using System;

using System.Collections.Generic;

//https://stackoverflow.com/questions/7874066/state-pattern-c-sharp-with-previous-states

​

public class Program

{

    static void Main(string[] args)

    {       

        PhaseState p = new PhaseState();

        Console.WriteLine("Current State = " + p.CurrentState);

        Console.WriteLine("Command.Begin: Current State = " + p.MoveNext(Command.Begin));

        Console.WriteLine("Command.Pause: Current State = " + p.MoveNext(Command.Pause));

        Console.WriteLine("Command.End: Current State = " + p.MoveNext(Command.End));

        Console.WriteLine("Command.Exit: Current State = " + p.MoveNext(Command.Exit));

        Console.WriteLine("\n");

        //var c = new LungStaircaseRecruitmentProtocol();

        Console.WriteLine("Rewind:");

        for (int i = 0; i < 3; i++)

        {           

        }

        Console.WriteLine("Advance:");

        for (int i = 0; i < 10; i++)

        {           

        }

        Console.WriteLine("Rewind:");

        for (int i = 0; i < 5; i++)

        {           

        }

​

    }

}

public enum CyclePhase

{

    BeforeBegin,

    RestBefore,

    Pressurizing,

    Decremental,

    ApplyingIdealPEEP,

    EndedProtocol

}

//https://stackoverflow.com/a/5924053/2752308 :

//https://dotnetfiddle.net/NX1Eui

    public enum State

    {

        Inactive,

        Active,

        Paused,

        Terminated

    }

    public enum Command

    {

        Begin,

        End,

        Pause,

        Resume,

        Exit

    }

public class PhaseState

    {

        class StateTransition

        {

            readonly State CurrentState;

            readonly Command Command;

​

            public StateTransition(State currentState, Command command)

            {

                CurrentState = currentState;

                Command = command;

            }

​

            public override int GetHashCode()

            {

                return 17 + 31 * CurrentState.GetHashCode() + 31 * Command.GetHashCode();

            }

​

            public override bool Equals(object obj)

            {

                StateTransition other = obj as StateTransition;

                return other != null && this.CurrentState == other.CurrentState && this.Command == other.Command;

            }

        }

​

        Dictionary<StateTransition, State> transitions;

        public State CurrentState { get; private set; }

​

        public PhaseState()

        {

            CurrentState = State.Inactive;

            transitions = new Dictionary<StateTransition, State>

            {

                { new StateTransition(State.Inactive, Command.Exit), State.Terminated },

                { new StateTransition(State.Inactive, Command.Begin), State.Active },

                { new StateTransition(State.Active, Command.End), State.Inactive },

                { new StateTransition(State.Active, Command.Pause), State.Paused },

                { new StateTransition(State.Paused, Command.End), State.Inactive },

                { new StateTransition(State.Paused, Command.Resume), State.Active }

            };

        }

​

        public State GetNext(Command command)

        {

            StateTransition transition = new StateTransition(CurrentState, command);

            State nextState;

            if (!transitions.TryGetValue(transition, out nextState))

                throw new Exception("Invalid transition: " + CurrentState + " -> " + command);

            return nextState;

        }

​

        public State MoveNext(Command command)

        {

            CurrentState = GetNext(command);

            return CurrentState;

        }

        public static State Inactivate()

        {           

            return State.Inactive;

        }

        public static State Activate()

        {           

            return State.Active;

        }

    }

​