Copyright (C) 2008 North State Software, LLC

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;

using NorthStateFramework;

namespace CommandProcessorExample
{
    public class CommandProcessor : NSFStateMachine
    {
        #region Fields

        private Queue<String> commandQueue = new Queue<string>();
        private Queue<String> responseQueue = new Queue<string>();

        private NSFEvent responseTimeoutEvent;
        private NSFInitialState initialState;
        private NSFCompositeState waitForCommandState;
        private NSFCompositeState waitForResponseState;
        private NSFCompositeState errorState;

        #endregion Fields

        #region Constructors

        public CommandProcessor(String name, ThreadPriority priority)
            : base(name, new NSFEventThread(name, priority))
        {
            // Events
            responseTimeoutEvent = new NSFEvent("ResponseTimeout", this, this);

            // Regions and States
            initialState = new NSFInitialState("Initial", this);
            waitForCommandState = new NSFCompositeState("WaitForCommand", this, null, null);
            waitForResponseState = new NSFCompositeState("WaitForResponse", this, waitForResponseEntryActions, waitForResponseExitActions);
            errorState = new NSFCompositeState("Error", this, errorEntryActions, null);

            // Transitions
            new NSFExternalTransition(initialState, waitForCommandState, null, null, null);
            new NSFExternalTransition(waitForCommandState, waitForResponseState, null, hasCommand, sendCommand);
            new NSFExternalTransition(waitForResponseState, waitForCommandState, null, hasResponse, handleResponse);
            new NSFExternalTransition(waitForResponseState, errorState, responseTimeoutEvent, null, null);
        }

        #endregion Constructors

        #region Methods

        public void addCommand(string newCommand)
        {
            commandQueue.Enqueue(newCommand);
            forceStateMachineEvaluation();
        }

        public void addResponse(string newResponse)
        {
            responseQueue.Enqueue(newResponse);
            forceStateMachineEvaluation();
        }

        private bool hasCommand(NSFState source, NSFStateEventArgs eventArgs)
        {
            return (commandQueue.Count != 0);
        }

        private bool hasResponse(NSFState source, NSFStateEventArgs eventArgs)
        {
            return (responseQueue.Count != 0);
        }

        private void sendCommand(NSFState source, NSFStateEventArgs eventArgs)
        {
            // Code to send the command goes here
            // ...

            // Log trace of command sent
            NSFTraceLog.logTrace(NSFTraceTags.messageSentTag, NSFTraceTags.sourceTag, this.Name, NSFTraceTags.messageTag, commandQueue.Dequeue());
        }

        private void waitForResponseEntryActions(NSFState source, NSFStateEventArgs eventArgs)
        {
            // Schedule timeout event in 1000 mS, in case no response received           
            responseTimeoutEvent.schedule(1000, 0);
        }

        private void waitForResponseExitActions(NSFState source, NSFStateEventArgs eventArgs)
        {
            // Unschedule the timeout event
            responseTimeoutEvent.unschedule();
        }

        private void handleResponse(NSFState source, NSFStateEventArgs eventArgs)
        {
            // Code to handle the response goes here
            // ...

            // Log trace of command sent
            NSFTraceLog.logTrace(NSFTraceTags.messageReceivedTag, NSFTraceTags.sourceTag, this.Name, NSFTraceTags.messageTag, responseQueue.Dequeue());
        }

        private void errorEntryActions(NSFState source, NSFStateEventArgs eventArgs)
        {
            // Code to handle the error goes here
            // ...
        }

        #endregion Methods
    }
}