- Add drawing methods to the API

- Improve tests

src/Board.cpp

@@ -74,14 +74,11 @@ std::string Board::GetKingLocation(bool isBlack) {
 void Board::Move(std::string move) {
   std::string src(move.substr(0, 2));
   std::string dst(move.substr(2, 2));
-  if (!IsEmpty(src)) {
-    if (!IsEmpty(dst)) {
-      RemovePiece(dst);
-    }
-    for (Piece &p : pieces) {
-      if (p.coord == src) {
-        p.coord = dst;
-      }
+  for (Piece &p : pieces) {
+    if (p.coord == src) {
+      RemovePiece(dst); // Remove piece on dst if exists
+      p.coord = dst;
+      break;
     }
   }
 }
@@ -116,6 +113,9 @@ bool Board::IsMovePossible(std::string move) {
   }
 
   // Check colors on dst square
+  // Seems that checking that is empty
+  // instead of catching NoPieceFound exception is
+  // more performant
   if (!IsEmpty(dst)) {
     Piece dstp = GetPieceAt(dst);
     if (srcp.isBlack == dstp.isBlack)

src/ChessArbiter.cpp

@@ -5,8 +5,10 @@ ChessArbiter::ChessArbiter()
     : wPawn(1), wRook(5), wKnight(3), wBishop(3), wQueen(9), wKing(0) {}
 
 void ChessArbiter::Setup(std::string fen) {
+  positions.clear();
   SetFEN(fen);
   fen_last = this->fen;
+  positions[this->fen.board] = 1;
 }
 
 void ChessArbiter::SetFEN(FEN fen) { SetFEN(FENParser::Serialize(fen)); }
@@ -114,6 +116,13 @@ bool ChessArbiter::Play(std::string move) {
       return (false);
     }
 
+    // Update position map (repetitions draw)
+    if (positions.count(fen.board) == 0) {
+      positions[fen.board] = 1;
+    } else {
+      positions[fen.board] += 1;
+    }
+
     return (true);
   }
   return (false);
@@ -292,16 +301,48 @@ bool ChessArbiter::IsPlayable() {
   return (false);
 }
 
+bool ChessArbiter::IsDrawByFiftyMoveRule() { return (fen.halfmove >= 100); }
+
+bool ChessArbiter::IsDrawByNoMoves() {
+  if (!IsCheck(fen.player)) {
+    std::vector<std::string> moves = ListLegalMoves(fen.player);
+    for (std::string &move : moves) {
+      if (Play(move)) {
+        positions[fen.board]--; // If move work, remove its position
+        SetFEN(fen_last);
+        return (false);
+      }
+    }
+    return (true);
+  }
+  return (false);
+}
+
+bool ChessArbiter::IsDrawByRepetitions() {
+  for (auto const &[key, val] : positions) {
+    if (val >= 3) {
+      return (true);
+    }
+  }
+  return (false);
+}
+
+bool ChessArbiter::IsDraw() {
+  return (IsDrawByFiftyMoveRule() || IsDrawByNoMoves() ||
+          IsDrawByRepetitions());
+}
+
 bool ChessArbiter::IsCheckMate() {
   if (IsCheck(fen.player)) {
     std::vector<std::string> moves = ListLegalMoves(fen.player);
-    for(std::string &move: moves){
-      if(Play(move)){
+    for (std::string &move : moves) {
+      if (Play(move)) {
+        positions[fen.board]--; // If move work, remove its position
         SetFEN(fen_last);
-        return(false);
+        return (false);
       }
     }
-    return(true);
+    return (true);
   }
   return (false);
 }

src/ChessArbiter.hpp

@@ -1,6 +1,7 @@
 #include "Board.hpp"
 #include "Fen.hpp"
 #include <iostream>
+#include <unordered_map>
 
 namespace chessarbiter {
 class ChessArbiter {
@@ -8,12 +9,15 @@ class ChessArbiter {
   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);
 
 public:
   ChessArbiter();
   void Setup(std::string);
-  void SetFEN(std::string);
-  void SetFEN(FEN);
   std::string GetFEN();
   /// @brief Check which player is going to play
   bool IsBlackTurn();
@@ -27,7 +31,7 @@ public:
   std::string GetBoard();
   /// @brief Get current position evaluation according to player's material
   int GetMaterialScore();
-  /// @brief Check if position is legal
+  /// @brief Check if position is legal to be played
   bool IsPlayable();
   /// @brief Get pieces captures by a player
   std::string GetCaptures(bool);
@@ -36,5 +40,10 @@ public:
   /// @brief Check if a specific castle is possible by a player
   bool IsCastlePossible(bool, bool);
   bool IsCheckMate();
+  /// @brief Draws check
+  bool IsDrawByFiftyMoveRule();
+  bool IsDrawByNoMoves();
+  bool IsDrawByRepetitions();
+  bool IsDraw();
 };
 } // namespace chessarbiter

tests/chessarbiter.cpp

@@ -300,3 +300,61 @@ TEST_CASE("IsCheckmate", "[chessarbiter/IsCheckmate]") {
   CHECK(a.GetFEN() ==
         "r3qbr1/p1p1pkp1/1p2p1p1/8/8/8/PPPPP1PP/RNBQ1RK1 b - - 1 1");
 }
+
+TEST_CASE("IsDrawByFiftyMoveRule", "[chessarbiter/IsDrawByFiftyMoveRule]") {
+  ChessArbiter a;
+  a.Setup("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");
+  CHECK_FALSE(a.IsDrawByFiftyMoveRule());
+
+  a.Setup("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 99 1");
+  CHECK_FALSE(a.IsDrawByFiftyMoveRule());
+  a.Play("b1c3");
+  CHECK(a.IsDrawByFiftyMoveRule());
+
+  a.Setup("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 100 1");
+  CHECK(a.IsDrawByFiftyMoveRule());
+}
+
+TEST_CASE("IsDrawByNoMoves", "[chessarbiter/IsDrawByNoMoves]") {
+  ChessArbiter a;
+
+  // No move for black
+  a.Setup("8/8/8/8/8/8/5K1p/7k b - - 0 1");
+  CHECK(a.IsDrawByNoMoves());
+
+  // But move for white
+  a.Setup("8/8/8/8/8/8/5K1p/7k w - - 0 1");
+  CHECK_FALSE(a.IsDrawByNoMoves());
+
+  // No move for white
+  a.Setup("8/8/7r/2K5/b7/2k5/6q1/8 w - - 0 1");
+  CHECK(a.IsDrawByNoMoves());
+
+  // But move for black
+  a.Setup("8/8/7r/2K5/b7/2k5/6q1/8 b - - 0 1");
+  CHECK_FALSE(a.IsDrawByNoMoves());
+}
+
+TEST_CASE("IsDrawByRepetitions", "[chessarbiter/IsDrawByRepetitions]") {
+  ChessArbiter a;
+  // One time
+  a.Setup("8/3kp3/8/8/4P3/3K4/8/8 w - - 0 1");
+
+  a.Play("d3d4");
+  a.Play("d7d6");
+  CHECK_FALSE(a.IsDrawByRepetitions());
+
+  // Two time
+  a.Play("d4d3");
+  a.Play("d6d7");
+  CHECK_FALSE(a.IsDrawByRepetitions());
+
+  a.Play("d3d4");
+  a.Play("d7d6");
+  CHECK_FALSE(a.IsDrawByRepetitions());
+
+  // Three time
+  a.Play("d4d3");
+  a.Play("d6d7");
+  CHECK(a.IsDrawByRepetitions());
+}