refactor(chess): 重构象棋程序基础结构,使用Nullable重构核心代码

- 更新了多个文件的代码结构和类型定义，提高了代码的健壮性和可维护性
- 优化了事件处理、棋子管理和移动逻辑，为后续功能扩展打下坚实基础
- 修复了一些潜在的空指针异常问题，提高了程序的稳定性
- 修复部分bug

.gitignore

@@ -25,3 +25,10 @@ bin/
 *.sln
 *.error
 *.key*
+
+# cs project files
+!*.csproj
+
+# Test files
+Test/bin
+Test/obj

Chinese_Chess.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Godot.NET.Sdk/4.3.0">
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework Condition=" '$(GodotTargetPlatform)' == 'android' ">net7.0</TargetFramework>
+    <TargetFramework Condition=" '$(GodotTargetPlatform)' == 'ios' ">net8.0</TargetFramework>
+    <EnableDynamicLoading>true</EnableDynamicLoading>
+
+    <Nullable>enable</Nullable>
+    <!-- <TreatWarningsAsErrors>true</TreatWarningsAsErrors> -->
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Remove="Test\**\*" />
+  </ItemGroup>
+</Project>

Scripts/Lib/RPClient.cs

@@ -4,21 +4,26 @@ using Godot.Collections;
 namespace RPPackage {
 public partial class RPClientBaseEDWS : EventDrivenWebSocket {
 
-    public delegate void RPClientEventHandler(string cmd, Dictionary data);
+    public delegate void RPClientEventHandler(string cmd, Dictionary? data);
     public delegate void RPClientErrorHandler(string errCode, string type, string cmd, string errMsg);
 
-    public event RPClientEventHandler OnRPCUser;
+    public event RPClientEventHandler? OnRPCUser;
-    public event RPClientEventHandler OnRPCRegion;
+    public event RPClientEventHandler? OnRPCRegion;
-    public event RPClientEventHandler OnRPCSession;
+    public event RPClientEventHandler? OnRPCSession;
-    public event RPClientEventHandler OnRPCMsg;
+    public event RPClientEventHandler? OnRPCMsg;
-    public event RPClientErrorHandler OnRPCError;
+    public event RPClientErrorHandler? OnRPCError;
 
     public RPClientBaseEDWS() : base() {
         OnText += (text) => {
             // GD.Print($"response: {text}");
-            RPMessage msg = RPHelper.HandleIncomingMessage(text);
+            RPMessage? msg = RPHelper.HandleIncomingMessage(text);
+            if (msg == null) {
+                MakeRPCError("9999", "Unknown Msg", "Error", null);
+                return;
+            }
             if (msg.Code != "0000") {
-                OnRPCError?.Invoke(msg.Code, msg.Type, msg.Cmd, msg.Data.ToString());
+                OnRPCError?.Invoke(msg.Code ?? "9999", msg.Type, msg.Cmd,
+                        msg.Data?.ToString() ?? "");
                 return;
             }
             switch (msg.Type) {
@@ -35,32 +40,36 @@ public partial class RPClientBaseEDWS : EventDrivenWebSocket {
                     OnRPCMsg?.Invoke(msg.Cmd, msg.Data);
                     break;
                 default:
-                    OnRPCError?.Invoke(msg.Code, "unknown", msg.Cmd, msg.Data.ToString());
+                    MakeRPCError(msg.Code, "unknown", msg.Cmd, msg.Data?.ToString());
                     break;
             }
         };
     }
 
-    protected void MakeRPCError(string errCode, string type, string cmd, string errMsg) {
+    protected void MakeRPCError(string errCode, string type, string cmd, string? errMsg) {
-        this.OnRPCError?.Invoke(errCode, type, cmd, errMsg ?? "null");
+        OnRPCError?.Invoke(errCode, type, cmd, errMsg ?? "null");
     }
 }
 
 public partial class RPClientEDWS : RPClientBaseEDWS {
-    string userName;
+    string? userName;
-    string userId;
+    string? userId;
-    string userToken;
+    string? userToken;
-    string regionId;
+    string? regionId;
 
-    public string GetUserId() { return userId; }
+    public string? GetUserId() { return userId; }
     
