Check which color should be moving and fix knight moves.

chess/bishop.go

@@ -17,5 +17,5 @@ func (b Bishop) GetColor() types.ChessColor {
 }
 
 func (b Bishop) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
-	return []types.Coordinate{}
+	return board.GetNonBlockedDiagonals(fromSquare)
 }

chess/board.go

@@ -10,14 +10,16 @@ import (
 type Position map[types.Coordinate]Piece
 
 type Board struct {
-	position Position
+	position    Position
-	history  []types.Move
+	history     []types.Move
+	colorToMove types.ChessColor
 }
 
 func newBoard() Board {
 	return Board{
-		position: make(Position),
+		position:    make(Position),
-		history:  make([]types.Move, 0),
+		history:     make([]types.Move, 0),
+		colorToMove: types.White,
 	}
 }
 
@@ -63,7 +65,11 @@ func (b *Board) CheckAndPlay(move types.Move) (bool, string) {
 	if pieceAtStartSquare == nil {
 		return false, "no piece at start square"
 	}
+
 	move.ColorMoved = pieceAtStartSquare.GetColor()
+	if move.ColorMoved != tempBoard.colorToMove {
+		return false, "wrong color moved"
+	}
 	move.PieceMoved = GetShortNameForPiece(pieceAtStartSquare)
 
 	//Check end square of move
@@ -114,6 +120,7 @@ func (b *Board) CheckAndPlay(move types.Move) (bool, string) {
 	//We play the move on the real board
 	b.position = tempBoard.position
 	b.history = tempBoard.history
+	b.colorToMove = b.colorToMove.Opposite()
 	b.appendMoveToHistory(move)
 	return true, ""
 }
@@ -176,6 +183,7 @@ func (b Board) getCopyOfBoard() Board {
 	return Board{
 		position: b.position.getCopyOfPosition(),
 		history:  b.history,
+        colorToMove: b.colorToMove,
 	}
 }
 

chess/free_squares.go

@@ -8,10 +8,10 @@ func (b *Board) GetNonBlockedRowAndColumn(fromSquare types.Coordinate) []types.C
 	squaresAbove := fromSquare.GetStraightInDirection(types.Coordinate.Up)
 	squaresBelow := fromSquare.GetStraightInDirection(types.Coordinate.Down)
 
-	nonBlocked := b.getNonBlocked(squaresLeft, fromSquare)
+	nonBlocked := b.getNonBlockedConsecutive(squaresLeft, fromSquare)
-	nonBlocked = append(nonBlocked, b.getNonBlocked(squaresRight, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(squaresRight, fromSquare)...)
-	nonBlocked = append(nonBlocked, b.getNonBlocked(squaresAbove, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(squaresAbove, fromSquare)...)
-	nonBlocked = append(nonBlocked, b.getNonBlocked(squaresBelow, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(squaresBelow, fromSquare)...)
 
 	return nonBlocked
 }
@@ -22,20 +22,20 @@ func (b *Board) GetNonBlockedDiagonals(fromSquare types.Coordinate) []types.Coor
 	leftDown := fromSquare.GetDiagonalInDirection(types.Coordinate.Left, types.Coordinate.Down)
 	rightDown := fromSquare.GetDiagonalInDirection(types.Coordinate.Right, types.Coordinate.Down)
 
-	nonBlocked := b.getNonBlocked(rightUp, fromSquare)
+	nonBlocked := b.getNonBlockedConsecutive(rightUp, fromSquare)
-	nonBlocked = append(nonBlocked, b.getNonBlocked(leftUp, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(leftUp, fromSquare)...)
-	nonBlocked = append(nonBlocked, b.getNonBlocked(leftDown, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(leftDown, fromSquare)...)
-	nonBlocked = append(nonBlocked, b.getNonBlocked(rightDown, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlockedConsecutive(rightDown, fromSquare)...)
 
