using System.Net;
using System.Net.Sockets;
using System.Text;

namespace UdpTestApp;

public class Program
{
    private static StringComparer stringComparer = StringComparer.OrdinalIgnoreCase;
    private static bool _continue;
    private static Thread readThread;
    private static UdpClient udpClient = null, receivingUdpClient = null;

    public static bool applicationQuitRequested { get; private set; }

    static void Main(string[] args)
    {
        while (applicationQuitRequested == false)
        {
            Console.WriteLine($"----- UDP PROTOCOL TEST APP -----");
            Console.WriteLine($"Command list:");
            Console.WriteLine($"s = start");
            Console.WriteLine($"q = quit");

            var key = Console.ReadKey();

            switch (key.Key)
            {
                // start
                case ConsoleKey.S:
                    Console.Write($"Write hostname: ");
                    string? hostname = Console.ReadLine();

                    if (hostname == null ||
                       String.IsNullOrEmpty(hostname))
                    {
                        Console.WriteLine($"Invalid hostname entered.");
                        break;
                    }

                    Console.Write($"Write port number: ");
                    string? portString = Console.ReadLine();
                    int port;

                    if (portString == null ||
                        portString == "" ||
                        Int32.TryParse(portString, out port) == false)
                    {
                        Console.WriteLine($"Invalid port entered.");
                        break;
                    }

                    try
                    {
                        udpClient = new UdpClient();
                        receivingUdpClient = new UdpClient(11001);
                        udpClient.Connect(hostname, port);
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine($"Could not create UDP client. \n {ex}");
                        break;
                    }

                    _continue = true;
                    readThread = new Thread(Read);
                    readThread.Start();

                    Console.WriteLine("Connected to device. Write 'quit' to end communication.");

                    while (_continue)
                    {
                        var message = Console.ReadLine();

                        if (stringComparer.Equals("quit", message))
                        {
                            _continue = false;
                        }
                        else if (message != null && String.IsNullOrEmpty(message) == false)
                        {
                            try
                            {
                                byte[] msgBytes = Encoding.ASCII.GetBytes(message);
                                List<byte> listBytes = new List<byte>();
                                listBytes.AddRange(msgBytes);
                                listBytes.Add((byte)'\n');
                                var array = listBytes.ToArray();
                                udpClient.Send(array, array.Length);
                            }
                            catch (Exception)
                            {
                                Console.WriteLine("Message could not be sent.");
                            }

                        }
                    }

                    readThread.Join(TimeSpan.FromSeconds(2));
                    //readThread.Abort();
                    readThread = null;
                    receivingUdpClient.Close();
                    receivingUdpClient = null;
                    udpClient.Close();
                    udpClient = null;
                    Console.WriteLine("Closed connection.");


                    break;

                // quit
                case ConsoleKey.Q:
                    applicationQuitRequested = true;
                    break;

                default:
                    Console.WriteLine($"{Environment.NewLine}Did not recognize key.. {Environment.NewLine}");
                    break;
            }


        }
    }

    public static void Read()
    {
        while (_continue)
        {
            try
            {
                //IPEndPoint object will allow us to read datagrams sent from any source.
                IPEndPoint RemoteIpEndPoint = new IPEndPoint(IPAddress.Any, 0);

                // Blocks until a message returns on this socket from a remote host.
                Byte[] receiveBytes = receivingUdpClient.Receive(ref RemoteIpEndPoint);
                string returnData = Encoding.ASCII.GetString(receiveBytes);

                // Uses the IPEndPoint object to determine which of these two hosts responded.
                Console.WriteLine("Message received: " + returnData.ToString());
                Console.WriteLine("Was sent from " +
                                            RemoteIpEndPoint.Address.ToString() +
                                            " on their port number " +
                                            RemoteIpEndPoint.Port.ToString());
            }
            catch { }
        }
    }
}