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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

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

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;

    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }

    mapping (bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");

        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");

        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
        _roles[role].adminRole = adminRole;
    }

    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }

    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

// 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/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/EnumerableSet.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// File: contracts/bridge/BridgeConfigV3.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

import '@openzeppelin/contracts/access/AccessControl.sol';
import '@openzeppelin/contracts/math/SafeMath.sol';

/**
 * @title BridgeConfig contract
 * @notice This token is used for configuring different tokens on the bridge and mapping them across chains.
**/

contract BridgeConfigV3 is AccessControl {
    using SafeMath for uint256;
    bytes32 public constant BRIDGEMANAGER_ROLE = keccak256('BRIDGEMANAGER_ROLE');
    bytes32[] private _allTokenIDs;
    mapping(bytes32 => Token[]) private _allTokens; // key is tokenID
    mapping(uint256 => mapping(string => bytes32)) private _tokenIDMap; // key is chainID,tokenAddress
    mapping(bytes32 => mapping(uint256 => Token)) private _tokens; // key is tokenID,chainID
    mapping(address => mapping(uint256 => Pool)) private _pool; // key is tokenAddress,chainID
    mapping(uint256 => uint256) private _maxGasPrice; // key is tokenID,chainID
    uint256 public constant bridgeConfigVersion = 3;

    // the denominator used to calculate fees. For example, an
    // LP fee might be something like tradeAmount.mul(fee).div(FEE_DENOMINATOR)
    uint256 private constant FEE_DENOMINATOR = 10**10;

    // this struct must be initialized using setTokenConfig for each token that directly interacts with the bridge
    struct Token {
        uint256 chainId;
        string tokenAddress;
        uint8 tokenDecimals;
        uint256 maxSwap;
        uint256 minSwap;
        uint256 swapFee;
        uint256 maxSwapFee;
        uint256 minSwapFee;
        bool hasUnderlying;
        bool isUnderlying;
    }


    struct Pool {
        address tokenAddress;
        uint256 chainId;
        address poolAddress;
        bool metaswap;
    }


    constructor() public {
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }

    /**
     * @notice Returns a list of all existing token IDs converted to strings
     */
    function getAllTokenIDs() public view returns (string[] memory result) {
        uint256 length = _allTokenIDs.length;
        result = new string[](length);
        for (uint256 i = 0; i < length; ++i) {
            result[i] = toString(_allTokenIDs[i]);
        }
    }

    function _getTokenID(string memory tokenAddress, uint256 chainID) internal view returns (string memory)  {
        return toString(_tokenIDMap[chainID][tokenAddress]);
    }

    function getTokenID(string memory tokenAddress, uint256 chainID) public view returns (string memory)  {
        return _getTokenID(_toLower(tokenAddress), chainID);
    }

    /**
     * @notice Returns the token ID (string) of the cross-chain token inputted
     * @param tokenAddress address of token to get ID for
     * @param chainID chainID of which to get token ID for
     */
    function getTokenID(address tokenAddress, uint256 chainID) public view returns (string memory)  {
        return _getTokenID(toString(tokenAddress), chainID);
    }

    /**
     * @notice Returns the full token config struct
     * @param tokenID String input of the token ID for the token
     * @param chainID Chain ID of which token address + config to get
     */
    function getToken(string memory tokenID, uint256 chainID) public view returns (Token memory token) {
        return _tokens[toBytes32(tokenID)][chainID];
    }

    /**
    * @notice Returns the full token config struct
     * @param tokenID String input of the token ID for the token
     * @param chainID Chain ID of which token address + config to get
     */
    function getTokenByID(string memory tokenID, uint256 chainID) public view returns (Token memory token) {
        return _tokens[toBytes32(tokenID)][chainID];
    }

    /**
     * @notice Returns token config struct, given an address and chainID
     * @param tokenAddress Matches the token ID by using a combo of address + chain ID
     * @param chainID Chain ID of which token to get config for
     */
    function getTokenByAddress(string memory tokenAddress, uint256 chainID) public view returns (Token memory token) {
        return _tokens[_tokenIDMap[chainID][tokenAddress]][chainID];
    }

    function getTokenByEVMAddress(address tokenAddress, uint256 chainID) public view returns (Token memory token) {
        return _tokens[_tokenIDMap[chainID][_toLower(toString(tokenAddress))]][chainID];
    }

