Setup Timezone specification support

src/env/schema.mjs

@@ -1,6 +1,7 @@
 // @ts-check
 import { z } from 'zod';
 
+const TimezoneSchema = z.enum(Intl.supportedValuesOf("timeZone"));
 /**
  * Specify your server-side environment variables schema here.
  * This way you can ensure the app isn't built with invalid env vars.
@@ -18,5 +19,6 @@ export const serverSchema = z.object({
 	EDGE_CACHE_TIME_SECONDS: z.coerce.number().int().nonnegative().default(60),
 	REDIS_URL: z.string().url(),
 	DISCORD_TOKEN: z.string(),
-	DISCORD_TARGET_USER_ID: z.string()
+	DISCORD_TARGET_USER_ID: z.string(),
+	TIMEZONE: TimezoneSchema
 });

src/env/server.mjs

@@ -19,7 +19,8 @@ const _serverEnv = serverSchema.safeParse({
 	EDGE_CACHE_TIME_SECONDS: process.env.EDGE_CACHE_TIME_SECONDS,
 	REDIS_URL: process.env.REDIS_URL,
 	DISCORD_TOKEN: process.env.DISCORD_TOKEN,
-	DISCORD_TARGET_USER_ID: process.env.DISCORD_TARGET_USER_ID
+	DISCORD_TARGET_USER_ID: process.env.DISCORD_TARGET_USER_ID,
+	TIMEZONE: process.env.TIMEZONE
 });
 
 if (_serverEnv.success === false) {

src/pages/api/health.ts

@@ -5,6 +5,7 @@ import { env } from "@/env/server.mjs";
 type ResponseData = {
   now: number;
   status: string;
+  timezone: string;
 };
 
 export default async function handler(
@@ -14,5 +15,6 @@ export default async function handler(
   res.status(200).json({
     now: new Date().getTime(),
     status: req.query.key == env.API_KEY ? "Authorized" : "Unauthorized",
+    timezone: env.TIMEZONE
   });
 }

src/utils/timezone.ts

@@ -0,0 +1,13 @@
+import { utcToZonedTime } from 'date-fns-tz';
+import { z } from 'zod';
+import { env } from '@/env/server.mjs';
+
+// @ts-ignore TS2339 -- TODO: Figure out why Intl.supportedValuesOf isn't seen by Typescript
+export const TimezoneSchema = z.enum(Intl.supportedValuesOf('timeZone'));
+export type Timezone = z.infer<typeof TimezoneSchema>;
+
+export function localNow(now?: Date, zone?: Timezone): Date {
+	zone = zone ?? env.TIMEZONE;
+	now = now ?? new Date();
+	return utcToZonedTime(now, zone);
+}