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ChessEngine -naive algorithm.py
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ChessEngine -naive algorithm.py
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class GameState():
def __init__(self):
self.board = [
["bR", "bN", "bB", "bQ", "bK", "bB", "bN", "bR"],
["bp", "bp", "bp", "bp", "bp", "bp", "bp", "bp"],
["--", "--", "--", "--", "--", "--", "--", "--"],
["--", "--", "--", "--", "--", "--", "--", "--"],
["--", "--", "--", "--", "--", "--", "--", "--"],
["--", "--", "--", "--", "--", "--", "--", "--"],
["wp", "wp", "wp", "wp", "wp", "wp", "wp", "wp"],
["wR", "wN", "wB", "wQ", "wK", "wB", "wN", "wR"]
]
self.moveFunctions = {'p': self.getPawnMoves, 'R': self.getRookMoves, 'N': self.getKnightMoves,
'B': self.getBishopMoves, 'Q': self.getQueenMoves, 'K': self.getKingMoves,}
self.whiteToMove = True
self.moveLog = []
self.whiteKingLocate = (7, 4)
self.blackKingLocate = (0, 4)
self.checkMate = False
self.staleMate = False
self.enpassantPossible = ()
def makeMove(self, move):
self.board[move.startRow][move.startCol] = "--"
self.board[move.endRow][move.endCol] = move.pieceMoved
self.moveLog.append(move)
self.whiteToMove = not self.whiteToMove
if move.pieceMoved == "wK":
self.whiteKingLocate = (move.endRow, move.endCol)
if move.pieceMoved == "bK":
self.blackKingLocate = (move.endRow, move.endCol)
# Enpassant Move
if move.isEnpassantMove:
print("HERE")
self.board[move.startRow][move.endCol] = "--" # capturing the pawn
# EnpassantPossible update
if move.pieceMoved[1] == 'p' and (abs(move.startRow - move.endRow) == 2): # only 2 squares pawn move
self.enpassantPossible = ((move.startRow + move.endRow) // 2, move.endCol)
else:
self.enpassantPossible = () # not en passant move
def undoMove(self):
if len(self.moveLog) != 0:
move = self.moveLog.pop()
self.board[move.startRow][move.startCol] = move.pieceMoved
self.board[move.endRow][move.endCol] = move.pieceCaptured
self.whiteToMove = not self.whiteToMove
if move.pieceMoved == "wK":
self.whiteKingLocate = (move.startRow, move.startCol)
if move.pieceMoved == "bK":
self.blackKingLocate = (move.startRow, move.startCol)
if move.isEnpassantMove:
self.board[move.endRow][move.endCol] = "--"
self.board[move.startRow][move.endCol] = move.pieceCaptured
self.enpassantPossible = (move.endRow, move.endCol)
if move.pieceMoved[1] == 'p' and abs(move.startRow - move.endRow) == 2:
self.enpassantPossible = ()
def getValidMoves(self):
tempEnpassantPossible = self.enpassantPossible
moves = self.getAllPossibleMoves()
for i in range(len(moves)-1, -1, -1):
self.makeMove(moves[i])
self.whiteToMove = not self.whiteToMove
if self.inCheck():
moves.remove(moves[i])
self.undoMove()
self.whiteToMove = not self.whiteToMove
if len(moves) == 0:
if self.inCheck():
self.checkMate = True
print("checkMate")
else:
self.staleMate = True
print("staleMate")
else:
self.checkMate = False
self.staleMate = False
self.enpassantPossible = tempEnpassantPossible
return moves
def inCheck(self):
if self.whiteToMove:
return self.sqUnderAttack(self.whiteKingLocate[0], self.whiteKingLocate[1])
else:
return self.sqUnderAttack(self.blackKingLocate[0], self.blackKingLocate[1])
def sqUnderAttack(self, r, c):
self.whiteToMove = not self.whiteToMove
oppMoves = self.getAllPossibleMoves()
self.whiteToMove = not self.whiteToMove
for move in oppMoves:
if move.endRow == r and move.endCol == c:
return True
return False
def getAllPossibleMoves(self):
moves = []
for r in range(len(self.board)):
for c in range(len(self.board[r])):
turn = self.board[r][c][0]
if (turn == 'w' and self.whiteToMove) or (turn == 'b' and not self.whiteToMove):
piece = self.board[r][c][1]
self.moveFunctions[piece](r, c, moves)
return moves
def getPawnMoves(self, r, c, moves):
if self.whiteToMove:
if self.board[r-1][c] == "--":
moves.append(Move((r, c), (r-1, c), self.board))
if self.board[r-2][c] == "--" and r == 6:
moves.append(Move((r, c), (r-2, c), self.board))
if c-1 >= 0:
if self.board[r-1][c-1][0] == "b":
moves.append(Move((r, c), (r-1, c-1), self.board))
