feat: migrate persistence from JSON to SQLModel (Phase 1)

- Integrated SQLModel with SQLite for robust data persistence
- Refactored UserManager and WatchlistManager to use SQL queries
- Migrated models to SQLModel with relationships and primary keys
- Updated test suite with in-memory database isolation
- Removed deprecated JSON storage files

app/models/watchlist.py

@@ -1,8 +1,11 @@
-"""Pydantic models for Watchlist and Auto-Download system"""
-from pydantic import BaseModel, Field
-from typing import Optional, Literal
+"""Models for Watchlist and Auto-Download system with SQLModel support"""
+import uuid
+import json
+from pydantic import BaseModel, Field as PydanticField
+from typing import Optional, Literal, List
 from datetime import datetime
 from enum import Enum
+from sqlmodel import SQLModel, Field, Relationship, Column, String
 
 
 class WatchlistStatus(str, Enum):
@@ -21,34 +24,80 @@ class QualityPreference(str, Enum):
     P480 = "480p"               # SD
 
 
-class WatchlistItem(BaseModel):
-    """An anime being tracked for automatic episode downloads"""
-    id: str = Field(..., description="Unique identifier (UUID)")
-    user_id: str = Field(..., description="User ID who owns this watchlist item")
-    anime_title: str = Field(..., description="Title of the anime")
-    anime_url: str = Field(..., description="URL to the anime page")
-    provider_id: str = Field(..., description="Provider ID (animesama, nekosama, etc.)")
-    lang: Literal["vostfr", "vf"] = Field(default="vostfr", description="Language preference")
+class WatchlistItemBase(SQLModel):
+    """Base schema for watchlist items"""
+    anime_title: str = Field(index=True)
+    anime_url: str
+    provider_id: str
+    lang: str = Field(default="vostfr")
 
     # Tracking state
-    last_checked: Optional[datetime] = Field(None, description="Last time we checked for new episodes")
-    last_episode_downloaded: int = Field(default=0, description="Last episode number downloaded")
-    total_episodes: Optional[int] = Field(None, description="Total episodes if known")
+    last_checked: Optional[datetime] = None
+    last_episode_downloaded: int = Field(default=0)
+    total_episodes: Optional[int] = None
 
     # Settings
-    auto_download: bool = Field(default=True, description="Automatically download new episodes")
-    quality_preference: QualityPreference = Field(default=QualityPreference.AUTO, description="Preferred quality")
-    status: WatchlistStatus = Field(default=WatchlistStatus.ACTIVE, description="Tracking status")
+    auto_download: bool = Field(default=True)
+    quality_preference: QualityPreference = Field(default=QualityPreference.AUTO)
+    status: WatchlistStatus = Field(default=WatchlistStatus.ACTIVE)
 
     # Metadata
-    poster_image: Optional[str] = Field(None, description="URL to poster image")
-    cover_image: Optional[str] = Field(None, description="URL to cover image")
-    synopsis: Optional[str] = Field(None, description="Anime synopsis")
-    genres: list[str] = Field(default_factory=list, description="Anime genres")
-
+    poster_image: Optional[str] = None
+    cover_image: Optional[str] = None
+    synopsis: Optional[str] = None
+    
     # Timestamps
-    added_at: datetime = Field(default_factory=datetime.now, description="When added to watchlist")
-    updated_at: datetime = Field(default_factory=datetime.now, description="Last update time")
+    added_at: datetime = Field(default_factory=datetime.now)
+    updated_at: datetime = Field(default_factory=datetime.now)
+
+
+class WatchlistItemTable(WatchlistItemBase, table=True):
+    """Database table for watchlist items"""
+    __tablename__ = "watchlist_items"
+    
+    id: str = Field(
+        default_factory=lambda: str(uuid.uuid4()),
+        primary_key=True,
+        index=True,
+        nullable=False
+    )
+    user_id: str = Field(foreign_key="users.id", index=True)
+    
+    # Store list as JSON string in SQLite
+    genres_json: Optional[str] = Field(default="[]", sa_column=Column(String))
+    
+    @property
+    def genres(self) -> List[str]:
+        return json.loads(self.genres_json or "[]")
+    
+    @genres.setter
+    def genres(self, value: List[str]):
+        self.genres_json = json.dumps(value or [])
+    
+    # Relationships
+    user: Optional["UserTable"] = Relationship(back_populates="watchlist_items")
+
+
+class WatchlistItem(BaseModel):
+    """An anime being tracked for automatic episode downloads (API Response)"""
+    id: str
+    user_id: str
+    anime_title: str
+    anime_url: str
+    provider_id: str
+    lang: str
+    last_checked: Optional[datetime] = None
+    last_episode_downloaded: int = 0
+    total_episodes: Optional[int] = None
+    auto_download: bool = True
+    quality_preference: QualityPreference = QualityPreference.AUTO
+    status: WatchlistStatus = WatchlistStatus.ACTIVE
+    poster_image: Optional[str] = None
+    cover_image: Optional[str] = None
+    synopsis: Optional[str] = None
+    genres: List[str] = []
+    added_at: datetime
+    updated_at: datetime
 
     class Config:
         json_encoders = {
@@ -64,12 +113,10 @@ class WatchlistItemCreate(BaseModel):
     lang: Literal["vostfr", "vf"] = "vostfr"
     auto_download: bool = True
     quality_preference: QualityPreference = QualityPreference.AUTO
-
-    # Optional metadata
     poster_image: Optional[str] = None
     cover_image: Optional[str] = None
     synopsis: Optional[str] = None
-    genres: list[str] = []
+    genres: List[str] = []
 
 
 class WatchlistItemUpdate(BaseModel):
@@ -96,26 +143,15 @@ class AutoDownloadResult(BaseModel):
     watchlist_item_id: str
     anime_title: str
     new_episodes_found: int
-    episodes_downloaded: list[int] = Field(default_factory=list)
-    episodes_failed: list[tuple[int, str]] = Field(default_factory=list)  # (episode_number, error_message)
-    checked_at: datetime = Field(default_factory=datetime.now)
+    episodes_downloaded: list[int] = PydanticField(default_factory=list)
+    episodes_failed: list[tuple[int, str]] = PydanticField(default_factory=list)
+    checked_at: datetime = PydanticField(default_factory=datetime.now)
 
 
 class WatchlistSettings(BaseModel):
     """Global watchlist settings"""
-    check_interval_hours: int = Field(default=6, ge=1, le=168, description="Check interval (1-168 hours)")
-    auto_download_enabled: bool = Field(default=True, description="Global auto-download toggle")
-    max_concurrent_auto_downloads: int = Field(default=2, ge=1, le=10, description="Max concurrent auto-downloads")
-    notify_on_new_episodes: bool = Field(default=False, description="Send notifications for new episodes")
-    include_completed_anime: bool = Field(default=False, description="Check completed anime too")
-
-    class Config:
-        json_schema_extra = {
-            "example": {
-                "check_interval_hours": 6,
-                "auto_download_enabled": True,
-                "max_concurrent_auto_downloads": 2,
-                "notify_on_new_episodes": False,
-                "include_completed_anime": False
-            }
-        }
+    check_interval_hours: int = PydanticField(default=6, ge=1, le=168)
+    auto_download_enabled: bool = PydanticField(default=True)
+    max_concurrent_auto_downloads: int = PydanticField(default=2, ge=1, le=10)
+    notify_on_new_episodes: bool = PydanticField(default=False)
+    include_completed_anime: bool = PydanticField(default=False)