pawns have their legal move list

src/logic/board.py

@@ -37,6 +37,16 @@ class Board:
             self._white[pos_w_piece] = piece(pos_w_piece, Piece.WHITE)
             self._black[pos_b_piece] = piece(pos_b_piece, Piece.BLACK)
 
+    def piece_at(self, x: int, y: int) -> Piece | None:
+        pos = Position(x, y)
+        white_piece = self._white.get(pos, None)
+        black_piece = self._black.get(pos, None)
+
+        assert white_piece == None or black_piece == None, f"There are two pieces at the same position {pos}, this shouldn't happen!"
+
+        if white_piece != None:
+            return white_piece
+        return black_piece
 
 def create_board():
     return Board()

src/logic/pieces/pawn.py

@@ -1,7 +1,31 @@
-from .piece import Piece
+from logic.position import Position
+from logic.pieces.piece import Piece
 
 class Pawn(Piece):
-    def __init__(self, pos) -> None:
-        super().__init__(pos)
-        self.already_moved = False
+    def legal_moves(self, board) -> list[Position]:
+        ret = []
 
+        # can we capture to the left?
+        if self.pos.x > 0 and (
+            (self.colour == self.WHITE and (capturable_piece := board.piece_at(self.pos.x - 1, self.pos.y + 1)))
+            or
+            (self.colour == self.BLACK and (capturable_piece := board.piece_at(self.pos.x - 1, self.pos.y - 1)))
+        ):
+            if capturable_piece.colour != self.colour:
+                ret.append(capturable_piece.pos)
+
+        # can we capture to the right?
+        if self.pos.x < 7 and (
+            (self.colour == self.WHITE and (capturable_piece := board.piece_at(self.pos.x + 1, self.pos.y + 1)))
+            or
+            (self.colour == self.BLACK and (capturable_piece := board.piece_at(self.pos.x + 1, self.pos.y - 1)))
+        ):
+            if capturable_piece.colour != self.colour:
+                ret.append(capturable_piece.pos)
+
+        for dy in range(1, 3 if self.pos.y == 1 else 2):
+            if self.pos.y + dy > 7 or board.piece_at(self.pos.x, self.pos.y + dy):
+                break
+            ret.append(Position(self.pos.x, self.pos.y + dy))
+
+        return ret