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added rule for en passant #1

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47 changes: 33 additions & 14 deletions src/components/ChessBoard.vue
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Original file line number Diff line number Diff line change
@@ -1,11 +1,10 @@

<script setup lang="ts">

import {ref, onMounted} from 'vue'
import BoardSquare from './BoardSquare.vue';
import { ChessPiece } from '@/ChessPiece';
import type { TileSquare } from '@/types/tilesquare.ts';
import { getKnightMoves, getWhitePawnMoves, getBlackPawnMoves, getRookMoves, getBishopMoves, getQueenMoves, getKingMoves, isKingInCheck } from '@/services/ChessRules';
import { getKnightMoves, getWhitePawnMoves, getBlackPawnMoves, getRookMoves, getBishopMoves, getQueenMoves, getKingMoves, isKingInCheck, enPassantPossible } from '@/services/ChessRules';


const board = ref<TileSquare[]>([]); // ref([])
Expand All @@ -28,14 +27,9 @@ const initialPieces: Record<number, ChessPiece> = {
59: ChessPiece.WHITE_QUEEN, 60: ChessPiece.WHITE_KING, 61: ChessPiece.WHITE_BISHOP,
62: ChessPiece.WHITE_KNIGHT, 63: ChessPiece.WHITE_ROOK
};
// const initialPieces: Record<NumericKeys, string> = {
// 0: "♜", 1: "♞", 2: "♝", 3: "♛", 4: "♚", 5: "♝", 6: "♞", 7: "♜",
// 8: "♟", 9: "♟", 10: "♟", 11: "♟", 12: "♟", 13: "♟", 14: "♟", 15: "♟",
// 48: "♙", 49: "♙", 50: "♙", 51: "♙", 52: "♙", 53: "♙", 54: "♙", 55: "♙",
// 56: "♖", 57: "♘", 58: "♗", 59: "♕", 60: "♔", 61: "♗", 62: "♘", 63: "♖"
// };

const isWhiteTurn = ref(true);
const lastMove = ref<{ from: number; to: number; piece: string } | undefined>(undefined);

const initializeBoard = () => {
board.value = Array.from({length: 64}, (_,i) => ({
Expand All @@ -52,22 +46,37 @@ const movePiece = ({ from, to }: { from: TileSquare; to: TileSquare }) => {

// If the piece exists at the source square
if (board.value[fromIndex].piece) {
const movingPiece = board.value[fromIndex].piece;

// Get valid moves for the piece
const validMoves = getValidMoves(board.value[fromIndex].piece, from.row, from.col);
const validMoves = getValidMoves(movingPiece, from.row, from.col);

// Check if the target square is a valid move
if (validMoves.some(move => move.row === to.row && move.col === to.col)) {
// Check if the move is valid (doesn't leave the king in check)
if (isValidBoard(fromIndex, toIndex)) {
// Check if this is an en passant capture
const epCaptures = enPassantPossible(board.value, lastMove.value);
if (epCaptures) {
const epMove = epCaptures.find(ep => ep.attackerIndex === fromIndex && ep.captureIndex === toIndex);
if (epMove) {
// Remove the captured pawn
board.value[epMove.victimIndex].piece = null;
}
}

// Update the board
board.value[toIndex].piece = board.value[fromIndex].piece;
board.value[fromIndex].piece = null;

// Record this move for en passant detection
lastMove.value = { from: fromIndex, to: toIndex, piece: movingPiece };

// Switch turns
isWhiteTurn.value = !isWhiteTurn.value;

console.log(
`Moved ${board.value[toIndex].piece} from ${board.value[fromIndex].notation} to ${board.value[toIndex].notation}`
`Moved ${board.value[toIndex].piece} from ${from.notation} to ${to.notation}`
);
} else {
console.log("Invalid move: King would be in check.");
Expand All @@ -83,11 +92,20 @@ const isValidBoard = (fromIndex: number, toIndex: number): boolean => {
const boardCopy = board.value.map(tile => ({ ...tile }));

// Simulate the move
boardCopy[toIndex].piece = boardCopy[fromIndex].piece;
const movingPiece = boardCopy[fromIndex].piece;
boardCopy[toIndex].piece = movingPiece;
boardCopy[fromIndex].piece = null;

const isWhiteKing = isWhiteTurn.value;
// Simulate en passant capture if applicable
const epCaptures = enPassantPossible(board.value, lastMove.value);
if (epCaptures) {
const epMove = epCaptures.find(ep => ep.attackerIndex === fromIndex && ep.captureIndex === toIndex);
if (epMove) {
boardCopy[epMove.victimIndex].piece = null;
}
}

const isWhiteKing = isWhiteTurn.value;
const isCheck = isKingInCheck(boardCopy, isWhiteKing);

