Final call controller

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System.Threading;
using System.Net.Sockets;
using System;
using System.Net;
using System.Diagnostics;

public class CallController : MonoBehaviour
{
    private static CallController controller = null;
    public static CallController Instance
    {
        get
        {
            return controller;
        }
    }

    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
    private static void Init()
    {
        var go = new GameObject("Call controller");
        DontDestroyOnLoad(go);

        controller = go.AddComponent<CallController>();
    }

    private interface IOnCompleteCommandHandler
    {
        void OnComplete(CallController callController);
    }

    private abstract class Command
    {
        public virtual float CommandTimeout
        {
            get
            {
                return 20.0f;
            }
        }

        public abstract void Execute(CallController callController, Socket socket);
    }

    private class CallCommand : Command, IOnCompleteCommandHandler
    {
        private readonly string number;

        public CallCommand(string number)
        {
            this.number = number;
        }

        public override void Execute(CallController callController, Socket socket)
        {
            UnityEngine.Debug.Log("Executing call command to number: " + number);
            socket.Send(System.Text.Encoding.ASCII.GetBytes(string.Format("call {0}", number)));

            callController.IsCalling = true;
        }

        void IOnCompleteCommandHandler.OnComplete(CallController callController)
        {
            callController.IsCalling = false;
        }
    }

    private class EndCallCommand : Command, IOnCompleteCommandHandler
    {
        public override void Execute(CallController callController, Socket socket)
        {
            socket.Send(System.Text.Encoding.ASCII.GetBytes("raw_command AT+CHUP"));
        }

        void IOnCompleteCommandHandler.OnComplete(CallController callController)
        {
            callController.IsCalling = false;
        }
    }

    Thread controlThread;

    private volatile bool isRunning = true;

    private object commandLocker = new object();
    private Command command = null;

    private object ipLocker = new object();
    private string ip = string.Empty;
    public string Ip
    {
        get
        {
            lock (ipLocker)
                return ip;
        }

        set
        {
            lock (ipLocker)
                ip = value;
        }
    }


    private object isCallingLocker = new object();
    private bool isCalling = false;
    public bool IsCalling
    {
        get
        {
            lock (isCallingLocker)
                return isCalling;
        }

        private set
        {
            lock (isCallingLocker)
                isCalling = value;
        }
    }

    private bool HasCommand
    {
        get
        {
            lock (commandLocker)
                return command != null;
        }
    }

    private void Start()
    {
        controlThread = new Thread(ControlThread);
        controlThread.IsBackground = true;
        controlThread.Start();
    }

    private void AddCommand(Command command)
    {
        lock (commandLocker)
        {
            if (this.command != null)
            {
                UnityEngine.Debug.Log("There is a command. You can't assign another one while this one is not finished");
                return;
            }

            this.command = command;
        }
    }

    public void Call(string number)
    {
        if (IsCalling)
        {
            UnityEngine.Debug.LogError("Can't call. We are already calling!");
            return;
        }

        AddCommand(new CallCommand(number));
    }

    public void EndCall()
    {
        if (!IsCalling)
        {
            UnityEngine.Debug.LogError("Can't stop calling. We don't calling now.");
            return;
        }

        AddCommand(new EndCallCommand());
    }

    private void ControlThread()
    {
        byte[] buffer = new byte[65535];
        while (isRunning)
        {
            Thread.Sleep(200);

            IPAddress ipAddress = default(IPAddress);
            EndPoint endPoint = default(EndPoint);

            try
            {
                ipAddress = IPAddress.Parse(Ip);
                endPoint = new IPEndPoint(ipAddress, 5551);
            }
            catch (System.Threading.ThreadAbortException abort)
            {
                UnityEngine.Debug.Log("Exiting control thread");
                return;
            }
            catch (System.Exception ex)
            {
                UnityEngine.Debug.LogException(ex);
                continue;
            }

            Command commandToExecute = null;
            lock (commandLocker)
            {
                if (command == null)
                    continue;

                commandToExecute = command;
                command = null;
            }

            try
            {
                using (Socket socket = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp))
                {
                    UnityEngine.Debug.Log("Executing command");

                    socket.Connect(endPoint);
                    commandToExecute.Execute(this, socket);
                    string receivedString = string.Empty;
                    Stopwatch stopwatch = new Stopwatch();
                    stopwatch.Start();
                    do
                    {
                        if (socket.Available > 0)
                        {
                            int received = socket.Receive(buffer);
                            if (received <= 0)
                                continue;

                            receivedString = System.Text.Encoding.UTF8.GetString(buffer, 0, received);

                            var callString = "calling";
                            if (receivedString.StartsWith(callString))
                            {
                                UnityEngine.Debug.Log("Reseting timeout. Got some result");
                                stopwatch.Reset();
                                stopwatch.Start();
                            }

                            var finishString = "command finished";
                            if (receivedString.StartsWith(finishString))
                                break;
                        }

                        if (stopwatch.ElapsedMilliseconds > commandToExecute.CommandTimeout * 1000)
                        {
                            UnityEngine.Debug.LogError("Command has been timed out");
                            break;
                        }

                    } while (isRunning && !HasCommand);

                    if (commandToExecute is IOnCompleteCommandHandler)
                        (commandToExecute as IOnCompleteCommandHandler).OnComplete(this);

                    UnityEngine.Debug.Log("Command execution has finished");
                }
            }
            catch (System.Threading.ThreadAbortException abort)
            {
                UnityEngine.Debug.Log("Exiting control thread");
                return;
            }
            catch (System.Exception ex)
            {
                UnityEngine.Debug.LogError("Error executing command");
            }
        }
    }

    private void OnDestroy()
    {
        isRunning = false;
        if (controlThread != null)
            controlThread.Abort();
    }
}