import 'package:dio/dio.dart';
import 'package:file_picker/file_picker.dart';
import 'fileUtils.dart';


const _show_debug_info = false;



/// 上传状态枚举
enum UploadStatus {
  uploading,
  completed,
  failed,
}

/// 上传结果
class UploadResult<T> {
  final UploadStatus status;
  final String? filePath;
  final double? progress;
  final int? errorCode;
  final String? errorReason;
  final T? returnData;

  bool get isCompleted => status == UploadStatus.completed;
  bool get isUploading => status == UploadStatus.uploading;
  bool get isFailed => status == UploadStatus.failed;


  /// ----- error code -----
  static const int errorCodeError = -1;
  static const int errorCodeUserCancel = 1;
  static const int errorCodeFileIsNotExist = -2;


  /// ----- constructor -----
  UploadResult({
    required this.status,
    this.filePath,
    this.progress,
    this.errorCode,
    this.errorReason,
    this.returnData,
  });

  factory UploadResult.uploading(double progress) {
    if (progress < 0) { progress = 0; }
    else if (progress > 1) { progress = 1; }
    return UploadResult(
      status: UploadStatus.uploading,
      progress: progress,
    );
  }

  factory UploadResult.failed({
    int errorCode = errorCodeError,
    String? errorReason,
  }) {
    return UploadResult(
      status: UploadStatus.failed,
      errorCode: errorCode,
      errorReason: errorReason,
    );
  }

  factory UploadResult.completed({
    required String filePath,
    T? returnData,
  }) {
    return UploadResult(
      status: UploadStatus.completed,
      filePath: filePath,
      progress: 1.0,
      returnData: returnData,
    );
  }
}



/// -----------------------------------------------------------
/// HttpUploader
///

class HttpUploader {

  //上传
  static Future<UploadResult<T>> upload<T>({
    required String receiverUrl,
    String? filePath,
    String? fileName,
    Map<String, String>? headers,
    Map<String, dynamic>? extraData,
    void Function(UploadResult)? onProgress,
  }) async {

    // 选择文件
    String selectedFilePath;
    if (filePath != null) {
      if (await isFileExists(filePath)) {
        selectedFilePath = filePath;
      } else {
        final result = UploadResult<T>.failed(
          errorCode: UploadResult.errorCodeFileIsNotExist,
          errorReason: 'file is not exist',
        );
        if (onProgress != null) {
          onProgress(result);
        }
        return result;
      }
    } else {
      FilePickerResult? result = await FilePicker.platform.pickFiles();
      if (result == null) {
        final result = UploadResult<T>.failed(
          errorCode: UploadResult.errorCodeUserCancel,
          errorReason: 'Selection canceled by user',
        );
        if (onProgress != null) {
          onProgress(result);
        }
        return result;
      }
      PlatformFile file = result.files.first;
      selectedFilePath = file.path!;
    }

    FormData formData = FormData.fromMap({
      'file': await MultipartFile.fromFile(selectedFilePath, filename: fileName),
      ...?extraData,
    });

    final dio = Dio();
    try {

      if (_show_debug_info) {
        print('┌────────────────────────────────────────────────────────────────────────────────────────');
        print('│ ⬆️ start upload file: $selectedFilePath');
        print('│    toServer: $receiverUrl');
        print('└────────────────────────────────────────────────────────────────────────────────────────');
      }

      final response = await dio.post<T>(
        receiverUrl,
        data: formData,
        options: Options(
          headers: headers,
          contentType: 'multipart/form-data',
        ),
        onSendProgress: (sent, total) {
          if (_show_debug_info) {
            print('upload: $sent / $total');
          }
          if (onProgress != null) {
            final progress = total != 0 ? sent / total : 0.0;
            onProgress(UploadResult<T>.uploading(progress));
          }
        },
      );

      if (_show_debug_info) {
        print('$filePath 上传完成: $response');
      }
      final result = UploadResult<T>.completed(
        filePath: selectedFilePath,
        returnData: response.data,
      );
      if (onProgress != null) {
        onProgress(result);
      }
      return result;

    } catch (e) {
      print('上传失败: $e');
      final result = UploadResult<T>.failed(
        errorReason: e.toString(),
      );
      if (onProgress != null) {
        onProgress(result);
      }
      return result;
    }
  }
}