-    public delegate void SessionRecvHandle(Dictionary msg);
+    public delegate void SessionRecvHandle(Dictionary? msg);
-    public event SessionRecvHandle OnPRCSessionRecv;
+    public event SessionRecvHandle? OnPRCSessionRecv;
 
-    public event RPClientEventHandler OnPRCSessionExit;
+    public event RPClientEventHandler? OnPRCSessionExit;
 
     public RPClientEDWS() : base() {
         OnRPCUser += (cmd, msg) => {
+            if (msg == null) {
+                MakeRPCError("0000", "User", "unknown", "unknown");
+                return;
+            }
             switch (cmd) {
                 case "init":
                     userId = msg["userId"].AsString();
@@ -113,7 +122,7 @@ public partial class RPClientEDWS : RPClientBaseEDWS {
         OnRPCMsg += (cmd, msg) => {
             switch(cmd) {
                 case "echo":
-                    GD.Print(msg["_"].AsString());
+                    GD.Print(msg?["_"].AsString());
                     break;
                 default:
                     break;
@@ -148,7 +157,7 @@ public partial class RPClientEDWS : RPClientBaseEDWS {
     }
 
     public delegate bool UserInitCallback();
-    private UserInitCallback _userInitCallback;
+    private UserInitCallback? _userInitCallback;
     public bool UserInit(string userName, string fingerPrint, UserInitCallback callback) {
         if (this.GetIsConnected() == false) {
             return false;
@@ -201,14 +210,14 @@ public partial class RPClientEDWS : RPClientBaseEDWS {
     public delegate bool RegionInspectCallback(
         Array<Dictionary<string, string>> _
     );
-    private RPClientEventHandler _regionRecvCallback;
+    private RPClientEventHandler? _regionRecvCallback;
     public bool RegionInspect(string regionId, RegionInspectCallback callback) {
         if (this.GetIsConnected() == false || this.userId == null) {
             return false;
         }
         _regionRecvCallback = null;
         _regionRecvCallback += (cmd, msg) => {
-            if (cmd != "inspect") {
+            if (cmd != "inspect" || msg == null) {
                 return;
             }
             callback(msg["_"].AsGodotArray<Dictionary<string, string>>());
@@ -228,17 +237,18 @@ public partial class RPClientEDWS : RPClientBaseEDWS {
     public delegate bool SessionAckCreateCallback(
         string sessionId,
         bool res,
-        string reqUserId,
+        string? reqUserId,
-        string reqUserName
+        string? reqUserName
     );
-    private RPClientEventHandler _sessionAckCreateCallback;
+    private RPClientEventHandler? _sessionAckCreateCallback;
     public void RegSessionAckCreateCallback(SessionAckCreateCallback recvCallback) {
         _sessionAckCreateCallback = null;
         _sessionAckCreateCallback += (cmd, msg) => {
+            if (msg == null) return;
             string sessionId = msg["sessionId"].AsString();
             bool res = msg.ContainsKey("res") && msg["res"].AsBool();
-            string reqUserId = msg.ContainsKey("reqUserId") ? msg["reqUserId"].AsString() : null;
+            string? reqUserId = msg.ContainsKey("reqUserId") ? msg["reqUserId"].AsString() : null;
-            string reqUserName = msg.ContainsKey("reqUserName") ? msg["reqUserName"].AsString() : null;
+            string? reqUserName = msg.ContainsKey("reqUserName") ? msg["reqUserName"].AsString() : null;
             recvCallback(sessionId, res, reqUserId, reqUserName);
         };
     }

Scripts/Lib/RPHelper.cs

@@ -9,12 +9,14 @@ public static class RPHelper
         return message.ToDictionary();
     }
 
-    public static RPMessage DeserializeRPMessage(Dictionary data)
+    public static RPMessage? DeserializeRPMessage(Dictionary data)
     {
-        return new RPMessage
+        if (!data.ContainsKey("type") || !data.ContainsKey("cmd")) {
-        {
+            return null;
-            Type    = data.ContainsKey("type") ? (string)data["type"] : null,
+        }
-            Cmd     = data.ContainsKey("cmd") ? (string)data["cmd"] : null,
+        return new RPMessage {
+            Type    = (string)data["type"],
+            Cmd     = (string)data["cmd"],
             Code    = data.ContainsKey("code") ? (string)data["code"] : null,
             Uid     = data.ContainsKey("uid") ? (string)data["uid"] : null,
             Token   = data.ContainsKey("token") ? (string)data["token"] : null,
@@ -28,7 +30,7 @@ public static class RPHelper
         ws.SendJsonEx(RPHelper.SerializeRPMessage(message));
     }
 
