many many changes again.

chess/bishop.go

@@ -1,15 +1,21 @@
 package chess
 
-import "mchess_server/types"
+import (
+	"mchess_server/types"
+)
 
 type Bishop struct {
 	Color types.ChessColor
 }
 
+func (b Bishop) GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate {
+	return b.GetAllNonBlockedMoves(board, fromSquare)
+}
+
 func (b Bishop) GetColor() types.ChessColor {
 	return b.Color
 }
 
-func (b Bishop) GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate {
+func (b Bishop) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
 	return []types.Coordinate{}
 }

chess/board.go

@@ -1,6 +1,7 @@
 package chess
 
 import (
+	"errors"
 	"mchess_server/types"
 
 	"github.com/samber/lo"
@@ -78,7 +79,7 @@ func (b *Board) CheckAndPlay(move types.Move) (bool, string) {
 	if !wasSpecialMove {
 		// At the moment, we do not need to check if the correct color is moving,
 		//since we are only reading moves from the player whose turn it is.
-		allMovesExceptBlocked := pieceAtStartSquare.GetAllMovesButBlocked(tempBoard, move.StartSquare)
+		allMovesExceptBlocked := pieceAtStartSquare.GetAllNonBlockedMoves(tempBoard, move.StartSquare)
 		legal := lo.Contains(allMovesExceptBlocked, move.EndSquare)
 		if !legal {
 			return false, "not a legal square"
@@ -89,16 +90,12 @@ func (b *Board) CheckAndPlay(move types.Move) (bool, string) {
 		tempBoard.position[move.EndSquare] = pieceAtStartSquare
 	}
 
-	//Check if king of moving color is in check -> move not allowed
+	kingAttacked, err := tempBoard.isKingOfMovingColorInCheck(move.ColorMoved)
-	//Do that by checking if the king is in a square attacked by the other color.
+	if err != nil {
-	ownKingCoordinate := tempBoard.getSquareOfPiece(King{Color: move.ColorMoved})
+		return false, "something went wrong"
-	if ownKingCoordinate == nil {
-		return false, string(move.ColorMoved) + " king not found"
 	}
-
+	if kingAttacked {
-	kingIsAttacked := tempBoard.isSquareAttacked(*ownKingCoordinate, move.ColorMoved.Opposite())
+		return false, "king would be in check after move"
-	if kingIsAttacked {
-		return false, "king is attacked after move"
 	}
 
 	//Check for checkmat&e
@@ -118,10 +115,24 @@ func (b *Board) CheckAndPlay(move types.Move) (bool, string) {
 	b.position = tempBoard.position
 	b.history = tempBoard.history
 	b.appendMoveToHistory(move)
-
 	return true, ""
 }
 
+func (b Board) isKingOfMovingColorInCheck(color types.ChessColor) (bool, error) {
+	//Check if king of moving color is in check -> move not allowed
+	//Do that by checking if the king is in a square attacked by the other color.
+	ownKingCoordinate := b.getSquareOfPiece(King{Color: color})
+	if ownKingCoordinate == nil {
+		return false, errors.New("no king found")
+	}
+
+	kingIsAttacked := b.isSquareAttacked(*ownKingCoordinate, color.Opposite())
+	if kingIsAttacked {
+		return true, nil
+	}
+	return false, nil
+}
+
 func (b Board) getSquareOfPiece(piece Piece) *types.Coordinate {
 	for k, v := range b.position {
 		if v == piece {
@@ -135,9 +146,10 @@ func (b Board) isSquareAttacked(square types.Coordinate, byColor types.ChessColo
 	var attackedSquares []types.Coordinate
 
 	for square, piece := range b.position {
-		attackedSquares = append(attackedSquares, piece.GetAllMovesButBlocked(b, square)...)
+		if piece.GetColor() == byColor {
+			attackedSquares = append(attackedSquares, piece.GetAllAttackedSquares(b, square)...)
+		}
 	}
-
 	return lo.Contains(attackedSquares, square)
 }
 
@@ -146,7 +158,6 @@ func (b Board) getPieceAt(coord types.Coordinate) Piece {
 	if !found {
 		return nil
 	}
-
 	return piece
 }
 
