///
/// Copyright (c) 2013-2015 Sensus Slovensko a.s.
///
using System;

namespace TBF.Rig
{
    /// <summary>
    /// This interface has to be implemented by each 'operation'. 'operations' are classes
    /// in TBF.Rig name space with a class name ending with 'Op' (e.g. TimerOp).
    /// This class name rule is a convention, not a requirement.
    /// </summary>
    public interface IOperation
    {
        /// <summary>
        /// Method is called when a state machine enters a state in which this operation
        /// takes place/ will be executed.
        /// Method is not called when this operation took place also in the previous state.
        /// StateMachine checks whether Start() should be called depending on the previous
        /// and the current state.
        /// </summary>
        /// <returns>true on success</returns>
        void Start();

        /// <summary>
        /// Method is called in regular time intervals when state machine is
        /// in a state in which this operation takes place.
        /// During operation the IOparation derived object may issue events,
        /// that means Run() method returns a value different from Event.Void (=0).
        /// Examples: Timer expired
        /// </summary>
        /// <returns></returns>
        Event Run();

        /// <summary>
        /// Method is called when the state machine leaves a state in which
        /// this operation takes place / was executed.
        /// Method is not called when this operation takes place also in the next state.
        /// StateMachine checks whether Start() should be called depending on the previous
        /// and the current state.
        /// </summary>
        void Stop();
    }
}