using System;
using System.Net.Sockets;
using System.Threading;
using System.Threading.Tasks;

namespace Mistox.Server {
    public class TCPConnection : IDisposable {
        
        TcpClient _client;
        TcpClientConnection _connection;

        public TCPConnection( TcpClient tcpClient, string ConnectionID ) {
            _client = tcpClient;
            _client.NoDelay = true;
            _connection = ServerInterface.Connections[ConnectionID];
            ServerInterface.ServerInstance.InvokeUserConnected( ServerInterface.Connections[ConnectionID] );
            // Start the receive thread
            Thread receiveThread = new Thread(async () => await ReceiveThread() );
            receiveThread.Start();
        }

        async Task ReceiveThread() {
            using( NetworkStream ns = _client.GetStream() ) {
                try {
                    byte[] headerBuffer = new byte[DataPacket.HeaderLength];    
                    byte[] payloadBuffer = new byte[65535];                     // Upper limit for safety
                    while( _connection.Connected ) {
                        
                        // Read the header off
                        await ns.ReadExactlyAsync(headerBuffer, 0, 3);

                        // Parse the header
                        byte packetbyte = headerBuffer[0];
                        ushort dataLength = (ushort)((headerBuffer[1] << 8) | headerBuffer[2]);

                        // Make sure the data looks valid
                        if (dataLength > payloadBuffer.Length) {
                            throw new Exception("Incoming TCP payload is too large for the pre-allocated buffer.");
                        }

                        // Read off the data
                        await ns.ReadExactlyAsync(payloadBuffer, 0, dataLength);

                        // Create the dataobject
                        dynamic dataobject = DataPacket.Deserialize( packetbyte, dataLength, payloadBuffer.AsMemory(DataPacket.HeaderLength, dataLength) );

                        // Return the object
                        ServerInterface.ServerInstance.InvokeDataReceived(dataobject);

                    }
                } catch (Exception e) {
                    ClientInterface.ServerClientInstance.Alive = false;
                    Dispose();
                    Console.WriteLine("TCP Receive exception: " + e.Message);
                }
            }
        }

        public async Task Send<T>( T packet ) {
            byte[] byteData = DataPacket.Serialize( packet );
            await _client.GetStream().WriteAsync( byteData, 0, byteData.Length );
        }

        public void Dispose() {
            _connection.Connected = false;
            ServerInterface.ServerInstance.InvokeUserDisconnected( _connection );
            ServerInterface.ServerInstance.Alive = false;
            ServerInterface.Connections.TryRemove( _connection.UserName, out _ );
        }
    }
}