Cleaning arbiter:

- Add backup macros
  - User can fetch last captured piece

src/ChessArbiter.cpp

@@ -2,13 +2,12 @@
 
 namespace chessarbiter {
 ChessArbiter::ChessArbiter()
-    : wPawn(1), wRook(5), wKnight(3), wBishop(3), wQueen(9), wKing(0), SAN("") {
-}
+    : wPawn(1), wRook(5), wKnight(3), wBishop(3), wQueen(9), wKing(0), SAN(""),
+      capture(' '), capture_last(' ') {}
 
 void ChessArbiter::Setup(std::string fen) {
   positions.clear();
   SetFEN(fen);
-  fen_last = this->fen;
   positions[this->fen.board] = 1;
 }
 
@@ -46,9 +45,13 @@ bool ChessArbiter::Play(std::string move) {
     std::string dst = move.substr(2, 2);
     bool IsCapture = !board.IsEmpty(dst);
     FEN newFen = fen;
-    SAN_last = SAN;
+    INIT_BACKUP();
     SAN = "";
 
+    if (IsCapture) {
+      capture = board.GetPieceAt(dst).piece;
+    }
+
     // Perform the move
     if (move == "O-O" || move == "O-O-O") {
       if (fen.player && move == "O-O") {
@@ -134,13 +137,11 @@ bool ChessArbiter::Play(std::string move) {
     }
 
     // Update fen!
-    fen_last = fen;
     fen = newFen;
 
     // Check for illegal move
     if (IsCheck(!fen.player)) {
-      SetFEN(fen_last);
-      SAN = SAN_last;
+      RESTORE_BACKUP();
       return (false);
     }
 
@@ -334,10 +335,9 @@ bool ChessArbiter::IsDrawByNoMoves() {
   if (!IsCheck(fen.player)) {
     std::vector<std::string> moves = ListLegalMoves(fen.player);
     for (std::string &move : moves) {
+      INIT_BACKUP();
       if (Play(move)) {
-        positions[fen.board]--; // If move work, remove its position
-        SetFEN(fen_last);
-        SAN = SAN_last;
+        RESTORE_BACKUP();
         return (false);
       }
     }
@@ -364,10 +364,9 @@ bool ChessArbiter::IsCheckMate() {
   if (IsCheck(fen.player)) {
     std::vector<std::string> moves = ListLegalMoves(fen.player);
     for (std::string &move : moves) {
+      INIT_BACKUP();
       if (Play(move)) {
-        positions[fen.board]--; // If move work, remove its position
-        SetFEN(fen_last);
-        SAN = SAN_last;
+        RESTORE_BACKUP();
         return (false);
       }
     }
@@ -377,5 +376,5 @@ bool ChessArbiter::IsCheckMate() {
 }
 
 std::string ChessArbiter::GetSAN() { return (SAN); }
-
+char ChessArbiter::GetCapture() { return (capture); }
 } // namespace chessarbiter

src/ChessArbiter.hpp

@@ -4,18 +4,34 @@
 #include <iostream>
 #include <unordered_map>
 
+#define INIT_BACKUP()                                                          \
+  FEN fen_backup = fen;                                                        \
+  char positions_backup = 0;                                                   \
+  if (positions.find(fen.board) != positions.end())                            \
+    positions_backup = positions[fen.board];                                   \
+  std::string SAN_backup = SAN;                                                \
+  char capture_backup = capture;
+
+#define RESTORE_BACKUP()                                                       \
+  SetFEN(fen_backup);                                                          \
+  if (positions_backup != 0)                                                   \
+    positions[fen.board] = positions_backup;                                   \
+  SAN = SAN_backup;                                                            \
+  capture = capture_backup;
+
 namespace chessarbiter {
 class ChessArbiter {
   Board board;
   FEN fen;
-  FEN fen_last; // To undo a move
   int wPawn, wRook, wKnight, wBishop, wQueen, wKing;
   /// @brief Use to compute occurences of positions
   std::unordered_map<std::string, char> positions;
   /// @brief FEN methods used internally
   void SetFEN(std::string);
   void SetFEN(FEN);
-  std::string SAN,SAN_last;
+  std::string SAN, SAN_last;
+  char capture, capture_last;
+
 public:
   ChessArbiter();
   void Setup(std::string);
@@ -36,6 +52,7 @@ public:
   bool IsPlayable();
   /// @brief Get pieces captures by a player
   std::string GetCaptures(bool);
+  char GetCapture();
   /// @brief Get the english SAN format of the last move
   std::string GetSAN();
   /// @brief List all the legal moves of a player

tests/chessarbiter.cpp

@@ -367,4 +367,5 @@ TEST_CASE("SimpleCapture", "[SimplePieceCapture]") {
   a.Play("e4d5");
   CHECK(a.GetFEN() ==
         "rnbqkbnr/ppp1pppp/8/3P4/8/8/PPPP1PPP/RNBQKBNR b KQkq - 0 2");
+  CHECK(a.GetCapture()=='p');
 }