ChessAgine MCP

import { Chess, Color, WHITE, BLACK, PAWN, Square } from "chess.js"; import { PositionalPawn } from "../types/types.js"; export function getSidePositionalCount(chess: Chess, side: Color): PositionalPawn { const pawnSquares = chess.findPiece({type: PAWN, color: side}); const doublePawns = getDoublePawnCount(pawnSquares); const isolatedPawnCount = getSideIsolatedPawnCount(pawnSquares); const backwardPawnCount = getSideBackwardPawnCount(chess, pawnSquares, side); const passedPawnCount = getPassedPawnCount(chess, side); // Get enemy's pawn weaknesses for comparison const enemySide = side === WHITE ? BLACK : WHITE; const enemyPawnSquares = chess.findPiece({type: PAWN, color: enemySide}); const enemyDoublePawns = getDoublePawnCount(enemyPawnSquares); const enemyIsolatedPawnCount = getSideIsolatedPawnCount(enemyPawnSquares); const enemyBackwardPawnCount = getSideBackwardPawnCount(chess, enemyPawnSquares, enemySide); const enemyPassedPawnCount = getPassedPawnCount(chess, enemySide); // Calculate raw weakness/strength scores // Weaknesses are negative, strengths are positive const ourWeaknesses = doublePawns + isolatedPawnCount + backwardPawnCount; const ourStrengths = passedPawnCount * 3; // Passed pawns are very valuable const ourScore = ourStrengths - ourWeaknesses; const enemyWeaknesses = enemyDoublePawns + enemyIsolatedPawnCount + enemyBackwardPawnCount; const enemyStrengths = enemyPassedPawnCount * 3; const enemyScore = enemyStrengths - enemyWeaknesses; // Positional advantage: our score minus enemy score // Positive = we have better pawn structure // Negative = enemy has better pawn structure const positionalAdvantage = ourScore - enemyScore; return { doublepawncount: doublePawns, isolatedpawncount: isolatedPawnCount, backwardpawncount: backwardPawnCount, passedpawncount: passedPawnCount, positionalAdvatange: positionalAdvantage, // This is now a comparative advantage score }; } function getPassedPawnCount(chess: Chess, side: Color): number { const enemySide = side === WHITE ? BLACK : WHITE; const myPawns = chess.findPiece({type: PAWN, color: side}); const enemyPawns = chess.findPiece({type: PAWN, color: enemySide}); let passedCount = 0; for (const pawnSquare of myPawns) { const file = pawnSquare[0]; const rank = parseInt(pawnSquare[1]); let isPassed = true; // Check if any enemy pawns block this pawn's path or can capture it for (const enemyPawn of enemyPawns) { const enemyFile = enemyPawn[0]; const enemyRank = parseInt(enemyPawn[1]); // Check same file and adjacent files (capture squares) const fileDiff = Math.abs(enemyFile.charCodeAt(0) - file.charCodeAt(0)); if (fileDiff <= 1) { // For white pawns, enemy pawns ahead block the path if (side === WHITE && enemyRank > rank) { isPassed = false; break; } // For black pawns, enemy pawns behind (lower rank) block the path else if (side === BLACK && enemyRank < rank) { isPassed = false; break; } } } if (isPassed) { passedCount++; } } return passedCount; } function getSideIsolatedPawnCount(pawnSquares: string[]): number { const pawnFiles = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h']; const filesWithPawns = new Set(pawnSquares.map(sq => sq[0])); let isolatedCount = 0; for (const file of filesWithPawns) { const fileIndex = pawnFiles.indexOf(file); const hasLeftNeighbor = fileIndex > 0 && filesWithPawns.has(pawnFiles[fileIndex - 1]); const hasRightNeighbor = fileIndex < 7 && filesWithPawns.has(pawnFiles[fileIndex + 1]); if (!hasLeftNeighbor && !hasRightNeighbor) { // Count how many pawns are on this isolated file isolatedCount += pawnSquares.filter(sq => sq[0] === file).length; } } return isolatedCount; } function getSideBackwardPawnCount(chess: Chess, pawnSquares: string[], side: Color): number { const pawnMap = new Map<string, number[]>(); // Group pawns by file for (const square of pawnSquares) { const file = square[0]; const rank = parseInt(square[1], 10); if (!pawnMap.has(file)) pawnMap.set(file, []); pawnMap.get(file)?.push(rank); } let backwardCount = 0; for (const [file, ranks] of pawnMap.entries()) { // Sort ranks appropriately for the side ranks.sort((a, b) => side === WHITE ? b - a : a - b); const fileIndex = "abcdefgh".indexOf(file); const leftRanks = fileIndex > 0 ? pawnMap.get("abcdefgh"[fileIndex - 1]) || [] : []; const rightRanks = fileIndex < 7 ? pawnMap.get("abcdefgh"[fileIndex + 1]) || [] : []; // Get the most advanced friendly pawns on adjacent files const mostAdvancedLeft = side === WHITE ? Math.max(...leftRanks, 0) : Math.min(...leftRanks, 9); const mostAdvancedRight = side === WHITE ? Math.max(...rightRanks, 0) : Math.min(...rightRanks, 9); for (const rank of ranks) { // A pawn is backward if it cannot advance safely and is behind neighboring pawns let isBackward = false; if (side === WHITE) { // For white, backward if behind both neighbors and cannot advance if (rank < mostAdvancedLeft && rank < mostAdvancedRight) { // Check if the square in front is attacked by enemy pawns or occupied const nextRank = rank + 1; if (nextRank <= 8 && !canAdvanceSafely(chess, file + nextRank, side)) { isBackward = true; } } } else { // For black, backward if behind both neighbors and cannot advance if (rank > mostAdvancedLeft && rank > mostAdvancedRight) { // Check if the square in front is attacked by enemy pawns or occupied const nextRank = rank - 1; if (nextRank >= 1 && !canAdvanceSafely(chess, file + nextRank, side)) { isBackward = true; } } } if (isBackward) { backwardCount++; } } } return backwardCount; } function canAdvanceSafely(chess: Chess, square: string, side: Color): boolean { // Check if the square is occupied const piece = chess.get(square as Square); if (piece) { return false; } // Check if the square is attacked by enemy pawns const enemySide = side === WHITE ? BLACK : WHITE; const enemyPawns = chess.findPiece({type: PAWN, color: enemySide}); const file = square[0]; const rank = parseInt(square[1]); for (const enemyPawn of enemyPawns) { const enemyFile = enemyPawn[0]; const enemyRank = parseInt(enemyPawn[1]); // Check if this enemy pawn can capture on the target square const fileDiff = Math.abs(enemyFile.charCodeAt(0) - file.charCodeAt(0)); if (fileDiff === 1) { // Adjacent files if (enemySide === WHITE && enemyRank + 1 === rank) { return false; // White pawn can capture } else if (enemySide === BLACK && enemyRank - 1 === rank) { return false; // Black pawn can capture } } } return true; } function getDoublePawnCount(pawnSquares: string[]): number { const fileCounts = new Map<string, number>(); for (const square of pawnSquares) { const file = square[0]; fileCounts.set(file, (fileCounts.get(file) || 0) + 1); } let doublePawns = 0; for (const count of fileCounts.values()) { if (count > 1) { doublePawns += count - 1; // Each extra pawn beyond the first is a doubled pawn } } return doublePawns; }