"""
任务追踪服务：追踪 Celery 任务状态
"""
import json
import logging
from typing import List, Dict, Optional, Any
from datetime import datetime, timezone

from services.redis_service import redis_service

logger = logging.getLogger(__name__)


class TaskTracker:
    """任务追踪器，使用 Redis 存储任务状态"""
    
    # Redis key 前缀
    KEY_PREFIX = "task:user:"
    # 任务记录过期时间（1小时）
    TASK_TTL = 3600
    
    async def add_task(self, user_id: str, task_id: str, task_type: str = "memoir") -> bool:
        """
        记录新任务
        
        Args:
            user_id: 用户 ID
            task_id: Celery 任务 ID
            task_type: 任务类型
        
        Returns:
            是否成功
        """
        try:
            client = await redis_service.get_client()
            key = f"{self.KEY_PREFIX}{user_id}:tasks"
            
            task_info = {
                "task_id": task_id,
                "task_type": task_type,
                "status": "pending",
                "created_at": datetime.now(timezone.utc).isoformat(),
            }
            
            # 使用 hash 存储任务信息
            await client.hset(key, task_id, json.dumps(task_info))
            await client.expire(key, self.TASK_TTL)
            
            logger.info(f"任务已记录: user_id={user_id}, task_id={task_id}")
            return True
        except Exception as e:
            logger.error(f"记录任务失败: {e}")
            return False
    
    async def update_task_status(self, user_id: str, task_id: str, status: str, result: Any = None) -> bool:
        """
        更新任务状态
        
        Args:
            user_id: 用户 ID
            task_id: Celery 任务 ID
            status: 新状态 (pending, running, success, failure)
            result: 任务结果
        
        Returns:
            是否成功
        """
        try:
            client = await redis_service.get_client()
            key = f"{self.KEY_PREFIX}{user_id}:tasks"
            
            # 获取现有任务信息
            data = await client.hget(key, task_id)
            if data:
                task_info = json.loads(data)
            else:
                task_info = {"task_id": task_id}
            
            task_info["status"] = status
            task_info["updated_at"] = datetime.now(timezone.utc).isoformat()
            if result is not None:
                task_info["result"] = result
            
            await client.hset(key, task_id, json.dumps(task_info))
            return True
        except Exception as e:
            logger.error(f"更新任务状态失败: {e}")
            return False
    
    async def get_user_tasks(self, user_id: str) -> List[Dict]:
        """
        获取用户的所有任务
        
        Args:
            user_id: 用户 ID
        
        Returns:
            任务列表
        """
        try:
            client = await redis_service.get_client()
            key = f"{self.KEY_PREFIX}{user_id}:tasks"
            
            tasks_data = await client.hgetall(key)
            tasks = []
            for task_id, data in tasks_data.items():
                task_info = json.loads(data)
                tasks.append(task_info)
            
            return tasks
        except Exception as e:
            logger.error(f"获取用户任务失败: {e}")
            return []
    
    async def get_pending_tasks(self, user_id: str) -> List[Dict]:
        """
        获取用户的待处理任务
        
        Args:
            user_id: 用户 ID
        
        Returns:
            待处理任务列表
        """
        tasks = await self.get_user_tasks(user_id)
        return [t for t in tasks if t.get("status") in ("pending", "running")]
    
    async def check_tasks_status(self, user_id: str) -> Dict:
        """
        检查用户任务状态汇总
        
        Args:
            user_id: 用户 ID
        
        Returns:
            状态汇总 {total, pending, running, success, failure, all_completed}
        """
        tasks = await self.get_user_tasks(user_id)
        
        status_counts = {
            "total": len(tasks),
            "pending": 0,
            "running": 0,
            "success": 0,
            "failure": 0,
        }
        
        for task in tasks:
            status = task.get("status", "pending")
            if status in status_counts:
                status_counts[status] += 1
        
        status_counts["all_completed"] = (
            status_counts["total"] > 0 and 
            status_counts["pending"] == 0 and 
            status_counts["running"] == 0
        )
        
        return status_counts
    
    async def clear_user_tasks(self, user_id: str) -> bool:
        """
        清除用户的所有任务记录
        
        Args:
            user_id: 用户 ID
        
        Returns:
            是否成功
        """
        try:
            client = await redis_service.get_client()
            key = f"{self.KEY_PREFIX}{user_id}:tasks"
            await client.delete(key)
            return True
        except Exception as e:
            logger.error(f"清除用户任务失败: {e}")
            return False
    
    async def remove_task(self, user_id: str, task_id: str) -> bool:
        """
        移除单个任务记录
        
        Args:
            user_id: 用户 ID
            task_id: 任务 ID
        
        Returns:
            是否成功
        """
        try:
            client = await redis_service.get_client()
            key = f"{self.KEY_PREFIX}{user_id}:tasks"
            await client.hdel(key, task_id)
            return True
        except Exception as e:
            logger.error(f"移除任务失败: {e}")
            return False


# 全局实例
task_tracker = TaskTracker()