Fix everything related to undoing an en-passant move

Sopel97 · May 30, 2020 · 3677656 · 3677656
1 parent 0b8e92f
commit 3677656
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Showing 4 changed files with 30 additions and 8 deletions.
diff --git a/src/app/board/controls/ChessBoard.cs b/src/app/board/controls/ChessBoard.cs
@@ -105,11 +105,15 @@ public void SetGame(ChessGame game)
             SetGame(FenProvider.StartPos, game);
         }
 
-        public void SetGame(string startpos, ChessGame game)
+        public void SetGame(string startpos, ChessGame game, int offset = 0)
         {
             SetPosition(startpos);
+            int i = 0;
             foreach (var move in game.Moves)
             {
+                ++i;
+                if (i <= offset)
+                    continue;
                 DoMove(move.SAN, true);
             }
             SetSelection(FirstPly);

diff --git a/src/app/forms/Application.cs b/src/app/forms/Application.cs
@@ -1802,9 +1802,16 @@ private void retractionsGridView_CellContentDoubleClick(object sender, DataGridV
                 var fen = chessBoard.GetFen();
                 var game = new ChessGame(fen);
                 var prevGame = reverseMove.AppliedTo(game);
-                var prevFen = prevGame.GetFen();
+                string prevFen = prevGame.GetFen();
                 prevGame.MakeMove(reverseMove.Move, true);
-                chessBoard.SetGame(prevFen, prevGame);
+                // YOU WOULD EXPECT THAT prevGame NOW HAS ONLY ONE MOVE MADE
+                // BUT YOU WOULD BE FUCKING WRONG BECAUSE
+                // THIS FUCKING LIBRARY ADDS A PAWN MOVE BEFORE EN PASSANT
+                // SO THEN prevFen DOESN'T MATCH THE ACTUAL FIRST POSITION IN prevGame
+                // (DID I MENTION THAT THE LIBRARY DOESN'T PROVIDE A WAY TO UNDO MOVES
+                //  NOR GET THE START FEN IN A GAME?)
+                // SO WE PASS AN OFFSET TO INDICATE WHERE TO START READING MOVES
+                chessBoard.SetGame(prevFen, prevGame, prevGame.Moves.Count - 1);
             }
         }
 

diff --git a/src/chess/Eran.cs b/src/chess/Eran.cs
@@ -141,7 +141,7 @@ public static string MakeFromBoardAndMove(
             ChessGame before, 
             DetailedMove move)
         {
-            var ep = before.GetGameCreationData().EnPassant;
+            var ep = before.GetFen().Split(' ')[3];
             string eran = "";
 
             var pieceChar = Char.ToUpper(move.Piece.GetFenCharacter());
@@ -195,9 +195,9 @@ public static string MakeFromBoardAndMove(
 
             eran += ' ';
 
-            if (ep != null)
+            if (ep != "-")
             {
-                eran += ep.ToString().ToLower();
+                eran += ep;
             }
             else
             {

diff --git a/src/chess/ReverseMove.cs b/src/chess/ReverseMove.cs
@@ -48,12 +48,23 @@ public ChessGame AppliedTo(ChessGame game)
                     movedPiece = game.GetPieceAt(Move.NewPosition);
                 }
 
-                creationData.Board[8 - Move.NewPosition.Rank][(int)Move.NewPosition.File] = CapturedPiece;
-                creationData.Board[8 - Move.OriginalPosition.Rank][(int)Move.OriginalPosition.File] = movedPiece;
+                if (movedPiece is Pawn && OldEpSquare == Move.NewPosition)
+                {
+                    int offset = prevPlayer == Player.White ? 1 : -1;
+                    creationData.Board[8 - Move.NewPosition.Rank + offset][(int)Move.NewPosition.File] = CapturedPiece;
+                    creationData.Board[8 - Move.NewPosition.Rank][(int)Move.NewPosition.File] = null;
+                    creationData.Board[8 - Move.OriginalPosition.Rank][(int)Move.OriginalPosition.File] = movedPiece;
+                }
+                else
+                {
+                    creationData.Board[8 - Move.NewPosition.Rank][(int)Move.NewPosition.File] = CapturedPiece;
+                    creationData.Board[8 - Move.OriginalPosition.Rank][(int)Move.OriginalPosition.File] = movedPiece;
+                }
             }
 
             creationData.Moves = new DetailedMove[0];
 
+            // IT ADDS A PAWN MOVE IF EnPassant IS SET... WTF IS THIS LIBRARY...
             return new ChessGame(creationData);
         }