     * @notice Check whether the given staker is staked
     * @param staker Staker address to check
     * @return True or False for whether the staker was staked
     */
    function isStaked(address staker) public view override returns (bool) {
        return _stakerMap[staker].isStaked;
    }

    /**
     * @notice Get the latest staked node of the given staker
     * @param staker Staker address to lookup
     * @return Latest node staked of the staker
     */
    function latestStakedNode(address staker) public view override returns (uint256) {
        return _stakerMap[staker].latestStakedNode;
    }

    /**
     * @notice Get the current challenge of the given staker
     * @param staker Staker address to lookup
     * @return Current challenge of the staker
     */
    function currentChallenge(address staker) public view override returns (address) {
        return _stakerMap[staker].currentChallenge;
    }

    /**
     * @notice Get the amount staked of the given staker
     * @param staker Staker address to lookup
     * @return Amount staked of the staker
     */
    function amountStaked(address staker) public view override returns (uint256) {
        return _stakerMap[staker].amountStaked;
    }

    /**
     * @notice Get the original staker address of the zombie at the given index
     * @param zombieNum Index of the zombie to lookup
     * @return Original staker address of the zombie
     */
    function zombieAddress(uint256 zombieNum) public view override returns (address) {
        return _zombies[zombieNum].stakerAddress;
    }

    /**
     * @notice Get Latest node that the given zombie at the given index is staked on
     * @param zombieNum Index of the zombie to lookup
     * @return Latest node that the given zombie is staked on
     */
    function zombieLatestStakedNode(uint256 zombieNum) public view override returns (uint256) {
        return _zombies[zombieNum].latestStakedNode;
    }

    /// @return Current number of un-removed zombies
    function zombieCount() public view override returns (uint256) {
        return _zombies.length;
    }

    function isZombie(address staker) public view override returns (bool) {
        for (uint256 i = 0; i < _zombies.length; i++) {
            if (staker == _zombies[i].stakerAddress) {
                return true;
            }
        }
        return false;
    }

    /**
     * @notice Get the amount of funds withdrawable by the given address
     * @param owner Address to check the funds of
     * @return Amount of funds withdrawable by owner
     */
    function withdrawableFunds(address owner) public view override returns (uint256) {
        return _withdrawableFunds[owner];
    }

    /**
     * @return Index of the first unresolved node
     * @dev If all nodes have been resolved, this will be latestNodeCreated + 1
     */
    function firstUnresolvedNode() public view override returns (uint256) {
        return _firstUnresolvedNode;
    }

    /// @return Index of the latest confirmed node
    function latestConfirmed() public view override returns (uint256) {
        return _latestConfirmed;
    }

    /// @return Index of the latest rollup node created
    function latestNodeCreated() public view override returns (uint256) {
        return _latestNodeCreated;
    }

    /// @return Ethereum block that the most recent stake was created
    function lastStakeBlock() public view override returns (uint256) {
        return _lastStakeBlock;
    }

    /// @return Number of active stakers currently staked
    function stakerCount() public view override returns (uint256) {
        return _stakerList.length;
    }

    /**
     * @notice Initialize the core with an initial node
     * @param initialNode Initial node to start the chain with
     */
    function initializeCore(INode initialNode) internal {
        _nodes[0] = initialNode;
        _firstUnresolvedNode = 1;
    }

    /**
     * @notice React to a new node being created by storing it an incrementing the latest node counter
     * @param node Node that was newly created
     * @param nodeHash The hash of said node
     */
    function nodeCreated(INode node, bytes32 nodeHash) internal {
        _latestNodeCreated++;
        _nodes[_latestNodeCreated] = node;
        _nodeHashes[_latestNodeCreated] = nodeHash;
    }

    /// @return Node hash as of this node number
    function getNodeHash(uint256 index) public view override returns (bytes32) {
        return _nodeHashes[index];
    }

    function resetNodeHash(uint256 index) internal {
        _nodeHashes[index] = 0;
    }

    /**
     * @notice Update the latest node created
     * @param newLatestNodeCreated New value for the latest node created
     */
    function updateLatestNodeCreated(uint256 newLatestNodeCreated) internal {
        _latestNodeCreated = newLatestNodeCreated;
    }

    /// @notice Reject the next unresolved node
    function rejectNextNode() internal {
        destroyNode(_firstUnresolvedNode);
        _firstUnresolvedNode++;
    }

