import { getWechatLocationDetailed } from '@dukang/weixin-sdk';
import { apiBase } from './api';
import { weixinSdk } from './weixin';
import { regionFromGeo, type RegionSelection } from './region-data';

export const GPS_CITY_STORAGE_KEY = 'dukang_gps_city';
export const CITY_STORAGE_KEY = 'dukang_selected_city';
export const FALLBACK_CITY_CODE = '410100';

export type ResolvedUserCity = {
  province: string;
  city: string;
  district: string;
  cityCode?: string;
  cityName?: string;
  openCity: boolean;
  region: RegionSelection;
  displayCity: string;
};

type GpsCityCache = ResolvedUserCity & { timestamp: number };

function readCache(): GpsCityCache | null {
  try {
    const raw = sessionStorage.getItem(GPS_CITY_STORAGE_KEY);
    if (!raw) return null;
    const parsed = JSON.parse(raw) as GpsCityCache;
    if (Date.now() - parsed.timestamp > 30 * 60 * 1000) return null;
    return parsed;
  } catch {
    return null;
  }
}

function writeCache(data: ResolvedUserCity) {
  sessionStorage.setItem(
    GPS_CITY_STORAGE_KEY,
    JSON.stringify({ ...data, timestamp: Date.now() } satisfies GpsCityCache),
  );
}

async function reportLocationToServer(payload: {
  latitude?: number;
  longitude?: number;
  sdk: 'jssdk' | 'geolocation';
  status: 'success' | 'fail';
  errMsg?: string;
}) {
  const token = localStorage.getItem('accessToken');
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    'X-Client-App': 'USER_H5',
  };
  if (token) headers.Authorization = `Bearer ${token}`;

  const res = await fetch(`${apiBase}/common/wechat/location`, {
    method: 'POST',
    headers,
    body: JSON.stringify(payload),
  });
  const json = await res.json();
  if (json.code !== 0) {
    throw new Error(json.message || '定位上报失败');
  }
  return json.data as {
    province?: string;
    city?: string;
    district?: string;
    cityCode?: string;
    cityName?: string;
    openCity?: boolean;
  };
}

function toResolved(data: {
  province?: string;
  city?: string;
  district?: string;
  cityCode?: string;
  cityName?: string;
  openCity?: boolean;
}): ResolvedUserCity | null {
  if (!data.province || !data.city) return null;
  const region = regionFromGeo(data.province, data.city, data.district);
  const displayCity = data.cityName ?? (data.city.endsWith('市') ? data.city : `${data.city}市`);
  return {
    province: data.province,
    city: data.city,
    district: data.district ?? '',
    cityCode: data.cityCode,
    cityName: data.cityName,
    openCity: !!data.openCity,
    region,
    displayCity,
  };
}

/** 获取并解析用户当前城市（微信 JSSDK 优先），失败返回 null */
export async function resolveUserCity(force = false): Promise<ResolvedUserCity | null> {
  if (!force) {
    const cached = readCache();
    if (cached) return cached;
  }

  const outcome = await getWechatLocationDetailed({
    apiBase,
    clientApp: 'USER_H5',
    getAccessToken: () => localStorage.getItem('accessToken'),
  });

  if (!outcome.location) {
    await reportLocationToServer({
      sdk: outcome.sdk,
      status: 'fail',
      errMsg: outcome.errMsg,
    }).catch(() => {});
    return null;
  }

  try {
    const data = await reportLocationToServer({
      latitude: outcome.location.latitude,
      longitude: outcome.location.longitude,
      sdk: outcome.sdk,
      status: 'success',
    });
    const resolved = toResolved(data);
    if (resolved) {
      writeCache(resolved);
      if (resolved.openCity && resolved.cityCode) {
        localStorage.setItem(CITY_STORAGE_KEY, resolved.cityCode);
      }
    }
    return resolved;
  } catch {
    return null;
  }
}

export function syncCityCodeFromGps(resolved: ResolvedUserCity) {
  if (resolved.openCity && resolved.cityCode) {
    localStorage.setItem(CITY_STORAGE_KEY, resolved.cityCode);
  }
}