Create engine/endgame.py

engine/endgame.py

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+"""
+Endgame Detection for Nexus-Core
+Simplified endgame handling
+"""
+
+import chess
+
+
+class EndgameDetector:
+    """Basic endgame phase detection"""
+    
+    def __init__(self):
+        self.phase = 'middlegame'
+    
+    def detect_phase(self, board: chess.Board) -> str:
+        """Detect game phase"""
+        
+        # Count material
+        total_material = 0
+        piece_values = {
+            chess.PAWN: 1,
+            chess.KNIGHT: 3,
+            chess.BISHOP: 3,
+            chess.ROOK: 5,
+            chess.QUEEN: 9
+        }
+        
+        for piece_type in piece_values:
+            count = len(board.pieces(piece_type, chess.WHITE))
+            count += len(board.pieces(piece_type, chess.BLACK))
+            total_material += count * piece_values[piece_type]
+        
+        # Phase detection
+        if board.fullmove_number < 10:
+            self.phase = 'opening'
+        elif total_material <= 16:
+            self.phase = 'endgame'
+        else:
+            self.phase = 'middlegame'
+        
+        return self.phase
+    
+    def is_known_draw(self, board: chess.Board) -> bool:
+        """Check for known draws"""
+        
+        if board.is_insufficient_material():
+            return True
+        
+        if board.halfmove_clock >= 100:
+            return True
+        
+        return False
+    
+    def adjust_evaluation(self, board: chess.Board, eval_score: float) -> float:
+        """Adjust evaluation for endgame"""
+        
+        phase = self.detect_phase(board)
+        
+        if self.is_known_draw(board):
+            return 0.0
+        
+        # Endgame adjustments
+        if phase == 'endgame':
+            # King activity bonus
+            king_activity = self._king_activity_bonus(board)
+            eval_score += king_activity
+        
+        return eval_score
+    
+    def _king_activity_bonus(self, board: chess.Board) -> float:
+        """King activity in endgame"""
+        bonus = 0.0
+        
+        for color in [chess.WHITE, chess.BLACK]:
+            king_sq = board.king(color)
+            if king_sq is None:
+                continue
+            
+            # Distance to center
+            rank, file = divmod(king_sq, 8)
+            center_distance = abs(rank - 3.5) + abs(file - 3.5)
+            
+            activity = (7 - center_distance) * 5
+            
+            if color == chess.WHITE:
+                bonus += activity
+            else:
+                bonus -= activity
+        
+        return bonus