    /// @notice Confirm the next unresolved node
    function confirmNextNode() internal {
        destroyNode(_latestConfirmed);
        _latestConfirmed = _firstUnresolvedNode;
        _firstUnresolvedNode++;
    }

    /// @notice Confirm the next unresolved node
    function confirmLatestNode() internal {
        destroyNode(_latestConfirmed);
        uint256 latestNode = _latestNodeCreated;
        _latestConfirmed = latestNode;
        _firstUnresolvedNode = latestNode + 1;
    }

    /**
     * @notice Create a new stake
     * @param stakerAddress Address of the new staker
     * @param depositAmount Stake amount of the new staker
     */
    function createNewStake(address payable stakerAddress, uint256 depositAmount) internal {
        uint256 stakerIndex = _stakerList.length;
        _stakerList.push(stakerAddress);
        _stakerMap[stakerAddress] = Staker(
            stakerIndex,
            _latestConfirmed,
            depositAmount,
            address(0),
            true
        );
        _lastStakeBlock = block.number;
    }

    /**
     * @notice Check to see whether the two stakers are in the same challenge
     * @param stakerAddress1 Address of the first staker
     * @param stakerAddress2 Address of the second staker
     * @return Address of the challenge that the two stakers are in
     */
    function inChallenge(address stakerAddress1, address stakerAddress2)
        internal
        view
        returns (address)
    {
        Staker storage staker1 = _stakerMap[stakerAddress1];
        Staker storage staker2 = _stakerMap[stakerAddress2];
        address challenge = staker1.currentChallenge;
        require(challenge == staker2.currentChallenge, "IN_CHAL");
        require(challenge != address(0), "NO_CHAL");
        return challenge;
    }

    /**
     * @notice Make the given staker as not being in a challenge
     * @param stakerAddress Address of the staker to remove from a challenge
     */
    function clearChallenge(address stakerAddress) internal {
        Staker storage staker = _stakerMap[stakerAddress];
        staker.currentChallenge = address(0);
    }

    /**
     * @notice Mark both the given stakers as engaged in the challenge
     * @param staker1 Address of the first staker
     * @param staker2 Address of the second staker
     * @param challenge Address of the challenge both stakers are now in
     */
    function challengeStarted(
        address staker1,
        address staker2,
        address challenge
    ) internal {
        _stakerMap[staker1].currentChallenge = challenge;
        _stakerMap[staker2].currentChallenge = challenge;
    }

    /**
     * @notice Add to the stake of the given staker by the given amount
     * @param stakerAddress Address of the staker to increase the stake of
     * @param amountAdded Amount of stake to add to the staker
     */
    function increaseStakeBy(address stakerAddress, uint256 amountAdded) internal {
        Staker storage staker = _stakerMap[stakerAddress];
        staker.amountStaked = staker.amountStaked.add(amountAdded);
    }

    /**
     * @notice Reduce the stake of the given staker to the given target
     * @param stakerAddress Address of the staker to reduce the stake of
     * @param target Amount of stake to leave with the staker
     * @return Amount of value released from the stake
     */
    function reduceStakeTo(address stakerAddress, uint256 target) internal returns (uint256) {
        Staker storage staker = _stakerMap[stakerAddress];
        uint256 current = staker.amountStaked;
        require(target <= current, "TOO_LITTLE_STAKE");
        uint256 amountWithdrawn = current.sub(target);
        staker.amountStaked = target;
        _withdrawableFunds[stakerAddress] = _withdrawableFunds[stakerAddress].add(amountWithdrawn);
        return amountWithdrawn;
    }

    /**
     * @notice Remove the given staker and turn them into a zombie
     * @param stakerAddress Address of the staker to remove
     */
    function turnIntoZombie(address stakerAddress) internal {
        Staker storage staker = _stakerMap[stakerAddress];
        _zombies.push(Zombie(stakerAddress, staker.latestStakedNode));
        deleteStaker(stakerAddress);
    }

    /**
     * @notice Update the latest staked node of the zombie at the given index
     * @param zombieNum Index of the zombie to move
     * @param latest New latest node the zombie is staked on
     */
    function zombieUpdateLatestStakedNode(uint256 zombieNum, uint256 latest) internal {
        _zombies[zombieNum].latestStakedNode = latest;
    }

    /**
     * @notice Remove the zombie at the given index
     * @param zombieNum Index of the zombie to remove
     */
    function removeZombie(uint256 zombieNum) internal {
        _zombies[zombieNum] = _zombies[_zombies.length - 1];
        _zombies.pop();
    }

