import os
from PIL import Image
import piexif
import logging
import pandas as pd
from datetime import datetime


class GPSExtractor:
    """从图像文件提取GPS坐标和拍摄日期"""

    def __init__(self, image_dir):
        self.image_dir = image_dir
        self.logger = logging.getLogger('UAV_Preprocess.GPSExtractor')

    @staticmethod
    def _dms_to_decimal(dms):
        """将DMS格式转换为十进制度"""
        return dms[0][0] / dms[0][1] + (dms[1][0] / dms[1][1]) / 60 + (dms[2][0] / dms[2][1]) / 3600

    @staticmethod
    def _parse_datetime(datetime_str):
        """解析EXIF中的日期时间字符串"""
        try:
            # EXIF日期格式通常为 'YYYY:MM:DD HH:MM:SS'
            return datetime.strptime(datetime_str.decode(), '%Y:%m:%d %H:%M:%S')
        except Exception:
            return None

    def get_gps_and_date(self, image_path):
        """提取单张图片的GPS坐标和拍摄日期"""
        try:
            image = Image.open(image_path)
            exif_data = piexif.load(image.info['exif'])
            
            # 提取GPS信息
            gps_info = exif_data.get("GPS", {})
            lat = lon = None
            if gps_info:
                lat = self._dms_to_decimal(gps_info.get(2, []))
                lon = self._dms_to_decimal(gps_info.get(4, []))
                self.logger.debug(f"成功提取图片GPS坐标: {image_path} - 纬度: {lat}, 经度: {lon}")
            
            # 提取拍摄日期
            date_info = None
            if "Exif" in exif_data:
                # 优先使用DateTimeOriginal
                date_str = exif_data["Exif"].get(36867)  # DateTimeOriginal
                if not date_str:
                    # 备选DateTime
                    date_str = exif_data["Exif"].get(36868)  # DateTimeDigitized
                if not date_str:
                    # 最后使用基本DateTime
                    date_str = exif_data["0th"].get(306)  # DateTime
                
                if date_str:
                    date_info = self._parse_datetime(date_str)
                    self.logger.debug(f"成功提取图片拍摄日期: {image_path} - {date_info}")

            if not gps_info:
                self.logger.warning(f"图片无GPS信息: {image_path}")
            if not date_info:
                self.logger.warning(f"图片无拍摄日期信息: {image_path}")
                
            return lat, lon, date_info
            
        except Exception as e:
            self.logger.error(f"提取图片信息时发生错误: {image_path} - {str(e)}")
            return None, None, None

    def extract_all_gps(self):
        """提取所有图片的GPS坐标和拍摄日期"""
        self.logger.info(f"开始从目录提取GPS坐标和拍摄日期: {self.image_dir}")
        gps_data = []
        total_images = 0
        successful_extractions = 0
        
        for image_file in os.listdir(self.image_dir):
            if image_file.lower().endswith('.jpg'):
                total_images += 1
                image_path = os.path.join(self.image_dir, image_file)
                lat, lon, date = self.get_gps_and_date(image_path)
                if lat and lon:  # 仍然以GPS信息作为主要判断依据
                    successful_extractions += 1
                    gps_data.append({
                        'file': image_file,
                        'lat': lat,
                        'lon': lon,
                        'date': date
                    })
        
        self.logger.info(f"GPS坐标和拍摄日期提取完成 - 总图片数: {total_images}, 成功提取: {successful_extractions}, 失败: {total_images - successful_extractions}")
        return pd.DataFrame(gps_data)