sinoMedCloud/lib/media/image_processor.dart

import 'dart:io';
import 'package:image/image.dart' as img;
import 'package:sino_med_cloud/core/utils/logger.dart';
import 'media_exception.dart';

/// 图片处理封装（压缩 / 裁剪 / 医疗脱敏）
class ImageProcessor {
  /// 默认压缩宽度（医疗场景推荐）
  static const int defaultMaxWidth = 1080;
  
  /// 默认压缩质量（85% 平衡质量和体积）
  static const int defaultQuality = 85;

  /// 压缩图片
  /// 
  /// 医疗场景：降低上传体积、去EXIF、图片标准化
  /// 
  /// - [file] 原始图片文件
  /// - [maxWidth] 最大宽度，默认 1080px
  /// - [quality] 压缩质量（1-100），默认 85
  /// 
  /// 返回压缩后的文件（覆盖原文件）
  static Future<File> compress(
    File file, {
    int maxWidth = defaultMaxWidth,
    int quality = defaultQuality,
  }) async {
    try {
      if (!await file.exists()) {
        throw ImageProcessingException('图片文件不存在: ${file.path}');
      }

      final bytes = await file.readAsBytes();
      if (bytes.isEmpty) {
        throw ImageProcessingException('图片文件为空: ${file.path}');
      }

      final image = img.decodeImage(bytes);
      if (image == null) {
        throw ImageProcessingException('无法解析图片: ${file.path}');
      }

      // 如果图片宽度小于等于最大宽度，只进行质量压缩
      File? resultFile;
      if (image.width <= maxWidth) {
        final compressed = img.encodeJpg(image, quality: quality);
        resultFile = File(file.path)..writeAsBytesSync(compressed);
      } else {
        // 先缩放再压缩
        final resized = img.copyResize(
          image,
          width: maxWidth,
          maintainAspect: true,
        );
        final compressed = img.encodeJpg(resized, quality: quality);
        resultFile = File(file.path)..writeAsBytesSync(compressed);
      }

      AppLogger.d('图片压缩完成: ${file.path}, 原始大小: ${bytes.length} bytes, 压缩后: ${resultFile.lengthSync()} bytes');
      return resultFile;
    } catch (e) {
      if (e is ImageProcessingException) {
        rethrow;
      }
      AppLogger.e('图片压缩失败: ${file.path}', e);
      throw ImageProcessingException(
        '图片压缩失败: ${e.toString()}',
        originalError: e,
      );
    }
  }

  /// 获取图片信息
  /// 
  /// 返回图片的宽度、高度和文件大小
  static Future<Map<String, dynamic>> getImageInfo(File file) async {
    try {
      if (!await file.exists()) {
        throw ImageProcessingException('图片文件不存在: ${file.path}');
      }

      final bytes = await file.readAsBytes();
      final image = img.decodeImage(bytes);
      
      if (image == null) {
        throw ImageProcessingException('无法解析图片: ${file.path}');
      }

      return {
        'width': image.width,
        'height': image.height,
        'size': bytes.length,
        'format': image.format.toString(),
      };
    } catch (e) {
      if (e is ImageProcessingException) {
        rethrow;
      }
      AppLogger.e('获取图片信息失败: ${file.path}', e);
      throw ImageProcessingException(
        '获取图片信息失败: ${e.toString()}',
        originalError: e,
      );
    }
  }

  /// 医疗脱敏处理（去除 EXIF 信息）
  /// 
  /// 移除图片中的 EXIF 元数据，保护患者隐私
  /// 
  /// - [file] 原始图片文件
  /// 
  /// 返回脱敏后的文件（覆盖原文件）
  static Future<File> removeExif(File file) async {
    try {
      if (!await file.exists()) {
        throw ImageProcessingException('图片文件不存在: ${file.path}');
      }

      final bytes = await file.readAsBytes();
      final image = img.decodeImage(bytes);
      
      if (image == null) {
        throw ImageProcessingException('无法解析图片: ${file.path}');
      }

      // 重新编码图片会移除 EXIF 信息
      final cleaned = img.encodeJpg(image, quality: 100);
      final cleanedFile = File(file.path)..writeAsBytesSync(cleaned);

      AppLogger.d('图片脱敏完成: ${file.path}');
      return cleanedFile;
    } catch (e) {
      if (e is ImageProcessingException) {
        rethrow;
      }
      AppLogger.e('图片脱敏失败: ${file.path}', e);
      throw ImageProcessingException(
        '图片脱敏失败: ${e.toString()}',
        originalError: e,
      );
    }
  }
}