#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Celery任務管理服務

Author: PANJIT IT Team
Created: 2025-09-04
"""

from celery import Celery
from app.utils.logger import get_logger
import os

logger = get_logger(__name__)


def get_celery_app():
    """取得Celery應用實例"""
    try:
        from celery_app import app as celery_app
        return celery_app
    except ImportError:
        # 如果無法導入，創建一個簡單的Celery實例
        broker_url = os.getenv('REDIS_URL', 'redis://localhost:6379/0')
        celery_app = Celery('translation_worker', broker=broker_url)
        return celery_app


def revoke_task(job_uuid):
    """
    撤銷指定任務的Celery任務
    
    Args:
        job_uuid (str): 任務UUID
        
    Returns:
        bool: 撤銷是否成功
    """
    try:
        celery_app = get_celery_app()
        
        # Celery任務ID通常與job_uuid相同或相關
        task_id = f"translate_document_{job_uuid}"
        
        # 嘗試撤銷任務
        celery_app.control.revoke(task_id, terminate=True, signal='SIGKILL')
        
        logger.info(f"Successfully revoked Celery task: {task_id}")
        return True
        
    except Exception as e:
        logger.error(f"Failed to revoke Celery task for job {job_uuid}: {str(e)}")
        return False


def get_active_tasks():
    """
    取得當前活躍的Celery任務
    
    Returns:
        list: 活躍任務列表
    """
    try:
        celery_app = get_celery_app()
        
        # 取得活躍任務
        inspect = celery_app.control.inspect()
        active_tasks = inspect.active()
        
        if active_tasks:
            return active_tasks
        else:
            return {}
            
    except Exception as e:
        logger.error(f"Failed to get active tasks: {str(e)}")
        return {}


def is_task_active(job_uuid):
    """
    檢查指定任務是否在Celery中活躍
    
    Args:
        job_uuid (str): 任務UUID
        
    Returns:
        bool: 任務是否活躍
    """
    try:
        active_tasks = get_active_tasks()
        task_id = f"translate_document_{job_uuid}"
        
        # 檢查所有worker的活躍任務
        for worker, tasks in active_tasks.items():
            for task in tasks:
                if task.get('id') == task_id:
                    return True
        
        return False
        
    except Exception as e:
        logger.error(f"Failed to check if task is active for job {job_uuid}: {str(e)}")
        return False


def cleanup_stale_tasks():
    """
    清理卡住的Celery任務
    
    Returns:
        int: 清理的任務數量
    """
    try:
        from app.models.job import TranslationJob
        from datetime import datetime, timedelta
        
        # 找出超過30分鐘仍在處理中的任務
        stale_threshold = datetime.utcnow() - timedelta(minutes=30)
        stale_jobs = TranslationJob.query.filter(
            TranslationJob.status == 'PROCESSING',
            TranslationJob.processing_started_at < stale_threshold
        ).all()
        
        cleanup_count = 0
        for job in stale_jobs:
            if not is_task_active(job.job_uuid):
                # 任務不在Celery中活躍，標記為失敗
                job.update_status('FAILED', error_message='任務處理超時，已自動取消')
                cleanup_count += 1
                logger.info(f"Cleaned up stale job: {job.job_uuid}")
        
        return cleanup_count
        
    except Exception as e:
        logger.error(f"Failed to cleanup stale tasks: {str(e)}")
        return 0