feat: better time format inference

README.md

@@ -35,8 +35,9 @@ All of these parameters are optional.
 - `temperature`: `celsius` (default) / `fahrenheit`
 - `wind_speed`: `mps` (default) / `kmph` / `mph` / `knot`  
   Note that `mph` means miles per hour, while `mps` means meters per second.
-- `time_format`: `auto` (default) / `12h` / `24h` / `24hn`  
-  `24hn` means 24-hour notation with no leading zero.
+- `time_format`: `auto` (default) / `12h` / `24h` / `24hn` / `native`  
+  `24hn` means 24-hour notation with no leading zero.  
+  `native` means the native datetime format (including year) of the language.
 - `lang`: `auto` (default) / BCP 47 tag, e.g., `en-US`  
   Specifies the language of the weather information, the datetime format, and the location name if `location` not provided.  
   Detected automatically from `Accept-Language` header if `auto` is specified.

src/widget/WeatherWidget.tsx

@@ -73,11 +73,45 @@ function OpacityAnimation({
   );
 }
 
+function detectTimeFormat(language: string): "12h" | "24h" | "24hn" | null {
+  const strDate1 = new Date("2024-01-03T17:07:09Z").toLocaleTimeString(
+    language,
+    {
+      timeZone: "UTC",
+      timeStyle: "short",
+    }
+  );
+
+  const has5 = strDate1.includes("5");
+  const has17 = strDate1.includes("17");
+  if (has5 === has17) {
+    return null;
+  }
+
+  if (has5) {
+    return "12h";
+  }
+
+  const strDate2 = new Date("2024-01-03T05:07:09Z").toLocaleTimeString(
+    language,
+    {
+      timeZone: "UTC",
+      timeStyle: "short",
+    }
+  );
+  return strDate2.includes("05") ? "24h" : "24hn";
+}
+
 function formatDateTime(
   datetime: string,
   language: string,
   prefTimeFormat: PreferencesSchema["time_format"]
 ): [weekday: string, dateTime: string] {
+  const timeFormat =
+    prefTimeFormat === "auto"
+      ? detectTimeFormat(language) ?? "native"
+      : prefTimeFormat;
+
   const date = new Date(datetime + "Z");
   return [
     date.toLocaleString(language, {
@@ -86,13 +120,13 @@ function formatDateTime(
     }),
     date.toLocaleString(language, {
       timeZone: "UTC",
-      ...(prefTimeFormat === "auto"
+      ...(timeFormat === "native"
         ? { dateStyle: "medium", timeStyle: "short" }
         : {
             month: "short",
             day: "numeric",
-            hour: prefTimeFormat === "24h" ? "2-digit" : "numeric",
-            hour12: prefTimeFormat === "12h",
+            hour: timeFormat === "24h" ? "2-digit" : "numeric",
+            hour12: timeFormat === "12h",
             minute: "2-digit",
           }),
     }),

src/widget/schemas.ts

@@ -58,7 +58,10 @@ export const preferencesSchema = object({
     ),
     "mps"
   ),
-  time_format: nullish(picklist(["auto", "12h", "24h", "24hn"]), "auto"),
+  time_format: nullish(
+    picklist(["auto", "12h", "24h", "24hn", "native"]),
+    "auto"
+  ),
   lang: pipe(
     string("lang must be a string"),
     custom(isValidLanguageTag, "invalid lang string specified")