    /**
     * @notice Returns true if the token has an underlying token -- meaning the token is deposited into the bridge
     * @param tokenID String to check if it is a withdraw/underlying token
     */
    function hasUnderlyingToken(string memory tokenID) public view returns (bool) {
        bytes32 bytesTokenID = toBytes32(tokenID);
        Token[] memory _mcTokens = _allTokens[bytesTokenID];
        for (uint256 i = 0; i < _mcTokens.length; ++i) {
            if (_mcTokens[i].hasUnderlying) {
                return true;
            }
        }
        return false;
    }

    /**
     * @notice Returns which token is the underlying token to withdraw
     * @param tokenID string token ID
     */
    function getUnderlyingToken(string memory tokenID) public view returns (Token memory token) {
        bytes32 bytesTokenID = toBytes32(tokenID);
        Token[] memory _mcTokens = _allTokens[bytesTokenID];
        for (uint256 i = 0; i < _mcTokens.length; ++i) {
            if (_mcTokens[i].isUnderlying) {
                return _mcTokens[i];
            }
        }
    }

    /**
     @notice Public function returning if token ID exists given a string
     */
    function isTokenIDExist(string memory tokenID) public view returns (bool) {
        return _isTokenIDExist(toBytes32(tokenID));
    }

    /**
     @notice Internal function returning if token ID exists given bytes32 version of the ID
     */
    function _isTokenIDExist(bytes32 tokenID) internal view returns(bool) {
        for (uint256 i = 0; i < _allTokenIDs.length; ++i) {
            if (_allTokenIDs[i] == tokenID) {
                return true;
            }
        }
        return false;
    }

    /**
     * @notice Internal function which handles logic of setting token ID and dealing with mappings
     * @param tokenID bytes32 version of ID
     * @param chainID which chain to set the token config for
     * @param tokenToAdd Token object to set the mapping to
     */
    function _setTokenConfig(bytes32 tokenID, uint256 chainID, Token memory tokenToAdd) internal returns(bool) {
        _tokens[tokenID][chainID] = tokenToAdd;
        if (!_isTokenIDExist(tokenID)) {
            _allTokenIDs.push(tokenID);
        }

        Token[] storage _mcTokens = _allTokens[tokenID];
        for (uint256 i = 0; i < _mcTokens.length; ++i) {
            if (_mcTokens[i].chainId == chainID) {
                string memory oldToken = _mcTokens[i].tokenAddress;
                if (compareStrings(tokenToAdd.tokenAddress, oldToken)) {
                    _mcTokens[i].tokenAddress = tokenToAdd.tokenAddress ;
                    _tokenIDMap[chainID][oldToken] = keccak256('');
                    _tokenIDMap[chainID][tokenToAdd.tokenAddress] = tokenID;
                }
            }
        }
        _mcTokens.push(tokenToAdd);
        _tokenIDMap[chainID][tokenToAdd.tokenAddress] = tokenID;
        return true;
    }

    /**
 * @notice Main write function of this contract - Handles creating the struct and passing it to the internal logic function
     * @param tokenID string ID to set the token config object form
     * @param chainID chain ID to use for the token config object
     * @param tokenAddress token address of the token on the given chain
     * @param tokenDecimals decimals of token
     * @param maxSwap maximum amount of token allowed to be transferred at once - in native token decimals
     * @param minSwap minimum amount of token needed to be transferred at once - in native token decimals
     * @param swapFee percent based swap fee -- 10e6 == 10bps
     * @param maxSwapFee max swap fee to be charged - in native token decimals
     * @param minSwapFee min swap fee to be charged - in native token decimals - especially useful for mainnet ETH
     * @param hasUnderlying bool which represents whether this is a global mint token or one to withdraw()
     * @param isUnderlying bool which represents if this token is the one to withdraw on the given chain
     */
    function setTokenConfig(
        string calldata tokenID,
        uint256 chainID,
        address tokenAddress,
        uint8 tokenDecimals,
        uint256 maxSwap,
        uint256 minSwap,
        uint256 swapFee,
        uint256 maxSwapFee,
        uint256 minSwapFee,
        bool hasUnderlying,
        bool isUnderlying
    ) public returns (bool) {
        require(hasRole(BRIDGEMANAGER_ROLE, msg.sender));
        return setTokenConfig(
            tokenID,
            chainID,
            toString(tokenAddress),
            tokenDecimals,
            maxSwap,
            minSwap,
            swapFee,
            maxSwapFee,
            minSwapFee,
            hasUnderlying,
            isUnderlying
        );
    }

