// File: contracts/SmartInvoice.sol



// SPDX-License-Identifier: MIT
// solhint-disable not-rely-on-time, max-states-count

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/proxy/utils/Initializable.sol";
import "./interfaces/ISmartInvoice.sol";
import "./interfaces/IArbitrable.sol";
import "./interfaces/IArbitrator.sol";
import "./interfaces/IWRAPPED.sol";

// splittable digital deal lockers w/ embedded arbitration tailored for guild work
contract SmartInvoice is
    ISmartInvoice,
    IArbitrable,
    Initializable,
    Context,
    ReentrancyGuard
{
    using SafeERC20 for IERC20;

    uint256 public constant NUM_RULING_OPTIONS = 5; // excludes options 0, 1 and 2
    // Note that Aragon Court treats the possible outcomes as arbitrary numbers, leaving the Arbitrable (us) to define how to understand them.
    // Some outcomes [0, 1, and 2] are reserved by Aragon Court: "missing", "leaked", and "refused", respectively.
    // Note that Aragon Court emits the LOWEST outcome in the event of a tie.

    // solhint-disable-next-line var-name-mixedcase
    uint8[2][6] public RULINGS = [
        [1, 1], // 0 = refused to arbitrate
        [1, 0], // 1 = 100% to client
        [3, 1], // 2 = 75% to client
        [1, 1], // 3 = 50% to client
        [1, 3], // 4 = 25% to client
        [0, 1] // 5 = 0% to client
    ];

    uint256 public constant MAX_TERMINATION_TIME = 63113904; // 2-year limit on locker
    address public wrappedNativeToken;

    enum ADR {INDIVIDUAL, ARBITRATOR}

    address public client;
    address public provider;
    ADR public resolverType;
    address public resolver;
    address public token;
    uint256 public terminationTime;
    uint256 public resolutionRate;
    bytes32 public details;

    uint256[] public amounts; // milestones split into amounts
    uint256 public total = 0;
    bool public locked;
    uint256 public milestone = 0; // current milestone - starts from 0 to amounts.length
    uint256 public released = 0;
    uint256 public disputeId;

    event Register(
        address indexed client,
        address indexed provider,
        uint256[] amounts
    );
    event Deposit(address indexed sender, uint256 amount);
    event Release(uint256 milestone, uint256 amount);
    event Withdraw(uint256 balance);
    event Lock(address indexed sender, bytes32 details);
    event Resolve(
        address indexed resolver,
        uint256 clientAward,
        uint256 providerAward,
        uint256 resolutionFee,
        bytes32 details
    );
    event Rule(
        address indexed resolver,
        uint256 clientAward,
        uint256 providerAward,
        uint256 ruling
    );

    // solhint-disable-next-line no-empty-blocks
    function initLock() external initializer {}

    function init(
        address _client,
        address _provider,
        uint8 _resolverType,
        address _resolver,
        address _token,
        uint256[] calldata _amounts,
        uint256 _terminationTime, // exact termination date in seconds since epoch
        uint256 _resolutionRate,
        bytes32 _details,
        address _wrappedNativeToken
    ) external override initializer {
        require(_client != address(0), "invalid client");
        require(_provider != address(0), "invalid provider");
        require(_resolverType <= uint8(ADR.ARBITRATOR), "invalid resolverType");
        require(_resolver != address(0), "invalid resolver");
        require(_token != address(0), "invalid token");
        require(_terminationTime > block.timestamp, "duration ended");
        require(
            _terminationTime <= block.timestamp + MAX_TERMINATION_TIME,
            "duration too long"
        );
        require(_resolutionRate > 0, "invalid resolutionRate");
        require(
            _wrappedNativeToken != address(0),
            "invalid wrappedNativeToken"
        );

        client = _client;
        provider = _provider;
        resolverType = ADR(_resolverType);
        resolver = _resolver;
        token = _token;
        amounts = _amounts;
        for (uint256 i = 0; i < amounts.length; i++) {
            total = total + amounts[i];
        }
        terminationTime = _terminationTime;
        resolutionRate = _resolutionRate;
        details = _details;
        wrappedNativeToken = _wrappedNativeToken;

        emit Register(_client, _provider, amounts);
    }

    function _release() internal {
        // client transfers locker milestone funds to provider