@@ -191,5 +202,3 @@ func (b *Board) handleSpecialMove(move types.Move) bool {
 	}
 	return was
 }
-
-

chess/board_test.go

@@ -122,14 +122,18 @@ func Test_CheckMove_invalidPawnMoves(t *testing.T) {
 
 		board.position[types.Coordinate{Col: 1, Row: 6}] = King{Color: types.White}
 		board.position[types.Coordinate{Col: 2, Row: 6}] = Pawn{Color: types.White}
-		board.position[types.Coordinate{Col: 8, Row: 6}] = King{Color: types.Black}
+		board.position[types.Coordinate{Col: 7, Row: 6}] = Rook{Color: types.Black}
+		board.position[types.Coordinate{Col: 8, Row: 8}] = King{Color: types.Black}
+        boardBeforeMove := board
 
 		move := types.Move{
 			StartSquare: types.Coordinate{Col: 2, Row: 6},
 			EndSquare:   types.Coordinate{Col: 2, Row: 7},
 		}
 		good, _ := board.CheckAndPlay(move)
+
 		assert.False(t, good)
+        assert.Equal(t, boardBeforeMove, board)
 	})
 }
 
@@ -139,7 +143,7 @@ func Test_CheckMove_validPromotion(t *testing.T) {
 	board.position[types.Coordinate{Col: 1, Row: 7}] = Pawn{Color: types.White}
 	board.position[types.Coordinate{Col: 1, Row: 1}] = King{Color: types.White}
 
-	board.position[types.Coordinate{Col: 8, Row: 7}] = King{Color: types.Black}
+	board.position[types.Coordinate{Col: 7, Row: 7}] = King{Color: types.Black}
 
 	shortName := types.QueenShortName
 	move := types.Move{

chess/free_squares.go

@@ -3,13 +3,12 @@ package chess
 import "mchess_server/types"
 
 func (b *Board) GetNonBlockedRowAndColumn(fromSquare types.Coordinate) []types.Coordinate {
-	squaresLeft := fromSquare.GetAllSquaresLeft()
+	squaresLeft := fromSquare.GetStraightInDirection(types.Coordinate.Left)
-	squaresRight := fromSquare.GetAllSquaresRight()
+	squaresRight := fromSquare.GetStraightInDirection(types.Coordinate.Right)
-	squaresAbove := fromSquare.GetAllSquaresAbove()
+	squaresAbove := fromSquare.GetStraightInDirection(types.Coordinate.Up)
-	squaresBelow := fromSquare.GetAllSquaresBelow()
+	squaresBelow := fromSquare.GetStraightInDirection(types.Coordinate.Down)
-	nonBlocked := []types.Coordinate{}
 
-    nonBlocked = append(nonBlocked, b.getNonBlocked(squaresLeft, fromSquare)...)
+	nonBlocked := b.getNonBlocked(squaresLeft, fromSquare)
 	nonBlocked = append(nonBlocked, b.getNonBlocked(squaresRight, fromSquare)...)
 	nonBlocked = append(nonBlocked, b.getNonBlocked(squaresAbove, fromSquare)...)
 	nonBlocked = append(nonBlocked, b.getNonBlocked(squaresBelow, fromSquare)...)
@@ -17,6 +16,25 @@ func (b *Board) GetNonBlockedRowAndColumn(fromSquare types.Coordinate) []types.C
 	return nonBlocked
 }
 
+func (b *Board) GetNonBlockedDiagonals(fromSquare types.Coordinate) []types.Coordinate {
+	rightUp := fromSquare.GetDiagonalInDirection(types.Coordinate.Right, types.Coordinate.Up)
+	leftUp := fromSquare.GetDiagonalInDirection(types.Coordinate.Left, types.Coordinate.Up)
+	leftDown := fromSquare.GetDiagonalInDirection(types.Coordinate.Left, types.Coordinate.Down)
+	rightDown := fromSquare.GetDiagonalInDirection(types.Coordinate.Right, types.Coordinate.Down)
+
+	nonBlocked := b.getNonBlocked(rightUp, fromSquare)
+	nonBlocked = append(nonBlocked, b.getNonBlocked(leftUp, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlocked(leftDown, fromSquare)...)
+	nonBlocked = append(nonBlocked, b.getNonBlocked(rightDown, fromSquare)...)
+
+	return nonBlocked
+}
+
+func (b *Board) GetNonBlockedKnightMoves(fromSquare types.Coordinate) []types.Coordinate {
+	allKnightMoves := fromSquare.GetAllKnightMoves()
+	return b.getNonBlocked(allKnightMoves, fromSquare)
+}
+
 func (b *Board) getNonBlocked(
 	squaresToCheck []types.Coordinate,
 	sourceSquare types.Coordinate,

chess/king.go

@@ -1,15 +1,21 @@
 package chess
 
-import "mchess_server/types"
+import (
+	"mchess_server/types"
+)
 
 type King struct {
 	Color types.ChessColor
 }
 
+func (k King) GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate {
+	return k.GetAllNonBlockedMoves(board, fromSquare)
+}
+
 func (k King) GetColor() types.ChessColor {
 	return k.Color
 }
 
