feat: add tag management functionality to items route with add and remove tag endpoints

backend/routes/items.py

@@ -3,7 +3,7 @@ from sqlalchemy.orm import Session, joinedload
 from uuid import UUID
 from backend.database import get_db
 from backend import models
-from backend.schemas import ItemCreate, ItemOut
+from backend.schemas import ItemCreate, ItemOut, TagIdPayload, TagOut
 
 router = APIRouter(prefix="/items", tags=["items"])
 
@@ -42,6 +42,39 @@ def create_item(payload: ItemCreate, db: Session = Depends(get_db)):
 
     return item
 
+@router.post("/{item_id}/tags", response_model=ItemOut)
+def add_tag_to_item(item_id: UUID, payload: TagIdPayload, db: Session = Depends(get_db)):
+    tag_id = payload.tag_id
+    item = db.get(models.Item, item_id)
+    if not item:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    tag = db.get(models.Tag, tag_id)
+    if not tag or tag.user_id != item.user_id:
+        raise HTTPException(status_code=404, detail="Tag not found")
+    
+    if tag in item.tags:
+        raise HTTPException(status_code=400, detail="Tag already associated with item")
+
+    item.tags.append(tag)
+    db.commit()
+    db.refresh(item)
+    return item
+
+@router.delete("/{item_id}/tags/{tag_id}", response_model=ItemOut)
+def remove_tag_from_item(item_id: UUID, tag_id: UUID, db: Session = Depends(get_db)):
+    item = db.get(models.Item, item_id)
+    if not item:
+        raise HTTPException(status_code=404, detail="Item not found")
+
+    tag = db.get(models.Tag, tag_id)
+    if not tag or tag.user_id != item.user_id:
+        raise HTTPException(status_code=404, detail="Tag not found")
+
+    item.tags.remove(tag)
+    db.commit()
+    db.refresh(item)
+    return item
 
 @router.delete("/{item_id}", status_code=204)
 def delete_item(item_id: UUID, db: Session = Depends(get_db)):

backend/schemas.py

@@ -15,6 +15,9 @@ class TagOut(TagBase):
     class Config:
         orm_mode = True
 
+class TagIdPayload(BaseModel):
+    tag_id: UUID
+
 class ItemBase(BaseModel):
     name: str