        require(!locked, "locked");
        require(_msgSender() == client, "!client");

        uint256 currentMilestone = milestone;
        uint256 balance = IERC20(token).balanceOf(address(this));

        if (currentMilestone < amounts.length) {
            uint256 amount = amounts[currentMilestone];
            if (currentMilestone == amounts.length - 1 && amount < balance) {
                amount = balance;
            }
            require(balance >= amount, "insufficient balance");

            milestone = milestone + 1;
            IERC20(token).safeTransfer(provider, amount);
            released = released + amount;
            emit Release(currentMilestone, amount);
        } else {
            require(balance > 0, "balance is 0");

            IERC20(token).safeTransfer(provider, balance);
            released = released + balance;
            emit Release(currentMilestone, balance);
        }
    }

    function release() external override nonReentrant {
        return _release();
    }

    function release(uint256 _milestone) external override nonReentrant {
        // client transfers locker funds upto certain milestone to provider
        require(!locked, "locked");
        require(_msgSender() == client, "!client");
        require(_milestone >= milestone, "milestone passed");
        require(_milestone < amounts.length, "invalid milestone");
        uint256 balance = IERC20(token).balanceOf(address(this));
        uint256 amount = 0;
        for (uint256 j = milestone; j <= _milestone; j++) {
            if (j == amounts.length - 1 && amount + amounts[j] < balance) {
                emit Release(j, balance - amount);
                amount = balance;
            } else {
                emit Release(j, amounts[j]);
                amount = amount + amounts[j];
            }
        }
        require(balance >= amount, "insufficient balance");

        IERC20(token).safeTransfer(provider, amount);
        released = released + amount;
        milestone = _milestone + 1;
    }

    // release non-invoice tokens
    function releaseTokens(address _token) external override nonReentrant {
        if (_token == token) {
            _release();
        } else {
            require(_msgSender() == client, "!client");
            uint256 balance = IERC20(_token).balanceOf(address(this));
            IERC20(_token).safeTransfer(provider, balance);
        }
    }

    function _withdraw() internal {
        require(!locked, "locked");
        require(block.timestamp > terminationTime, "!terminated");
        uint256 balance = IERC20(token).balanceOf(address(this));
        require(balance > 0, "balance is 0");

        IERC20(token).safeTransfer(client, balance);
        milestone = amounts.length;

        emit Withdraw(balance);
    }

    // withdraw locker remainder to client if termination time passes & no lock
    function withdraw() external override nonReentrant {
        return _withdraw();
    }

    // withdraw non-invoice tokens
    function withdrawTokens(address _token) external override nonReentrant {
        if (_token == token) {
            _withdraw();
        } else {
            require(block.timestamp > terminationTime, "!terminated");
            uint256 balance = IERC20(_token).balanceOf(address(this));
            require(balance > 0, "balance is 0");

            IERC20(_token).safeTransfer(client, balance);
        }
    }

    // client or main (0) provider can lock remainder for resolution during locker period / update request details
    function lock(bytes32 _details) external payable override nonReentrant {
        require(!locked, "locked");
        uint256 balance = IERC20(token).balanceOf(address(this));
        require(balance > 0, "balance is 0");
        require(block.timestamp < terminationTime, "terminated");
        require(_msgSender() == client || _msgSender() == provider, "!party");

        if (resolverType == ADR.ARBITRATOR) {
            disputeId = IArbitrator(resolver).createDispute{value: msg.value}(
                NUM_RULING_OPTIONS,
                abi.encodePacked(details)
            );
        }
        locked = true;

        emit Lock(_msgSender(), _details);
    }

    function resolve(
        uint256 _clientAward,
        uint256 _providerAward,
        bytes32 _details
    ) external override nonReentrant {
        // called by individual
        require(resolverType == ADR.INDIVIDUAL, "!individual resolver");
        require(locked, "!locked");
        uint256 balance = IERC20(token).balanceOf(address(this));
        require(balance > 0, "balance is 0");
        require(_msgSender() == resolver, "!resolver");

        uint256 resolutionFee = balance / resolutionRate; // calculates dispute resolution fee (div(20) = 5% of remainder)

        require(
            _clientAward + _providerAward == balance - resolutionFee,
            "resolution != remainder"
        );

