///
/// Copyright (c) 2013-2015 Sensus Metering Systems
///
using System;
using log4net;
using TBF.Boxes;

namespace TBF.BenchControl.Elde.RegisterReader
{
	public class ReadRegisterOp : IOperation
	{
		private static readonly ILog log = LogManager.GetLogger(typeof(ReadRegisterOp));
		public override string ToString() { return string.Format("ReadRegisterOp({0})", reader.Name); }

		/// Set by the constructor
		readonly RegisterReader reader;
        
        IntBox pulses;
		int lastPulses;
		bool lastPulsesValid;
		
        IntBox refPulses;

		/// <summary>
		/// Events:  Event.ReadRegisterDone or Event.Error
		/// </summary>
		/// <param name="reader">Register reader reference</param>
		/// <param name="pulses">Reference to a field with the water meter pulses</param>
		public ReadRegisterOp(GenericDevices.IRegisterReader reader, ref IntBox pulses)
        {
			this.reader = reader as RegisterReader;
			if (reader == null) throw new ArgumentNullException("reader is null or it is not Elde");

			this.pulses = pulses;
			lastPulsesValid = false;
			log.Debug(this.ToString());
        }

		/// <summary>
		/// Events:  Event.ReadRegisterDone or Event.Error
		/// </summary>
		/// <param name="reader">Register reader reference</param>
		/// <param name="pulses">Reference to a Box with the water meter pulses</param>
		/// <param name="refPulses">Reference to a Box with the reference flow meter pulses synchronized with the water meter</param>
		public ReadRegisterOp(GenericDevices.IRegisterReader reader, ref IntBox pulses, ref IntBox refPulses)
			: this(reader, ref pulses)
		{
			this.refPulses = refPulses;
			log.Debug(this.ToString());
		}

		private void ReadPulses()
		{
			if (!lastPulsesValid)
			{
				lastPulses = (int)reader.ControlBoard.WMeterPulses(reader.Position);
				lastPulsesValid = true;
			}
			else
			{
				UInt16 lowerWord = reader.ControlBoard.WMeterPulses(reader.Position);
				int uncorrected = (int)(((uint)lastPulses & 0xFFFF0000) | lowerWord);
				if (Math.Abs(uncorrected - lastPulses) <= Int16.MaxValue)
				{
					lastPulses = uncorrected;
				}
				else if (Math.Abs(uncorrected + 65536 - lastPulses) <= Int16.MaxValue)
				{
                    lastPulses = uncorrected + 65536;
				}
                else if (Math.Abs(uncorrected - 65536 - lastPulses) <= Int16.MaxValue)
				{
                    lastPulses = uncorrected - 65536;
				}
			}
			pulses.Val = lastPulses;

			if (refPulses != null)
			{
				refPulses.Val = (int)reader.ControlBoard.EtPulses(reader.Position);
			}
		}

		/// <summary>Start this operation</summary>
		public void Start()
        {
			ReadPulses();
		}

		/// <summary>Run this operation</summary>
		/// <returns>eventDone</returns>
		public Event Run()
		{
			ReadPulses();
			return Event.ReadRegisterDone;
		}

		/// <summary>Stop this operation</summary>
		public void Stop()
		{
		}
	}
}