    /**
     * @notice Remove the given staker and return their stake
     * @param stakerAddress Address of the staker withdrawing their stake
     */
    function withdrawStaker(address stakerAddress) internal {
        Staker storage staker = _stakerMap[stakerAddress];
        _withdrawableFunds[stakerAddress] = _withdrawableFunds[stakerAddress].add(
            staker.amountStaked
        );
        deleteStaker(stakerAddress);
    }

    /**
     * @notice Advance the given staker to the given node
     * @param stakerAddress Address of the staker adding their stake
     * @param nodeNum Index of the node to stake on
     */
    function stakeOnNode(
        address stakerAddress,
        uint256 nodeNum,
        uint256 confirmPeriodBlocks
    ) internal {
        Staker storage staker = _stakerMap[stakerAddress];
        INode node = _nodes[nodeNum];
        uint256 newStakerCount = node.addStaker(stakerAddress);
        staker.latestStakedNode = nodeNum;
        if (newStakerCount == 1) {
            INode parent = _nodes[node.prev()];
            parent.newChildConfirmDeadline(block.number.add(confirmPeriodBlocks));
        }
    }

    /**
     * @notice Clear the withdrawable funds for the given address
     * @param owner Address of the account to remove funds from
     * @return Amount of funds removed from account
     */
    function withdrawFunds(address owner) internal returns (uint256) {
        uint256 amount = _withdrawableFunds[owner];
        _withdrawableFunds[owner] = 0;
        return amount;
    }

    /**
     * @notice Increase the withdrawable funds for the given address
     * @param owner Address of the account to add withdrawable funds to
     */
    function increaseWithdrawableFunds(address owner, uint256 amount) internal {
        _withdrawableFunds[owner] = _withdrawableFunds[owner].add(amount);
    }

    /**
     * @notice Remove the given staker
     * @param stakerAddress Address of the staker to remove
     */
    function deleteStaker(address stakerAddress) private {
        Staker storage staker = _stakerMap[stakerAddress];
        uint256 stakerIndex = staker.index;
        _stakerList[stakerIndex] = _stakerList[_stakerList.length - 1];
        _stakerMap[_stakerList[stakerIndex]].index = stakerIndex;
        _stakerList.pop();
        delete _stakerMap[stakerAddress];
    }

    /**
     * @notice Destroy the given node and clear out its address
     * @param nodeNum Index of the node to remove
     */
    function destroyNode(uint256 nodeNum) internal {
        _nodes[nodeNum].destroy();
        _nodes[nodeNum] = INode(0);
    }

    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }
}

// File: contracts/rollup/RollupEventBridge.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "./Rollup.sol";
import "./facets/IRollupFacets.sol";

import "../bridge/interfaces/IBridge.sol";
import "../bridge/interfaces/IMessageProvider.sol";
import "./INode.sol";
import "../libraries/Cloneable.sol";

contract RollupEventBridge is IMessageProvider, Cloneable {
    uint8 internal constant INITIALIZATION_MSG_TYPE = 4;
    uint8 internal constant ROLLUP_PROTOCOL_EVENT_TYPE = 8;

    uint8 internal constant CREATE_NODE_EVENT = 0;
    uint8 internal constant CONFIRM_NODE_EVENT = 1;
    uint8 internal constant REJECT_NODE_EVENT = 2;
    uint8 internal constant STAKE_CREATED_EVENT = 3;
    uint8 internal constant CLAIM_NODE_EVENT = 4;

    IBridge bridge;
    address rollup;

    modifier onlyRollup {
        require(msg.sender == rollup, "ONLY_ROLLUP");
        _;
    }

    function initialize(address _bridge, address _rollup) external {
        require(rollup == address(0), "ALREADY_INIT");
        bridge = IBridge(_bridge);
        rollup = _rollup;
    }

    function rollupInitialized(
        uint256 confirmPeriodBlocks,
        uint256 arbGasSpeedLimitPerBlock,
        uint256 baseStake,
        address stakeToken,
        address owner,
        bytes calldata extraConfig
    ) external onlyRollup {
        bytes memory initMsg =
            abi.encodePacked(
                confirmPeriodBlocks,
                arbGasSpeedLimitPerBlock / 100, // convert avm gas to arbgas
                uint256(0),
                baseStake,
                uint256(uint160(bytes20(stakeToken))),
                uint256(uint160(bytes20(owner))),
                extraConfig
            );
        uint256 num =
            bridge.deliverMessageToInbox(INITIALIZATION_MSG_TYPE, msg.sender, keccak256(initMsg));
        emit InboxMessageDelivered(num, initMsg);
    }

