using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
using ChannelSockets;
using System.Collections.Concurrent;

namespace ExampleServer
{
	public class Client
	{
		public IPEndPoint EndPoint { get; set; }
		public string Username { get; set; }
		public ushort ID { get; set; }
	}

	class Program
	{
		public struct Channels
		{
			public const byte UnreliableUpdate = 0;
			public const byte ReliableUpdate = 1;
			public const byte Chat = 2;
			public const byte Downloads = 3;
		}

		public static ChannelSocket socket = new ChannelSocket(30303);

		static Dictionary<IPEndPoint, Client> clients = new Dictionary<IPEndPoint,Client>();
		static Queue<ushort> clientIDs = new Queue<ushort>(Enumerable.Range(0, 1000).Select(i => (ushort)i));

		static ConcurrentQueue<Client> pendingClients = new ConcurrentQueue<Client>();
		static ConcurrentQueue<IPEndPoint> disconnectedEndPoints = new ConcurrentQueue<IPEndPoint>();

		static void Main(string[] args)
		{
			socket.Add(Channels.UnreliableUpdate, ChannelType.Unreliable);
			socket.Add(Channels.ReliableUpdate, ChannelType.Reliable);
			socket.Add(Channels.Chat, ChannelType.Reliable);
			socket.Add(Channels.Downloads, ChannelType.Reliable);

			socket.Connection = (c) =>
			{
				// Ban connections like this
				if (!c.EndPoint.Equals(IPAddress.Parse("111.111.111.111")))
				{
					c.Allow = false;
					return;
				}

				// Authenticate users like this
				string username;
				string password;
				if (c.Packet.ReadString(out username) && c.Packet.ReadString(out password) &&
				    username == "foo" && password == "bar")
				{
					pendingClients.Enqueue(new Client() { EndPoint = c.EndPoint, Username = username });
				}
				else
				{
					c.Allow = false;
				}
			};

			// Callback if an endpoint times out or disconnects
			socket.Disconnection = (c) =>
			{
				// Destination initiated the disconnection or server did or the connection timed out
				disconnectedEndPoints.Enqueue(c.EndPoint);
			};

			// Server command line interface
			while (true)
			{
				Console.WriteLine("Enter command");
				Console.WriteLine("1. List clients");
				Console.WriteLine("2. Read chat");
				Console.WriteLine("3. Send 'hello world' to clients");
				Console.WriteLine("4. Disconnect clients");

				var key = Console.ReadKey().Key;

				Console.Clear();

				// Process clients that just disconnected or connected. This would be done in a game loop normally
				IPEndPoint disconnectedEndPoint;
				while (disconnectedEndPoints.TryDequeue(out disconnectedEndPoint))
				{
					Client client;
					if (clients.TryGetValue(disconnectedEndPoint, out client))
					{
						// Recycle the client ID
						clientIDs.Enqueue(client.ID);
						clients.Remove(disconnectedEndPoint);
					}
				}

				Client connectedClient;
				while (pendingClients.TryDequeue(out connectedClient))
				{
					// Assign a unique client ID to the client
					connectedClient.ID = clientIDs.Dequeue();
					clients.Add(connectedClient.EndPoint, connectedClient);
				}

				switch (key)
				{
					case ConsoleKey.D1:
						Console.WriteLine("Clients:");
						foreach (Client client in clients.Values)
						{
							Console.WriteLine(client.Username);
						}
						break;
					case ConsoleKey.D2:
						Console.WriteLine("Chat:");
						EndPointPacket endPointPacket;
						while (socket[Channels.Chat].Packets.TryDequeue(out endPointPacket))
						{
							ushort clientID;
							string message;
							if (endPointPacket.Packet.ReadUInt16(out clientID) && endPointPacket.Packet.ReadString(out message))
							{
								Client client;
								if (clientID == ushort.MaxValue && clients.TryGetValue(endPointPacket.EndPoint, out client))
								{
									// TODO: Remove non-visible characters
									Console.WriteLine(client.Username + ": " + message.Trim());
								}
							}
						}
						break;
					case ConsoleKey.D3:
						foreach (IPEndPoint endPoint in clients.Keys)
						{
							var packet = socket[Channels.Chat].CreatePacket();
							packet.WriteUInt16(ushort.MaxValue); // Client ID, ushort.MaxValue is the Server
							packet.WriteString("hello world");
							socket[Channels.Chat].Send(packet, endPoint);
						}
						Console.WriteLine("Messages sent");
						break;
					case ConsoleKey.D4:
						foreach (IPEndPoint endPoint in clients.Keys)
						{
							socket.Disconnect(endPoint);
						}
						Console.WriteLine("Disconnected clients");
						break;
				}
				Console.WriteLine();
				Console.WriteLine("Press any key...");
				Console.ReadKey(true);
			}
		}
	}
}