///
/// Copyright (c) 2017 Sensus Metering Systems
///
namespace TBF.BenchControl.Modbus.TankSelector
{
	public class SelectTankOp : IOperation
	{
		TankSelector tankSelector;
		TankId tankId;
		ushort bitMask;
		ushort unselectBitMask;
		bool alreadySet;
		bool unselectedWaitLevel;
		bool doUnselect;
		int time;

		public SelectTankOp(TankSelector tankSelector, TankId tankId)
		{
			this.tankSelector = tankSelector;
			this.tankId = tankId;				/// tankId is always TankId.Cold, TankId.Warm or TankId.Hot
			this.bitMask = (ushort)((tankId == TankId.Cold) ? QuidoOutputs.SelectColdTank
								  : (tankId == TankId.Warm) ? QuidoOutputs.SelectWarmTank
													 		: QuidoOutputs.SelectHotTank);
		}


		/// <summary>Start this operation</summary>
		public void Start()
		{
			if (tankSelector.CurrentActivity == Activity.Selected && tankSelector.CurrentTank == tankId)
			{
				alreadySet = true;	/// Nothing to be done in Run()
				unselectedWaitLevel = false;
				doUnselect = false;
			}
			else if (tankSelector.CurrentActivity == Activity.Selected_Waiting1min && tankSelector.CurrentTank == tankId)
			{
				alreadySet = false;
				unselectedWaitLevel = false;
				doUnselect = false;
				time = 1;			/// Skip resetting button bit in Run(), wait 1 min.
			}
			else if (tankSelector.CurrentActivity == Activity.Idle ||
					 tankSelector.CurrentActivity == Activity.Unknown)
			{
				SelectTankFromIdleState();
			}
			else if (tankSelector.CurrentActivity == Activity.Unselected_WaitingLevel)
			{
				alreadySet = false;
				unselectedWaitLevel = true;
				doUnselect = false;
			}
			else if (tankSelector.CurrentActivity == Activity.Selected ||
					 tankSelector.CurrentActivity == Activity.Selected_Waiting1min)
			{
				///
				/// it follows that (tankSelector.CurrentTank != tankId) => unselect the tank first
				///
				alreadySet = false;
				unselectedWaitLevel = false;
				doUnselect = true;

				TankId selectedTankId = tankSelector.CurrentTank;

				unselectBitMask = (ushort)((selectedTankId == TankId.Cold) ? QuidoOutputs.PumpToColdTank
										 : (selectedTankId == TankId.Warm) ? QuidoOutputs.PumpToWarmTank
																		   : QuidoOutputs.PumpToHotTank);

				tankSelector.State = (selectedTankId == TankId.Cold) ? State.ColdTankUnselected_WaitingLevel
								   : (selectedTankId == TankId.Warm) ? State.WarmTankUnselected_WaitingLevel
																	 : State.HotTankUnselected_WaitingLevel;

				tankSelector.ResetBit(unselectBitMask);
			}
		}

		void SelectTankFromIdleState()
		{
			/// tankId is always TankId.Cold, TankId.Warm or TankId.Hot
			tankSelector.State = (tankId == TankId.Cold) ? State.ColdTankSelected_Waiting1min
							   : (tankId == TankId.Warm) ? State.WarmTankSelected_Waiting1min
														 : State.HotTankSelected_Waiting1min;

			alreadySet = false;
			unselectedWaitLevel = false;
			doUnselect = false;
			time = 0;			/// Reset button bit in Run(), wait 1 min.

			tankSelector.SetBit(bitMask);
		}

		/// <summary>Run this operation</summary>
		public Event Run()
		{
			if (alreadySet)
			{
				return Event.ConditionMet;
			}
			else if (doUnselect)
			{
				tankSelector.ResetBit(unselectBitMask);
				doUnselect = false;
				unselectedWaitLevel = true;
				return Event.ConditionNotMet;
			}
			else if (unselectedWaitLevel)
			{
				if (tankSelector.CurrentActivity == Activity.Idle)
				{
					SelectTankFromIdleState();
				}
				return Event.ConditionNotMet;
			}
			else if (time == 0)
			{
				tankSelector.ResetBit(bitMask);
				time++;
				return Event.ConditionNotMet;
			}
			else if (time <= 60)
			{
				time++;
				return Event.ConditionNotMet;
			}
			else
			{
				return Event.ConditionMet;
			}
		}

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