From 663dcb13a5b5085b58ebb10ee5f5eff4bb3d07ce Mon Sep 17 00:00:00 2001
From: Kit La Touche <kit@transneptune.net>
Date: Sun, 30 Nov 2025 22:59:21 -0500
Subject: Show number of unread conversations in app badge

---
 ui/service-worker.js | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

(limited to 'ui/service-worker.js')

diff --git a/ui/service-worker.js b/ui/service-worker.js
index cb32d0d..eee3397 100644
--- a/ui/service-worker.js
+++ b/ui/service-worker.js
@@ -53,11 +53,55 @@ self.addEventListener('fetch', (event) => {
   event.respondWith(cacheFirst(event.request));
 });
 
+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;
+  }
 });
-- 
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