using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;

namespace Syroot.Worms.Mgame.GameServer
{
    /// <summary>
    /// Represents a server listening for incoming client connections and dispatching them into <see cref="Client"/>
    /// instances.
    /// </summary>
    internal class Server
    {
        // ---- FIELDS -------------------------------------------------------------------------------------------------

        private readonly List<Client> _clients = new List<Client>();

        // ---- CONSTRUCTORS & DESTRUCTOR ------------------------------------------------------------------------------

        internal Server()
        {
            // Create and read the configuration.
            Config = new ConfigurationBuilder()
                .AddJsonFile("ServerConfig.json", true)
                .Build()
                .Get<Config>();
        }

        // ---- PROPERTIES ---------------------------------------------------------------------------------------------

        internal Config Config { get; }

        internal Log Log { get; } = new Log();

        // ---- METHODS (INTERNAL) -------------------------------------------------------------------------------------

        /// <summary>
        /// Starts the server by accepting new client connections under the given <paramref name="port"/> and
        /// dispatching them into asynchronous handling threads. This call is blocking.
        /// </summary>
        /// <param name="port">The port on which to listen for new client connections.</param>
        internal void Listen()
        {
            TcpListener tcpListener = new TcpListener(IPAddress.Any, Config.Port);
            tcpListener.Start();
            Log.Write(LogCategory.Server, $"Listening on {Config.EndPoint}...");

            while (true)
            {
                // Continually accept clients.
                TcpClient tcpClient = tcpListener.AcceptTcpClient();
                Log.Write(LogCategory.Connect, $"{tcpClient.Client.RemoteEndPoint} connected");
                Client client = new Client(tcpClient, this);
                _clients.Add(client);

                // Dispatch the client into its listening thread and remove it when listening aborts.
                Task.Run(client.Listen).ContinueWith(_ =>
                {
                    Log.Write(LogCategory.Disconnect, $"{client.TcpClient.Client.RemoteEndPoint} disconnected");
                    _clients.Remove(client);
                    client.Dispose();
                });
            }
        }
    }
}