interface ISetToken is IERC20 {

    /* ============ Enums ============ */

    enum ModuleState {
        NONE,
        PENDING,
        INITIALIZED
    }

    /* ============ Structs ============ */
    /**
     * The base definition of a SetToken Position
     *
     * @param component           Address of token in the Position
     * @param module              If not in default state, the address of associated module
     * @param unit                Each unit is the # of components per 10^18 of a SetToken
     * @param positionState       Position ENUM. Default is 0; External is 1
     * @param data                Arbitrary data
     */
    struct Position {
        address component;
        address module;
        int256 unit;
        uint8 positionState;
        bytes data;
    }

    /**
     * A struct that stores a component's cash position details and external positions
     * This data structure allows O(1) access to a component's cash position units and 
     * virtual units.
     *
     * @param virtualUnit               Virtual value of a component's DEFAULT position. Stored as virtual for efficiency
     *                                  updating all units at once via the position multiplier. Virtual units are achieved
     *                                  by dividing a "real" value by the "positionMultiplier"
     * @param componentIndex            
     * @param externalPositionModules   List of external modules attached to each external position. Each module
     *                                  maps to an external position
     * @param externalPositions         Mapping of module => ExternalPosition struct for a given component
     */
    struct ComponentPosition {
      int256 virtualUnit;
      address[] externalPositionModules;
      mapping(address => ExternalPosition) externalPositions;
    }

    /**
     * A struct that stores a component's external position details including virtual unit and any
     * auxiliary data.
     *
     * @param virtualUnit       Virtual value of a component's EXTERNAL position.
     * @param data              Arbitrary data
     */
    struct ExternalPosition {
      int256 virtualUnit;
      bytes data;
    }


    /* ============ Functions ============ */
    
    function addComponent(address _component) external;
    function removeComponent(address _component) external;
    function editDefaultPositionUnit(address _component, int256 _realUnit) external;
    function addExternalPositionModule(address _component, address _positionModule) external;
    function removeExternalPositionModule(address _component, address _positionModule) external;
    function editExternalPositionUnit(address _component, address _positionModule, int256 _realUnit) external;
    function editExternalPositionData(address _component, address _positionModule, bytes calldata _data) external;

    function invoke(address _target, uint256 _value, bytes calldata _data) external returns(bytes memory);

    function editPositionMultiplier(int256 _newMultiplier) external;

    function mint(address _account, uint256 _quantity) external;
    function burn(address _account, uint256 _quantity) external;

    function lock() external;
    function unlock() external;

    function addModule(address _module) external;
    function removeModule(address _module) external;
    function initializeModule() external;

    function setManager(address _manager) external;

    function manager() external view returns (address);
    function moduleStates(address _module) external view returns (ModuleState);
    function getModules() external view returns (address[] memory);
    
    function getDefaultPositionRealUnit(address _component) external view returns(int256);
    function getExternalPositionRealUnit(address _component, address _positionModule) external view returns(int256);
    function getComponents() external view returns(address[] memory);
    function getExternalPositionModules(address _component) external view returns(address[] memory);
    function getExternalPositionData(address _component, address _positionModule) external view returns(bytes memory);
    function isExternalPositionModule(address _component, address _module) external view returns(bool);
    function isComponent(address _component) external view returns(bool);
    
    function positionMultiplier() external view returns (int256);
    function getPositions() external view returns (Position[] memory);
    function getTotalComponentRealUnits(address _component) external view returns(int256);

    function isInitializedModule(address _module) external view returns(bool);
    function isPendingModule(address _module) external view returns(bool);
    function isLocked() external view returns (bool);
}
/**
 * @title ISetToken
 * @author Set Protocol
 *
 * Interface for operating with SetTokens.
 */
function addComponent(address _component) external;
/* ============ Functions ============ */