[database] Slight improvement of the Lichess puzzles import

Author: olivierphi

src/apps/daily_challenge/management/commands/dailychallenge_create_from_lichess_puzzles_csv.py

@@ -2,11 +2,18 @@
 import re
 from pathlib import Path
 
+import chess
 from django.core.management import BaseCommand
 from django.db.models.functions import Substr
 
 from apps.daily_challenge.models import DailyChallenge
 
+THEMES_TO_IGNORE = {
+    "oneMove",
+    "mateIn1",
+    "mateIn2",
+}
+
 
 class Command(BaseCommand):
     def add_arguments(self, parser):
@@ -18,20 +25,20 @@ def add_arguments(self, parser):
         parser.add_argument(
             "--batch-size",
             type=int,
-            default=1000,
+            default=10,  # low batch size to avoid OOM on low-end Fly.io plan
             help="DailyChallenges creation batch size.",
         )
         parser.add_argument(
             "--min-popularity",
             type=int,
-            default=85,
+            default=90,
             help="Only consider puzzles that have at least that Popularity.",
         )
         parser.add_argument(
             "--rating-range",
             type=rating_range,
             dest="rating_min_max",
-            default=(800, 1300),
+            default=(900, 1100),
             help="Only consider puzzles that have a Rating in this 'min-max' range.",
         )
         parser.add_argument(
@@ -63,6 +70,10 @@ def handle(
         with csv_file_path.open(newline="") as csv_file:
             reader = csv.DictReader(csv_file)
             for row in reader:
+                themes: set[str] = set(row.get("Themes", "").split())
+                if themes & THEMES_TO_IGNORE:
+                    self.stdout.write("Skipping too short puzzle")
+                    continue
                 if (popularity := int(row["Popularity"])) < min_popularity:
                     self.stdout.write(f"Skipping puzzle with Popularity {popularity}")
                     continue
@@ -80,6 +91,10 @@ def handle(
                     f"Creating DailyChallenge for puzzle '{puzzle_id}' with Popularity {popularity}, rating {rating}, FEN '{fen}'"
                 )
 
+                if " b " in fen:  # quick and dirty way to detect if black is to move
+                    self.stdout.write("Mirroring puzzle with black to move")
+                    fen = chess.Board(fen).mirror().fen()
+
                 current_batch.append(
                     DailyChallenge(
                         source=f"lichess-{puzzle_id}",