125 lines
3.7 KiB
Go
125 lines
3.7 KiB
Go
package chess
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import (
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"local/m/mchess_server/types"
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"github.com/samber/lo"
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)
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type Board map[types.Coordinate]Piece
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func (b Board) Init() {
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var coord types.Coordinate
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for i := 1; i <= 8; i++ {
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coord.Row = 2
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coord.Col = i
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b[coord] = Pawn{Color: types.White, HasMoved: false}
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coord.Row = 7
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coord.Col = i
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b[coord] = Pawn{Color: types.Black, HasMoved: false}
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}
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b[types.Coordinate{Row: 1, Col: 1}] = Rook{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 2}] = Knight{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 3}] = Bishop{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 4}] = Queen{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 5}] = King{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 6}] = Bishop{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 7}] = Knight{Color: types.White}
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b[types.Coordinate{Row: 1, Col: 8}] = Rook{Color: types.White}
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b[types.Coordinate{Row: 8, Col: 1}] = Rook{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 2}] = Knight{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 3}] = Bishop{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 4}] = Queen{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 5}] = King{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 6}] = Bishop{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 7}] = Knight{Color: types.Black}
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b[types.Coordinate{Row: 8, Col: 8}] = Rook{Color: types.Black}
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}
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func (b Board) CheckMove(move types.Move) (bool, string) {
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pieceAtStartSquare := b.getPieceAt(move.StartSquare)
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if pieceAtStartSquare == nil {
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return false, "no piece at start square"
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}
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movingColor := pieceAtStartSquare.GetColor()
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pieceAtEndSquare := b.getPieceAt(move.EndSquare)
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if pieceAtEndSquare != nil {
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if pieceAtEndSquare.GetColor() == pieceAtStartSquare.GetColor() {
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return false, "same-coloured piece at end square"
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}
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}
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// At the moment, we do not need to check if the correct color is moving,
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//since we are only reading moves from the player whose turn it is.
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legal := lo.Contains(pieceAtStartSquare.GetAllLegalAndIllegalMoves(b, move.StartSquare), move.EndSquare)
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if !legal {
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return false, "not a legal square"
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}
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//Check if king of moving color is in check -> move not allowed
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//Do that by checking if the king is in a square attacked by the other color.
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ownKingCoordinate := b.getSquareOfPiece(King{Color: movingColor})
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if ownKingCoordinate == nil {
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return false, string(movingColor) + " king not found"
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}
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kingIsAttacked := b.isSquareAttacked(*ownKingCoordinate, movingColor.Opposite())
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if kingIsAttacked {
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return false, "king is attacked after move"
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}
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//Check for checkmate
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//Is every square that the king can move to attacked? And can no other
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//piece block? -> checkmate
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//only check if paths of attacking pieces can be blocked
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//Maybe for checking checkmate, we have to check the 'path' in which the
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//checkmate is given
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// |K| | | | |Q|
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// in this scenaria the path are all the squares between queen and king.
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// If a piece can be moved into the path, it is no checkmate
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//We play the move
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delete(b, move.StartSquare)
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b[move.EndSquare] = pieceAtStartSquare
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pieceAtStartSquare.AfterMoveAction()
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return true, ""
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}
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func (b Board) getSquareOfPiece(piece Piece) *types.Coordinate {
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for k, v := range b {
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if v == piece {
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return &k
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}
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}
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return nil
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}
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func (b Board) isSquareAttacked(square types.Coordinate, byColor types.ChessColor) bool {
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var attackedSquares []types.Coordinate
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for square, piece := range b {
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attackedSquares = append(attackedSquares, piece.GetAllLegalAndIllegalMoves(b, square)...)
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}
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return lo.Contains(attackedSquares, square)
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}
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func (b Board) getPieceAt(coord types.Coordinate) Piece {
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piece, found := b[coord]
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if !found {
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return nil
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}
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return piece
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}
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