contract Ownable is Modifiable, SelfDestructible {
    //
    // Variables
    // -----------------------------------------------------------------------------------------------------------------
    address public deployer;
    address public operator;

    //
    // Events
    // -----------------------------------------------------------------------------------------------------------------
    event SetDeployerEvent(address oldDeployer, address newDeployer);
    event SetOperatorEvent(address oldOperator, address newOperator);

    //
    // Constructor
    // -----------------------------------------------------------------------------------------------------------------
    constructor(address _deployer) internal notNullOrThisAddress(_deployer) {
        deployer = _deployer;
        operator = _deployer;
    }

    //
    // Functions
    // -----------------------------------------------------------------------------------------------------------------
    /// @notice Return the address that is able to initiate self-destruction
    function destructor()
    public
    view
    returns (address)
    {
        return deployer;
    }

    /// @notice Set the deployer of this contract
    /// @param newDeployer The address of the new deployer
    function setDeployer(address newDeployer)
    public
    onlyDeployer
    notNullOrThisAddress(newDeployer)
    {
        if (newDeployer != deployer) {
            // Set new deployer
            address oldDeployer = deployer;
            deployer = newDeployer;

            // Emit event
            emit SetDeployerEvent(oldDeployer, newDeployer);
        }
    }

    /// @notice Set the operator of this contract
    /// @param newOperator The address of the new operator
    function setOperator(address newOperator)
    public
    onlyOperator
    notNullOrThisAddress(newOperator)
    {
        if (newOperator != operator) {
            // Set new operator
            address oldOperator = operator;
            operator = newOperator;

            // Emit event
            emit SetOperatorEvent(oldOperator, newOperator);
        }
    }

    /// @notice Gauge whether message sender is deployer or not
    /// @return true if msg.sender is deployer, else false
    function isDeployer()
    internal
    view
    returns (bool)
    {
        return msg.sender == deployer;
    }

    /// @notice Gauge whether message sender is operator or not
    /// @return true if msg.sender is operator, else false
    function isOperator()
    internal
    view
    returns (bool)
    {
        return msg.sender == operator;
    }

    /// @notice Gauge whether message sender is operator or deployer on the one hand, or none of these on these on
    /// on the other hand
    /// @return true if msg.sender is operator, else false
    function isDeployerOrOperator()
    internal
    view
    returns (bool)
    {
        return isDeployer() || isOperator();
    }

    // Modifiers
    // -----------------------------------------------------------------------------------------------------------------
    modifier onlyDeployer() {
        require(isDeployer());
        _;
    }

    modifier notDeployer() {
        require(!isDeployer());
        _;
    }

    modifier onlyOperator() {
        require(isOperator());
        _;
    }

    modifier notOperator() {
        require(!isOperator());
        _;
    }

    modifier onlyDeployerOrOperator() {
        require(isDeployerOrOperator());
        _;
    }

    modifier notDeployerOrOperator() {
        require(!isDeployerOrOperator());
        _;
    }
}
/**
 * @title Ownable
 * @notice A modifiable that has ownership roles
 */
function isDeployer()
internal
view
returns (bool)
{
    return msg.sender == deployer;
}

/// @notice Gauge whether message sender is deployer or not
/// @return true if msg.sender is deployer, else false