Implement preconditions check on connecting (#9)

Author: hibo98

CS2M.API/Networking/Player.cs

@@ -24,7 +24,7 @@ protected set
             }
         }
 
-        private PlayerType _playerType;
+        private PlayerType _playerType = PlayerType.NONE;
         public PlayerType PlayerType
         {
             get => _playerType;

CS2M.API/Networking/PlayerStatus.cs

@@ -17,7 +17,7 @@ public enum PlayerStatus
         GET_SERVER_INFO,
 
         /// <summary>
-        /// The client is trying to connect NAT punchthrough to coonect to the server
+        /// The client is trying to connect through NAT hole punching to the server
         /// </summary>
         NAT_CONNECT,
 
@@ -26,6 +26,16 @@ public enum PlayerStatus
         /// </summary>
         DIRECT_CONNECT,
 
+        /// <summary>
+        /// The client connected on network level, but has not joined the game
+        /// </summary>
+        CONNECTION_ESTABLISHED,
+
+        /// <summary>
+        /// The client fulfilled all preconditions and is waiting to join the game
+        /// </summary>
+        WAITING_TO_JOIN,
+
         /// <summary>
         /// The player is connected and downloading the map/save from
         /// the server
@@ -45,8 +55,8 @@ public enum PlayerStatus
         PLAYING,
 
         /// <summary>
-        /// The player is blocked from interacting with the game
+        /// The players game is blocked, because a new player is joining or a resync is in progress
         /// </summary>
-        BLOCKED
+        BLOCKED,
     }
 }

CS2M.API/Networking/PlayerType.cs

@@ -2,6 +2,7 @@
 {
     public enum PlayerType
     {
+        NONE,
         CLIENT,
         SERVER,
     }

CS2M/Commands/CommandInternal.cs

@@ -125,6 +125,11 @@ public byte[] Serialize(CommandBase command)
             return MessagePackSerializer.Serialize(command, _model);
         }
 
+        public CommandBase Deserialize(byte[] bytes)
+        {
+            return MessagePackSerializer.Deserialize<CommandBase>(bytes, _model);
+        }
+
         public void RefreshModel()
         {
             _cmdMapping.Clear();

CS2M/Commands/Data/Internal/PreconditionsCheckCommand.cs

@@ -0,0 +1,17 @@
+namespace CS2M.Commands.Data.Internal
+{
+    public class PreconditionsCheckCommand : PreconditionsDataCommand
+    {
+        /// <summary>
+        ///     The username this user will be playing as, important
+        ///     as the server will keep track of this user.
+        /// </summary>
+        public string Username { get; set; }
+
+        /// <summary>
+        ///     An optional password if the server is set up to
+        ///     require a password.
+        /// </summary>
+        public string Password { get; set; }
+    }
+}

CS2M/Commands/Data/Internal/PreconditionsDataCommand.cs

@@ -0,0 +1,28 @@
+using System.Collections.Generic;
+using CS2M.API.Commands;
+
+namespace CS2M.Commands.Data.Internal
+{
+    public abstract class PreconditionsDataCommand : CommandBase
+    {
+        /// <summary>
+        ///     What version of the mod the sender has installed.
+        /// </summary>
+        public System.Version ModVersion { get; set; }
+
+        /// <summary>
+        ///     What version of the game the sender is running.
+        /// </summary>
+        public Colossal.Version GameVersion { get; set; }
+
+        /// <summary>
+        ///     A list of mods with multiplayer support that were loaded.
+        /// </summary>
+        public List<string> Mods { get; set; }
+
+        /// <summary>
+        ///     A list of DLCs that were loaded.
+        /// </summary>
+        public List<int> DlcIds { get; set; }
+    }
+}

CS2M/Commands/Data/Internal/PreconditionsErrorCommand.cs

@@ -0,0 +1,12 @@
+using CS2M.Util;
+
+namespace CS2M.Commands.Data.Internal
+{
+    public class PreconditionsErrorCommand : PreconditionsDataCommand
+    {
+        /// <summary>
+        ///     A bitfield of errors from preconditions checking (can be multiple)
+        /// </summary>
+        public PreconditionsUtil.Errors Errors { get; set; }
+    }
+}

