#region  --------------- Copyright Dresser Wayne Pignone -------------
/*
 * $Log: /Wrk/WayneLibraries/Wrk/StateEngine/Generic/TimeoutState.cs $
 * 
 * 6     08-07-30 11:35 roger.månsson
 * 
 * 5     08-05-07 15:35 roger.månsson
 * Obsoleted constructor with main object reference again. Instead, use
 * WritableMain property. When this is set on a composite state object,
 * the abstract method "ConfigureCompositeStateMachine" is called, and the
 * configuration of the state machine can be made.
 * 
 * 4     08-04-24 15:45 Mattias.larsson
 * 
 * 3     07-10-04 15:31 roger.månsson
 * Fixed glitch that let a timeout event slip out of the state even though
 * the state was left. It occured if the timeout was fired at the same
 * time the state exited for another reason.
 */
#endregion
using System;
using System.Collections.Generic;
using System.Text;

namespace Wayne.Lib.StateEngine.Generic
{
    /// <summary>
    /// Generic timeout state class that has a main object of a generic type.
    /// </summary>
    /// <typeparam name="TMain">Specifies the type of the main object.</typeparam>
    public abstract class TimeoutState<TMain> : State<TMain>
    {
        #region Fields

        Wayne.Lib.StateEngine.Timer timer;
        object myToken;

        #endregion
        
        #region Methods
        /// <summary>
        /// See State.Enter
        /// </summary>
        /// <param name="stateEntry"></param>
        /// <param name="transition"></param>
        protected override void Enter(Wayne.Lib.StateEngine.StateEntry stateEntry, ref Wayne.Lib.StateEngine.Transition transition)
        {
            base.Enter(stateEntry, ref transition);
            myToken = new object();
            var timeoutInterval = TimeoutInterval;
            if (timeoutInterval > 0)
            {
                timer = new Wayne.Lib.StateEngine.Timer(this, GenericEventType.Timeout, timeoutInterval, myToken);
                ActivateTimer(timer);
            }
        }


        /// <summary>
        /// HandleEvent is sealed, use HandleNonTimeoutEvent method to override instead.
        /// </summary>
        /// <param name="stateEngineEvent"></param>
        /// <param name="transition"></param>
        protected sealed override void HandleEvent(Wayne.Lib.StateEngine.StateEngineEvent stateEngineEvent, ref Wayne.Lib.StateEngine.Transition transition)
        {
            base.HandleEvent(stateEngineEvent, ref transition);

            if (stateEngineEvent.Type.Equals(GenericEventType.Timeout))
            {
                Wayne.Lib.StateEngine.TimerEvent timerEvent = stateEngineEvent as Wayne.Lib.StateEngine.TimerEvent;
                if (timerEvent != null)
                {
                    if (timerEvent.UserToken.Equals(myToken))
                    {
                        Timeout(ref transition);
                        timerEvent.Handled = true;
                        timer = null;
                    }
                }
            }

            if (!stateEngineEvent.Handled)
                HandleNonTimeoutEvent(stateEngineEvent, ref transition);
        }

        /// <summary>
        /// See State.Exit
        /// </summary>
        protected override void Exit()
        {
            base.Exit();
            myToken = null;
            if (this.timer != null)
            {
                this.timer.Disable();
                this.timer = null;
            }
        }

        /// <summary>
        /// Method that is implemented by descendant classes to receive events that were not the timeout event.
        /// </summary>
        /// <param name="stateEngineEvent"></param>
        /// <param name="transition"></param>
        protected abstract void HandleNonTimeoutEvent(Wayne.Lib.StateEngine.StateEngineEvent stateEngineEvent, ref Wayne.Lib.StateEngine.Transition transition);

        /// <summary>
        /// Method that is used by descendant classes to set the timeout of the state.
        /// </summary>
        /// <returns></returns>
        protected abstract int TimeoutInterval { get;}

        /// <summary>
        /// Method that is used by descendant classes to be signaled when the timeout has fired.
        /// </summary>
        /// <param name="transition"></param>
        protected abstract void Timeout(ref Wayne.Lib.StateEngine.Transition transition);

        /// <summary>
        /// Cancels the currently running timer.
        /// </summary>
        protected void CancelTimer()
        {
            if (this.timer != null)
            {
                this.timer.Disable();
                this.timer = null;
            }
        }

        /// <summary>
        /// Restarts the timer. If a timer is active, it is restarted, and if the timer is not active anymore, it is started again.
        /// </summary>
        protected void ResetTimer()
        {
            CancelTimer();

            timer = new Wayne.Lib.StateEngine.Timer(this, GenericEventType.Timeout, TimeoutInterval, myToken);

            ActivateTimer(timer);
        }
        #endregion
    }
}