add experimental method to reload APNs token

src/services/NotificationService.ts

@@ -1,4 +1,7 @@
 import { GetterRepository } from "../repositories/GetterRepository";
+import * as crypto from "node:crypto";
+import jwt from "jsonwebtoken";
+import * as fs from "node:fs";
 
 interface ScheduledNotificationData {
   deviceId: string;
@@ -7,8 +10,46 @@ interface ScheduledNotificationData {
 }
 
 export class NotificationService {
+  private token: string | undefined = undefined;
+  private lastRefreshedTimeMs: number | undefined = undefined;
+
   constructor(private repository: GetterRepository) {}
 
+  private encryptionKey = crypto.randomBytes(32);
+  private iv = crypto.randomBytes(16);
+
+  public async reloadAPNsTokenIfTimePassed() {
+    if (this.lastReloadedTimeForAPNsIsTooRecent()) {
+      return;
+    }
+
+    const keyId = process.env.APNS_KEY_ID;
+    const teamId = process.env.APNS_TEAM_ID;
+    const privateKeyPath = process.env.APNS_KEY_PATH;
+    if (!privateKeyPath) return;
+    const privateKey = fs.readFileSync(privateKeyPath);
+
+    const tokenHeader = {
+      alg: "ES256",
+      "kid": keyId,
+    };
+
+    const claimsPayload = {
+      "iss": teamId,
+      "iat": Date.now(),
+    };
+
+    this.token = jwt.sign(claimsPayload, privateKey, {
+      algorithm: "ES256",
+      header: tokenHeader
+    });
+  }
+
+  private lastReloadedTimeForAPNsIsTooRecent() {
+    const thirtyMinutesMs = 1800000;
+    return this.lastRefreshedTimeMs && Date.now() - this.lastRefreshedTimeMs < thirtyMinutesMs;
+  }
+
   public async scheduleNotification({ deviceId, shuttleId, stopId }: ScheduledNotificationData) {
 
   }