const { secure } = require("./api");

const STORAGE_KEY = "pet_environment_v1";
let value;
let attempted = false;
let pending;
let failure;

function cached() {
  if (value === undefined) {
    const saved = wx.getStorageSync(STORAGE_KEY);
    value =
      saved &&
      typeof saved.locationName === "string" &&
      typeof saved.weatherLabel === "string" &&
      Number.isFinite(saved.updatedAt)
        ? saved
        : null;
  }
  return value;
}

async function fetchEnvironment(tapped) {
  const settings = await new Promise((resolve, reject) =>
    wx.getSetting({ success: resolve, fail: reject }),
  );
  if (settings.authSetting["scope.userLocation"] === false) {
    if (!tapped) throw new Error("location-denied");
    const enabled = await new Promise((resolve, reject) =>
      wx.openSetting({ success: resolve, fail: reject }),
    );
    if (!enabled.authSetting["scope.userLocation"])
      throw new Error("location-denied");
  }
  const point = await new Promise((resolve, reject) =>
    wx.getLocation({ type: "gcj02", success: resolve, fail: reject }),
  );
  const result = await secure("/environment", "GET", {
    latitude: point.latitude,
    longitude: point.longitude,
  });
  if (!result || !result.location_name)
    throw new Error("位置和天气获取失败，请重试");
  const previous = cached();
  value = {
    locationName: result.location_name,
    weatherLabel: result.weather
      ? `${result.weather.description} ${result.weather.temperature}°C`
      : previous && previous.locationName === result.location_name
        ? previous.weatherLabel
        : "天气暂不可用",
    updatedAt: Date.now(),
  };
  // Store display data only; precise coordinates are not persisted here.
  try {
    wx.setStorageSync(STORAGE_KEY, value);
  } catch (_) {}
  return value;
}

function refresh(tapped = false) {
  if (pending) return pending;
  // Module lifetime follows the app, including recreated pages and warm resumes.
  // Failed automatic attempts also wait for a tap or the next cold start.
  if (attempted && !tapped)
    return failure ? Promise.reject(failure) : Promise.resolve(cached());
  attempted = true;
  pending = fetchEnvironment(tapped)
    .then(
      (result) => {
        failure = null;
        return result;
      },
      (error) => {
        failure = error;
        throw error;
      },
    )
    .finally(() => {
      pending = null;
    });
  return pending;
}

module.exports = { cached, refresh };