-func (k King) GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate {
+func (k King) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
 	return []types.Coordinate{}
 }

chess/knight.go

@@ -1,19 +1,21 @@
 package chess
 
-import "mchess_server/types"
+import (
+	"mchess_server/types"
+)
 
 type Knight struct {
 	Color types.ChessColor
 }
 
-// AfterMoveAction implements Piece.
+func (k Knight) GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate {
-func (k Knight) AfterMoveAction() {
+	return k.GetAllNonBlockedMoves(board, fromSquare)
 }
 
 func (k Knight) GetColor() types.ChessColor {
 	return k.Color
 }
 
-func (k Knight) GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate {
+func (k Knight) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
-	return []types.Coordinate{}
+	return board.GetNonBlockedKnightMoves(fromSquare)
 }

chess/pawn.go

@@ -10,7 +10,18 @@ type Pawn struct {
 	Color types.ChessColor
 }
 
-func (p Pawn) GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate {
+func (p Pawn) GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate {
+    attackingMoves := make([]types.Coordinate,0,2)
+    allMoves := p.GetAllNonBlockedMoves(board, fromSquare)
+    for _,move := range allMoves {
+       if move.Col != fromSquare.Col {
+        attackingMoves = append(attackingMoves, move)
+       }
+    }
+    return attackingMoves
+}
+
+func (p Pawn) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
 	theoreticalSquares := p.getAllMoves(fromSquare)
 	legalSquares := p.filterBlockedSquares(board, fromSquare, theoreticalSquares)
 
@@ -176,4 +187,3 @@ func (p Pawn) filterBlockedSquares(board Board, fromSquare types.Coordinate, squ
 	}
 	return lo.Intersect(nonBlockedSquares, squaresToBeFiltered)
 }
-

chess/piece_interface.go

@@ -5,7 +5,8 @@ import (
 )
 
 type Piece interface {
-	GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate
+	GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate
+    GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate
 	GetColor() types.ChessColor
 }
 

chess/queen.go

@@ -1,15 +1,23 @@
 package chess
 
-import "mchess_server/types"
+import (
+	"mchess_server/types"
+)
 
 type Queen struct {
 	Color types.ChessColor
 }
 
+func (q Queen) GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate {
+	return q.GetAllNonBlockedMoves(board, fromSquare)
+}
+
 func (q Queen) GetColor() types.ChessColor {
 	return q.Color
 }
 
-func (q Queen) GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate {
+func (q Queen) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
-	return []types.Coordinate{}
+    squares := board.GetNonBlockedRowAndColumn(fromSquare)
+    squares = append(squares, board.GetNonBlockedDiagonals(fromSquare)...)
+    return squares
 }

chess/rook.go

@@ -1,11 +1,17 @@
 package chess
 
-import "mchess_server/types"
+import (
+	"mchess_server/types"
+)
 
 type Rook struct {
 	Color types.ChessColor
 }
 
+func (r Rook) GetAllAttackedSquares(board Board, fromSquare types.Coordinate) []types.Coordinate {
+	return r.GetAllNonBlockedMoves(board, fromSquare)
+}
+
 func (r Rook) AfterMoveAction() {
 }
 
@@ -13,6 +19,6 @@ func (r Rook) GetColor() types.ChessColor {
 	return r.Color
 }
 
-func (r Rook) GetAllMovesButBlocked(board Board, fromSquare types.Coordinate) []types.Coordinate {
+func (r Rook) GetAllNonBlockedMoves(board Board, fromSquare types.Coordinate) []types.Coordinate {
 	return board.GetNonBlockedRowAndColumn(fromSquare)
 }

chess/rook_test.go

@@ -14,9 +14,8 @@ func Test_Rook_GetNonBlockedSquares(t *testing.T) {
 		rook := Rook{Color: types.Black}
 
 		board.position[types.Coordinate{Col: 5, Row: 5}] = rook
-		squares := rook.GetAllMovesButBlocked(board, types.Coordinate{Col: 5, Row: 5})
+		squares := rook.GetAllNonBlockedMoves(board, types.Coordinate{Col: 5, Row: 5})
 		assert.Len(t, squares, 14)
-		assert.Equal(t, types.Coordinate{Col: 4, Row: 5}, squares[0])
 	})
 
 	t.Run("free row and column", func(t *testing.T) {
@@ -29,7 +28,7 @@ func Test_Rook_GetNonBlockedSquares(t *testing.T) {
 		board.position[types.Coordinate{Col: 5, Row: 6}] = Pawn{Color: types.White}
 		board.position[types.Coordinate{Col: 6, Row: 5}] = Pawn{Color: types.Black}
 