-    public static RPMessage HandleIncomingMessage(string jsonMessage)
+    public static RPMessage? HandleIncomingMessage(string jsonMessage)
     {
         var dataDict = Json.ParseString(jsonMessage).AsGodotDictionary();
         if (dataDict != null)

Scripts/Lib/RPMessage.cs

@@ -4,20 +4,21 @@ using Godot.Collections;
 namespace RPPackage {
 public class RPMessage
 {
-    public string Type { get; set; }
+    public string Type { get; set; } = string.Empty;
-    public string Cmd { get; set; }
+    public string Cmd { get; set; } = string.Empty;
-    public Dictionary Data { get; set; }
+    public Dictionary? Data { get; set; }
     
-    public string Uid { get; set; }
+    public string? Uid { get; set; }
-    public string Token { get; set; }
+    public string? Token { get; set; }
-    public string Code { get; set; }
+    public string? Code { get; set; }
     public Dictionary ToDictionary()
     {
-        var dict = new Dictionary();
+        var dict = new Dictionary {
-        if (Type != null)
+            // if (Type != null)
-            dict.Add("type", Type);
+            { "type", Type },
-        if (Cmd != null)
+            // if (Cmd != null)
-            dict.Add("cmd", Cmd);
+            { "cmd", Cmd }
+        };
         if (Data != null)
             dict.Add("data", Data);
         

Scripts/Lib/gdws.cs

@@ -2,16 +2,16 @@ using Godot;
 using Godot.Collections;
 
 public partial class EventDrivenWebSocket : WebSocketPeer {
-    public delegate void WebSocketEventHandler(string eventName, params object[] args);
+    public delegate void WebSocketEventHandler(string eventName, params object[]? args);
     public delegate void WSBinMsgEventHandler(byte[] args);
     public delegate void WSMsgEventHandler(string args);
 
-    public event WebSocketEventHandler OnOpen;
+    public event WebSocketEventHandler? OnOpen;
-    public event WSBinMsgEventHandler OnMessage;
+    public event WSBinMsgEventHandler? OnMessage;
-    public event WSMsgEventHandler OnText;
+    public event WSMsgEventHandler? OnText;
-    public event WSBinMsgEventHandler OnBinary;
+    public event WSBinMsgEventHandler? OnBinary;
-    public event WebSocketEventHandler OnClose;
+    public event WebSocketEventHandler? OnClose;
-    public event WebSocketEventHandler OnError;
+    public event WebSocketEventHandler? OnError;
 
     private bool isConnected = false;
     private bool isCloseEventFired = false;
@@ -32,7 +32,7 @@ public partial class EventDrivenWebSocket : WebSocketPeer {
     }
 
     public void ConnectToUrlEx(string url, double delayTime = 3,
-        TlsOptions tlsClientOptions = null) {
+        TlsOptions? tlsClientOptions = null) {
         if (connectingTime >= 0) {
             return;
         }

Scripts/Src/AbstractBoard.cs

@@ -6,20 +6,20 @@ using static IBoard;
 public abstract class AbstractBoard : IBoard {
     private readonly int rows;
     private readonly int cols;
-    protected readonly IPiece[,] pieces;
+    protected readonly IPiece?[,] pieces;
     protected readonly List<MoveRecord> moveRecords = new();
     protected readonly int MAX_RECORDS;
 
     public int Rows => rows;
     public int Cols => cols;
 
-    public event EventHandler<SetPieceEventArgs> OnSetPiece;
+    public event EventHandler<SetPieceEventArgs>? OnSetPiece;
-    public event EventHandler<IPiece> OnInsert;
+    public event EventHandler<IPiece>? OnInsert;
-    public event EventHandler<IPiece> OnRemove;
+    public event EventHandler<IPiece>? OnRemove;
-    public event EventHandler<MoveEventArgs> OnMove;
+    public event EventHandler<MoveEventArgs>? OnMove;
 
