using log4net;

namespace TBF.BenchControl.Operations
{
    /// <summary>
    /// Implements timer function
    /// 
    /// Constructors:
    ///     Timer(timerTimeMs) ................ use Event.TimerExpired as eventExpired
    ///     Timer(timerTimeMs, eventExpired) .. use constructor argument as eventExpired
    ///     
    /// Start argument:
    ///     
    /// Events:
    ///     Event.None ........ operation is in progress
    ///     eventExpired ...... timer expired
    /// </summary>
    public class TimerOp : IOperation
    {
		private static readonly ILog log = LogManager.GetLogger(typeof(TimerOp));
		public override string ToString() { return string.Format("TimerOp({0}s, Event.{1})", timerTime, eventExpired); }
		
		/// Private fields
        bool timeExpired = false;
		int expireTime;

		/// Set by constructors
        int timerTime;
		Event eventExpired;
        TBF.Boxes.IntBox remainingTimeSec;

        /// <summary>
        /// Constructors, optional argument is a timer name (you can create more then one timer)
        /// </summary>
        public TimerOp(int timerTimeSec, Event eventExpired, TBF.Boxes.IntBox remainingTimeSec)
        {
            this.timerTime = timerTimeSec;
            this.eventExpired = eventExpired;
            this.remainingTimeSec = remainingTimeSec;
        }
        public TimerOp(int timerTimeSec, Event eventExpired)
            : this(timerTimeSec, eventExpired, null)
		{
		}
        public TimerOp(int timerTime, TBF.Boxes.IntBox remainingTimeSec)
            : this(timerTime, Event.TimerExpired, remainingTimeSec)
        {
        }
        public TimerOp(int timerTime)
			: this(timerTime, Event.TimerExpired, null)
        {
        }

        void UpdateRemainingTime()
        {
            if (remainingTimeSec != null)
            {
                remainingTimeSec.Val = System.Math.Max(expireTime - StateMachine.Time, 0);
            }
        }
        
        /// <param name="obj">Time period (TimeSpan)</param>
        public void Start()
        {
            timeExpired = false;
            expireTime = StateMachine.Time + timerTime;

            UpdateRemainingTime();
        }

        public Event Run()
        {
            UpdateRemainingTime();

            if (timeExpired)
            {
                return eventExpired;
            }
            else if (StateMachine.Time >= expireTime)
            {
                timeExpired = true;
                return eventExpired;
            }
            else
            {
                return Event.TimerBusy;
            }
        }

        public void Stop()
        {
            timeExpired = false;
        }
    }
}