 	return nonBlocked
 }
 
 func (b *Board) GetNonBlockedKnightMoves(fromSquare types.Coordinate) []types.Coordinate {
 	allKnightMoves := fromSquare.GetAllKnightMoves()
-	return b.getNonBlocked(allKnightMoves, fromSquare)
+	return b.getNonBlockedForKnights(allKnightMoves, fromSquare)
 }
 
-func (b *Board) getNonBlocked(
+func (b *Board) getNonBlockedConsecutive(
 	squaresToCheck []types.Coordinate,
 	sourceSquare types.Coordinate,
 ) []types.Coordinate {
@@ -46,6 +46,8 @@ func (b *Board) getNonBlocked(
 		piece := b.getPieceAt(square)
 		if piece != nil {
 			if piece.GetColor() == pieceOnSourceSquare.GetColor() {
+                //We do not append squares with same-colored pieces
+                //and also not the squares behind it
 				break
 			}
 			// if there is an opposite colored piece we append it but
@@ -57,3 +59,19 @@ func (b *Board) getNonBlocked(
 	}
 	return nonBlocked
 }
+
+func (b *Board) getNonBlockedForKnights(
+	squaresToCheck []types.Coordinate,
+	sourceSquare types.Coordinate,
+) []types.Coordinate {
+    pieceOnSourceSquare := b.getPieceAt(sourceSquare)
+    nonBlocked := []types.Coordinate{}
+
+    for _, square := range squaresToCheck {
+        piece := b.getPieceAt(square)
+        if piece == nil || piece.GetColor() != pieceOnSourceSquare.GetColor() {
+            nonBlocked = append(nonBlocked, square)
+        }
+    }
+    return nonBlocked
+}

types/coordinate.go

@@ -20,6 +20,12 @@ type CoordinateBuilder struct {
 	coordinate Coordinate
 }
 
+func newCoordinateBuilder(c Coordinate) *CoordinateBuilder {
+	return &CoordinateBuilder{
+		coordinate: c,
+	}
+}
+
 func (b *CoordinateBuilder) Up(number int) *CoordinateBuilder {
 	b.coordinate.Row += number
 	return b
@@ -45,34 +51,31 @@ func (b *CoordinateBuilder) Resolve() *Coordinate {
 	if c.Row <= RangeLastValid &&
 		c.Row >= RangeFirstValid &&
 		c.Col <= RangeLastValid &&
-		c.Col >= RangeLastValid {
+		c.Col >= RangeFirstValid {
-		return nil
+		return &c
 	}
 
-	return &c
+	return nil
 }
 
 func (c *Coordinate) GetAllKnightMoves() []Coordinate {
-    unfilteredMoves := make([]*Coordinate, 0, 8) 
+	unfilteredMoves := make([]*Coordinate, 0, 8)
-	
+
-    builder := CoordinateBuilder{coordinate: *c}
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Up(2).Right(1).Resolve())
-    
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Up(1).Right(2).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Up(2).Right(1).Resolve())
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Down(1).Right(2).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Up(1).Right(2).Resolve())
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Down(2).Right(1).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Down(1).Right(2).Resolve())
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Down(2).Left(1).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Down(2).Right(1).Resolve())
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Down(1).Left(2).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Down(2).Left(1).Resolve())
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Up(1).Left(2).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Down(1).Left(2).Resolve())
+	unfilteredMoves = append(unfilteredMoves, newCoordinateBuilder(*c).Up(2).Left(1).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Up(1).Left(2).Resolve())
-    unfilteredMoves = append(unfilteredMoves, builder.Up(2).Left(1).Resolve())
-    
 
 	return lo.FilterMap(unfilteredMoves, func(unfilteredMove *Coordinate, _ int) (Coordinate, bool) {
-        if unfilteredMove != nil {
+		if unfilteredMove != nil {
-            return *unfilteredMove, true
+			return *unfilteredMove, true
-        }
+		}
-        return Coordinate{}, false
+		return Coordinate{}, false
-    })
+	})
 }
 
 func (c Coordinate) Up(number int) *Coordinate {