-    public event EventHandler<MoveRecord> OnAddRecord;
+    public event EventHandler<MoveRecord>? OnAddRecord;
-    public event EventHandler<MoveRecord> OnUndoRecord;
+    public event EventHandler<MoveRecord>? OnUndoRecord;
 
     public AbstractBoard(int rows, int cols, int maxRecords = int.MaxValue) {
         this.rows = rows;
@@ -32,15 +32,15 @@ public abstract class AbstractBoard : IBoard {
         return arrayPos.X < 0 || arrayPos.X >= Rows || arrayPos.Y < 0 || arrayPos.Y >= Cols;
     }
 
-    public virtual IPiece GetPiece(Vector2I arrayPos) {
+    public virtual IPiece? GetPiece(Vector2I arrayPos) {
         if (IsPosOutOfRange(arrayPos)) return null;
         return pieces[arrayPos.X, arrayPos.Y];
     }
 
-    public virtual IPiece SetPiece(IPiece piece, Vector2I pos) {
+    public virtual IPiece? SetPiece(IPiece? piece, Vector2I pos) {
         if (IsPosOutOfRange(pos)) return null;
         
-        IPiece oldPiece = pieces[pos.X, pos.Y];
+        IPiece? oldPiece = pieces[pos.X, pos.Y];
         pieces[pos.X, pos.Y] = piece;
         if (piece != null) piece.Pos = pos;
         // if (oldPiece != null) oldPiece.Pos = Vector2I.Zero;
@@ -64,8 +64,8 @@ public abstract class AbstractBoard : IBoard {
             return false;
         }
 
-        IPiece piece = GetPiece(from);
+        IPiece? piece = GetPiece(from);
-        if (GetPiece(to) != null && piece == null) {
+        if (GetPiece(to) != null || piece == null) {
             return false;
         }
 
@@ -75,8 +75,9 @@ public abstract class AbstractBoard : IBoard {
         return true;
     }
 
-    public virtual IPiece RemovePiece(Vector2I pos) {
+    public virtual IPiece? RemovePiece(Vector2I pos) {
-        IPiece piece = GetPiece(pos);
+        IPiece? piece = GetPiece(pos);
+        if (piece == null) return null;
         OnRemove?.Invoke(this, piece);
         return SetPiece(null, pos);
     }
@@ -96,7 +97,7 @@ public abstract class AbstractBoard : IBoard {
         moveRecords.Clear();
     }
 
-    public virtual void AddRecord(IPiece From, IPiece To, Vector2I FromPos, Vector2I ToPos) {
+    public virtual void AddRecord(IPiece? From, IPiece? To, Vector2I FromPos, Vector2I ToPos) {
         if (moveRecords.Count >= MAX_RECORDS) {
             moveRecords.RemoveAt(0);
         }
@@ -125,12 +126,12 @@ public abstract class AbstractBoard : IBoard {
     }
 
     public class MoveRecord {
-        public IPiece From { get; }
+        public IPiece? From { get; }
-        public IPiece To { get; }
+        public IPiece? To { get; }
         public Vector2I FromPos { get; }
         public Vector2I ToPos { get; }
 
-        public MoveRecord(IPiece From, IPiece To, Vector2I FromPos, Vector2I ToPos) {
+        public MoveRecord(IPiece? From, IPiece? To, Vector2I FromPos, Vector2I ToPos) {
             this.From = From;
             this.To = To;
             this.ToPos = ToPos;

Scripts/Src/AbstractPiece.cs

@@ -46,10 +46,10 @@ public abstract class AbstractPiece : IPiece {
         set => data = value;
     }
 
-    public event EventHandler<Vector2I> OnPos;
+    public event EventHandler<Vector2I>? OnPos;
-    public event EventHandler<Vector2I> OnMove;
+    public event EventHandler<Vector2I>? OnMove;
-    public event EventHandler<bool> OnSelected;
+    public event EventHandler<bool>? OnSelected;
-    public event EventHandler<string> OnName;
+    public event EventHandler<string>? OnName;
 
     public virtual bool Move(Vector2I pos) {
         if (!CanMove(pos)) {
@@ -66,7 +66,7 @@ public abstract class AbstractPiece : IPiece {
         return $"{Name} at {pos}";
     }
 
-    public AbstractPiece(string name = "", Vector2I pos = null) {
+    public AbstractPiece(string name = "", Vector2I? pos = null) {
         this.name = name;
         this.pos = pos ?? new();
     }

