# File: backend/app/api/v1/endpoints/assistants.py (Update with DB session dependency)
# Description: 助手的 API 路由 (使用数据库会话)

from fastapi import APIRouter, HTTPException, Depends, status
from typing import List
from sqlalchemy.ext.asyncio import AsyncSession
from app.db.database import get_db_session # Import DB session dependency
from app.models.pydantic_models import AssistantRead, AssistantCreate, AssistantUpdate
from app.services.assistant_service import AssistantService # Import the class

router = APIRouter()

# --- Dependency Injection for Service and DB Session ---
# Service instance can be created per request or globally
# For simplicity, let's create it here, but pass db session to methods
assistant_service = AssistantService()

@router.post("/", response_model=AssistantRead, status_code=status.HTTP_201_CREATED)
async def create_new_assistant(
    assistant_data: AssistantCreate,
    db: AsyncSession = Depends(get_db_session) # Inject DB session
):
    return await assistant_service.create_assistant(db, assistant_data)

@router.get("/", response_model=List[AssistantRead])
async def read_all_assistants(
    db: AsyncSession = Depends(get_db_session)
):
    return await assistant_service.get_assistants(db)

@router.get("/{assistant_id}", response_model=AssistantRead)
async def read_assistant_by_id(
    assistant_id: str,
    db: AsyncSession = Depends(get_db_session)
):
    assistant = await assistant_service.get_assistant(db, assistant_id)
    if not assistant:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="找不到指定的助手")
    return assistant

@router.put("/{assistant_id}", response_model=AssistantRead)
async def update_existing_assistant(
    assistant_id: str,
    assistant_data: AssistantUpdate,
    db: AsyncSession = Depends(get_db_session)
):
    updated_assistant = await assistant_service.update_assistant(db, assistant_id, assistant_data)
    if not updated_assistant:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="找不到指定的助手")
    return updated_assistant

@router.delete("/{assistant_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_existing_assistant(
    assistant_id: str,
    db: AsyncSession = Depends(get_db_session)
):
    # Handle potential error from service if trying to delete default
    try:
        deleted = await assistant_service.delete_assistant(db, assistant_id)
        if not deleted:
             # Check if it exists to differentiate 404 from 403 (or handle in service)
             assistant = await assistant_service.get_assistant(db, assistant_id)
             if assistant and assistant_id == 'asst-default':
                  raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="不允许删除默认助手")
             raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="找不到指定的助手")
    except Exception as e: # Catch other potential DB errors
        print(f"删除助手时出错: {e}")
        raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail="删除助手失败")