elif (r - 1, c - 1) == self.enpassantPossible:
moves.append(Move((r, c), (r - 1, c - 1), self.board, isEnpassantMove=True))
if c+1 <= 7:
if self.board[r-1][c+1][0] == "b":
moves.append(Move((r, c), (r-1, c+1), self.board))
elif (r - 1, c + 1) == self.enpassantPossible:
moves.append(Move((r, c), (r - 1, c + 1), self.board, isEnpassantMove=True))
else:
if self.board[r+1][c] == "--":
moves.append(Move((r, c), (r+1, c), self.board))
if self.board[r+2][c] == "--" and r == 1:
moves.append(Move((r, c), (r+2, c), self.board))
if c-1 >= 0:
if self.board[r+1][c-1][0] == "w":
moves.append(Move((r, c), (r+1, c-1), self.board))
elif (r + 1, c - 1) == self.enpassantPossible:
moves.append(Move((r, c), (r + 1, c - 1), self.board, isEnpassantMove=True))
if c+1 <= 7:
if self.board[r+1][c+1][0] == "w":
moves.append(Move((r, c), (r+1, c+1), self.board))
elif (r + 1, c + 1) == self.enpassantPossible:
moves.append(Move((r, c), (r + 1, c + 1), self.board, isEnpassantMove=True))
def getRookMoves(self, r, c, moves):
straightDirections = ((-1, 0), (1, 0), (0, -1), (0, 1))
enemyColor = 'b' if self.whiteToMove else 'w'
for d in straightDirections:
for i in range(1, 8):
endRow = r + d[0] * i
endCol = c + d[1] * i
if (0 <= endRow < 8) and (0 <= endCol < 8):
endPiece = self.board[endRow][endCol]
if endPiece == "--":
moves.append(Move((r, c), (endRow, endCol), self.board))
elif endPiece[0] == enemyColor:
moves.append(Move((r, c), (endRow, endCol), self.board))
break
else:
break
else:
break
def getKnightMoves(self, r, c, moves):
knightDirections = ((-2, -1), (-1, -2), (1, -2), (2, -1), (2, 1), (1, 2), (-1, 2), (-2, 1))
allyColor = 'w' if self.whiteToMove else 'b'
for d in knightDirections:
endRow = r + d[0]
endCol = c + d[1]
if (0 <= endRow < 8) and (0 <= endCol < 8):
endPiece = self.board[endRow][endCol]
if endPiece[0] != allyColor:
moves.append(Move((r, c), (endRow, endCol), self.board))
def getBishopMoves(self, r, c, moves):
diagonalDirections = ((-1, -1), (1, 1), (1, -1), (-1, 1))
enemyColor = 'b' if self.whiteToMove else 'w'
for d in diagonalDirections:
for i in range(1, 8):
endRow = r + d[0] * i
endCol = c + d[1] * i
if (0 <= endRow < 8) and (0 <= endCol < 8):
endPiece = self.board[endRow][endCol]
if endPiece == "--":
moves.append(Move((r, c), (endRow, endCol), self.board))
elif endPiece[0] == enemyColor:
moves.append(Move((r, c), (endRow, endCol), self.board))
break
else:
break
else:
break
def getQueenMoves(self, r, c, moves):
self.getRookMoves(r, c, moves)
self.getBishopMoves(r, c, moves)
def getKingMoves(self, r, c, moves):
kingDirections = ((-1, 0), (1, 0), (0, -1), (0, 1), (-1, -1), (1, 1), (1, -1), (-1, 1))
allyColor = 'w' if self.whiteToMove else 'b'
for i in range(8):
endRow = r + kingDirections[i][0]
endCol = c + kingDirections[i][1]
if (0 <= endRow < 8) and (0 <= endCol < 8):
endPiece = self.board[endRow][endCol]
if endPiece[0] != allyColor:
moves.append(Move((r, c), (endRow, endCol), self.board))
class Move():
ranksToRows = {"1": 7, "2": 6, "3": 5, "4": 4, "5": 3, "6": 2, "7": 1, "8": 0}
rowsToRanks = {v: k for k, v in ranksToRows.items()}
filesToCols = {"a": 0, "b": 1, "c": 2, "d": 3, "e": 4, "f": 5, "g": 6, "h": 7}
colsToFiles = {v: k for k, v in filesToCols.items()}
def __init__(self, startSq, endSq, board, isEnpassantMove = False):
self.startRow = startSq[0]
self.startCol = startSq[1]
self.endRow = endSq[0]
self.endCol = endSq[1]
self.pieceMoved = board[self.startRow][self.startCol]
self.pieceCaptured = board[self.endRow][self.endCol]
self.isEnpassantMove = isEnpassantMove
if self.isEnpassantMove:
self.pieceCaptured = "wp" if self.pieceMoved == "bp" else "bp"
self.moveID = self.startCol * 1000 + self.startRow * 100 + self.endCol * 10 + self.endRow
def __eq__(self, other):
if isinstance(other, Move):
return self.moveID == other.moveID
else:
return False
def getChessNotation(self):
return self.getFileRank(self.startRow, self.startCol) + "-" + self.getFileRank(self.endRow, self.endCol)
def getFileRank(self, row, col):
return self.colsToFiles[col] + self.rowsToRanks[row]