// upload_file_service.dart
import 'dart:io';
import 'package:dio/dio.dart';
import 'package:flutter/foundation.dart';
import 'package:image_picker/image_picker.dart';

/// 上传结果 - 简单包装
class UploadResult {
  final String? filePath;
  final String? id;
  UploadResult({this.filePath, this.id});
}

/// 可接受的上传文件项：支持 File、XFile，或已有的 filePath（表示无需重新上传）
class UploadFileItem {
  final File? file;
  final XFile? xfile;
  final String? filePath; // 已有文件的返回路径（老文件）
  UploadFileItem({this.file, this.xfile, this.filePath});
}

/// UploadFileService: 可被 Provider/Consumer 或直接持有
class UploadFileService extends ChangeNotifier {
  final Dio dio;
  final Map<String, String> uploadPathEnum; // 对应 UPLOAD_FILE_PATH_ENUM
  final Set<String> uploadTypeEnum; // 对应 UPLOAD_FILE_TYPE_ENUM 的取值集合

  bool _loading = false;
  bool get loading => _loading;

  UploadFileService({
    Dio? dioInstance,
    required this.uploadPathEnum,
    required this.uploadTypeEnum,
  }) : dio = dioInstance ?? Dio();

  void _setLoading(bool v) {
    _loading = v;
    notifyListeners();
  }

  /// options:
  /// - files: List<UploadFileItem>
  /// - single: bool (default true)
  /// - params: Map<String, dynamic> (must contain 'type')
  ///
  /// 返回 UploadResult：
  /// - single: 返回 filePath 字段
  /// - batch(single==false): 返回 id 字段（对应 foreignKey）
  Future<UploadResult> uploadFile({
    required List<UploadFileItem>? files,
    bool single = true,
    required Map<String, dynamic>? params,
  }) async {
    if (params == null) {
      throw ArgumentError('请传入 options.params');
    }
    final type = params['type'];
    if (type == null) {
      throw ArgumentError('请传入 options.params.type');
    }
    if (!uploadTypeEnum.contains(type)) {
      throw ArgumentError('传入的 type 不在 UPLOAD_FILE_TYPE_ENUM 中');
    }

    final path = uploadPathEnum[type];
    if (path == null || path.isEmpty) {
      throw ArgumentError('未找到 type $type 对应的 path');
    }
    if (!single && (params['foreignKey'] == null)) {
      throw ArgumentError('single 为 false 时，options.params.foreignKey 必需');
    }

    _setLoading(true);

    try {
      final fileItems = files ?? [];

      // 如果没有文件则直接返回（与原逻辑一致）
      if (fileItems.isEmpty) {
        return single
            ? UploadResult(filePath: '')
            : UploadResult(id: '');
      }

      // 检查是否有真正需要上传的文件（File 或 XFile）
      final needUpload = fileItems.where((it) => it.file != null || it.xfile != null).toList();

      // 如果没有实际要上传的文件，返回老文件（files[0].filePath 或 params.foreignKey）
      if (needUpload.isEmpty) {
        _setLoading(false);
        return single
            ? UploadResult(filePath: fileItems[0].filePath ?? '')
            : UploadResult(id: params['foreignKey']?.toString() ?? '');
      }

      // 构建 FormData
      final formData = FormData();

      // 添加文件字段 - 同名 "files"（与后端约定）
      for (final it in needUpload) {
        String filePath;
        if (it.file != null) {
          filePath = it.file!.path;
        } else if (it.xfile != null) {
          // XFile.path 在 web 上不是本地文件（注意），这里只为移动端/桌面可用
          filePath = it.xfile!.path;
        } else {
          continue;
        }
        final filename = filePath.split(Platform.pathSeparator).last;
        final multipart = await MultipartFile.fromFile(filePath, filename: filename);
        formData.files.add(MapEntry('files', multipart));
      }

      // 添加 params 字段（全部作为字符串）
      params.forEach((k, v) {
        if (v == null) return;
        formData.fields.add(MapEntry(k, v.toString()));
      });

      // 添加 path 字段
      formData.fields.add(MapEntry('path', path));

      // 选择 URL：单文件/批量
      final url = single ? '/basicInfo/imgFiles/save' : '/basicInfo/imgFiles/batchSave';

      final response = await dio.post(
        url,
        data: formData,
        options: Options(
          contentType: 'multipart/form-data',
          // 如果需要加额外 headers 可以在这里传入
        ),
      );

      // 解析响应（假定后端返回结构与原 JS 一致：res.data.filePath / res.data.foreignKey）
      final resData = response.data;
      if (single) {
        final String? returnedPath = (resData is Map && resData['filePath'] != null)
            ? resData['filePath'].toString()
            : null;
        return UploadResult(filePath: returnedPath);
      } else {
        final String? foreignKey = (resData is Map && resData['foreignKey'] != null)
            ? resData['foreignKey'].toString()
            : null;
        return UploadResult(id: foreignKey);
      }
    } catch (e) {
      // 将错误上抛，调用方可 catch
      rethrow;
    } finally {
      _setLoading(false);
    }
  }
}