import 'dart:async';
import 'dart:convert';
import 'dart:io';

enum HttpClientStatus { idle, connecting, connected, disconnected, error }

typedef HttpClientStatusHandler = void Function(HttpClientStatus status);

/// 单次请求的 HTTP 状态与解码正文，不共享并发请求状态。
class HttpClientWrapResponse {
  final int statusCode;
  final dynamic data;

  const HttpClientWrapResponse({required this.statusCode, required this.data});
}

class HttpClientWrap {
  final Duration retryInterval;
  final Duration? connectionTimeout;
  final Duration? receiveTimeout;
  final Map<String, String>? defaultHeaders;

  HttpClient? _httpClient;
  bool _disposed = false;

  HttpClientStatus _status = HttpClientStatus.idle;
  HttpClientStatus get status => _status;

  final List<HttpClientStatusHandler> _statusHandlers = [];

  HttpClientWrap({
    this.retryInterval = const Duration(seconds: 5),
    this.defaultHeaders,
    this.connectionTimeout,
    this.receiveTimeout,
  });

  /// 发送 GET 请求
  Future<dynamic> get(
    String url, {
    Map<String, String>? headers,
    dynamic body,
  }) async {
    return _sendRequest(url, 'GET', headers: headers, body: body);
  }

  /// 发送 POST 请求
  Future<dynamic> post(
    String url, {
    Map<String, String>? headers,
    dynamic body,
  }) async {
    return _sendRequest(url, 'POST', headers: headers, body: body);
  }

  /// 发送 PUT 请求
  Future<dynamic> put(
    String url, {
    Map<String, String>? headers,
    dynamic body,
  }) async {
    return _sendRequest(url, 'PUT', headers: headers, body: body);
  }

  /// 发送 DELETE 请求
  Future<dynamic> delete(String url, {Map<String, String>? headers}) async {
    return _sendRequest(url, 'DELETE', headers: headers);
  }

  Future<dynamic> _sendRequest(
    String url,
    String method, {
    Map<String, String>? headers,
    dynamic body,
  }) async {
    return (await request(url, method, headers: headers, body: body)).data;
  }

  /// 返回 HTTP 状态与正文；旧 get/post/put/delete 仍仅返回正文。
  Future<HttpClientWrapResponse> request(
    String url,
    String method, {
    Map<String, String>? headers,
    dynamic body,
  }) async {
    if (_disposed) {
      throw StateError('HTTP Client has been disposed');
    }

    _updateStatus(HttpClientStatus.connecting);
    _httpClient ??= HttpClient()..connectionTimeout = connectionTimeout;

    try {
      late final Uri uri;
      if ((method == 'GET') && (body != null)) {
        // queryParameters Map value 只接受 String 和 List<String> 两种类型
        // final queryParams = body.map((key, value) {
        //   if (value is Iterable) {
        //     // 多值：转成 List<String>
        //     return MapEntry(key, value.map((v) => v.toString()).toList());
        //   } else {
        //     // 单值：转成 String
        //     return MapEntry(key, value.toString());
        //   }
        // });
        final queryParams = <String, dynamic>{};
        if (body is Map) {
          body.forEach((key, value) {
            if (value is Iterable) {
              // 多值：转成 List<String>
              queryParams[key.toString()] = value
                  .map((v) => v.toString())
                  .toList();
            } else {
              // 单值：转成 String
              queryParams[key.toString()] = value.toString();
            }
          });
        }
        uri = Uri.parse(url).replace(queryParameters: queryParams);

        // uri = Uri.parse(url).replace(
        //   queryParameters: body,
        // );
      } else {
        uri = Uri.parse(url);
      }

      final request = await _httpClient!.openUrl(method, uri);

      // 设置请求头
      final mergedHeaders = {...?defaultHeaders, ...?headers};
      mergedHeaders.forEach((key, value) {
        request.headers.set(key, value);
      });

      // 添加请求体（如果是POST/PUT）
      if (body != null && (method == 'POST' || method == 'PUT')) {
        if (body is Map || body is List) {
          request.write(jsonEncode(body));
        } else {
          request.write(body.toString());
        }
      }

      final responseFuture = request.close();
      final timeout = receiveTimeout;
      final response = await (timeout == null
          ? responseFuture
          : responseFuture.timeout(timeout));
      _updateStatus(HttpClientStatus.connected);

      // 处理响应
      final responseStream = response.transform(utf8.decoder);
      final responseBody =
          await (timeout == null
                  ? responseStream
                  : responseStream.timeout(timeout))
              .join();
      dynamic decodedResponse;

      try {
        decodedResponse = jsonDecode(responseBody);
      } catch (e) {
        decodedResponse = responseBody;
      }

      // Log.d('get response: $decodedResponse');

      _updateStatus(HttpClientStatus.idle);
      return HttpClientWrapResponse(
        statusCode: response.statusCode,
        data: decodedResponse,
      );
    } catch (e) {
      _handleError(e);
      // _scheduleRetry();
      _resetClient();
      rethrow; // 抛出异常以便调用方捕获
    }
  }

  /// 添加状态监听器
  void addStatusListener(HttpClientStatusHandler handler) {
    _statusHandlers.add(handler);
  }

  /// 移除状态监听器
  void removeStatusListener(HttpClientStatusHandler handler) {
    _statusHandlers.remove(handler);
  }

  void _resetClient() {
    _httpClient?.close(force: true);
    _httpClient = null;
  }

  /// 释放资源
  Future<void> dispose() async {
    _disposed = true;
    _httpClient?.close();
    _httpClient = null;
    _statusHandlers.clear();
    _updateStatus(HttpClientStatus.disconnected);
  }

  void _handleError(dynamic error) {
    _updateStatus(HttpClientStatus.error);
  }

  void _scheduleRetry() {
    if (_disposed) return;

    Timer(retryInterval, () {
      _updateStatus(HttpClientStatus.idle);
    });
  }

  void _updateStatus(HttpClientStatus status) {
    _status = status;
    for (final handler in _statusHandlers) {
      handler(status);
    }
  }
}