-		squares := rook.GetAllMovesButBlocked(board, types.Coordinate{Col: 5, Row: 5})
+		squares := rook.GetAllNonBlockedMoves(board, rookCoordinate)
 
 		squaresOnLeft := lo.Filter(squares, func(square types.Coordinate, _ int) bool {
 			return square.Row == rookCoordinate.Row && square.Col < rookCoordinate.Col

types/coordinate.go

@@ -1,5 +1,7 @@
 package types
 
+import "github.com/samber/lo"
+
 // coordinates starting at 1:1 and end at 8:8
 type Coordinate struct {
 	Col int `json:"col"`
@@ -14,6 +16,65 @@ const (
 	RangeLowerInvalid = 0
 )
 
+type CoordinateBuilder struct {
+	coordinate Coordinate
+}
+
+func (b *CoordinateBuilder) Up(number int) *CoordinateBuilder {
+	b.coordinate.Row += number
+	return b
+}
+
+func (b *CoordinateBuilder) Down(number int) *CoordinateBuilder {
+	b.coordinate.Row -= number
+	return b
+}
+
+func (b *CoordinateBuilder) Left(number int) *CoordinateBuilder {
+	b.coordinate.Col -= number
+	return b
+}
+
+func (b *CoordinateBuilder) Right(number int) *CoordinateBuilder {
+	b.coordinate.Col += number
+	return b
+}
+
+func (b *CoordinateBuilder) Resolve() *Coordinate {
+	c := b.coordinate
+	if c.Row <= RangeLastValid &&
+		c.Row >= RangeFirstValid &&
+		c.Col <= RangeLastValid &&
+		c.Col >= RangeLastValid {
+		return nil
+	}
+
+	return &c
+}
+
+func (c *Coordinate) GetAllKnightMoves() []Coordinate {
+    unfilteredMoves := make([]*Coordinate, 0, 8) 
+	
+    builder := CoordinateBuilder{coordinate: *c}
+    
+    unfilteredMoves = append(unfilteredMoves, builder.Up(2).Right(1).Resolve())
+    unfilteredMoves = append(unfilteredMoves, builder.Up(1).Right(2).Resolve())
+    unfilteredMoves = append(unfilteredMoves, builder.Down(1).Right(2).Resolve())
+    unfilteredMoves = append(unfilteredMoves, builder.Down(2).Right(1).Resolve())
+    unfilteredMoves = append(unfilteredMoves, builder.Down(2).Left(1).Resolve())
+    unfilteredMoves = append(unfilteredMoves, builder.Down(1).Left(2).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 {
+            return *unfilteredMove, true
+        }
+        return Coordinate{}, false
+    })
+}
+
 func (c Coordinate) Up(number int) *Coordinate {
 	check := c.Row + number
 	if check <= RangeLastValid {
@@ -45,11 +106,27 @@ func (c Coordinate) Left(number int) *Coordinate {
 	return nil
 }
 
-func (c Coordinate) GetAllSquaresLeft() []Coordinate {
+func (c Coordinate) GetAllSquaresOnStraights() []Coordinate {
+	squares := c.GetStraightInDirection(Coordinate.Up)
+	squares = append(squares, c.GetStraightInDirection(Coordinate.Down)...)
+	squares = append(squares, c.GetStraightInDirection(Coordinate.Left)...)
+	squares = append(squares, c.GetStraightInDirection(Coordinate.Right)...)
+	return squares
+}
+
+func (c Coordinate) GetAllSquaresOnDiagonals() []Coordinate {
+	squares := c.GetDiagonalInDirection(Coordinate.Up, Coordinate.Right)
+	squares = append(squares, c.GetDiagonalInDirection(Coordinate.Down, Coordinate.Right)...)
+	squares = append(squares, c.GetDiagonalInDirection(Coordinate.Down, Coordinate.Left)...)
+	squares = append(squares, c.GetDiagonalInDirection(Coordinate.Up, Coordinate.Left)...)
+	return squares
+}
+
+func (c Coordinate) GetStraightInDirection(dirFn func(Coordinate, int) *Coordinate) []Coordinate {
 	squares := []Coordinate{}
 	i := 1
 	for {
-		if square := c.Left(i); square != nil {
+		if square := dirFn(c, i); square != nil {
 			squares = append(squares, *square)
 			i += 1
 		} else {
@@ -58,70 +135,20 @@ func (c Coordinate) GetAllSquaresLeft() []Coordinate {
 	}
 }
 
