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

using BlubbFish.Utils;

namespace BroadcastSender {
  class Program {
    private readonly IPAddress s_mcastAddress;
    private readonly Int32 s_mcastPort;
    private Socket s_mcastSocket;
    private MulticastOption s_mcastOption;

    public Program(String[] args) {
      CmdArgs.Instance.SetArguments(new Dictionary<String, CmdArgs.VaildArguments>() {
        { "adapter", new CmdArgs.VaildArguments(CmdArgs.ArgLength.Touple, true) },
        { "multicast", new CmdArgs.VaildArguments(CmdArgs.ArgLength.Touple, false, "224.0.24.1") },
        { "count", new CmdArgs.VaildArguments(CmdArgs.ArgLength.Touple, false, "100") },
        { "wait", new CmdArgs.VaildArguments(CmdArgs.ArgLength.Touple, false, "500") }
      }, args);
      if(!CmdArgs.Instance.HasAllRequiredArguments()) {
        Console.Error.WriteLine(CmdArgs.Instance.GetUsageList("BroadcastReciever.exe"));
        _ = Console.ReadLine();
        return;
      }

      // Initialize the multicast address group and multicast port.
      // Both address and port are selected from the allowed sets as
      // defined in the related RFC documents. These are the same
      // as the values used by the sender.
      this.s_mcastAddress = IPAddress.Parse(CmdArgs.Instance.GetArgumentData("multicast"));
      this.s_mcastPort = 11000;

      // Join the listener multicast group.
      this.JoinMulticastGroup();

      // Display MulticastOption properties.
      this.MulticastOptionProperties();

      // Broadcast the message to the listener.
      this.BroadcastMessage("Hello multicast listener.");
    }

    void JoinMulticastGroup() {
      try {
        // Create a multicast socket.
        this.s_mcastSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp) {
          Ttl = 32
        };

        // Get the local IP address used by the listener and the sender to
        // exchange multicast messages.
        IPAddress localIPAddr = IPAddress.Parse(CmdArgs.Instance.GetArgumentData("adapter"));

        // Create an IPEndPoint object.
        // Bind this endpoint to the multicast socket.
        this.s_mcastSocket.Bind(new IPEndPoint(localIPAddr, 0));

        // Define a MulticastOption object specifying the multicast group
        // address and the local IP address.
        // The multicast group address is the same as the address used by the listener.
        this.s_mcastOption = new MulticastOption(this.s_mcastAddress, localIPAddr);

        this.s_mcastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, this.s_mcastOption);
        this.s_mcastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 64);
      } catch(Exception e) {
        Console.WriteLine("\n" + e.ToString());
        _ = Console.ReadLine();
        return;
      }
    }

    void BroadcastMessage(String message) {
      IPEndPoint endPoint;

      try {
        //Send multicast packets to the listener.
        for(Int32 i = 0; i < Int32.Parse(CmdArgs.Instance.GetArgumentData("count")); i++) {

          endPoint = new IPEndPoint(this.s_mcastAddress, this.s_mcastPort);
          _ = this.s_mcastSocket.SendTo(Encoding.ASCII.GetBytes(message+" "+i), endPoint);
          Console.WriteLine("Multicast data sent "+i+".....");
          Thread.Sleep(Int32.Parse(CmdArgs.Instance.GetArgumentData("wait")));
        }
      } catch(Exception e) {
        Console.WriteLine("\n" + e.ToString());
        _ = Console.ReadLine();
        return;
      }

      this.s_mcastSocket.Close();
    }

    private void MulticastOptionProperties() {
      Console.WriteLine("Current multicast group is: " + this.s_mcastOption.Group);
      Console.WriteLine("Current multicast local address is: " + this.s_mcastOption.LocalAddress);
      Console.WriteLine("Current multicast ttl: " + this.s_mcastSocket.GetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive));
      Console.WriteLine("Current ttl: " + this.s_mcastSocket.Ttl);
    }

    static void Main(String[] args) => _ = new Program(args);
  }
}