"""
图片下载器
支持多线程批量下载
"""
import os
import requests
from datetime import datetime
from typing import List, Dict, Callable, Optional
from concurrent.futures import ThreadPoolExecutor, as_completed
import threading
import sys

# 添加父目录到路径
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from config import DOWNLOAD_THREADS, DOWNLOAD_TIMEOUT, CREATE_SUBFOLDERS


class ImageDownloader:
    """图片下载器"""
    
    def __init__(self, sqlite_manager, max_workers: int = DOWNLOAD_THREADS):
        """
        初始化下载器
        
        Args:
            sqlite_manager: SQLite管理器实例
            max_workers: 最大并发数
        """
        self.sqlite_manager = sqlite_manager
        self.max_workers = max_workers
        self.is_cancelled = False
        self._lock = threading.Lock()
    
    def cancel(self):
        """取消下载"""
        self.is_cancelled = True
    
    def download_images(
        self,
        image_data_list: List[Dict],
        save_directory: str,
        progress_callback: Optional[Callable[[int, int, str], None]] = None,
        complete_callback: Optional[Callable[[int, int, List[str]], None]] = None
    ):
        """
        批量下载图片
        
        Args:
            image_data_list: 图片数据列表，每项包含：
                - id: 数据库ID
                - goods_id: 物品ID
                - goods_name: 物品名称
                - image_url: 图片URL
                - datasource: 数据源
                - create_time: 创建时间
            save_directory: 保存目录
            progress_callback: 进度回调函数 (当前数, 总数, 当前文件名)
            complete_callback: 完成回调函数 (成功数, 失败数, 错误列表)
        """
        self.is_cancelled = False
        total = len(image_data_list)
        success_count = 0
        failed_count = 0
        error_messages = []
        
        # 创建保存目录
        os.makedirs(save_directory, exist_ok=True)
        
        with ThreadPoolExecutor(max_workers=self.max_workers) as executor:
            # 提交所有下载任务
            future_to_data = {
                executor.submit(
                    self._download_single_image,
                    data,
                    save_directory
                ): data for data in image_data_list
            }
            
            # 处理完成的任务
            completed = 0
            for future in as_completed(future_to_data):
                if self.is_cancelled:
                    # 取消所有未完成的任务
                    for f in future_to_data:
                        f.cancel()
                    break
                
                data = future_to_data[future]
                completed += 1
                
                try:
                    success, error_msg = future.result()
                    if success:
                        success_count += 1
                    else:
                        failed_count += 1
                        if error_msg:
                            error_messages.append(error_msg)
                    
                    # 调用进度回调
                    if progress_callback:
                        progress_callback(completed, total, data['goods_name'])
                        
                except Exception as e:
                    failed_count += 1
                    error_messages.append(f"{data['goods_name']}: {str(e)}")
        
        # 调用完成回调
        if complete_callback and not self.is_cancelled:
            complete_callback(success_count, failed_count, error_messages)
    
    def _download_single_image(
        self,
        data: Dict,
        save_directory: str
    ) -> tuple[bool, Optional[str]]:
        """
        下载单张图片
        
        Returns:
            (是否成功, 错误信息)
        """
        try:
            # 检查是否已下载
            if self.sqlite_manager.is_downloaded(data['datasource'], data['image_url']):
                return True, None
            
            # 构建文件名: {分类}_{时间戳}_{ID}.jpg
            # 示例: 食材_20231127143022_1001.jpg
            create_time = data.get('create_time', '')
            if create_time:
                # 移除时间字符串中的特殊字符
                timestamp = create_time.replace('-', '').replace(':', '').replace(' ', '')
            else:
                timestamp = datetime.now().strftime('%Y%m%d%H%M%S')
            
            filename = f"img_{data['id']}.jpg"
            # filename = f"img_{timestamp}_{data['id']}.jpg"

            # 确定保存路径
            if CREATE_SUBFOLDERS:
                # 按分类创建子文件夹
                # subfolder = os.path.join(save_directory, data['datasource'])
                subfolder = os.path.join(save_directory)
                os.makedirs(subfolder, exist_ok=True)
                file_path = os.path.join(subfolder, filename)
            else:
                file_path = os.path.join(save_directory, filename)
            
            # 下载图片
            response = requests.get(
                data['image_url'],
                timeout=DOWNLOAD_TIMEOUT,
                stream=True
            )
            response.raise_for_status()
            
            # 保存图片
            with open(file_path, 'wb') as f:
                for chunk in response.iter_content(chunk_size=8192):
                    if chunk:
                        f.write(chunk)
            
            # 获取文件大小
            file_size = os.path.getsize(file_path)
            
            # 记录下载历史
            self.sqlite_manager.add_download_record(
                datasource=data['datasource'],
                goods_id=data.get('goods_id'),
                goods_name=data['goods_name'],
                image_url=data['image_url'],
                local_path=file_path,
                file_size=file_size
            )
            
            return True, None
            
        except requests.exceptions.RequestException as e:
            error_msg = f"{data['goods_name']} (ID:{data['id']}): 网络错误 - {str(e)}"
            return False, error_msg
        except Exception as e:
            error_msg = f"{data['goods_name']} (ID:{data['id']}): {str(e)}"
            return False, error_msg