Create Your Chess Bot with AI

Create a chess bot for ChessArena.dev following these rules:

🚨 CRITICAL RULES:
1. ⏰ 20-SECOND TIME LIMIT - Must call reportMove() or we LOSE
2. 🔄 ANYTIME ALGORITHM - Call reportMove() IMMEDIATELY, then improve
3. 📦 SHORTER CODE WINS - In draws, shorter code gets 0.6 points
4. 🚫 BOARD IS READ-ONLY - Use board.clone() to explore moves

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📋 FUNCTION SIGNATURE:
function makeMove(board, timeRemaining, reportMove, getMemory) {
    // board: Read-only chess board interface
    // timeRemaining: Milliseconds available for THIS move (typically 20000ms)
    // reportMove: Function to report your chosen move (anytime algorithm!)
    // getMemory: Function to check memory usage - returns { heapUsed, heapTotal, rss }
}

💾 MEMORY LIMIT:
Your bot has 256MB of memory per execution. Garbage collection runs automatically
between moves, so each move starts with a clean slate. Monitor with getMemory().heapUsed.

⏱️ TIME MANAGEMENT:
Each move gets 20 seconds. Track elapsed time with Date.now():
    const stop = Date.now() + timeRemaining - 500; // Leave 500ms safety margin
    while (Date.now() < stop) {
        // Search for better moves...
    }

🚫 FORBIDDEN:
❌ board.move(move) - CANNOT use on original board!
❌ board.undo() - CANNOT use on original board!
❌ fetch, eval, async, await - No network/dynamic code
❌ Code over 30KB

✅ ALLOWED:
board.moves() → Array of legal moves
board.clone() → Mutable copy (use move/undo on clone!)
board.get(square) → Piece at square
board.turn() → 'w' or 'b'
board.in_check() → Boolean

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💡 ANYTIME ALGORITHM PATTERN:
function makeMove(board, timeRemaining, reportMove) {
    const moves = board.moves();
    const stop = Date.now() + timeRemaining - 500;  // Safety margin

    // STEP 1: Report ANY move immediately (safety!)
    reportMove(moves[0]);

    // STEP 2: Iterative deepening
    for (let depth = 1; depth <= 10; depth++) {
        if (Date.now() >= stop) break;  // Check elapsed time!
        const best = searchAtDepth(board, depth);
        reportMove(best);  // Update with better move
    }
}

🔬 CORRECT CLONE PATTERN FOR MINIMAX:
// Create NEW clone for EACH top-level move
function searchBestMove(board, depth) {
    const moves = board.moves();
    let bestMove = moves[0];
    let bestScore = -Infinity;

    for (const move of moves) {
        const clone = board.clone();  // New clone per move!
        clone.move(move);  // ✅ Safe on clone
        const score = -minimax(clone, depth-1, -Infinity, Infinity);

        if (score > bestScore) {
            bestScore = score;
            bestMove = move;
        }
    }
    return bestMove;
}

// Recursion uses move/undo on the SAME clone
function minimax(clone, depth, alpha, beta) {
    if (depth === 0) return evaluate(clone);

    const moves = clone.moves();
    if (moves.length === 0) {
        return clone.in_checkmate() ? -100000 : 0;
    }

    let best = -Infinity;
    for (const move of moves) {
        clone.move(move);   // ✅ Works on clone
        const score = -minimax(clone, depth-1, -beta, -alpha);
        clone.undo();       // ✅ Works on clone

        if (score > best) best = score;
        if (best > alpha) alpha = best;
        if (alpha >= beta) break;
    }
    return best;
}

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🎯 IMPLEMENT:
1. Minimax or alpha-beta pruning
2. Position evaluation (material, piece-square tables)
3. Iterative deepening
4. Early reportMove() call
5. Time management

Keep code compact (shorter wins draws)!