    function nodeCreated(
        uint256 nodeNum,
        uint256 prev,
        uint256 deadline,
        address asserter
    ) external onlyRollup {
        deliverToBridge(
            abi.encodePacked(
                CREATE_NODE_EVENT,
                nodeNum,
                prev,
                block.number,
                deadline,
                uint256(uint160(bytes20(asserter)))
            )
        );
    }

    function nodeConfirmed(uint256 nodeNum) external onlyRollup {
        deliverToBridge(abi.encodePacked(CONFIRM_NODE_EVENT, nodeNum));
    }

    function nodeRejected(uint256 nodeNum) external onlyRollup {
        deliverToBridge(abi.encodePacked(REJECT_NODE_EVENT, nodeNum));
    }

    function stakeCreated(address staker, uint256 nodeNum) external onlyRollup {
        deliverToBridge(
            abi.encodePacked(
                STAKE_CREATED_EVENT,
                uint256(uint160(bytes20(staker))),
                nodeNum,
                block.number
            )
        );
    }

    function claimNode(uint256 nodeNum, address staker) external onlyRollup {
        Rollup r = Rollup(payable(rollup));
        INode node = r.getNode(nodeNum);
        require(node.stakers(staker), "NOT_STAKED");
        IRollupUser(address(r)).requireUnresolved(nodeNum);

        deliverToBridge(
            abi.encodePacked(CLAIM_NODE_EVENT, nodeNum, uint256(uint160(bytes20(staker))))
        );
    }

    function deliverToBridge(bytes memory message) private {
        emit InboxMessageDelivered(
            bridge.deliverMessageToInbox(
                ROLLUP_PROTOCOL_EVENT_TYPE,
                msg.sender,
                keccak256(message)
            ),
            message
        );
    }
}

// File: contracts/rollup/RollupLib.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../challenge/ChallengeLib.sol";
import "./INode.sol";

library RollupLib {
    struct Config {
        bytes32 machineHash;
        uint256 confirmPeriodBlocks;
        uint256 extraChallengeTimeBlocks;
        uint256 arbGasSpeedLimitPerBlock;
        uint256 baseStake;
        address stakeToken;
        address owner;
        address sequencer;
        uint256 sequencerDelayBlocks;
        uint256 sequencerDelaySeconds;
        bytes extraConfig;
    }

    struct ExecutionState {
        uint256 gasUsed;
        bytes32 machineHash;
        uint256 inboxCount;
        uint256 sendCount;
        uint256 logCount;
        bytes32 sendAcc;
        bytes32 logAcc;
        uint256 proposedBlock;
        uint256 inboxMaxCount;
    }

    function stateHash(ExecutionState memory execState) internal pure returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(
                    execState.gasUsed,
                    execState.machineHash,
                    execState.inboxCount,
                    execState.sendCount,
                    execState.logCount,
                    execState.sendAcc,
                    execState.logAcc,
                    execState.proposedBlock,
                    execState.inboxMaxCount
                )
            );
    }

    struct Assertion {
        ExecutionState beforeState;
        ExecutionState afterState;
    }

    function decodeExecutionState(
        bytes32[3] memory bytes32Fields,
        uint256[4] memory intFields,
        uint256 proposedBlock,
        uint256 inboxMaxCount
    ) internal pure returns (ExecutionState memory) {
        return
            ExecutionState(
                intFields[0],
                bytes32Fields[0],
                intFields[1],
                intFields[2],
                intFields[3],
                bytes32Fields[1],
                bytes32Fields[2],
                proposedBlock,
                inboxMaxCount
            );
    }

    function decodeAssertion(
        bytes32[3][2] memory bytes32Fields,
        uint256[4][2] memory intFields,
        uint256 beforeProposedBlock,
        uint256 beforeInboxMaxCount,
        uint256 inboxMaxCount
    ) internal view returns (Assertion memory) {
        return
            Assertion(
                decodeExecutionState(
                    bytes32Fields[0],
                    intFields[0],
                    beforeProposedBlock,
                    beforeInboxMaxCount
                ),
                decodeExecutionState(bytes32Fields[1], intFields[1], block.number, inboxMaxCount)
            );
    }

