Fix account tab persistence and viewer fallback

webui/viewer.js

@@ -87,6 +87,25 @@ function scrollToBottom() {
   setTimeout(go, 150);
 }
 
+function makeScrollSentinel() {
+  const sentinel = document.createElement("div");
+  sentinel.id = "scroll-sentinel";
+  sentinel.className = "scroll-sentinel";
+  return sentinel;
+}
+
+function resetMessageView(title = "Select a channel", subtitle = "Reading messages from the local SQLite database.") {
+  const root = document.getElementById("messages-list");
+  if (root) {
+    root.innerHTML = "";
+    root.appendChild(makeScrollSentinel());
+  }
+  document.getElementById("viewer-title").textContent = title;
+  document.getElementById("viewer-subtitle").textContent = subtitle;
+  viewerState.oldestMessageId = null;
+  viewerState.newestMessageId = null;
+}
+
 function renderChannelList() {
   const root = document.getElementById("viewer-channel-list");
   if (!root) return;
@@ -179,6 +198,13 @@ async function switchViewerAccount(accountId) {
   renderChannelList();
   if (viewerState.channelId) {
     await loadChannel(viewerState.channelId);
+  } else {
+    resetMessageView(
+      "No channels",
+      viewerState.accountId
+        ? "This account has no tracked channels yet."
+        : "No local legacy channels found."
+    );
   }
 }
 
@@ -190,10 +216,10 @@ async function loadViewerAccount(params) {
   } catch {
     viewerState.accounts = [];
   }
-  viewerState.accountId =
-    requested ||
-    viewerState.accounts[0]?.id ||
-    null;
+  const requestedExists = requested && viewerState.accounts.some((acc) => acc.id === requested);
+  viewerState.accountId = requestedExists
+    ? requested
+    : viewerState.accounts[0]?.id || null;
 
   renderAccountSelector();
 
@@ -289,8 +315,9 @@ function makeDateSep(text) {
 
 function renderMessages(payload, append = false) {
   const root = document.getElementById("messages-list");
-  const sentinel = document.getElementById("scroll-sentinel");
   if (!root) return;
+  let sentinel = document.getElementById("scroll-sentinel");
+  if (!sentinel) sentinel = makeScrollSentinel();
 
   const channel = payload.channel;
   document.getElementById("viewer-title").textContent =
@@ -408,14 +435,24 @@ async function main() {
   const params = new URLSearchParams(window.location.search);
   await loadViewerAccount(params);
   viewerState.channels = await api(channelsEndpoint());
-  viewerState.channelId =
-    params.get("channel") ||
-    viewerState.channels[0]?.channel_id ||
-    null;
+  const requestedChannel = params.get("channel");
+  const requestedChannelExists =
+    requestedChannel &&
+    viewerState.channels.some((channel) => channel.channel_id === requestedChannel);
+  viewerState.channelId = requestedChannelExists
+    ? requestedChannel
+    : viewerState.channels[0]?.channel_id || null;
   renderChannelList();
 
   if (viewerState.channelId) {
     await loadChannel(viewerState.channelId);
+  } else {
+    resetMessageView(
+      "No channels",
+      viewerState.accountId
+        ? "This account has no tracked channels yet."
+        : "No local legacy channels found."
+    );
   }
 
   setupInfiniteScroll();