bugfix: long castling not returning proper UOI notation

- this made long castling impossible using any notation other than SAN and depth calculation was thrown off since long castling and Kc1 appeared to be the same move.

board.go

@@ -261,12 +261,16 @@ func moveCastledPieces(b *Board, p1 Piece, m *Move) {
  b.bbWhitePawn = (b.bbWhitePawn & ^bbForSquare(C1)) | bbForSquare(B1)
  } else if p1.Color() == White && m.HasTag(FarPawnCastle) {
  b.bbWhitePawn = (b.bbWhitePawn & ^bbForSquare(D1)) | bbForSquare(B1)
+ // finagle the king back to C1 since move is technically to D1
+ b.bbWhiteKing = (b.bbWhiteKing & ^bbForSquare(D1)) | bbForSquare(C1)
  } else if p1.Color() == Black && m.HasTag(KnightCastle) {
  b.bbBlackKnight = (b.bbBlackKnight & ^bbForSquare(D4)) | bbForSquare(C4)
  } else if p1.Color() == Black && m.HasTag(ClosePawnCastle) {
  b.bbBlackPawn = (b.bbBlackPawn & ^bbForSquare(B4)) | bbForSquare(C4)
  } else if p1.Color() == Black && m.HasTag(FarPawnCastle) {
  b.bbBlackPawn = (b.bbBlackPawn & ^bbForSquare(A4)) | bbForSquare(C4)
+ // finagle the king back to B4 since move is technically to A4
+ b.bbBlackKing = (b.bbBlackKing ^ bbForSquare(A4)) | bbForSquare(B4)
  }
 }
 

engine.go

@@ -220,7 +220,7 @@ func castleMoves(pos *Position) []*Move {
  (^pos.board.emptySqs&(bbForSquare(C1))) == 0 &&
  !squaresAreAttacked(pos, C1) &&
  !pos.inCheck {
- m := &Move{s1: B1, s2: C1}
+ m := &Move{s1: B1, s2: D1}
  m.addTag(FarPawnCastle)
  addTags(m, pos)
  moves = append(moves, m)
@@ -249,7 +249,7 @@ func castleMoves(pos *Position) []*Move {
  (^pos.board.emptySqs&(bbForSquare(B4))) == 0 &&
  !squaresAreAttacked(pos, B4) &&
  !pos.inCheck {
- m := &Move{s1: C4, s2: B4}
+ m := &Move{s1: C4, s2: A4}
  m.addTag(FarPawnCastle)
  addTags(m, pos)
  moves = append(moves, m)

move_test.go

@@ -21,10 +21,10 @@ type perfTest struct {
 // https://www.chessprogramming.org/Perft_Results
 var perfResults = []perfTest{
  {pos: unsafeOFEN("ppkn/4/4/NKPP w NCFncf - 0 1"), nodesPerDepth: []int{
- 10, 84, 642, 4348, 29171, 183118,
+ 10, 84, 642, 4348, 29382, 185195,
  }},
  {pos: unsafeOFEN("ppkn/4/2P1/NK1P w NCFncf - 0 1"), nodesPerDepth: []int{
- 10, 75, 538, 3407,
+ 10, 75, 548, 3483,
  }},
 }
 
@@ -58,9 +58,9 @@ func countMoves(t *testing.T, originalPosition *Position, positions []*Position,
  t.Log("##############################")
  t.Log("# Details in JSONL (https://jsonlines.org)")
  t.Log("###")
- for _, pos := range positions {
-  t.Logf(`{"position": "%s", "moves": %d}`, pos.String(), len(pos.ValidMoves()))
- }
+ //for _, pos := range positions {
+ // //t.Logf(`{"position": "%s", "moves": %d}`, pos.String(), len(pos.ValidMoves()))
+ //}
  }
  countMoves(t, originalPosition, newPositions, nodesPerDepth[1:], maxDepth)
 }

notation.go

@@ -71,21 +71,20 @@ func (UOINotation) Decode(pos *Position, s string) (*Move, error) {
  }
  p := pos.Board().Piece(s1)
  p2 := pos.Board().Piece(s2)
- // TODO formally verify this decoding
- // TODO make sure piece destinations and criteria make sense
+
  if p.Type() == King {
  if ((s1 == B1 && s2 == A1) || (s1 == C4 && s2 == D4)) && p2.Type() == Knight && p.Color() == p2.Color() {
  m.addTag(KnightCastle)
  } else if ((s1 == B1 && s2 == C1) || (s1 == C4 && s2 == B4)) && p2.Type() == Pawn && p.Color() == p2.Color() {
  m.addTag(ClosePawnCastle)
  } else if ((s1 == B1 && s2 == D1) || (s1 == C4 && s2 == A4)) && p2.Type() == Pawn && p.Color() == p2.Color() {
  m.addTag(FarPawnCastle)
- fmt.Println("FAR PAWN CASTLE")
  }
  } else if p.Type() == Pawn && s2 == pos.enPassantSquare {
  m.addTag(EnPassant)
  m.addTag(Capture)
  }
+
  c1 := p.Color()
  c2 := pos.Board().Piece(s2).Color()
  if c2 != NoColor && c1 != c2 {
@@ -95,8 +94,8 @@ func (UOINotation) Decode(pos *Position, s string) (*Move, error) {
 }
 
 // AlgebraicNotation (or Standard Algebraic Notation) is the
-// official octad notation used by FIDE. Examples: e4, e5,
-// O-O (short castling), e8=Q (promotion)
+// official octad notation used by FIDE. Examples: c2, b3,
+// O-O (short castling), d4=Q (promotion)
 type AlgebraicNotation struct{}
 
 // String implements the fmt.Stringer interface and returns