    function executionStateChallengeHash(ExecutionState memory state)
        internal
        pure
        returns (bytes32)
    {
        return
            ChallengeLib.assertionHash(
                state.gasUsed,
                ChallengeLib.assertionRestHash(
                    state.inboxCount,
                    state.machineHash,
                    state.sendAcc,
                    state.sendCount,
                    state.logAcc,
                    state.logCount
                )
            );
    }

    function executionHash(Assertion memory assertion) internal pure returns (bytes32) {
        return
            ChallengeLib.bisectionChunkHash(
                assertion.beforeState.gasUsed,
                assertion.afterState.gasUsed - assertion.beforeState.gasUsed,
                RollupLib.executionStateChallengeHash(assertion.beforeState),
                RollupLib.executionStateChallengeHash(assertion.afterState)
            );
    }

    function challengeRoot(
        Assertion memory assertion,
        bytes32 assertionExecHash,
        uint256 blockProposed
    ) internal pure returns (bytes32) {
        return challengeRootHash(assertionExecHash, blockProposed, assertion.afterState.inboxCount);
    }

    function challengeRootHash(
        bytes32 execution,
        uint256 proposedTime,
        uint256 maxMessageCount
    ) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(execution, proposedTime, maxMessageCount));
    }

    function confirmHash(Assertion memory assertion) internal pure returns (bytes32) {
        return
            confirmHash(
                assertion.beforeState.sendAcc,
                assertion.afterState.sendAcc,
                assertion.afterState.logAcc,
                assertion.afterState.sendCount,
                assertion.afterState.logCount
            );
    }

    function confirmHash(
        bytes32 beforeSendAcc,
        bytes32 afterSendAcc,
        bytes32 afterLogAcc,
        uint256 afterSendCount,
        uint256 afterLogCount
    ) internal pure returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(
                    beforeSendAcc,
                    afterSendAcc,
                    afterSendCount,
                    afterLogAcc,
                    afterLogCount
                )
            );
    }

    function feedAccumulator(
        bytes memory messageData,
        uint256[] memory messageLengths,
        bytes32 beforeAcc
    ) internal pure returns (bytes32) {
        uint256 offset = 0;
        uint256 messageCount = messageLengths.length;
        uint256 dataLength = messageData.length;
        bytes32 messageAcc = beforeAcc;
        for (uint256 i = 0; i < messageCount; i++) {
            uint256 messageLength = messageLengths[i];
            require(offset + messageLength <= dataLength, "DATA_OVERRUN");
            bytes32 messageHash;
            assembly {
                messageHash := keccak256(add(messageData, add(offset, 32)), messageLength)
            }
            messageAcc = keccak256(abi.encodePacked(messageAcc, messageHash));
            offset += messageLength;
        }
        require(offset == dataLength, "DATA_LENGTH");
        return messageAcc;
    }

    function nodeHash(
        bool hasSibling,
        bytes32 lastHash,
        bytes32 assertionExecHash,
        bytes32 inboxAcc
    ) internal pure returns (bytes32) {
        uint8 hasSiblingInt = hasSibling ? 1 : 0;
        return keccak256(abi.encodePacked(hasSiblingInt, lastHash, assertionExecHash, inboxAcc));
    }

    function nodeAccumulator(bytes32 prevAcc, bytes32 newNodeHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(prevAcc, newNodeHash));
    }
}

// File: contracts/rollup/facets/IRollupFacets.sol



// SPDX-License-Identifier: Apache-2.0

/*
 * Copyright 2021, Offchain Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

pragma solidity ^0.6.11;

import "../INode.sol";
import "../../bridge/interfaces/IOutbox.sol";

interface IRollupUser {
    function initialize(address _stakeToken) external;

    function completeChallenge(address winningStaker, address losingStaker) external;

    function returnOldDeposit(address stakerAddress) external;

    function requireUnresolved(uint256 nodeNum) external view;

    function requireUnresolvedExists() external view;

    function countStakedZombies(INode node) external view returns (uint256);
}

interface IRollupAdmin {
    /**
     * @notice Add a contract authorized to put messages into this rollup's inbox
     * @param _outbox Outbox contract to add
     */
    function setOutbox(IOutbox _outbox) external;

    /**
     * @notice Disable an old outbox from interacting with the bridge
     * @param _outbox Outbox contract to remove
     */
    function removeOldOutbox(address _outbox) external;