        if (_providerAward > 0) {
            IERC20(token).safeTransfer(provider, _providerAward);
        }
        if (_clientAward > 0) {
            IERC20(token).safeTransfer(client, _clientAward);
        }
        if (resolutionFee > 0) {
            IERC20(token).safeTransfer(resolver, resolutionFee);
        }

        milestone = amounts.length;
        locked = false;

        emit Resolve(
            _msgSender(),
            _clientAward,
            _providerAward,
            resolutionFee,
            _details
        );
    }

    function rule(uint256 _disputeId, uint256 _ruling)
        external
        override
        nonReentrant
    {
        // called by arbitrator
        require(resolverType == ADR.ARBITRATOR, "!arbitrator resolver");
        require(locked, "!locked");
        require(_msgSender() == resolver, "!resolver");
        require(_disputeId == disputeId, "incorrect disputeId");
        require(_ruling <= NUM_RULING_OPTIONS, "invalid ruling");
        uint256 balance = IERC20(token).balanceOf(address(this));
        require(balance > 0, "balance is 0");

        uint8[2] memory ruling = RULINGS[_ruling];
        uint8 clientShare = ruling[0];
        uint8 providerShare = ruling[1];
        uint8 denom = clientShare + providerShare;
        uint256 providerAward = (balance * providerShare) / denom;
        uint256 clientAward = balance - providerAward;

        if (providerAward > 0) {
            IERC20(token).safeTransfer(provider, providerAward);
        }
        if (clientAward > 0) {
            IERC20(token).safeTransfer(client, clientAward);
        }

        milestone = amounts.length;
        locked = false;

        emit Rule(resolver, clientAward, providerAward, _ruling);
        emit Ruling(resolver, _disputeId, _ruling);
    }

    // receive eth transfers
    receive() external payable {
        require(!locked, "locked");
        require(token == wrappedNativeToken, "!wrappedNativeToken");
        IWRAPPED(wrappedNativeToken).deposit{value: msg.value}();
        emit Deposit(_msgSender(), msg.value);
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

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

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

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

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

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

    uint256 private _status;

    constructor () {
        _status = _NOT_ENTERED;
    }

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

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

        _;

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

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

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

// File: @openzeppelin/contracts/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT

// solhint-disable-next-line compiler-version
pragma solidity ^0.8.0;

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

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 */
abstract contract Initializable {

    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }
}

// File: contracts/interfaces/ISmartInvoice.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface ISmartInvoice {
    function init(
        address _client,
        address _provider,
        uint8 _resolverType,
        address _resolver,
        address _token,
        uint256[] calldata _amounts,
        uint256 _terminationTime, // exact termination date in seconds since epoch
        uint256 _resolutionRate,
        bytes32 _details,
        address _wrappedNativeToken
    ) external;

    function release() external;

    function release(uint256 _milestone) external;

    function releaseTokens(address _token) external;

    function withdraw() external;

    function withdrawTokens(address _token) external;

    function lock(bytes32 _details) external payable;

    function resolve(
        uint256 _clientAward,
        uint256 _providerAward,
        bytes32 _details
    ) external;
}

// File: contracts/interfaces/IArbitrable.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

/**
 * @title IArbitrable
 * Arbitrable interface.
 * When developing arbitrable contracts, we need to:
 * - Define the action taken when a ruling is received by the contract.
 * - Allow dispute creation. For this a function must call arbitrator.createDispute{value: _fee}(_choices,_extraData);
 */
interface IArbitrable {
    /**
     * @dev To be raised when a ruling is given.
     * @param _arbitrator The arbitrator giving the ruling.
     * @param _disputeID ID of the dispute in the Arbitrator contract.
     * @param _ruling The ruling which was given.
     */
    event Ruling(
        address indexed _arbitrator,
        uint256 indexed _disputeID,
        uint256 _ruling
    );

    /**
     * @dev Give a ruling for a dispute. Must be called by the arbitrator.
     * The purpose of this function is to ensure that the address calling it has the right to rule on the contract.
     * @param _disputeID ID of the dispute in the Arbitrator contract.
     * @param _ruling Ruling given by the arbitrator. Note that 0 is reserved for "Not able/wanting to make a decision".
     */
    function rule(uint256 _disputeID, uint256 _ruling) external;
}