Scripts/Src/ChineseChess/CCBoard.cs

@@ -6,7 +6,7 @@ using Vector2I = Vector.Vector2I;
 namespace ChineseChess;
 public class CCBoard : AbstractBoard
 {
-    public event EventHandler<int> OnStepsChanged;
+    public event EventHandler<int>? OnStepsChanged;
     private int steps = 0;
     public int Steps {
         get => steps;
@@ -20,7 +20,7 @@ public class CCBoard : AbstractBoard
     public CCBoard() : base(9, 10) {
     }
 
-    public override void AddRecord(IPiece From, IPiece To, Vector2I FromPos, Vector2I ToPos) {
+    public override void AddRecord(IPiece? From, IPiece? To, Vector2I FromPos, Vector2I ToPos) {
         base.AddRecord(From, To, FromPos, ToPos);
         Steps += 1;
     }

Scripts/Src/ChineseChess/CCMain.cs

@@ -33,12 +33,19 @@ public class ChessCore {
         playerSelf = new(board, Player.PlayerType.Human);
         playerOpponent = new(board, Player.PlayerType.Human);
 
-        void func(object _self, IBoard.MoveEventArgs record) {
+        void func(object? _self, IBoard.MoveEventArgs record) {
             // 防止 Undo 时 Selected Clear 出现 Null Pointer Exception
             playerSelf.SelectedClear();
             playerOpponent.SelectedClear();
-            board.AddRecord(board.GetPiece(record.From), board.GetPiece(record.To),
+
-                record.From, record.To);
+            // TODO FIXME it can be simple
+            if (record.From is null || record.To is null) {
+                return;
+            }
+
+            IPiece? from = record.From is not null ? board.GetPiece(record.From) : null;
+            IPiece? to = record.To is not null ? board.GetPiece(record.To) : null; 
+            board.AddRecord(from, to, record.From ?? new(), record.To ?? new());
         }
         playerSelf.OnMove += func;
         playerOpponent.OnMove += func;

Scripts/Src/ChineseChess/CCPiece.cs

@@ -7,7 +7,7 @@ using Vector;
 using static ChineseChess.ChessCore;
 
 public class CCPiece : AbstractPiece {
-    public string CNName { get; protected set; }
+    public string CNName { get; protected set; } = "unknown";
     public TurnsSideType TurnsSide { get; }
     protected CCBoard board;
     protected Vector2I localPos = new();
@@ -16,14 +16,15 @@ public class CCPiece : AbstractPiece {
         new(new Vector2I(1, 0), new Vector2I(0, -1), new Vector2I(-4, 9));
     static readonly Trans2DI transBlackGlobal2Local =
         new(new Vector2I(-1, 0), new Vector2I(0, 1), new Vector2I(4, 0));
-    public CCPiece(CCBoard board = null, TurnsSideType turnsSide = TurnsSideType.Red,
+    public CCPiece(CCBoard? board = null, TurnsSideType turnsSide = TurnsSideType.Red,
-            string name = "", Vector2I pos = null) : base(name) {
+            string name = "", Vector2I? pos = null) : base(name) {
-        this.board = board;
+        this.board = board ?? new();
         TurnsSide = turnsSide;
         OnPos += (sender, args) => {
             localPos = Global2Local(Pos);
         };
-        Pos = pos != null ? Local2Global(pos) : Vector2I.Zero;
+        Pos = pos is not null ? Local2Global(pos) : Vector2I.Zero;
+        localPos = Global2Local(Pos);
     }
 
     public override bool CanMove(Vector2I to) {
@@ -38,8 +39,8 @@ public class CCPiece : AbstractPiece {
         return TurnsSide == TurnsSideType.Red ? (transRedGlobal2Local * pos) : (transBlackGlobal2Local * pos);
     }
 