    /**
     * @notice Main write function of this contract - Handles creating the struct and passing it to the internal logic function
     * @param tokenID string ID to set the token config object form
     * @param chainID chain ID to use for the token config object
     * @param tokenAddress token address of the token on the given chain
     * @param tokenDecimals decimals of token
     * @param maxSwap maximum amount of token allowed to be transferred at once - in native token decimals
     * @param minSwap minimum amount of token needed to be transferred at once - in native token decimals
     * @param swapFee percent based swap fee -- 10e6 == 10bps
     * @param maxSwapFee max swap fee to be charged - in native token decimals
     * @param minSwapFee min swap fee to be charged - in native token decimals - especially useful for mainnet ETH
     * @param hasUnderlying bool which represents whether this is a global mint token or one to withdraw()
     * @param isUnderlying bool which represents if this token is the one to withdraw on the given chain
     */
    function setTokenConfig(
        string calldata tokenID,
        uint256 chainID,
        string memory tokenAddress,
        uint8 tokenDecimals,
        uint256 maxSwap,
        uint256 minSwap,
        uint256 swapFee,
        uint256 maxSwapFee,
        uint256 minSwapFee,
        bool hasUnderlying,
        bool isUnderlying
    ) public returns (bool) {
        require(hasRole(BRIDGEMANAGER_ROLE, msg.sender));
        Token memory tokenToAdd;
        tokenToAdd.tokenAddress = _toLower(tokenAddress);
        tokenToAdd.tokenDecimals = tokenDecimals;
        tokenToAdd.maxSwap = maxSwap;
        tokenToAdd.minSwap = minSwap;
        tokenToAdd.swapFee = swapFee;
        tokenToAdd.maxSwapFee = maxSwapFee;
        tokenToAdd.minSwapFee = minSwapFee;
        tokenToAdd.hasUnderlying = hasUnderlying;
        tokenToAdd.isUnderlying = isUnderlying;
        tokenToAdd.chainId = chainID;

        return _setTokenConfig(toBytes32(tokenID), chainID, tokenToAdd);
    }

    function _calculateSwapFee(
        string memory tokenAddress,
        uint256 chainID,
        uint256 amount
    ) internal view returns (uint256) {
        Token memory token = _tokens[_tokenIDMap[chainID][tokenAddress]][chainID];
        uint256 calculatedSwapFee = amount.mul(token.swapFee).div(FEE_DENOMINATOR);
        if (calculatedSwapFee > token.minSwapFee && calculatedSwapFee < token.maxSwapFee) {
            return calculatedSwapFee;
        } else if (calculatedSwapFee > token.maxSwapFee) {
            return token.maxSwapFee;
        } else {
            return token.minSwapFee;
        }
    }


    /**
     * @notice Calculates bridge swap fee based on the destination chain's token transfer.
     * @dev This means the fee should be calculated based on the chain that the nodes emit a tx on
     * @param tokenAddress address of the destination token to query token config for
     * @param chainID destination chain ID to query the token config for
     * @param amount in native token decimals
     * @return Fee calculated in token decimals
     */
    function calculateSwapFee(
        string memory tokenAddress,
        uint256 chainID,
        uint256 amount
    ) external view returns (uint256) {
        return _calculateSwapFee(tokenAddress, chainID, amount);
    }

    /**
    * @notice Calculates bridge swap fee based on the destination chain's token transfer.
     * @dev This means the fee should be calculated based on the chain that the nodes emit a tx on
     * @param tokenAddress address of the destination token to query token config for
     * @param chainID destination chain ID to query the token config for
     * @param amount in native token decimals
     * @return Fee calculated in token decimals
     */
    function calculateSwapFee(
        address tokenAddress,
        uint256 chainID,
        uint256 amount
    ) external view returns (uint256) {
        return _calculateSwapFee(toString(tokenAddress), chainID, amount);
    }


