feat(anime): add year to folder names on series add

- Add _compute_folder_name helper that deduplicates year (handles cases like 'Name (2023)' not becoming 'Name (2023) (2023)')
- Create anime folder on disk when adding series (not just DB + memory)
- Add rename_folder_if_needed to auto-rename existing folders without year
- Fetch year from aniworld_provider and include in folder as 'Name (YYYY)'

Closes: anime folders now include release year when available from provider

src/server/api/anime.py

@@ -1,4 +1,5 @@
 import logging
+import re
 import warnings
 from typing import Any, List, Optional
 
@@ -8,7 +9,6 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from src.config.settings import settings
 from src.server.database.models import AnimeSeries
-from src.server.utils.key_utils import generate_key_from_folder, is_valid_key
 from src.server.database.service import AnimeSeriesService
 from src.server.exceptions import (
     BadRequestError,
@@ -19,7 +19,6 @@ from src.server.exceptions import (
 from src.server.models.anime import AnimeMetadataUpdate
 from src.server.services.anime_service import AnimeService, AnimeServiceError
 from src.server.services.background_loader_service import BackgroundLoaderService
-
 from src.server.utils.dependencies import (
     get_anime_service,
     get_background_loader_service,
@@ -29,6 +28,7 @@ from src.server.utils.dependencies import (
     require_auth,
 )
 from src.server.utils.filesystem import sanitize_folder_name
+from src.server.utils.key_utils import generate_key_from_folder, is_valid_key
 from src.server.utils.validators import validate_filter_value, validate_search_query
 
 logger = logging.getLogger(__name__)
@@ -36,6 +36,31 @@ logger = logging.getLogger(__name__)
 router = APIRouter(prefix="/api/anime", tags=["anime"])
 
 
+def _compute_folder_name(name: str, year: Optional[int]) -> str:
+    """Compute sanitized folder name from display name and year.
+
+    If year is provided, strips any existing year in (YYYY) format to avoid
+    duplicates, then appends the new year. If year is None, preserves the
+    original name (with any existing year).
+
+    Args:
+        name: Display name of the series
+        year: Release year from provider, or None
+
+    Returns:
+        Sanitized folder name in format "Name (YYYY)" or just "Name"
+    """
+    if year:
+        # Strip any existing year in (YYYY) format before adding new year
+        clean_name = re.sub(r'\s*\(\d{4}\)\s*$', '', name).strip()
+        folder_name_with_year = f"{clean_name} ({year})"
+    else:
+        # No new year provided, preserve original name (with any existing year)
+        folder_name_with_year = name
+
+    return sanitize_folder_name(folder_name_with_year)
+
+
 @router.get("/status")
 async def get_anime_status(
     _auth: dict = Depends(require_auth),
@@ -764,18 +789,9 @@ async def add_series(
             except Exception as e:
                 logger.warning("Could not fetch year for %s: %s", key, e)
         
-        # Create folder name with year if available
+        # Step B: Compute sanitized folder name with year (deduplicates if year already in name)
-        if year:
-            year_suffix = f" ({year})"
-            if name.endswith(year_suffix):
-                folder_name_with_year = name
-            else:
-                folder_name_with_year = f"{name}{year_suffix}"
-        else:
-            folder_name_with_year = name
-        
         try:
-            folder = sanitize_folder_name(folder_name_with_year)
+            folder = _compute_folder_name(name, year)
         except ValueError as e:
             raise HTTPException(
                 status_code=status.HTTP_400_BAD_REQUEST,
@@ -784,7 +800,37 @@ async def add_series(
         
         db_id = None
         
-        # Step C: Save to database if available
+        # Step C: Create folder on disk if it doesn't exist, and rename if needed
+        # Determine the anime directory path
+        anime_dir = settings.anime_directory if hasattr(settings, 'anime_directory') else None
+        current_folder_on_disk = None
+        
+        if anime_dir:
+            import os
+            anime_path = os.path.join(anime_dir, folder)
+            
+            # Check if an existing folder (without year) needs renaming
+            # Look for folder that matches name without year
+            if year:
+                potential_old_name = sanitize_folder_name(name)
+                potential_old_path = os.path.join(anime_dir, potential_old_name)
+                if potential_old_path != anime_path and os.path.exists(potential_old_path):
+                    current_folder_on_disk = potential_old_name
+                    logger.info(
+                        "Found existing folder without year for %s: %s, renaming to %s",
+                        key,
+                        potential_old_name,
+                        folder
+                    )
+                elif not os.path.exists(anime_path):
+                    # No existing folder to rename, create new one
+                    os.makedirs(anime_path, exist_ok=True)
+            else:
+                # No year, just ensure folder exists
+                if not os.path.exists(anime_path):
+                    os.makedirs(anime_path, exist_ok=True)
+        
+        # Step D: Save to database if available
         if db is not None:
             # Check if series already exists in database
             existing = await AnimeSeriesService.get_by_key(db, key)
@@ -850,7 +896,32 @@ async def add_series(
                     year
                 )
         
