import logging
from fastapi import APIRouter, HTTPException
from concurrent.futures import ThreadPoolExecutor

from app.schemas.response_template import ResponseModel
from app.service.recommendation_system.precompute import run_precompute

logger = logging.getLogger()
router = APIRouter()

# 使用线程池执行器来运行长时间任务
executor = ThreadPoolExecutor(max_workers=1)
# 用于跟踪任务状态
task_status = {"running": False}


def run_precompute_task():
    """在后台线程中运行预计算任务"""
    try:
        task_status["running"] = True
        logger.info("开始执行预计算任务...")
        run_precompute()
        task_status["running"] = False
        logger.info("预计算任务完成")
    except Exception as e:
        task_status["running"] = False
        logger.error(f"预计算任务失败: {e}", exc_info=True)
        raise


@router.post("/precompute", response_model=ResponseModel)
async def precompute():
    """
    运行预计算任务
    
    该接口会异步执行预计算任务，包括：
    1. 优化数据库表结构
    2. 历史数据迁移
    3. 初始用户偏好向量生成
    
    任务在后台运行。
    """
    try:
        # 检查是否有任务正在运行
        if task_status["running"]:
            raise HTTPException(
                status_code=409,
                detail="已有预计算任务正在运行，请等待完成后再试"
            )
        
        # 在后台线程中执行任务
        executor.submit(run_precompute_task)
        
        return ResponseModel(
            code=200,
            msg="预计算任务已启动，正在后台执行",
            data={
                "status": "started",
                "tasks": [
                    "优化数据库表结构",
                    "历史数据迁移",
                    "初始用户偏好向量生成"
                ]
            }
        )
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"启动预计算任务失败: {e}", exc_info=True)
        raise HTTPException(status_code=500, detail=f"启动预计算任务失败: {str(e)}")


@router.get("/precompute/status", response_model=ResponseModel)
async def get_precompute_status():
    """
    获取预计算任务状态
    """
    return ResponseModel(
        code=200,
        msg="OK",
        data={
            "running": task_status["running"]
        }
    )