    /**
     * @notice Enable or disable an inbox contract
     * @param _inbox Inbox contract to add or remove
     * @param _enabled New status of inbox
     */
    function setInbox(address _inbox, bool _enabled) external;

    /**
     * @notice Pause interaction with the rollup contract
     */
    function pause() external;

    /**
     * @notice Resume interaction with the rollup contract
     */
    function resume() external;

    /**
     * @notice Set the addresses of rollup logic facets called
     * @param newAdminFacet address of logic that owner of rollup calls
     * @param newUserFacet ddress of logic that user of rollup calls
     */
    function setFacets(address newAdminFacet, address newUserFacet) external;

    /**
     * @notice Set the addresses of the validator whitelist
     * @dev It is expected that both arrays are same length, and validator at
     * position i corresponds to the value at position i
     * @param _validator addresses to set in the whitelist
     * @param _val value to set in the whitelist for corresponding address
     */
    function setValidator(address[] memory _validator, bool[] memory _val) external;

    /**
     * @notice Set a new owner address for the rollup
     * @param newOwner address of new rollup owner
     */
    function setOwner(address newOwner) external;

    /**
     * @notice Set minimum assertion period for the rollup
     * @param newPeriod new minimum period for assertions
     */
    function setMinimumAssertionPeriod(uint256 newPeriod) external;

    /**
     * @notice Set number of blocks until a node is considered confirmed
     * @param newConfirmPeriod new number of blocks until a node is confirmed
     */
    function setConfirmPeriodBlocks(uint256 newConfirmPeriod) external;

    /**
     * @notice Set number of extra blocks after a challenge
     * @param newExtraTimeBlocks new number of blocks
     */
    function setExtraChallengeTimeBlocks(uint256 newExtraTimeBlocks) external;

    /**
     * @notice Set speed limit per block
     * @param newArbGasSpeedLimitPerBlock maximum arbgas to be used per block
     */
    function setArbGasSpeedLimitPerBlock(uint256 newArbGasSpeedLimitPerBlock) external;

    /**
     * @notice Set base stake required for an assertion
     * @param newBaseStake maximum arbgas to be used per block
     */
    function setBaseStake(uint256 newBaseStake) external;

    /**
     * @notice Set the token used for stake, where address(0) == eth
     * @dev Before changing the base stake token, you might need to change the
     * implementation of the Rollup User facet!
     * @param newStakeToken address of token used for staking
     */
    function setStakeToken(address newStakeToken) external;

    /**
     * @notice Set max delay in blocks for sequencer inbox
     * @param newSequencerInboxMaxDelayBlocks max number of blocks
     */
    function setSequencerInboxMaxDelayBlocks(uint256 newSequencerInboxMaxDelayBlocks) external;

    /**
     * @notice Set max delay in seconds for sequencer inbox
     * @param newSequencerInboxMaxDelaySeconds max number of seconds
     */
    function setSequencerInboxMaxDelaySeconds(uint256 newSequencerInboxMaxDelaySeconds) external;

    /**
     * @notice Set execution bisection degree
     * @param newChallengeExecutionBisectionDegree execution bisection degree
     */
    function setChallengeExecutionBisectionDegree(uint256 newChallengeExecutionBisectionDegree)
        external;

    /**
     * @notice Updates a whitelist address for its consumers
     * @dev setting the newWhitelist to address(0) disables it for consumers
     * @param whitelist old whitelist to be deprecated
     * @param newWhitelist new whitelist to be used
     * @param targets whitelist consumers to be triggered
     */
    function updateWhitelistConsumers(
        address whitelist,
        address newWhitelist,
        address[] memory targets
    ) external;

    /**
     * @notice Updates a whitelist's entries
     * @dev user at position i will be assigned value i
     * @param whitelist whitelist to be updated
     * @param user users to be updated in the whitelist
     * @param val if user is or not allowed in the whitelist
     */
    function setWhitelistEntries(
        address whitelist,
        address[] memory user,
        bool[] memory val
    ) external;

    /**
     * @notice Updates a sequencer address at the sequencer inbox
     * @param newSequencer new sequencer address to be used
     */
    function setSequencer(address newSequencer) external;

    /**
     * @notice Upgrades the implementation of a beacon controlled by the rollup
     * @param beacon address of beacon to be upgraded
     * @param newImplementation new address of implementation
     */
    function upgradeBeacon(address beacon, address newImplementation) external;
}