contract Operatorable is Initializable {
    IBaseOperators internal operatorsInst;
    address private operatorsPending;

    event OperatorsContractChanged(address indexed caller, address indexed operatorsAddress);
    event OperatorsContractPending(address indexed caller, address indexed operatorsAddress);

    /**
     * @dev Reverts if sender does not have operator role associated.
     */
    modifier onlyOperator() {
        require(isOperator(msg.sender), "Operatorable: caller does not have the operator role");
        _;
    }

    /**
     * @dev Reverts if sender does not have admin role associated.
     */
    modifier onlyAdmin() {
        require(isAdmin(msg.sender), "Operatorable: caller does not have the admin role");
        _;
    }

    /**
     * @dev Reverts if sender does not have system role associated.
     */
    modifier onlySystem() {
        require(isSystem(msg.sender), "Operatorable: caller does not have the system role");
        _;
    }

    /**
     * @dev Reverts if sender does not have admin or system role associated.
     */
    modifier onlyAdminOrSystem() {
        require(isAdminOrSystem(msg.sender), "Operatorable: caller does not have the admin role nor system");
        _;
    }

    /**
     * @dev Reverts if sender does not have operator or system role associated.
     */
    modifier onlyOperatorOrSystem() {
        require(isOperatorOrSystem(msg.sender), "Operatorable: caller does not have the operator role nor system");
        _;
    }
    
    /**
     * @dev Initialization instead of constructor, called once. The setOperatorsContract function can be called only by Admin role with
     *       confirmation through the operators contract.
     * @param _baseOperators BaseOperators contract address.
     */
    function initialize(address _baseOperators) public initializer {
        _setOperatorsContract(_baseOperators);
    }

    /**
     * @dev Set the new the address of Operators contract, should be confirmed from operators contract by calling confirmFor(addr)
     *       where addr is the address of current contract instance. This is done to prevent the case when the new contract address is
     *       broken and control of the contract can be lost in such case
     * @param _baseOperators BaseOperators contract address.
     */
    function setOperatorsContract(address _baseOperators) public onlyAdmin {
        require(_baseOperators != address(0), "Operatorable: address of new operators contract can not be zero");
        operatorsPending = _baseOperators;
        emit OperatorsContractPending(msg.sender, _baseOperators);
    }

    /**
     * @dev The function should be called from new operators contract by admin to insure that operatorsPending address
     *       is the real contract address.
     */
    function confirmOperatorsContract() public {
        require(operatorsPending != address(0), "Operatorable: address of new operators contract can not be zero");
        require(msg.sender == operatorsPending, "Operatorable: should be called from new operators contract");
        _setOperatorsContract(operatorsPending);
    }

    /**
     * @return The address of the BaseOperators contract.
     */
    function getOperatorsContract() public view returns(address) {
        return address(operatorsInst);
    }

    /**
     * @return The pending address of the BaseOperators contract.
     */
    function getOperatorsPending() public view returns(address) {
        return operatorsPending;
    }

    /**
     * @return If '_account' has operator privileges.
     */
    function isOperator(address _account) public view returns (bool) {
        return operatorsInst.isOperator(_account);
    }

    /**
     * @return If '_account' has admin privileges.
     */
    function isAdmin(address _account) public view returns (bool) {
        return operatorsInst.isAdmin(_account);
    }

    /**
     * @return If '_account' has system privileges.
     */
    function isSystem(address _account) public view returns (bool) {
        return operatorsInst.isSystem(_account);
    }

    /**
     * @return If '_account' has admin or system privileges.
     */
    function isAdminOrSystem(address _account) public view returns (bool) {
        return (operatorsInst.isAdmin(_account) || operatorsInst.isSystem(_account));
    }

    /**
     * @return If '_account' has operator or system privileges.
     */
    function isOperatorOrSystem(address _account) public view returns (bool) {
        return (operatorsInst.isOperator(_account) || operatorsInst.isSystem(_account));
    }

    /** INTERNAL FUNCTIONS */
    function _setOperatorsContract(address _baseOperators) internal {
        require(_baseOperators != address(0), "Operatorable: address of new operators contract cannot be zero");
        operatorsInst = IBaseOperators(_baseOperators);
        emit OperatorsContractChanged(msg.sender, _baseOperators);
    }
}
function setOperatorsContract(address _baseOperators) public onlyAdmin {
    require(_baseOperators != address(0), "Operatorable: address of new operators contract can not be zero");
    operatorsPending = _baseOperators;
    emit OperatorsContractPending(msg.sender, _baseOperators);
}

/**
 * @dev Set the new the address of Operators contract, should be confirmed from operators contract by calling confirmFor(addr)
 *       where addr is the address of current contract instance. This is done to prevent the case when the new contract address is
 *       broken and control of the contract can be lost in such case
 * @param _baseOperators BaseOperators contract address.
 */