-        # Step E: Queue background loading task for episodes, NFO, and images
+        # Step E: Rename existing folder if needed (e.g., folder existed without year)
+        if current_folder_on_disk:
+            try:
+                renamed = await anime_service.rename_folder_if_needed(
+                    key=key,
+                    current_folder=current_folder_on_disk,
+                    target_folder=folder,
+                    db=db
+                )
+                if renamed:
+                    logger.info(
+                        "Successfully renamed folder for %s: %s -> %s",
+                        key,
+                        current_folder_on_disk,
+                        folder
+                    )
+            except Exception as e:
+                logger.warning(
+                    "Failed to rename folder for %s: %s -> %s: %s",
+                    key,
+                    current_folder_on_disk,
+                    folder,
+                    e
+                )
+        
+        # Step F: Queue background loading task for episodes, NFO, and images
         try:
             await background_loader.add_series_loading_task(
                 key=key,
@@ -871,7 +942,7 @@ async def add_series(
                 e
             )
 
-        # Step F: Scan missing episodes immediately if background loader is not running
+        # Step G: Scan missing episodes immediately if background loader is not running
         # Uses existing SerieScanner and AnimeService sync to avoid duplicates
         try:
             loader_running = bool(

src/server/services/anime_service.py

@@ -1204,6 +1204,100 @@ class AnimeService:
         
         return anime_series
 
+    async def rename_folder_if_needed(
+        self,
+        key: str,
+        current_folder: str,
+        target_folder: str,
+        db: Optional[AsyncSession] = None,
+    ) -> bool:
+        """Rename anime folder if current and target folders differ.
+
+        Compares current_folder with target_folder, and if different,
+        renames the folder on disk using shutil.move. Updates the DB
+        record and in-memory cache if rename succeeds.
+
+        Args:
+            key: Series unique identifier
+            current_folder: Current folder name (metadata from DB)
+            target_folder: Desired folder name (computed with year)
+            db: Optional database session for updating DB record
+
+        Returns:
+            True if rename was performed, False if no rename needed or failed
+        """
+        import os
+        import shutil
+
+        if current_folder == target_folder:
+            logger.debug(
+                "Folder rename not needed for %s: same folder name",
+                key
+            )
+            return False
+
+        current_path = self._directory / current_folder
+        target_path = self._directory / target_folder
+
+        if not current_path.exists():
+            logger.debug(
+                "Folder rename not needed for %s: current folder does not exist on disk",
+                key
+            )
+            return False
+
+        if target_path.exists():
+            logger.warning(
+                "Cannot rename folder for %s: target path already exists: %s",
+                key,
+                target_path
+            )
+            return False
+
+        try:
+            # Rename folder on disk
+            shutil.move(str(current_path), str(target_path))
+            logger.info(
+                "Renamed folder for %s: %s -> %s",
+                key,
+                current_folder,
+                target_folder
+            )
+
+            # Update in-memory cache
+            if key in self._app.list.keyDict:
+                self._app.list.keyDict[key].folder = target_folder
+                logger.debug(
+                    "Updated in-memory cache folder for %s: %s",
+                    key,
+                    target_folder
+                )
+
+            # Update database if session provided
+            if db is not None:
+                from src.server.database.service import AnimeSeriesService
+
+                # Look up series by key to get database ID
+                series = await AnimeSeriesService.get_by_key(db, key)
+                if series:
+                    await AnimeSeriesService.update(db, series_id=series.id, folder=target_folder)
+                    logger.debug(
+                        "Updated DB folder for %s: %s",
+                        key,
+                        target_folder
+                    )
+
+            return True
+
+        except Exception as e:
+            logger.exception(
+                "Failed to rename folder for %s: %s -> %s",
+                key,
+                current_folder,
+                target_folder
+            )
+            return False
+
     async def contains_in_db(self, key: str, db) -> bool:
         """
         Check if a series with the given key exists in the database.