Cache home location and weather across page navigation

pets-fe/utils/environment.js

@@ -0,0 +1,85 @@
+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 };