mchess-server/chess/board.go

package chess

import "local/m/mchess_server/types"

type Board map[types.Coordinate]types.Piece

func (b Board) Init() {
	var coord types.Coordinate

	for i := 1; i <= 8; i++ {
		coord.Row = 2
		coord.Col = i
		b[coord] = types.Piece{Class: types.Pawn, Color: types.White}

		coord.Row = 7
		coord.Col = i
		b[coord] = types.Piece{Class: types.Pawn, Color: types.Black}
	}

	b[types.Coordinate{Row: 1, Col: 1}] = types.Piece{Class: types.Rook, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 2}] = types.Piece{Class: types.Knight, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 3}] = types.Piece{Class: types.Bishop, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 4}] = types.Piece{Class: types.Queen, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 5}] = types.Piece{Class: types.King, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 6}] = types.Piece{Class: types.Bishop, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 7}] = types.Piece{Class: types.Knight, Color: types.White}
	b[types.Coordinate{Row: 1, Col: 8}] = types.Piece{Class: types.Rook, Color: types.White}

	b[types.Coordinate{Row: 8, Col: 1}] = types.Piece{Class: types.Rook, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 2}] = types.Piece{Class: types.Knight, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 3}] = types.Piece{Class: types.Bishop, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 4}] = types.Piece{Class: types.Queen, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 5}] = types.Piece{Class: types.King, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 6}] = types.Piece{Class: types.Bishop, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 7}] = types.Piece{Class: types.Knight, Color: types.Black}
	b[types.Coordinate{Row: 8, Col: 8}] = types.Piece{Class: types.Rook, Color: types.Black}
}

func (b Board) GetPieceAt(coord types.Coordinate) (types.Piece, bool) {
	piece, found := b[coord]

	if !found {
		piece = types.Piece{}
	}

	return piece, found
}

func (b Board) CheckMove(move types.Move) (bool, string) {
	pieceAtStartSquare, found := b.GetPieceAt(move.StartSquare)
	if !found {
		return false, "no piece at start square"
	}
	movingColor := pieceAtStartSquare.Color

	pieceAtEndSquare, found := b.GetPieceAt(move.EndSquare)
	if found {
		if pieceAtEndSquare.Color == pieceAtStartSquare.Color {
			return false, "same-coloured piece at end square"
		}
	}
	// 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.

	//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.
	oppKingCoordinate := b.getSquareOfPiece(types.Piece{
		Class: types.King,
		Color: movingColor})
    if oppKingCoordinate == nil {
        return false, string(movingColor) + " king not found" 
    }
            
    b.isSquareAttacked(*oppKingCoordinate, movingColor.Opposite())

	//Check for checkmate
	//Is every square that the king can move to attacked? And can no other
	//piece block? -> checkmate

	//Maybe for checking checkmate, we have to check the 'path' in which the
	//checkmate is given

	// |K| | | | |Q|
	// in this scenaria the path are all the squares between queen and king.
	// If a piece can be moved into the path, it is no checkmate

	return true, ""
}

func (b Board) getSquareOfPiece(piece types.Piece) *types.Coordinate {
	for k, v := range b {
		if v == piece {
			return &k
		}
	}
	return nil
}

func (b Board) isSquareAttacked(square types.Coordinate, byColor types.ChessColor) bool {
    attacked := false
    
    //get every legal move of color to check if this square is attacked
    return attacked
}