import { Injectable } from '@nestjs/common';
import { CourierApiError } from '../courier.error';
import { CourierConfigService } from '../courier.config';
import { buildXiaofeixiaSign } from './xiaofeixia.sign';
import { XIAOFEIXIA_SUCCESS_CODE } from './xiaofeixia.constants';
import type { XiaofeixiaApiResponse } from './xiaofeixia.types';

type RequestParams = Record<string, string | number | undefined>;

@Injectable()
export class XiaofeixiaClient {
  constructor(private readonly courierConfig: CourierConfigService) {}

  async request<T>(cmd: string, bizParams: RequestParams): Promise<T> {
    const cfg = this.courierConfig.load().xiaofeixia;

    if (!cfg.mchId || !cfg.apiKey) {
      throw new CourierApiError(
        '小飞侠商户配置不完整，请设置 XIAOFEIXIA_MCH_ID 与 XIAOFEIXIA_API_KEY',
        'CONFIG_ERROR',
        'XIAOFEIXIA',
      );
    }

    const baseParams: RequestParams = {
      mchId: cfg.mchId,
      cmd,
      signType: cfg.signType,
      ...bizParams,
    };

    if (cfg.appId) {
      baseParams.appId = cfg.appId;
    }

    const sign = buildXiaofeixiaSign(baseParams, cfg.apiKey, cfg.signType);
    const body = new URLSearchParams();

    for (const [key, value] of Object.entries({ ...baseParams, sign })) {
      if (value !== undefined && value !== null && value !== '') {
        body.append(key, String(value));
      }
    }

    let response: Response;
    try {
      response = await fetch(cfg.apiUrl, {
        method: 'POST',
        headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
        body: body.toString(),
      });
    } catch (error) {
      throw new CourierApiError(
        '小飞侠接口网络异常',
        '200000',
        'XIAOFEIXIA',
        error,
      );
    }

    if (!response.ok) {
      throw new CourierApiError(
        `小飞侠 HTTP 请求失败: ${response.status}`,
        '200000',
        'XIAOFEIXIA',
      );
    }

    const rawText = await response.text();
    let payload: XiaofeixiaApiResponse<T>;
    try {
      payload = rawText ? (JSON.parse(rawText) as XiaofeixiaApiResponse<T>) : (null as unknown as XiaofeixiaApiResponse<T>);
    } catch {
      throw new CourierApiError(
        `小飞侠响应非 JSON（HTTP ${response.status}）: ${rawText.slice(0, 200) || '(空)'}`,
        '200000',
        'XIAOFEIXIA',
        rawText,
      );
    }

    if (!payload) {
      throw new CourierApiError('小飞侠返回空响应', '200000', 'XIAOFEIXIA');
    }

    if (payload.code !== XIAOFEIXIA_SUCCESS_CODE) {
      throw new CourierApiError(
        payload.message || '小飞侠接口业务失败',
        payload.code,
        'XIAOFEIXIA',
        payload,
      );
    }

    return payload.data as T;
  }
}