// File: contracts/interfaces/IArbitrator.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

/**
 * @title Arbitrator
 * Arbitrator abstract contract.
 * When developing arbitrator contracts we need to:
 * - Define the functions for dispute creation (createDispute) and appeal (appeal). Don't forget to store the arbitrated contract and the disputeID (which should be unique, may nbDisputes).
 * - Define the functions for cost display (arbitrationCost and appealCost).
 * - Allow giving rulings. For this a function must call arbitrable.rule(disputeID, ruling).
 */
interface IArbitrator {
    enum DisputeStatus {Waiting, Appealable, Solved}

    /**
     * @dev To be emitted when a dispute is created.
     * @param _disputeID ID of the dispute.
     * @param _arbitrable The contract which created the dispute.
     */
    event DisputeCreation(
        uint256 indexed _disputeID,
        address indexed _arbitrable
    );

    /**
     * @dev To be emitted when a dispute can be appealed.
     * @param _disputeID ID of the dispute.
     * @param _arbitrable The contract which created the dispute.
     */
    event AppealPossible(
        uint256 indexed _disputeID,
        address indexed _arbitrable
    );

    /**
     * @dev To be emitted when the current ruling is appealed.
     * @param _disputeID ID of the dispute.
     * @param _arbitrable The contract which created the dispute.
     */
    event AppealDecision(
        uint256 indexed _disputeID,
        address indexed _arbitrable
    );

    /**
     * @dev Create a dispute. Must be called by the arbitrable contract.
     * Must be paid at least arbitrationCost(_extraData).
     * @param _choices Amount of choices the arbitrator can make in this dispute.
     * @param _extraData Can be used to give additional info on the dispute to be created.
     * @return disputeID ID of the dispute created.
     */
    function createDispute(uint256 _choices, bytes calldata _extraData)
        external
        payable
        returns (uint256 disputeID);

    /**
     * @dev Compute the cost of arbitration. It is recommended not to increase it often, as it can be highly time and gas consuming for the arbitrated contracts to cope with fee augmentation.
     * @param _extraData Can be used to give additional info on the dispute to be created.
     * @return cost Amount to be paid.
     */
    function arbitrationCost(bytes calldata _extraData)
        external
        view
        returns (uint256 cost);

    /**
     * @dev Appeal a ruling. Note that it has to be called before the arbitrator contract calls rule.
     * @param _disputeID ID of the dispute to be appealed.
     * @param _extraData Can be used to give extra info on the appeal.
     */
    function appeal(uint256 _disputeID, bytes calldata _extraData)
        external
        payable;

    /**
     * @dev Compute the cost of appeal. It is recommended not to increase it often, as it can be higly time and gas consuming for the arbitrated contracts to cope with fee augmentation.
     * @param _disputeID ID of the dispute to be appealed.
     * @param _extraData Can be used to give additional info on the dispute to be created.
     * @return cost Amount to be paid.
     */
    function appealCost(uint256 _disputeID, bytes calldata _extraData)
        external
        view
        returns (uint256 cost);

    /**
     * @dev Compute the start and end of the dispute's current or next appeal period, if possible. If not known or appeal is impossible: should return (0, 0).
     * @param _disputeID ID of the dispute.
     * @return start The start of the period.
     * @return end The end of the period.
     */
    function appealPeriod(uint256 _disputeID)
        external
        view
        returns (uint256 start, uint256 end);

    /**
     * @dev Return the status of a dispute.
     * @param _disputeID ID of the dispute to rule.
     * @return status The status of the dispute.
     */
    function disputeStatus(uint256 _disputeID)
        external
        view
        returns (DisputeStatus status);

    /**
     * @dev Return the current ruling of a dispute. This is useful for parties to know if they should appeal.
     * @param _disputeID ID of the dispute.
     * @return ruling The ruling which has been given or the one which will be given if there is no appeal.
     */
    function currentRuling(uint256 _disputeID)
        external
        view
        returns (uint256 ruling);
}

// File: contracts/interfaces/IWRAPPED.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.8.0;

interface IWRAPPED {
    // brief interface for canonical native token wrapper contract
    function deposit() external payable;
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^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);
            }
        }
    }
}