# 数据加载类


import pandas as pd
from typing import Optional, Tuple
import time
import traceback
import logging

from database import DatabaseManager
from file_scanner import ParquetFileInfo

logger = logging.getLogger(__name__)

class DataLoader:
    """数据加载器，处理单个parquet文件，支持三字段唯一键UPSERT"""
    
    def __init__(self, db_manager: DatabaseManager, table_name: str, 
                 batch_size: int = 1000, max_retries: int = 3, upsert: bool = True):
        self.db_manager = db_manager
        self.table_name = table_name
        self.batch_size = batch_size
        self.max_retries = max_retries
        self.upsert = upsert
        
    def load_file(self, file_info: ParquetFileInfo) -> Optional[Tuple[int, int, int]]:
        """
        加载单个parquet文件到数据库
        
        Args:
            file_info: 文件信息（包含时间字段名）
            
        Returns:
            (总行数, 插入行数, 更新行数)，失败返回None
        """
        retry_count = 0
        
        while retry_count <= self.max_retries:
            try:
                if self.upsert:
                    # 使用UPSERT方式，三字段唯一键
                    total_rows, inserted_rows, updated_rows = self.db_manager.upsert_parquet_data(
                        file_info=file_info,
                        table_name=self.table_name,
                        batch_size=self.batch_size,
                        max_retries=self.max_retries
                    )
                    return total_rows, inserted_rows, updated_rows
                else:
                    raise NotImplementedError("INSERT模式暂不支持")
                
            except Exception as e:
                retry_count += 1
                if retry_count > self.max_retries:
                    logger.error(f"加载文件 {file_info.file_path} 失败，已达到最大重试次数: {e}")
                    logger.error(traceback.format_exc())
                    return None
                else:
                    logger.warning(f"加载文件 {file_info.file_path} 失败，第 {retry_count} 次重试: {e}")
                    time.sleep(2 * retry_count)
        
        return None