Fix dark-mode email readability, silent reply failures, and add an IMAP connection watchdog

Dark theme: inbound email HTML intentionally keeps its own inline colors
for fidelity (sanitize-html.ts), but a sender's hardcoded dark text (the
common case) was unreadable once the surrounding chrome went dark. Now
forced to the theme's own text color in dark mode only; light mode keeps
full fidelity as before.

Send button: deliverAgentMessage awaited the outbound email/Telegram send
*before* recording the reply, so a broken mail/bot account (e.g. bad SMTP
creds) made the reply vanish entirely — not sent, not saved, no error
shown — with the API's catch-all masking the real cause as a generic
"Ticket not found". Channel delivery is now best-effort: the reply is
always recorded even if outbound delivery fails, and real errors surface
to the compose box instead of failing silently.

IMAP watchdog: a live IDLE connection has gone quietly unresponsive in
production more than once, with mail landing server-side but never
noticed here and no error ever firing. Added a periodic forced NOOP
round-trip with its own deadline, independent of ImapFlow's internal
socket timeout, that tears down and reconnects a connection that stops
answering.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gh2UXUQUVBWroWEnn1FLFG

src/app/(admin)/tickets/[id]/ticket-thread.tsx

@@ -37,6 +37,7 @@ export function TicketThread({
   const [visibility, setVisibility] = useState<"public" | "internal">("public");
   const [pendingFile, setPendingFile] = useState<File | null>(null);
   const [sending, setSending] = useState(false);
+  const [sendError, setSendError] = useState<string | null>(null);
   const [cannedResponses, setCannedResponses] = useState<{ id: string; title: string; body: string }[]>([]);
   const [cannedOpen, setCannedOpen] = useState(false);
   const bottomRef = useRef<HTMLDivElement>(null);
@@ -82,6 +83,7 @@ export function TicketThread({
   async function sendReply() {
     if (!draft.trim() && !pendingFile) return;
     setSending(true);
+    setSendError(null);
 
     let res: Response;
     if (pendingFile) {
@@ -103,6 +105,9 @@ export function TicketThread({
       setDraft("");
       setPendingFile(null);
       if (fileInputRef.current) fileInputRef.current.value = "";
+    } else {
+      const data = await res.json().catch(() => null);
+      setSendError(data?.error ?? "Не удалось отправить сообщение");
     }
   }
 
@@ -210,6 +215,7 @@ export function TicketThread({
             </button>
           </div>
         )}
+        {sendError && <p className="mb-1.5 text-xs text-danger-soft-text">{sendError}</p>}
         {pendingFile && (
           <div className="mb-1.5 flex items-center gap-2 rounded-md border border-border bg-surface-hover px-2.5 py-1.5 text-xs">
             <Paperclip size={12} />

src/app/api/tickets/[id]/attachments/route.ts

@@ -60,7 +60,8 @@ export async function POST(request: Request, { params }: { params: Promise<{ id:
       },
     });
     return NextResponse.json(result, { status: 201 });
-  } catch {
+  } catch (err) {
-    return NextResponse.json({ error: "Ticket not found" }, { status: 404 });
+    const message = err instanceof Error ? err.message : "Не удалось отправить вложение";
+    return NextResponse.json({ error: message }, { status: 400 });
   }
 }

src/app/api/tickets/[id]/messages/route.ts

@@ -44,7 +44,8 @@ export async function POST(request: Request, { params }: { params: Promise<{ id:
       visibility,
     });
     return NextResponse.json(result, { status: 201 });
-  } catch {
+  } catch (err) {
-    return NextResponse.json({ error: "Ticket not found" }, { status: 404 });
+    const message = err instanceof Error ? err.message : "Не удалось отправить сообщение";
+    return NextResponse.json({ error: message }, { status: 400 });
   }
 }

src/app/globals.css

@@ -203,6 +203,26 @@
   color-scheme: dark;
 }
 
+/* Inbound email HTML intentionally keeps its own inline colors (see the
+   sanitizeEmailHtml comment in lib/mail/sanitize-html.ts — full fidelity,
+   "exactly as the person sent it") — but a sender's hardcoded dark text,
+   the common case, becomes unreadable once the surrounding chrome goes
+   dark. Force every descendant in a message bubble back to the theme's
+   own readable text color in dark mode only; light mode is untouched and
+   keeps full fidelity as designed. */
+:root[data-theme="dark"] .message-html,
+:root[data-theme="dark"] .message-html * {
+  color: var(--text) !important;
+  background-color: transparent !important;
+}
+@media (prefers-color-scheme: dark) {
+  :root:not([data-theme="light"]) .message-html,
+  :root:not([data-theme="light"]) .message-html * {
+    color: var(--text) !important;
+    background-color: transparent !important;
+  }
+}
+
 /* Theme-toggle icon: both render always, CSS picks which shows — same
    data-theme cascade the palette above uses, so it never needs JS state. */
 .theme-toggle-btn .theme-icon-sun {

src/components/message-body-html.tsx

@@ -5,7 +5,7 @@
 export function MessageBodyHtml({ html, className = "" }: { html: string; className?: string }) {
   return (
     <div
-      className={`max-w-full overflow-x-auto text-sm break-words [&_img]:max-w-full [&_img]:cursor-zoom-in [&_table]:max-w-full [&_td]:break-words [&_th]:break-words ${className}`}
+      className={`message-html max-w-full overflow-x-auto text-sm break-words [&_img]:max-w-full [&_img]:cursor-zoom-in [&_table]:max-w-full [&_td]:break-words [&_th]:break-words ${className}`}
       dangerouslySetInnerHTML={{ __html: html }}
     />
   );

src/lib/mail/imap.ts

@@ -224,11 +224,54 @@ async function processUnseenMessages(client: ImapFlow): Promise<void> {
   }
 }
 
