refactoring of database.service + fixes

src/services/database.service.ts

@@ -111,23 +111,29 @@ export class Database {
     return objectList;
   }
 
-  private createMessageChannel(responseHandler: (event: MessageEvent) => void): MessageChannel {
-    const messageChannel = new MessageChannel();
-    messageChannel.port1.onmessage = responseHandler;
-    return messageChannel;
-  }
-
   private async initServiceWorker() {
-    if (this.messageChannel) {
-      console.log('Persistent update channel already initialized.');
-      return;
-    }
-    if ('serviceWorker' in navigator) {
-      try {
+    if (!('serviceWorker' in navigator)) return; // Ensure service workers are supported
+
+    try {
+        // Get existing service worker registrations
+        const registrations = await navigator.serviceWorker.getRegistrations();
+        if (registrations.length > 0) {
+            console.log('Existing Service Worker(s) detected. Unregistering...');
+            await Promise.all(registrations.map(reg => reg.unregister()));
+            console.log('All previous Service Workers unregistered.');
+        }
+
+        // Now check the messageChannel to avoid unnecessary reinitialization
+        if (this.messageChannel) {
+            console.log('Persistent update channel already initialized.');
+            return;
+        }
+
+        // Register the new service worker
         const registration = await navigator.serviceWorker.register('/src/service-workers/database.worker.js', { type: 'module' });
         console.log('Service Worker registered with scope:', registration.scope);
 
-        this.serviceWorkerRegistration = registration
+        this.serviceWorkerRegistration = registration;
         await this.checkForUpdates();
 
         // Set up the message channels
@@ -135,19 +141,36 @@ export class Database {
         this.messageChannelForGet = new MessageChannel();
         this.messageChannel.port1.onmessage = this.handleAddObjectResponse;
         this.messageChannelForGet.port1.onmessage = this.handleGetObjectResponse;
-        registration.active?.postMessage(
-          {
-            type: 'START',
-          },
-          [this.messageChannel.port2],
+
+        // Ensure the new service worker is activated before sending messages
+        const activeWorker = registration.active || (await this.waitForServiceWorkerActivation(registration));
+
+        activeWorker?.postMessage(
+            { type: 'START' },
+            [this.messageChannel.port2],
         );
-        // Optionally, initialize service worker with some data
-      } catch (error) {
+    } catch (error) {
         console.error('Service Worker registration failed:', error);
-      }
     }
   }
 
+  // Helper function to wait for service worker activation
+  private async waitForServiceWorkerActivation(registration: ServiceWorkerRegistration): Promise<ServiceWorker | null> {
+      return new Promise((resolve) => {
+          if (registration.active) {
+              resolve(registration.active);
+          } else {
+              const listener = () => {
+                  if (registration.active) {
+                      navigator.serviceWorker.removeEventListener('controllerchange', listener);
+                      resolve(registration.active);
+                  }
+              };
+              navigator.serviceWorker.addEventListener('controllerchange', listener);
+          }
+      });
+  }
+
   private async checkForUpdates() {
     if (this.serviceWorkerRegistration) {
       // Check for updates to the service worker
@@ -172,16 +195,23 @@ export class Database {
       service.setNotifications(data.data);
     } else if (data.type === 'TO_DOWNLOAD') {
       // Download the missing data
-      for (const hash in data.data) {
+      for (const hash of data.data) {
         try {
           const value = await service.fetchValueFromStorage(hash);
-          // Save data to db
-          const blob = new Blob([value], {type: "text/plain"});
-          await service.saveDataToDb(hash, blob);
+          if (value) {
+            // Save data to db
+            const blob = new Blob([value], {type: "text/plain"});
+            await service.saveBlobToDb(hash, blob);
+          } else {
+            // We first request the data from managers
+            console.log('Request data from managers of the process');
+          }
         } catch (e) {
           console.error(e);
         }
       }
+      // try to update list of my processes
+      await service.getMyProcesses();
     }
   };
 
@@ -225,14 +255,18 @@ export class Database {
     });
   } 
 
-  public updateMyProcesses(payload: { myProcessesId: string[] }): Promise<void> {
-    return new Promise((resolve, reject) => {
-      // Check if the service worker is active
-      if (!this.serviceWorkerRegistration?.active) {
-        reject(new Error('Service worker is not active'));
-        return;
+  public updateMyProcesses(myProcessesId: string[]): Promise<void> {
+    if (myProcessesId.length === 0) {
+      return;
+    }
+
+    return new Promise(async (resolve, reject) => {
+      if (!this.serviceWorkerRegistration) {
+        // console.warn('Service worker registration is not ready. Waiting...');
+        this.serviceWorkerRegistration = await navigator.serviceWorker.ready;
       }
 
+      const activeWorker = await this.waitForServiceWorkerActivation(this.serviceWorkerRegistration);
       // Create a message channel for communication
       const messageChannel = new MessageChannel();
 
@@ -247,8 +281,9 @@ export class Database {
       };
 
       try {
+        const payload = { myProcessesId };
         console.log('Sending UPDATE_PROCESSES msg with payload', payload);
-        this.serviceWorkerRegistration.active.postMessage(
+        activeWorker?.postMessage(
           {
             type: 'UPDATE_PROCESSES',