Add helper functions and fix the bug that replayed the move sent from the server.

lib/chess_bloc/chess_position.dart

@@ -1,12 +1,16 @@
 import 'dart:developer';
 
+import 'package:flutter/material.dart';
 import 'package:mchess/utils/chess_utils.dart';
 
 typedef ChessPositionType = Map<ChessCoordinate, ChessPiece>;
+typedef ChessMoveHistory = List<ChessMove>;
 
 class ChessPosition {
   static final ChessPosition _instance = ChessPosition._internal();
-  late ChessPositionType position;
+  final ChessPositionType position;
+
+  ChessMoveHistory history = ChessMoveHistory.empty(growable: true);
 
   static ChessPosition getInstance() {
     return _instance;
@@ -62,11 +66,17 @@ class ChessPosition {
   }
 
   ChessPositionType get currentPosition => position;
+  ChessMove get lastMove => history.last;
 
   void recordMove(ChessCoordinate from, ChessCoordinate to) {
     position[to] = position[from] ?? const ChessPiece.none();
     position[from] = const ChessPiece.none();
+
+    history.add(ChessMove(from: from, to: to));
+
     logPosition(position);
+
+    logHistory(history);
   }
 
   void logPosition(ChessPositionType p) {
@@ -86,4 +96,10 @@ class ChessPosition {
 
     log(logString);
   }
+
+  void logHistory(ChessMoveHistory hist) {
+    hist.forEach((element) {
+      log('${element.from.toAlphabetical()} -> ${element.to.toAlphabetical()}');
+    });
+  }
 }

lib/connection/ws_connection.dart

@@ -1,7 +1,7 @@
 import 'dart:developer';
-import 'package:flutter/foundation.dart';
 import 'package:mchess/chess_bloc/chess_bloc.dart';
 import 'package:mchess/chess_bloc/chess_events.dart';
+import 'package:mchess/chess_bloc/chess_position.dart';
 import 'package:mchess/utils/chess_utils.dart';
 import 'package:web_socket_channel/web_socket_channel.dart';
 
@@ -64,11 +64,17 @@ class ServerConnection {
       if (splitString[0] == ('mv')) {
         var startSquare = ChessCoordinate.fromString(splitString[1]);
         var endSquare = ChessCoordinate.fromString(splitString[2]);
+        if (ChessMove(from: startSquare, to: endSquare) ==
+            ChessPosition.getInstance().lastMove) {
+          //This is our own move that got resent by the server. Do not process.
+        } else {
+          log('lastMove: from: ${ChessPosition.getInstance().lastMove.from} to: ${ChessPosition.getInstance().lastMove.to}');
+          log('constructed move: from: $startSquare to: $endSquare)}');
+          log('Move received : ${startSquare.toAlphabetical()}:${endSquare.toAlphabetical()}');
 
-        log('Move received : ${splitString[1]}:${splitString[2]}');
-
-        ChessBloc.getInstance().add(
-            OpponentPieceMoved(startSquare: startSquare, endSquare: endSquare));
+          ChessBloc.getInstance().add(OpponentPieceMoved(
+              startSquare: startSquare, endSquare: endSquare));
+        }
       }
     });
   }

lib/utils/chess_utils.dart

@@ -91,6 +91,23 @@ class ChessCoordinate {
     return '$colStr$rowStr';
   }
 
+  String toAlphabetical() {
+    Map<int, String> columnMap = {
+      1: "a",
+      2: "b",
+      3: "c",
+      4: "d",
+      5: "e",
+      6: "f",
+      7: "g",
+      8: "h"
+    };
+    String rowStr = row.toString();
+    String colStr = columnMap[column]!;
+
+    return '$colStr$rowStr';
+  }
+
   @override
   operator ==(other) {
     return other is ChessCoordinate &&
@@ -136,6 +153,23 @@ class ChessPiece extends StatelessWidget {
   }
 }
 
+class ChessMove {
+  ChessCoordinate from;
+  ChessCoordinate to;
+
+  ChessMove({required this.from, required this.to});
+
+  @override
+  operator ==(other) {
+    return other is ChessMove && other.from == from && other.to == to;
+  }
+
+  @override
+  int get hashCode {
+    return hash2(from, to);
+  }
+}
+
 class PieceMovedFrom {
   ChessCoordinate fromSquare;
   ChessPiece? movedPiece;