import 'dart:convert';
import 'package:dio/dio.dart' as dio;
import 'package:flutter/foundation.dart';
import 'exception.dart';
import 'http_pool.dart';
import 'interceptor.dart';
import 'request.dart';

// ignore: unused_element
const _C_DIO_FUTURE_ERR_MSG = "Future already completed";
const _C_DIO_FUTURE_ERR_KEYWORDS = "browser_adapter";

/// JSON-RPC Client 基类
class JsonRpcClientBase {
  /// 服务主机地址
  final String host;

  late String _serviceName;

  /// 服务名称
  String get serviceName => _serviceName;

  /// 自定义Http header
  final Map<String, String>? headers;

  /// 超时时间(ms)
  final int? timeout;

  /// 服务请求地址
  String get servicePath =>
      host.endsWith('/') ? "$host$serviceName" : "$host/$serviceName";

  JsonRpcClientBase(
    this.host,
    String serviceName, {
    this.headers,
    this.timeout,
  }) {
    _serviceName = serviceName;
  }

  /// 设置服务名
  void setServiceName(String name) => _serviceName = name;

  /// 请求RPC method
  @protected
  Future<dynamic> call(String method, [args]) async {
    var request = JsonRpcRequest(method, args);
    return _transmit(request);
  }

  /// 通知 RPC method
  @protected
  void notify(String method, [args]) {
    var request = JsonRpcRequest(method, args, notify: true);
    _transmit(request);
  }

  Future<dynamic> _transmit(JsonRpcRequest request) async {
    final req = await jsonRpcInterceptHost.onRequestTransmit(request);

    String package = jsonEncode(req.toJson());

    var response = await _postRequest(package);
    if (response == null) throw JsonRpcException(message: "Response Empty");

    var result = await _handleDecoded(response);
    return result;
  }

  Future<dynamic> _postRequest(String package) async {
    try {
      final httpClient = jrpcHttpPool.getClient(this.host,
          timeout: this.timeout, headers: this.headers);

      var response =
          await httpClient.post('/${this.serviceName}', data: package);
      if (response.statusCode != 200) {
        throw JsonRpcException(
            message: "Http error.Status coder: ${response.statusCode}.");
      }
      return response.data;
    } on dio.DioError catch (e) {
      throw JsonRpcException(message: "Http error", data: e);
    } on StateError catch (e) {
      if (e.message == _C_DIO_FUTURE_ERR_MSG) {
        if (e.stackTrace != null &&
            e.stackTrace.toString().contains(_C_DIO_FUTURE_ERR_KEYWORDS)) {
          // don't rethrow
        }
      }
    }
  }

  Future<dynamic> _handleDecoded(Map<String, dynamic> response) async {
    final res = await jsonRpcInterceptHost.onResponse(response);
    if (res.containsKey('error')) {
      var error = JsonRpcServerError.fromJson(res['error']);
      error = await jsonRpcInterceptHost.onResponseError(error);
      throw error;
    }
    var result = res['result'];
    result = await jsonRpcInterceptHost.onResponseResult(result);
    return result;
  }
}

abstract class JsonRpcRequestModelBase {
  /// 转成Json Map
  Map<String, dynamic> toJson();
}