///
/// Copyright (c) 2013-2020 Sensus Slovensko a.s.
///
using System;
using log4net;

namespace TBF.Rig.MettlerToledo.Standard
{
	public class ZeroOp : IOperation
	{
		private static readonly ILog log = LogManager.GetLogger(typeof(ZeroOp));
        public override string ToString() { return string.Format("ZeroOp(.,.)"); }

		bool done;

		/// Set by the constructor
		BalanceDev scale;
        bool activityStarted;

		/// <summary>
		/// Events:  BalanceDone, Error
		/// </summary>
		/// <param name="scale">Balance device instance</param>
		/// <param name="result">Reference to variable for 'tara' in kg</param>
		public ZeroOp(BalanceDev scale)
		{
			if (scale == null) throw new ArgumentNullException("balanceDev");
			this.scale = scale;

			log.Debug(this.ToString());
		}

		/// <summary>Start this operation</summary>
		public void Start()
		{
			log.DebugFormat("{0} - ZeroOp - Start()", scale.Name);

			done = false;
            if (scale.Activity == Activity.Idle)
            {
                scale.SendZeroWhenStableCmd();
                activityStarted = true;
                scale.Activity = Activity.RunningOperation;
            }
            else
            {
                activityStarted = false;
            }
        }

		/// <summary>Run this operation</summary>
		/// <returns>
		///		Event.None
		///		Event.BalanceDone
		///		Event.Error . . . . . Current.Tick == null
		/// </returns>
		public Event Run()
		{
            if (!activityStarted && scale.Activity == Activity.Idle)
            {
                scale.SendZeroWhenStableCmd();
                activityStarted = true;
                scale.Activity = Activity.RunningOperation;
                return Event.Busy;
            }

            if (done) return Event.ScaleDone;			/// Zeroing has been done already

			if (scale.MsrmntState == MsrmntState.Busy) return Event.Busy;

            if (scale.MsrmntState == MsrmntState.Overload)
            {
                done = true;
                return Event.ScaleOverload;
            }

            if (scale.MsrmntState == MsrmntState.Valid)
			{
				done = true;
				return Event.ScaleDone;				/// Zeroing completed
			}

            scale.SendZeroWhenStableCmd();	            /// Failed -> repeat zeroing
			return Event.Busy;
		}

		/// <summary>Stop this operation</summary>
		public void Stop()
		{
            if (scale.MsrmntState == MsrmntState.Busy) scale.MsrmntState = MsrmntState.Failed;
            scale.Activity = Activity.Idle;
            log.DebugFormat("{0} - ZeroOp - Stop()", scale.Name);
		}
	}
}