-    protected CCPiece GetCCPieceLocal(in Vector2I pos) {
+    protected CCPiece? GetCCPieceLocal(in Vector2I pos) {
-        return (CCPiece)board.GetPiece(Local2Global(pos));
+        return (CCPiece?)board.GetPiece(Local2Global(pos));
     }
 
     public virtual List<Vector2I> CanMoveAllPosSelf() {
@@ -49,7 +50,8 @@ public class CCPiece : AbstractPiece {
     public IEnumerable<Vector2I> CanMoveAllPosLocal() {
         var self = CanMoveAllPosSelf().Select(item => item + localPos);// 转换局部坐标
         var ret = self.Where(item => {
-            bool ret = GetCCPieceLocal(item) == null || GetCCPieceLocal(item).TurnsSide != TurnsSide;
+            CCPiece? piece = GetCCPieceLocal(item);
+            bool ret = piece is null || piece.TurnsSide != TurnsSide;
             // Console.WriteLine($"{item} can move: {ret}");
             return ret;
         });  // 过滤无效位置
@@ -71,7 +73,7 @@ public class CCPiece : AbstractPiece {
         return board.IsPosOutOfRange(Local2Global(pos));
     }
 
-    protected CCPiece GetRecursivePieceLocal(Vector2I origin, Vector2I pos) {
+    protected CCPiece? GetRecursivePieceLocal(Vector2I origin, Vector2I pos) {
         Vector2I with = origin + pos;
         while (!IsPosOutOfRangeLocal(with) && GetCCPieceLocal(with) == null) {
             with += pos;

Scripts/Src/ChineseChess/CCPlayer.cs

@@ -7,7 +7,7 @@ public class Player {
 	private readonly CCBoard board;
 	private readonly SelectedPiece selectedNode;
 	
-	public EventHandler<IBoard.MoveEventArgs> OnMove;
+	public EventHandler<IBoard.MoveEventArgs>? OnMove;
 	public bool CanMove { get; set; } = true;
 
 	public enum PlayerType {
@@ -24,7 +24,7 @@ public class Player {
 	public void HandleBoardPosClick(Vector2I clickPos) {
 		if (board.IsPosOutOfRange(clickPos)) return;
 		// Console.WriteLine($"VirtualBoard {clickPos} clicked");
-		IPiece clickChess = board.GetPiece(clickPos);
+		IPiece? clickChess = board.GetPiece(clickPos);
 
 		if (!selectedNode.HasSelected()) {
 			// Select piece
@@ -45,9 +45,10 @@ public class Player {
 
 	public void MoveAndRecord(Vector2I toPos, Vector2I fromPos) {
 		// GD.Print($"{fromPos} move to {toPos}");
-		IPiece toChess = board.GetPiece(toPos);
+		IPiece? toChess = board.GetPiece(toPos);
-        IPiece fromChess = board.GetPiece(fromPos);
+        IPiece? fromChess = board.GetPiece(fromPos);
 		if (fromChess != null) fromChess.IsSelected = false;
+		else return;
 		
 		selectedNode.Clear();
 		if (!fromChess.CanMove(toPos)) {
@@ -55,7 +56,8 @@ public class Player {
 		}
 
 		// MUST BE THERE !!! 防止删除节点后在启动回调导致错误
-		OnMove?.Invoke(this, new IBoard.MoveEventArgs { From = fromPos, To = toPos });
+		OnMove?.Invoke(this, new IBoard.MoveEventArgs
+			{ From = fromPos, To = toPos, Piece = fromChess });;
 
         if (toChess != null) {
             board.RemovePiece(toPos);
@@ -76,9 +78,9 @@ public class Player {
 	private class SelectedPiece {
 		// Called when the node enters the scene tree for the first time.
 		private Vector2I selectedNodePos = Vector2I.MaxValue;
-		private IPiece piece;
+		private IPiece? piece = null;
 		private readonly CCBoard board;
-		public ArrayList allowedPieces = null;
+		public ArrayList? allowedPieces = null;
 
 		public SelectedPiece(CCBoard board) {
 			this.board = board;
@@ -87,6 +89,7 @@ public class Player {
 		public void Clear() {
 			if (selectedNodePos != Vector2I.MaxValue) {
 				selectedNodePos = Vector2I.MaxValue;
+				if (piece != null)
 					piece.IsSelected = false;
 			}
 			// Console.WriteLine("SelectedPiece.Clear {0}", piece);
@@ -98,11 +101,13 @@ public class Player {
 				return;
 			}
 			selectedNodePos = pos;
+			if (piece == null)
+				return;
 			piece.IsSelected = true;
 			Console.WriteLine("SelectedPiece.SetPos {0}", piece);
 		}
 
