1 files changed, 45 insertions, 0 deletions
diff --git a/ui/service-worker.js b/ui/service-worker.js
index 446fbc8..56bfca9 100644
--- a/ui/service-worker.js
+++ b/ui/service-worker.js
@@ -11,11 +11,56 @@ self.addEventListener('activate', (event) => {
   event.waitUntil(self.clients.claim());
 });
 
+// ###### Handle unread badge:
+const conversationReadStatus = {
+  // Format:
+  // conversationId: { lastRead: Optional(Datetime), lastMessage: Datetime }
+};
+
+function countUnreadChannels() {
+  return Object.values(conversationReadStatus)
+    .map(({ lastRead, lastMessage }) => {
+      return !lastRead || lastRead < lastMessage ? 1 : 0;
+    })
+    .reduce((total, current) => total + current, 0);
+}
+
 self.addEventListener('push', (event) => {
+  // Let's show a notification right away so Safari doesn't tell Apple to be
+  // mad at us:
   event.waitUntil(
     self.registration.showNotification('Test notification', {
       actions: [],
       body: event.data.text(),
     }),
   );
+  // Now we can do slower things that might fail:
+  conversationReadStatus[event.conversationId] ||= { lastRead: null, lastMessage: null };
+  conversationReadStatus[event.conversationId].lastMessage = new Date();
+  event.waitUntil(
+    (async () => {
+      if (navigator.setAppBadge) {
+        navigator.setAppBadge(countUnreadChannels());
+      }
+    })(),
+  );
+});
+
+// The client has to tell us when it has read a conversation:
+self.addEventListener('message', (event) => {
+  switch (event.data?.type) {
+    case 'CONVERSATION_READ':
+      conversationReadStatus[event.data.conversationId] ||= { lastRead: null, lastMessage: null };
+      conversationReadStatus[event.data.conversationId].lastMessage = event.data.at || new Date();
+      event.waitUntil(
+        (async () => {
+          if (navigator.setAppBadge) {
+            navigator.setAppBadge(countUnreadChannels());
+          }
+        })(),
+      );
+      break;
+    default:
+      break;
+  }
 });