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

---
 package-lock.json                             |  2 +-
 ui/lib/components/ChannelMeta.svelte          | 44 +++++++++++++++++++++++++++
 ui/routes/(app)/c/[conversation]/+page.svelte | 15 +++++++++
 ui/service-worker.js                          | 44 +++++++++++++++++++++++++++
 ui/styles/app-bar.css                         |  2 ++
 ui/styles/forms.css                           |  8 +++++
 ui/styles/messages.css                        | 24 +++++++++++++++
 7 files changed, 138 insertions(+), 1 deletion(-)
 create mode 100644 ui/lib/components/ChannelMeta.svelte

diff --git a/package-lock.json b/package-lock.json
index 849a38c..211ad61 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -37,7 +37,7 @@
         "vitest": "^4.0.8"
       },
       "engines": {
-        "node": ">=22.0.0 <23.0.0",
+        "node": ">=22.12.0 <23.0.0",
         "npm": ">=10.0.0 <11.0.0"
       }
     },
diff --git a/ui/lib/components/ChannelMeta.svelte b/ui/lib/components/ChannelMeta.svelte
new file mode 100644
index 0000000..2ee13b6
--- /dev/null
+++ b/ui/lib/components/ChannelMeta.svelte
@@ -0,0 +1,44 @@
+<script>
+  let { vapid, subscription, startExpanded = false, subscribe = async () => null } = $props();
+  let pending = $state(false);
+  let expanded = $state(startExpanded);
+
+  function onsubmit(callback) {
+    return async (evt) => {
+      evt.preventDefault();
+      // Without this, the toggleExpanded function defined below will trigger:
+      evt.stopPropagation();
+
+      pending = true;
+      try {
+        // TODO: is this working?
+        await callback();
+      } finally {
+        pending = false;
+      }
+    };
+  }
+
+  function toggleExpanded() {
+    // TODO: in messages.css we need to slide the whole div up, not leave its
+    // contents static. We need to show three little lines as a handle. We need
+    // to fix colours. We need to keep the meta consistently over the rest of
+    // the message list.  We need to fix mobile click-area. Too easy to hit the
+    // title and go to / instead.
+    // Also: we can start expanded optionally, if there is a message we need to
+    // show. This can work for prompts like "activate your notifications".
+    expanded = !expanded;
+  }
+</script>
+
+<div class="channel-meta {expanded ? 'expanded' : ''}" onclick={toggleExpanded}>
+  &nbsp;
+  <div class="inner">
+    {#if !subscription}
+      <form class="form" onsubmit={onsubmit(subscribe)}>
+        <button disabled={pending} type="submit">create push subscription</button>
+      </form>
+    {/if}
+  </div>
+  <div class="handle">&equiv;</div>
+</div>
diff --git a/ui/routes/(app)/c/[conversation]/+page.svelte b/ui/routes/(app)/c/[conversation]/+page.svelte
index 24baa47..be97737 100644
--- a/ui/routes/(app)/c/[conversation]/+page.svelte
+++ b/ui/routes/(app)/c/[conversation]/+page.svelte
@@ -1,6 +1,7 @@
 <script>
   import { DateTime } from 'luxon';
   import { page } from '$app/state';
+  import ChannelMeta from '$lib/components/ChannelMeta.svelte';
   import MessageInput from '$lib/components/MessageInput.svelte';
   import MessageRun from '$lib/components/MessageRun.svelte';
   import Message from '$lib/components/Message.svelte';
@@ -10,6 +11,9 @@
   const { session, outbox } = data;
   let activeConversation;
 
+  const subscription = $derived(session.push.subscription);
+  const vapid = $derived(session.push.vapidKey);
+
   const conversationId = $derived(page.params.conversation);
   const conversation = $derived(
     session.conversations.find((conversation) => conversation.id === conversationId),
@@ -56,6 +60,11 @@
     if (!!at) {
       session.local.updateLastReadAt(conversationId, at);
     }
+    navigator.serviceWorker.controller.postMessage({
+      type: 'CONVERSATION_READ',
+      conversationId,
+      at,
+    });
   }
 
   $effect(() => {
@@ -82,6 +91,11 @@
     lastReadCallback = setTimeout(setLastRead, 2 * 1000);
   }
 
+  async function subscribe() {
+    // TODO: we need to provide specific subscription stuff, right?
+    await session.push.subscribe();
+  }
+
   async function sendMessage(message) {
     outbox.sendToConversation(conversationId, message);
   }
@@ -93,6 +107,7 @@
 
 <svelte:window onkeydown={handleKeydown} />
 
+<ChannelMeta {subscribe} {vapid} {subscription} />
 <div class="active-conversation" {onscroll} bind:this={activeConversation}>
   {#each messageRuns as { sender, ownMessage, messages }}
     <MessageRun
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;
+  }
 });
diff --git a/ui/styles/app-bar.css b/ui/styles/app-bar.css
index ce52712..272810a 100644
--- a/ui/styles/app-bar.css
+++ b/ui/styles/app-bar.css
@@ -7,6 +7,8 @@
   align-items: stretch;
   background-color: var(--colour-header-bg);
   color: var(--light-text);
+  z-index: 2;
+  position: relative;
 }
 
 .app-bar > * {
diff --git a/ui/styles/forms.css b/ui/styles/forms.css
index f4d218f..19d31b7 100644
--- a/ui/styles/forms.css
+++ b/ui/styles/forms.css
@@ -26,3 +26,11 @@ form.form > button {
 .disabled {
   color: var(--light-text);
 }
+
+button {
+  cursor: pointer;
+}
+button:active {
+  border-color: red;
+  background-color: blue;
+}
diff --git a/ui/styles/messages.css b/ui/styles/messages.css
index 5488fa5..52355b7 100644
--- a/ui/styles/messages.css
+++ b/ui/styles/messages.css
@@ -1,3 +1,27 @@
+.channel-meta {
+  border-width: 0 1px 1px 1px;
+  border-color: red;
+  border-style: solid;
+  border-radius: 0 0 4px 4px;
+  background-color: mistyrose;
+  overflow: clip;
+  transition: margin-top 0.25s ease-in;
+  z-index: 1;
+  margin-top: -5rem;
+}
+
+.channel-meta.expanded {
+  margin-top: 0rem;
+}
+
+.channel-meta .handle {
+  text-align: center;
+}
+
+.channel-meta .inner {
+  padding: 1rem;
+}
+
 .message-run {
   border-radius: 0.25rem;
   margin-top: 1rem;
-- 
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