using System;
using R3;
using RebootKit.Engine.Foundation;
using RebootKit.Engine.Main;
using RebootKit.Engine.Multiplayer;
using Steamworks;
using Steamworks.Data;
using Logger = RebootKit.Engine.Foundation.Logger;

namespace RebootKit.Engine.Steam {
    class SteamNetworkTransport : INetworkTransport {
        static readonly Logger s_Logger = new Logger(nameof(SteamNetworkTransport));
        
        const int k_DefaultPort = 420;

        ServerCallbacks m_SocketManager;
        ClientCallbacks m_ConnectionManager;
        IDisposable m_TickDisposable;
        
        SteamId m_HostSteamID;

        public void Initialize() {
            m_TickDisposable = Observable.EveryUpdate()
                                         .Subscribe(_ => Tick());

            SteamNetworkingUtils.DebugLevel = NetDebugOutput.Debug;

            SteamNetworkingSockets.OnConnectionStatusChanged += OnConnectionStatusChanged;
            SteamNetworkingUtils.OnDebugOutput += OnSteamNetworkDebugOutput;
            
            SteamNetworkingUtils.InitRelayNetworkAccess();
        }

        public void Shutdown() {
            Disconnect();
            
            SteamNetworkingUtils.OnDebugOutput -= OnSteamNetworkDebugOutput;
            SteamNetworkingSockets.OnConnectionStatusChanged -= OnConnectionStatusChanged;
 
            m_TickDisposable.Dispose();
        }
        
        public bool IsServer() {
            return m_SocketManager != null;
        }
        
        public bool IsClient() {
            return m_ConnectionManager != null;
        }

        public bool StartServer() {
            Disconnect();

            s_Logger.Info("Creating server...");

            try {
                m_HostSteamID = SteamNetworkingSockets.Identity.SteamId;
                
                m_SocketManager = SteamNetworkingSockets.CreateRelaySocket<ServerCallbacks>(k_DefaultPort);
                m_ConnectionManager = SteamNetworkingSockets.ConnectRelay<ClientCallbacks>(m_HostSteamID, k_DefaultPort);
            } catch (Exception e) {
                s_Logger.Error($"Failed to create server: {e.Message}");
                m_SocketManager = null;
                m_ConnectionManager = null;

                return false;
            }

            return true;
        }

        public void StopServer() {
            Disconnect();
        }

        public bool Connect(ulong serverID) {
            if (IsServer()) {
                s_Logger.Error("Cannot connect to a server while running as a server.");
                return false;
            }

            Disconnect();

            s_Logger.Info("Connecting to server with steam ID: " + serverID);
            try {
                m_ConnectionManager = SteamNetworkingSockets.ConnectRelay<ClientCallbacks>(serverID, k_DefaultPort);
                m_HostSteamID = serverID;
            } catch (Exception e) {
                s_Logger.Error($"Failed to connect to server with ID {serverID}: {e.Message}");
                m_ConnectionManager = null;

                return false;
            }

            return true;
        }

        public void Disconnect() {
            if (m_ConnectionManager != null) {
                s_Logger.Info("Disconnecting from the server...");
                m_ConnectionManager.Close();
                m_ConnectionManager = null;
            }

            if (m_SocketManager != null) {
                s_Logger.Info("Shutting down the server...");
                m_SocketManager.Close();
                m_SocketManager = null;
            }
        }

        public void Send(ulong clientID, ArraySegment<byte> data, SendMode mode) {
            if (clientID == 0) {
                clientID = m_HostSteamID;
            }
            
        }

        void OnSteamNetworkDebugOutput(NetDebugOutput level, string message) {
            LogLevel logLevel = level switch {
                NetDebugOutput.Debug => LogLevel.Debug,
                NetDebugOutput.Msg => LogLevel.Info,
                NetDebugOutput.Warning => LogLevel.Warning,
                NetDebugOutput.Error => LogLevel.Error,
                _ => LogLevel.Info
            };

            s_Logger.Log(logLevel, message);
        }

        void Tick() {
            m_SocketManager?.Receive();
            m_ConnectionManager?.Receive();
        }

        void OnConnectionStatusChanged(Connection connection, ConnectionInfo info) {
            s_Logger.Info($"OnConnectionStatusChanged: {connection.Id} - {info.Identity} - Status: {info.State}");
        }

        class ServerCallbacks : SocketManager {
            public override void OnConnecting(Connection connection, ConnectionInfo data) {
                base.OnConnecting(connection, data);
                connection.Accept();

                s_Logger.Info($"OnConnecting: {connection.Id} - {data.Identity}");
            }

            public override void OnConnected(Connection connection, ConnectionInfo data) {
                base.OnConnected(connection, data);

                s_Logger.Info($"OnConnected: {connection.Id} - {data.Identity}");

                connection.SendMessage(new byte[] {
                    0xBE,
                    0xFE,
                    0x00,
                    0x00
                }, 0, 4, 0);
            }

            public override void OnDisconnected(Connection connection, ConnectionInfo data) {
                base.OnDisconnected(connection, data);

                s_Logger.Info($"OnDisconnected: {connection.Id} - {data.Identity}");
            }

            public override void OnMessage(Connection connection,
                                           NetIdentity identity,
                                           IntPtr data,
                                           int size,
                                           long messageNum,
                                           long recvTime,
                                           int channel) {
                base.OnMessage(connection, identity, data, size, messageNum, recvTime, channel);

                byte[] buffer = new byte[size];
                System.Runtime.InteropServices.Marshal.Copy(data, buffer, 0, size);
                RR.OnServerDataReceived(buffer);

                s_Logger.Info($"OnMessage: {connection.Id} - {identity} - Size: {size} - Channel: {channel}");
            }
        }

        class ClientCallbacks : ConnectionManager {
            public override void OnConnected(ConnectionInfo info) {
                base.OnConnected(info);
                s_Logger.Info("ConnectionOnConnected");
            }

            public override void OnConnecting(ConnectionInfo info) {
                base.OnConnecting(info);
                s_Logger.Info("ConnectionOnConnecting");
            }

            public override void OnDisconnected(ConnectionInfo info) {
                base.OnDisconnected(info);
                s_Logger.Info("ConnectionOnDisconnected");
            }

            public override void OnMessage(IntPtr data, int size, long messageNum, long recvTime, int channel) {
                byte[] buffer = new byte[size];
                System.Runtime.InteropServices.Marshal.Copy(data, buffer, 0, size);
                RR.OnClientDataReceived(buffer);

                s_Logger.Info($"OnMessage: Size: {size} - Channel: {channel}");
            }
        }
    }
}