refactor: simplify recommendation filtering and enhance theme-based service logic

Author: TimilsinaBimal

app/services/recommendation/filtering.py

@@ -143,10 +143,6 @@ def get_genre_multiplier(genre_ids: list[int] | None, whitelist: set[int]) -> fl
         if not gids:
             return 1.0
 
-        # Special handling for Animation (16): Heavy penalty if not in whitelist
-        if 16 in gids and 16 not in whitelist:
-            return 0.1
-
         # If it has at least one preferred genre, full score
         if gids & whitelist:
             return 1.0

app/services/recommendation/item_based.py

@@ -98,6 +98,13 @@ async def _fetch_candidates(self, tmdb_id: int, mtype: str) -> list[dict[str, An
             return_exceptions=True,
         )
 
+        if not results:
+            # fetch similar
+            results = await asyncio.gather(
+                *[self.tmdb_service.get_similar(tmdb_id, mtype, page=p) for p in [1, 2]],
+                return_exceptions=True,
+            )
+
         for res in results:
             if isinstance(res, Exception):
                 logger.warning(f"Error fetching recommendations for {tmdb_id}: {res}")

app/services/recommendation/theme_based.py

@@ -1,14 +1,17 @@
 import asyncio
+from datetime import datetime
 from typing import Any
 
 from loguru import logger
 
 from app.models.taste_profile import TasteProfile
+from app.services.profile.constants import TOP_PICKS_MIN_RATING, TOP_PICKS_MIN_VOTE_COUNT
 from app.services.profile.scorer import ProfileScorer
 from app.services.recommendation.filtering import RecommendationFiltering
 from app.services.recommendation.metadata import RecommendationMetadata
 from app.services.recommendation.scoring import RecommendationScoring
 from app.services.recommendation.utils import content_type_to_mtype, filter_by_genres, filter_watched_by_imdb
+from app.services.tmdb.service import TMDBService
 
 
 class ThemeBasedService:
@@ -24,7 +27,7 @@ class ThemeBasedService:
     """
 
     def __init__(self, tmdb_service: Any, user_settings: Any = None):
-        self.tmdb_service = tmdb_service
+        self.tmdb_service: TMDBService = tmdb_service
         self.user_settings = user_settings
         self.scorer = ProfileScorer()
 
@@ -77,11 +80,13 @@ async def get_recommendations_for_theme(
         # Fetch candidates
         candidates = await self._fetch_discover_candidates(content_type, params, pages_to_fetch)
 
-        # Use provided whitelist (or empty set if not provided)
-        whitelist = whitelist or set()
+        # # Use provided whitelist (or empty set if not provided)
+        # whitelist = whitelist or set()
 
-        # Initial filter (watched + genre whitelist)
-        filtered = self._filter_candidates(candidates, watched_tmdb, whitelist)
+        # # Initial filter (watched + genre whitelist)
+        # filtered = self._filter_candidates(candidates, watched_tmdb, whitelist)
+
+        filtered = candidates
 
         # If not enough candidates, fetch more pages
         if len(filtered) < limit * 2 and max(pages_to_fetch) < 15:
@@ -123,6 +128,9 @@ async def get_recommendations_for_theme(
             scored.sort(key=lambda x: x[0], reverse=True)
             filtered = [item for _, item in scored]
 
+        # limit items to limit *2
+        filtered = filtered[: limit * 2]
+
         # Enrich metadata
         enriched = await RecommendationMetadata.fetch_batch(
             self.tmdb_service, filtered, content_type, user_settings=self.user_settings
@@ -168,17 +176,28 @@ def _parse_theme_id(self, theme_id: str, content_type: str) -> dict[str, Any]:
                     is_tv = content_type in ("tv", "series")
                     prefix = "first_air_date" if is_tv else "primary_release_date"
                     params[f"{prefix}.gte"] = f"{year}-01-01"
-                    params[f"{prefix}.lte"] = f"{year+9}-12-31"
+                    end_year = year + 9
+                    end_date_str = f"{end_year}-12-31"
+                    today_str = datetime.now().strftime("%Y-%m-%d")
+                    # If the calculated end date is after today, use today
+                    if end_date_str > today_str:
+                        params[f"{prefix}.lte"] = today_str
+                    else:
+                        params[f"{prefix}.lte"] = end_date_str
                 except Exception:
                     pass
             elif part == "sort-vote":
                 params["sort_by"] = "vote_average.desc"
-                params["vote_count.gte"] = 200
+                params["vote_count.gte"] = TOP_PICKS_MIN_VOTE_COUNT
 
         # Default sort
         if "sort_by" not in params:
             params["sort_by"] = "popularity.desc"
 
+        # add default vote count and vote average
+        params["vote_count.gte"] = TOP_PICKS_MIN_VOTE_COUNT
+        params["vote_average.gte"] = TOP_PICKS_MIN_RATING
+
         return params
 
     def _calculate_pages_to_fetch(self, num_excluded_genres: int) -> list[int]: