Enhance story item management with track editing functionality

- Introduced StoryTrackEditor component for managing story item positions and tracks.
- Updated StoriesTab to conditionally render the track editor based on selected story.
- Implemented moveStoryItem API endpoint to handle item repositioning and track changes.
- Enhanced story item data model to include track information.
- Improved audio playback management to support multiple tracks using Web Audio API.
- Added hooks for moving story items and managing playback timing.

backend/database.py

@@ -70,6 +70,7 @@ class StoryItem(Base):
     story_id = Column(String, ForeignKey("stories.id"), nullable=False)
     generation_id = Column(String, ForeignKey("generations.id"), nullable=False)
     start_time_ms = Column(Integer, nullable=False, default=0)  # Milliseconds from story start
+    track = Column(Integer, nullable=False, default=0)  # Track number (0 = main track)
     created_at = Column(DateTime, default=datetime.utcnow)
 
 
@@ -245,6 +246,16 @@ def _run_migrations(engine):
             
             conn.commit()
             print("Migrated story_items table to use start_time_ms (removed position column)")
+    
+    # Migration: Add track column if it doesn't exist
+    # Re-check columns after potential position migration
+    columns = {col['name'] for col in inspector.get_columns('story_items')}
+    if 'track' not in columns:
+        print("Migrating story_items: adding track column")
+        with engine.connect() as conn:
+            conn.execute(text("ALTER TABLE story_items ADD COLUMN track INTEGER NOT NULL DEFAULT 0"))
+            conn.commit()
+            print("Added track column to story_items")
 
 
 def get_db():

backend/main.py

@@ -809,6 +809,20 @@ async def reorder_story_items(
     return items
 
 
+@app.put("/stories/{story_id}/items/{generation_id}/move", response_model=models.StoryItemDetail)
+async def move_story_item(
+    story_id: str,
+    generation_id: str,
+    data: models.StoryItemMove,
+    db: Session = Depends(get_db),
+):
+    """Move a story item (update position and/or track)."""
+    item = await stories.move_story_item(story_id, generation_id, data, db)
+    if item is None:
+        raise HTTPException(status_code=404, detail="Story item not found")
+    return item
+
+
 @app.get("/stories/{story_id}/export-audio")
 async def export_story_audio(
     story_id: str,

backend/models.py

@@ -220,6 +220,7 @@ class StoryItemDetail(BaseModel):
     story_id: str
     generation_id: str
     start_time_ms: int
+    track: int = 0
     created_at: datetime
     # Generation details
     profile_id: str
@@ -253,6 +254,7 @@ class StoryItemCreate(BaseModel):
     """Request model for adding a generation to a story."""
     generation_id: str
     start_time_ms: Optional[int] = None  # If not provided, will be calculated automatically
+    track: Optional[int] = 0  # Track number (0 = main track)
 
 
 class StoryItemUpdateTime(BaseModel):
@@ -269,3 +271,9 @@ class StoryItemBatchUpdate(BaseModel):
 class StoryItemReorder(BaseModel):
     """Request model for reordering story items."""
     generation_ids: List[str] = Field(..., min_length=1)
+
+
+class StoryItemMove(BaseModel):
+    """Request model for moving a story item (position and/or track)."""
+    start_time_ms: int = Field(..., ge=0)
+    track: int = 0

backend/stories.py

@@ -17,6 +17,7 @@ from .models import (
     StoryItemDetail,
     StoryItemCreate,
     StoryItemBatchUpdate,
+    StoryItemMove,
 )
 from .database import Story as DBStory, StoryItem as DBStoryItem, Generation as DBGeneration, VoiceProfile as DBVoiceProfile
 from .utils.audio import load_audio, save_audio
@@ -127,6 +128,7 @@ async def get_story(
             story_id=item.story_id,
             generation_id=item.generation_id,
             start_time_ms=item.start_time_ms,
+            track=item.track,
             created_at=item.created_at,
             profile_id=generation.profile_id,
             profile_name=profile_name,
@@ -249,6 +251,7 @@ async def add_item_to_story(
             story_id=existing.story_id,
             generation_id=existing.generation_id,
             start_time_ms=existing.start_time_ms,
+            track=existing.track,
             created_at=existing.created_at,
             profile_id=generation.profile_id,
             profile_name=profile.name if profile else "Unknown",
@@ -288,12 +291,16 @@ async def add_item_to_story(
             # Add 200ms gap after the last item
             start_time_ms = max_end_time_ms + 200
 
+    # Get track from data or default to 0
+    track = data.track if data.track is not None else 0
+
     # Create item
     item = DBStoryItem(
         id=str(uuid.uuid4()),
         story_id=story_id,
         generation_id=data.generation_id,
         start_time_ms=start_time_ms,
+        track=track,
         created_at=datetime.utcnow(),
     )
 
@@ -313,6 +320,72 @@ async def add_item_to_story(
         story_id=item.story_id,
         generation_id=item.generation_id,
         start_time_ms=item.start_time_ms,
+        track=item.track,
+        created_at=item.created_at,
+        profile_id=generation.profile_id,
+        profile_name=profile.name if profile else "Unknown",
+        text=generation.text,
+        language=generation.language,
+        audio_path=generation.audio_path,
+        duration=generation.duration,
+        seed=generation.seed,
+        instruct=generation.instruct,
+        generation_created_at=generation.created_at,
+    )
+
+
+async def move_story_item(
+    story_id: str,
+    generation_id: str,
+    data: StoryItemMove,
+    db: Session,
+) -> Optional[StoryItemDetail]:
+    """
+    Move a story item (update position and/or track).
+
+    Args:
+        story_id: Story ID
+        generation_id: Generation ID of the item to move
+        data: New position and track data
+        db: Database session
+
+    Returns:
+        Updated item detail or None if not found
+    """
+    # Get the item
+    item = db.query(DBStoryItem).filter_by(
+        story_id=story_id,
+        generation_id=generation_id
+    ).first()
+    if not item:
+        return None
+
+    # Get the generation
+    generation = db.query(DBGeneration).filter_by(id=generation_id).first()
+    if not generation:
+        return None
+
+    # Update position and track
+    item.start_time_ms = data.start_time_ms
+    item.track = data.track
+
+    # Update story updated_at
+    story = db.query(DBStory).filter_by(id=story_id).first()
+    if story:
+        story.updated_at = datetime.utcnow()
+
+    db.commit()
+    db.refresh(item)
+
+    # Get profile name
+    profile = db.query(DBVoiceProfile).filter_by(id=generation.profile_id).first()
+
+    return StoryItemDetail(
+        id=item.id,
+        story_id=item.story_id,
+        generation_id=item.generation_id,
+        start_time_ms=item.start_time_ms,
+        track=item.track,
         created_at=item.created_at,
         profile_id=generation.profile_id,
         profile_name=profile.name if profile else "Unknown",
@@ -464,6 +537,7 @@ async def reorder_story_items(
             story_id=item.story_id,
             generation_id=item.generation_id,
             start_time_ms=item.start_time_ms,
+            track=item.track,
             created_at=item.created_at,
             profile_id=generation.profile_id,
             profile_name=profile_name,