-func (c Coordinate) GetAllSquaresRight() []Coordinate {
+func (c Coordinate) GetDiagonalInDirection(dirFn1, dirFn2 func(Coordinate, int) *Coordinate) []Coordinate {
 	squares := []Coordinate{}
 	i := 1
 	for {
-		if square := c.Right(i); square != nil {
+		if squareRight := dirFn1(c, i); squareRight != nil {
+			if square := dirFn2(*squareRight, i); square != nil {
 				squares = append(squares, *square)
 				i += 1
 			} else {
-			return squares
-		}
-	}
-}
-
-func (c Coordinate) GetAllSquaresAbove() []Coordinate {
-	squares := []Coordinate{}
-	i := 1
-	for {
-		if square := c.Up(i); square != nil {
-			squares = append(squares, *square)
-			i += 1
-		} else {
-			return squares
-		}
-	}
-}
-
-func (c Coordinate) GetAllSquaresBelow() []Coordinate {
-	squares := []Coordinate{}
-	i := 1
-	for {
-		if square := c.Down(i); square != nil {
-			squares = append(squares, *square)
-			i += 1
-		} else {
-			return squares
-		}
-	}
-}
-func (c Coordinate) GetSquaresOnRow() []Coordinate {
-	rowToReturn := []Coordinate{}
-	leftMostSquareOnRow := Coordinate{Col: RangeFirstValid, Row: c.Row}
-	index := 0
-	for {
-		squareToAppend := leftMostSquareOnRow.Right(index)
-		if squareToAppend == nil {
 				break
 			}
-		rowToReturn = append(rowToReturn, *squareToAppend)
+		} else {
-		index = index + 1
-	}
-	return rowToReturn
-}
-
-func (c Coordinate) GetSquaresOnColumn() []Coordinate {
-	columnToReturn := []Coordinate{}
-	bottomSquareOnColumn := Coordinate{Col: c.Col, Row: RangeFirstValid}
-	index := 0
-	for {
-		squareToAppend := bottomSquareOnColumn.Up(index)
-		if squareToAppend == nil {
 			break
 		}
-		columnToReturn = append(columnToReturn, *squareToAppend)
-		index = index + 1
 	}
-	return columnToReturn
+	return squares
 }

types/coordinate_test.go

@@ -6,20 +6,33 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func Test_Coordinate_GetSquaresOfRow(t *testing.T) {
+func Test_Coordinate_GetSquaresOfRowExcludingStartSquare(t *testing.T) {
 	t.Run("get row for a coordinate", func(t *testing.T) {
 		startSquare := Coordinate{Col: 4, Row: 2}
-        row := startSquare.GetSquaresOnRow()
+		row := startSquare.GetStraightInDirection(Coordinate.Left)
-        assert.Len(t, row, 8)
+		row = append(row, startSquare.GetStraightInDirection(Coordinate.Right)...)
-        assert.Equal(t,row[0].Col, 1)
+		assert.Len(t, row, 7)
-        assert.Equal(t,row[7].Col, 8)
+		assert.Equal(t, row[0], Coordinate{Col: 3, Row: 2})
+		assert.Equal(t, row[1], Coordinate{Col: 2, Row: 2})
 	})
 
 	t.Run("get column for a coordinate", func(t *testing.T) {
 		startSquare := Coordinate{Col: 4, Row: 2}
-        column := startSquare.GetSquaresOnColumn()
+		column := startSquare.GetStraightInDirection(Coordinate.Up)
-        assert.Len(t, column, 8)
+		column = append(column, startSquare.GetStraightInDirection(Coordinate.Down)...)
-        assert.Equal(t,column[0].Row, 1)
+		assert.Len(t, column, 7)
-        assert.Equal(t,column[7].Row, 8)
+		assert.Equal(t, column[0], Coordinate{Col: 4, Row: 3})
 	})
 }
+
+func Test_GetDiagonals(t *testing.T) {
+	square := Coordinate{Col: 5, Row: 5}
+	diagonal := square.GetDiagonalInDirection(Coordinate.Right, Coordinate.Up)
+
+	assert.Len(t, diagonal, 3)
+	assert.Equal(t, []Coordinate{
+		{Col: 6, Row: 6},
+		{Col: 7, Row: 7},
+		{Col: 8, Row: 8},
+	}, diagonal)
+}