some extra checks

src/routes/mail-scheduler/config/flowMap.ts

@@ -14,7 +14,7 @@ export type IflowMap = {
 const flowMap = {
   testEmail: {
     when: {
-      seconds: 5,
+      hours: 2,
     },
     subject: "Welcome To Gazar.dev",
     body: "This is a test Email sent from Gazar.dev based on your request",

src/routes/mail-scheduler/controller.ts

@@ -13,8 +13,28 @@ const postEvent = async (req, res) => {
     });
   }
 
-  if (req.mailSchedulerFlowManager)
-    req.mailSchedulerFlowManager.emit(req.body.eventName, req.body.userEmail);
+  if (req.mailSchedulerFlowManager) {
+    if (req.mailSchedulerFlowManager.taskQueueServiceObj.getLength() < 20) {
+      if (
+        !req.mailSchedulerFlowManager.taskQueueServiceObj.search(
+          req.body.userEmail
+        )
+      ) {
+        req.mailSchedulerFlowManager.emit(
+          req.body.eventName,
+          req.body.userEmail
+        );
+      } else {
+        res.status(400).json({
+          message: "User already in queue",
+        });
+      }
+    } else {
+      res.status(400).json({
+        message: "System is overloaded with tasks, you can try later",
+      });
+    }
+  }
 
   res.status(200).json({
     message: "event emitted",

src/routes/mail-scheduler/services/TaskQueueService.ts

@@ -1,6 +1,9 @@
 interface Task {
   executionTime: number;
-  data: any;
+  data: {
+    userEmail: string;
+    retry?: number;
+  };
 }
 
 class TaskHeapService {
@@ -75,6 +78,12 @@ class TaskHeapService {
     return min;
   }
 
+  search(userEmail) {
+    return (
+      this.heap.findIndex((item) => item.data.userEmail === userEmail) !== -1
+    );
+  }
+
   getLength() {
     return this.heap.length;
   }