-		public IPiece GetPiece() {
+		public IPiece? GetPiece() {
 			return piece;
 		}
 

Scripts/Src/ChineseChess/CCTypes.cs

@@ -4,7 +4,7 @@ using Vector2I = Vector.Vector2I;
 
 namespace ChineseChess;
 public class CCGeneral : CCPiece {
-    public CCGeneral(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCGeneral(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "General", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "帅";
@@ -31,7 +31,7 @@ public class CCGeneral : CCPiece {
 }
 
 public class CCAdvisor : CCPiece {
-    public CCAdvisor(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCAdvisor(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "Advisor", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "仕";
@@ -58,7 +58,7 @@ public class CCAdvisor : CCPiece {
 }
 
 public class CCElephant : CCPiece {
-    public CCElephant(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCElephant(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "Bishop", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "相";
@@ -85,7 +85,7 @@ public class CCElephant : CCPiece {
 }
 
 public class CCHorse : CCPiece {
-    public CCHorse(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCHorse(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "Horse", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "馬";
@@ -125,7 +125,7 @@ public class CCHorse : CCPiece {
 }
 
 public class CCChariot : CCPiece {
-    public CCChariot(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCChariot(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "Chariot", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "車";
@@ -145,7 +145,7 @@ public class CCChariot : CCPiece {
                     break;
                 }
                 if (GetCCPieceLocal(ptr) != null) {
-                    list.Add(ptr);
+                    list.Add(ptr - localPos);
                     break;
                 }
                 list.Add(ptr - localPos);
@@ -161,7 +161,7 @@ public class CCChariot : CCPiece {
 }
 
 public class CCCannon : CCPiece {
-    public CCCannon(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCCannon(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "Cannon", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "砲";
@@ -202,7 +202,7 @@ public class CCCannon : CCPiece {
 }
 
 public class CCPawn : CCPiece {
-    public CCPawn(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I pos = null)
+    public CCPawn(CCBoard board, TurnsSideType turnsSide = TurnsSideType.Red, Vector2I? pos = null)
     : base(board, turnsSide, name : "Pawn", pos) {
         if (turnsSide == TurnsSideType.Red) {
             CNName = "兵";

Scripts/Src/IBoard.cs

@@ -6,15 +6,15 @@ public interface IBoard {
     public int Cols { get; }
 
     public class SetPieceEventArgs : EventArgs {
-        public IPiece OldPiece { get; set; }
+        public IPiece? OldPiece { get; set; }
-        public IPiece NewPiece { get; set; }
+        public IPiece? NewPiece { get; set; }
-        public Vector2I Pos { get; set; }
+        public Vector2I Pos { get; set; } = new();
     }
 
     public class MoveEventArgs : EventArgs {
-        public IPiece Piece { get; set; }
+        public IPiece? Piece { get; set; }
-        public Vector2I From { get; set; }
+        public Vector2I From { get; set; } = new();
-        public Vector2I To { get; set; }
+        public Vector2I To { get; set; } = new();
     }
 
     event EventHandler<IPiece> OnInsert;
@@ -23,10 +23,10 @@ public interface IBoard {
     event EventHandler<SetPieceEventArgs> OnSetPiece;
 
     bool IsPosOutOfRange(Vector2I pos);
-    IPiece GetPiece(Vector2I pos);
+    IPiece? GetPiece(Vector2I pos);
-    IPiece SetPiece(IPiece piece, Vector2I pos);
+    IPiece? SetPiece(IPiece piece, Vector2I pos);
     bool InsertPiece(IPiece piece, Vector2I pos);
     bool MovePiece(Vector2I from, Vector2I to);
-    IPiece RemovePiece(Vector2I pos);
+    IPiece? RemovePiece(Vector2I pos);
     void Clear();
 }

Scripts/Src/Vector.cs

@@ -51,7 +51,7 @@ public class Vector2I {
         return X * with.X + Y * with.Y;
     }
 
-    public override bool Equals(object obj) {
+    public override bool Equals(object? obj) {
         if (obj is Vector2I other) {
             return this == other;
         }

Test/Test.csproj

@@ -0,0 +1,31 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="NUnit.Framework" />
+  </ItemGroup>
+
+  <!-- <ItemGroup>
+    <ProjectReference Include="..\Chinese_Chess.csproj" />
+  </ItemGroup> -->
+  <ItemGroup>
+    <Compile Include="..\Scripts\Src\*.cs" />
+  </ItemGroup>
+
+</Project>

