From 2743721e932c62423a80e6d90ada6a183946b89c Mon Sep 17 00:00:00 2001
From: Swapnil Bhattacharya <swapnilb050203@gmail.com>
Date: Sun, 23 Feb 2025 20:07:26 +0530
Subject: [PATCH] Fix QStash reminder scheduling logic

---
 controllers/workflow.controller.js | 69 ++++++++++++++++++++----------
 1 file changed, 47 insertions(+), 22 deletions(-)

diff --git a/controllers/workflow.controller.js b/controllers/workflow.controller.js
index a70b5dc..762e819 100644
--- a/controllers/workflow.controller.js
+++ b/controllers/workflow.controller.js
@@ -1,48 +1,73 @@
-import dayjs from 'dayjs'
-import { createRequire } from 'module';
+import dayjs from "dayjs";
+import { createRequire } from "module";
 const require = createRequire(import.meta.url);
 const { serve } = require("@upstash/workflow/express");
-import Subscription from '../models/subscription.model.js';
-import { sendReminderEmail } from '../utils/send-email.js'
+import Subscription from "../models/subscription.model.js";
+import { sendReminderEmail } from "../utils/send-email.js";
 
-const REMINDERS = [7, 5, 2, 1]
+const REMINDERS = [7, 5, 2, 1]; // IN DAYS
 
 export const sendReminders = serve(async (context) => {
   const { subscriptionId } = context.requestPayload;
   const subscription = await fetchSubscription(context, subscriptionId);
 
-  if(!subscription || subscription.status !== 'active') return;
+  if (!subscription || subscription.status !== "active") return; // STOP WORKFLOW IF SUBSCRIPTION IS NOT ACTIVE
 
   const renewalDate = dayjs(subscription.renewalDate);
 
-  if(renewalDate.isBefore(dayjs())) {
-    console.log(`Renewal date has passed for subscription ${subscriptionId}. Stopping workflow.`);
+  // STOP WORKFLOW IF RENEWAL DATE HAS PASSED
+  if (renewalDate.isBefore(dayjs())) {
+    console.log(
+      `Renewal date has passed for subscription ${subscriptionId}. Stopping workflow...`
+    );
     return;
   }
 
   for (const daysBefore of REMINDERS) {
-    const reminderDate = renewalDate.subtract(daysBefore, 'day');
+    const reminderDate = renewalDate.subtract(daysBefore, "day");
 
-    if(reminderDate.isAfter(dayjs())) {
-      await sleepUntilReminder(context, `Reminder ${daysBefore} days before`, reminderDate);
+    // SEND REMINDERS UNTIL RENEWAL DATE
+    if (reminderDate.isAfter(dayjs())) {
+      await sleepUntilReminder(
+        context,
+        `Reminder ${daysBefore} days before`,
+        reminderDate
+      );
     }
 
-    if (dayjs().isSame(reminderDate, 'day')) {
-      await triggerReminder(context, `${daysBefore} days before reminder`, subscription);
+    // TRIGGER REMINDER ON RENEWAL DATE
+    if (dayjs().isSame(reminderDate, "day")) {
+      await triggerReminder(
+        context,
+        `${daysBefore} days before reminder`,
+        subscription
+      );
     }
   }
 });
 
 const fetchSubscription = async (context, subscriptionId) => {
-  return await context.run('get subscription', async () => {
-    return Subscription.findById(subscriptionId).populate('user', 'name email');
-  })
-}
+  return await context.run("get subscription", async () => {
+    return Subscription.findById(subscriptionId).populate("user", "name email");
+  });
+};
 
 const sleepUntilReminder = async (context, label, date) => {
+  const now = dayjs();
+  const delayInSeconds = date.diff(now, "second");
+
+  // QStash MAX_DELAY is 11.5 days
+  if (delayInSeconds > 1_000_000) {
+    // IF REMINDER IS MORE THAN 11.5 DAYS, SKIP SLEEP
+    console.warn(
+      `Skipping sleep for ${label} because it's beyond QStash max delay (11.5 days).`
+    );
+    return;
+  }
+
   console.log(`Sleeping until ${label} reminder at ${date}`);
-  await context.sleepUntil(label, date.toDate());
-}
+  await context.sleepUntil(label, date.toDate()); // SLEEP UNTIL RENEWAL DATE
+};
 
 const triggerReminder = async (context, label, subscription) => {
   return await context.run(label, async () => {
@@ -52,6 +77,6 @@ const triggerReminder = async (context, label, subscription) => {
       to: subscription.user.email,
       type: label,
       subscription,
-    })
-  })
-}
\ No newline at end of file
+    });
+  });
+};