    // GAS PRICING

    /**
    * @notice sets the max gas price for a chain
    */
    function setMaxGasPrice(uint256 chainID, uint256 maxPrice) public {
        require(hasRole(BRIDGEMANAGER_ROLE, msg.sender));
        _maxGasPrice[chainID] = maxPrice;
    }

    /**
    * @notice gets the max gas price for a chain
    */
    function getMaxGasPrice(uint256 chainID) public view returns (uint256){
        return _maxGasPrice[chainID];
    }


    // POOL CONFIG

    function getPoolConfig(address tokenAddress, uint256 chainID) external view returns (Pool memory) {
        return _pool[tokenAddress][chainID];
    }

    function setPoolConfig(
        address tokenAddress,
        uint256 chainID,
        address poolAddress,
        bool metaswap
    ) external returns (Pool memory) {
        require(
            hasRole(BRIDGEMANAGER_ROLE, msg.sender),
            'Caller is not Bridge Manager'
        );
        Pool memory newPool = Pool(tokenAddress, chainID, poolAddress, metaswap);
        _pool[tokenAddress][chainID] = newPool;
        return newPool;
    }

    // UTILITY FUNCTIONS

    function toString(bytes32 data) internal pure returns (string memory) {
        uint8 i = 0;
        while (i < 32 && data[i] != 0) {
            ++i;
        }
        bytes memory bs = new bytes(i);
        for (uint8 j = 0; j < i; ++j) {
            bs[j] = data[j];
        }
        return string(bs);
    }

    // toBytes32 converts a string to a bytes 32
    function toBytes32(string memory str) internal pure returns (bytes32 result) {
        require(bytes(str).length <= 32);
        assembly {
            result := mload(add(str, 32))
        }
    }


    function toString(address x)
    internal
    pure
    returns (string memory)
    {
        bytes memory s = new bytes(40);
        for (uint i = 0; i < 20; i++) {
            bytes1 b = bytes1(uint8(uint(uint160(x)) / (2**(8*(19 - i)))));
            bytes1 hi = bytes1(uint8(b) / 16);
            bytes1 lo = bytes1(uint8(b) - 16 * uint8(hi));
            s[2*i] = char(hi);
            s[2*i+1] = char(lo);
        }

        string memory addrPrefix = '0x';

        return concat(addrPrefix, string(s));
    }

    function concat(string memory _x, string memory _y) pure internal returns (string memory) {
        bytes memory _xBytes = bytes(_x);
        bytes memory _yBytes = bytes(_y);

        string memory _tmpValue = new string(_xBytes.length + _yBytes.length);
        bytes memory _newValue = bytes(_tmpValue);

        uint i;
        uint j;

        for(i=0;i<_xBytes.length;i++) {
            _newValue[j++] = _xBytes[i];
        }

        for(i=0;i<_yBytes.length;i++) {
            _newValue[j++] = _yBytes[i];
        }

        return string(_newValue);
    }

    function char(bytes1 b)
    pure internal
    returns (bytes1 c)
    {
        if (uint8(b) < 10) {
            c = bytes1(uint8(b) + 0x30);
        } else {
            c = bytes1(uint8(b) + 0x57);
        }
    }

    function compareStrings(string memory a, string memory b) pure internal returns (bool) {
        return (keccak256(abi.encodePacked((a))) == keccak256(abi.encodePacked((b))));
    }

    function _toLower(string memory str) pure internal returns (string memory) {
        bytes memory bStr = bytes(str);
        bytes memory bLower = new bytes(bStr.length);
        for (uint i = 0; i < bStr.length; i++) {
            // Uppercase character...
            if ((uint8(bStr[i]) >= 65) && (uint8(bStr[i]) <= 90)) {
                // So we add 32 to make it lowercase
                bLower[i] = bytes1(uint8(bStr[i]) + 32);
            } else {
                bLower[i] = bStr[i];
            }
        }
        return string(bLower);
    }
}