return !isCheck;
Expand All @@ -100,9 +118,9 @@ const getValidMoves = (piece: ChessPiece, row: number, col: number): TileSquare[
case ChessPiece.BLACK_KNIGHT:
return getKnightMoves(row, col, board.value);
case ChessPiece.WHITE_PAWN:
return getWhitePawnMoves(row, col, board.value);
return getWhitePawnMoves(row, col, board.value, lastMove.value);
case ChessPiece.BLACK_PAWN:
return getBlackPawnMoves(row, col, board.value);
return getBlackPawnMoves(row, col, board.value, lastMove.value);
case ChessPiece.WHITE_ROOK:
case ChessPiece.BLACK_ROOK:
return getRookMoves(row, col, board.value);
Expand Down Expand Up @@ -137,6 +155,7 @@ const handleTileClick = (tile: TileSquare) => {
function resetChessBoard() {
initializeBoard()
isWhiteTurn.value = true;
lastMove.value = undefined;
}

onMounted(initializeBoard);
Expand Down
66 changes: 64 additions & 2 deletions src/services/ChessRules.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,44 @@ const isSquareUnderAttack = (row:number, col: number, board: TileSquare[], isWhi
return false;
};

// new implementation, lets see if it works
export const enPassantPossible = (board: TileSquare[], lastMove?: { from: number, to: number, piece: string }) => {
if (!lastMove) return null;

const movedPiece = lastMove?.piece;
if (movedPiece !== ChessPiece.WHITE_PAWN && movedPiece !== ChessPiece.BLACK_PAWN) return null;

const fromRow = Math.floor(lastMove.from / 8);
const toRow = Math.floor(lastMove.to / 8);

const toCol = lastMove.to % 8;

if (Math.abs(fromRow - toRow) !== 2) return null;

const attackerPiece = movedPiece === ChessPiece.WHITE_PAWN ? ChessPiece.BLACK_PAWN : ChessPiece.WHITE_PAWN;

const captureToRow = movedPiece === ChessPiece.WHITE_PAWN ? toRow + 1 : toRow - 1;

if (captureToRow < 0 || captureToRow > 7) return null;

const results: { attackerIndex: number; victimIndex: number; captureIndex: number}[] = [];

for (const dc of [-1,1]) {
const attackerCol = toCol + dc;
if (attackerCol < 0 || attackerCol > 7) continue;

const attackerIndex = toRow * 8 + attackerCol;
if (board[attackerIndex].piece === attackerPiece) {
const captureToIndex = captureToRow * 8 + toCol;

if (!board[captureToIndex].piece) {
results.push({attackerIndex, victimIndex: lastMove.to, captureIndex: captureToIndex})
}
}
}
return results.length ? results : null;
}


export const isKingInCheck = (board: TileSquare[], isWhiteKing: boolean): boolean => {
// Find the king's position
Expand Down Expand Up @@ -117,7 +155,7 @@ export const getKnightMoves = (row: number, col: number, board: TileSquare[]): T
return moves;
}

export const getWhitePawnMoves = (row: number, col: number, board: TileSquare[]): TileSquare[] => {
export const getWhitePawnMoves = (row: number, col: number, board: TileSquare[], lastMove?: { from: number; to: number; piece: string }): TileSquare[] => {
const moves: TileSquare[] = [];

const piece = board[row * 8 + col].piece;
Expand Down Expand Up @@ -151,10 +189,22 @@ export const getWhitePawnMoves = (row: number, col: number, board: TileSquare[])
moves.push(board[captureRightIndex]);
}
}

// Check for en passant
const epCaptures = enPassantPossible(board, lastMove);
if (epCaptures) {
const currentIndex = row * 8 + col;
for (const ep of epCaptures) {
if (ep.attackerIndex === currentIndex) {
moves.push(board[ep.captureIndex]);
}
}
}

return moves;
}

export const getBlackPawnMoves = (row: number, col: number, board: TileSquare[]): TileSquare[] => {
export const getBlackPawnMoves = (row: number, col: number, board: TileSquare[], lastMove?: { from: number; to: number; piece: string }): TileSquare[] => {
const moves: TileSquare[] = [];

const piece = board[row * 8 + col].piece;
Expand Down Expand Up @@ -188,6 +238,18 @@ export const getBlackPawnMoves = (row: number, col: number, board: TileSquare[])
moves.push(board[captureRightIndex]);
}
}

// Check for en passant
const epCaptures = enPassantPossible(board, lastMove);
if (epCaptures) {
const currentIndex = row * 8 + col;
for (const ep of epCaptures) {
if (ep.attackerIndex === currentIndex) {
moves.push(board[ep.captureIndex]);
}
}
}

return moves;
}

Expand Down