Test/UnitTest1.cs

@@ -0,0 +1,16 @@
+using Vector;
+
+namespace Test;
+public class Tests
+{
+    [SetUp]
+    public void Setup()
+    {
+    }
+
+    [Test]
+    public void Test1()
+    {
+        Assert.Pass();
+    }
+}

Test/src/TestVector.cs

@@ -0,0 +1,93 @@
+using Vector;
+namespace Test;
+public class TestsVector
+{
+    [SetUp]
+    public void Setup()
+    {
+    }
+
+    [Test]
+    public void Test1()
+    {
+        Assert.Pass();
+    }
+
+    [Test]
+    public void TestVector2I_Constructors()
+    {
+        // Arrange & Act
+        var v1 = new Vector2I();
+        var v2 = new Vector2I(1, 2);
+        var v3 = new Vector2I(v2);
+
+        // Assert
+        Assert.That(v1.X, Is.EqualTo(0));
+        Assert.That(v1.Y, Is.EqualTo(0));
+        Assert.That(v2.X, Is.EqualTo(1));
+        Assert.That(v2.Y, Is.EqualTo(2));
+        Assert.That(v3.X, Is.EqualTo(1));
+        Assert.That(v3.Y, Is.EqualTo(2));
+    }
+
+    [Test]
+    public void TestVector2I_Operators()
+    {
+        // Arrange
+        var v1 = new Vector2I(1, 2);
+        var v2 = new Vector2I(3, 4);
+
+        // Act
+        var v3 = v1 + v2;
+        var v4 = v1 - v2;
+        var v5 = v1 * v2;
+
+        // Assert
+        Assert.That(v3, Is.EqualTo(new Vector2I(4, 6)));
+        Assert.That(v4, Is.EqualTo(new Vector2I(-2, -2)));
+        Assert.That(v5, Is.EqualTo(new Vector2I(3, 8)));
+    }
+
+    [Test]
+    public void TestTrans2DI_Constructors()
+    {
+        // Arrange & Act
+        var t1 = new Trans2DI();
+        var t2 = new Trans2DI(new Vector2I(1, 0), new Vector2I(0, 1), new Vector2I(0, 0));
+        var t3 = new Trans2DI(t2);
+        var t4 = new Trans2DI(1, 0, 0, 1, 0, 0);
+
+        // Assert
+        Assert.That(t1.XAxis, Is.EqualTo(new Vector2I(1, 0)));
+        Assert.That(t1.YAxis, Is.EqualTo(new Vector2I(0, 1)));
+        Assert.That(t1.Origin, Is.EqualTo(new Vector2I(0, 0)));
+
+        Assert.That(t2.XAxis, Is.EqualTo(new Vector2I(1, 0)));
+        Assert.That(t2.YAxis, Is.EqualTo(new Vector2I(0, 1)));
+        Assert.That(t2.Origin, Is.EqualTo(new Vector2I(0, 0)));
+
+        Assert.That(t3.XAxis, Is.EqualTo(new Vector2I(1, 0)));
+        Assert.That(t3.YAxis, Is.EqualTo(new Vector2I(0, 1)));
+        Assert.That(t3.Origin, Is.EqualTo(new Vector2I(0, 0)));
+
+        Assert.That(t4.XAxis, Is.EqualTo(new Vector2I(1, 0)));
+        Assert.That(t4.YAxis, Is.EqualTo(new Vector2I(0, 1)));
+        Assert.That(t4.Origin, Is.EqualTo(new Vector2I(0, 0)));
+    }
+
+    [Test]
+    public void TestTrans2DI_Operators()
+    {
+        // Arrange
+        var t1 = new Trans2DI(new Vector2I(1, 0), new Vector2I(0, 1), new Vector2I(1, 2));
+        var v1 = new Vector2I(3, 4);
+
+        // Act
+        var v2 = t1 * v1;
+        var v3 = v1 * t1;
+
+        // Assert
+        Assert.That(v2, Is.EqualTo(new Vector2I(4, 6)));
+        Assert.That(v3, Is.EqualTo(new Vector2I(2, 2)));
+    }
+}