CS2M/Commands/Data/Internal/PreconditionsSuccessCommand.cs

@@ -0,0 +1,8 @@
+using CS2M.API.Commands;
+
+namespace CS2M.Commands.Data.Internal
+{
+    public class PreconditionsSuccessCommand : CommandBase
+    {
+    }
+}

CS2M/Commands/Handler/Internal/PreconditionsCheckHandler.cs

@@ -0,0 +1,67 @@
+using System.Collections.Generic;
+using System.Linq;
+using CS2M.API.Commands;
+using CS2M.API.Networking;
+using CS2M.Commands.Data.Internal;
+using CS2M.Mods;
+using CS2M.Networking;
+using CS2M.Util;
+using LiteNetLib;
+
+namespace CS2M.Commands.Handler.Internal
+{
+    public class PreconditionsCheckHandler : CommandHandler<PreconditionsCheckCommand>
+    {
+        public PreconditionsCheckHandler()
+        {
+            TransactionCmd = false;
+        }
+
+        protected override void Handle(PreconditionsCheckCommand command)
+        {
+        }
+
+        public void HandleOnServer(PreconditionsCheckCommand command, NetPeer peer)
+        {
+            Log.Debug($"Received Preconditions Check [PeerId: {peer.Id}]");
+
+            PreconditionsUtil.Result result = PreconditionsUtil.CheckPreconditions(command);
+
+            // Check the client username to see if anyone on the server already have a username
+            if (NetworkInterface.Instance.PlayerListConnected.Any(p => p.Username.Equals(command.Username)))
+            {
+                Log.Debug($"[Preconditions Check] Username '{command.Username}' is already connected.");
+                result.Errors |= PreconditionsUtil.Errors.USERNAME_NOT_AVAILABLE;
+            }
+
+            // Check the password to see if it matches (only if the server has provided a password).
+            if (!string.IsNullOrEmpty(NetworkInterface.Instance.LocalPlayer.GetConnectionPassword()))
+            {
+                if (!NetworkInterface.Instance.LocalPlayer.GetConnectionPassword().Equals(command.Password))
+                {
+                    Log.Debug($"[Preconditions Check] Password '{command.Password}' is not correct.");
+                    result.Errors |= PreconditionsUtil.Errors.PASSWORD_INCORRECT;
+                }
+            }
+
+            if (result.Errors == PreconditionsUtil.Errors.NONE)
+            {
+                NetworkInterface.Instance.LocalPlayer.SendToClient(peer, new PreconditionsSuccessCommand());
+
+                // Add the new player as a connected player
+                NetworkInterface.Instance.PlayerConnected(new RemotePlayer(peer, command.Username, PlayerType.CLIENT));
+            }
+            else
+            {
+                NetworkInterface.Instance.LocalPlayer.SendToClient(peer, new PreconditionsErrorCommand()
+                {
+                    Errors = result.Errors,
+                    ModVersion = VersionUtil.GetModVersion(),
+                    GameVersion = VersionUtil.GetGameVersion(),
+                    Mods = ModSupport.Instance.RequiredModsForSync,
+                    DlcIds = new List<int>(), //TODO: Update with correct DLC List
+                });
+            }
+        }
+    }
+}

CS2M/Commands/Handler/Internal/PreconditionsErrorHandler.cs

@@ -0,0 +1,21 @@
+using CS2M.API.Commands;
+using CS2M.Commands.Data.Internal;
+using CS2M.Networking;
+
+namespace CS2M.Commands.Handler.Internal
+{
+    public class PreconditionsErrorHandler : CommandHandler<PreconditionsErrorCommand>
+    {
+        public PreconditionsErrorHandler()
+        {
+            TransactionCmd = false;
+        }
+
+        protected override void Handle(PreconditionsErrorCommand command)
+        {
+            Log.Debug($"[Preconditions Error] {command.Errors.ToString()}");
+            
+            NetworkInterface.Instance.LocalPlayer.Inactive();
+        }
+    }
+}