+/** Shared by the idle loop's own catch and the watchdog below — only one of them should ever win the race to reconnect. */
+function scheduleReconnect(client: ImapFlow, reason: string, err?: unknown): void {
+  if (state.client !== client) return; // already superseded (new client) or stopped — nothing to do
+  console.error(`[mail] ${reason}, will retry shortly:`, err ?? "");
+  state.client = null;
+  if (!state.stopping) {
+    setTimeout(() => {
+      ensureMailListenerStarted().catch((e) => console.error("Mail listener retry failed:", e));
+    }, 15_000);
+  }
+}
+
+const WATCHDOG_INTERVAL_MS = 5 * 60 * 1000;
+const WATCHDOG_TIMEOUT_MS = 20_000;
+
+/**
+ * A live IDLE connection has twice gone quietly unresponsive in production —
+ * mail kept landing server-side but this process never noticed — without
+ * ImapFlow's own error handler ever firing. A plain IDLE loop has no way to
+ * detect that on its own: if the socket is dead but no TCP-level event
+ * arrives, `client.idle()` just hangs forever. This periodically forces a
+ * real round trip (NOOP, which ImapFlow transparently breaks IDLE for and
+ * resumes after) with its own hard deadline, independent of whatever
+ * ImapFlow's internal socket timeout is doing — if it doesn't come back in
+ * time, the connection is presumed dead and torn down for a fresh reconnect.
+ */
+function startWatchdog(client: ImapFlow): void {
+  const interval = setInterval(() => {
+    if (state.client !== client) {
+      clearInterval(interval);
+      return;
+    }
+    const timeout = new Promise<never>((_, reject) =>
+      setTimeout(() => reject(new Error("watchdog NOOP timed out")), WATCHDOG_TIMEOUT_MS),
+    );
+    Promise.race([client.noop(), timeout]).catch((err) => {
+      clearInterval(interval);
+      scheduleReconnect(client, "IMAP watchdog check failed", err);
+    });
+  }, WATCHDOG_INTERVAL_MS);
+}
+
 async function runIdleLoop(client: ImapFlow): Promise<void> {
   try {
     await client.mailboxOpen("INBOX");
     console.log("[mail] IDLE listener connected, watching INBOX");
     await processUnseenMessages(client);
+    startWatchdog(client);
 
     // New mail is signaled by the 'exists' event while IDLE is active — it's
     // independent of when idle() itself resolves (that happens on periodic
@@ -243,15 +286,7 @@ async function runIdleLoop(client: ImapFlow): Promise<void> {
       await client.idle();
     }
   } catch (err) {
-    if (state.client === client) {
+    scheduleReconnect(client, "IMAP idle loop error", err);
-      console.error("IMAP idle loop error, will retry shortly:", err);
-      state.client = null;
-      if (!state.stopping) {
-        setTimeout(() => {
-          ensureMailListenerStarted().catch((e) => console.error("Mail listener retry failed:", e));
-        }, 15_000);
-      }
-    }
   }
 }
 

src/lib/tickets/delivery.ts

@@ -49,10 +49,18 @@ export async function deliverAgentMessage(params: {
     });
   }
 
+  // Channel delivery (email/Telegram) is best-effort: the agent's reply is
+  // the thing that must never be lost. Previously an SMTP/Telegram failure
+  // here threw straight out of this function, so recordAgentReply below was
+  // never reached — the reply vanished entirely (not recorded, nothing
+  // shown in the thread) and the API route's catch-all turned it into a
+  // misleading "Ticket not found". A broken mail/bot account should degrade
+  // to "reply saved internally, not delivered" — never silent data loss.
   let emailMessageId: string | undefined;
   if (ticket.channel === "email") {
     const context = await getEmailThreadContext(params.ticketId);
     if (context) {
+      try {
         emailMessageId = await sendTicketReplyEmail({
           to: context.customerEmail,
           subject: context.subject,
@@ -62,6 +70,9 @@ export async function deliverAgentMessage(params: {
             ? { filename: params.attachment.filename, content: params.attachment.buffer }
             : undefined,
         });
+      } catch (err) {
+        console.error(`Failed to send reply email for ticket ${params.ticketId}:`, err);
+      }
     }
   }
 
@@ -79,6 +90,7 @@ export async function deliverAgentMessage(params: {
       where: eq(customers.id, result.ticket.customerId),
     });
     if (customer?.telegramChatId) {
+      try {
         if (params.attachment) {
           await sendTelegramFile(
             customer.telegramChatId,
@@ -88,6 +100,9 @@ export async function deliverAgentMessage(params: {
         } else {
           await sendTelegramMessage(customer.telegramChatId, params.body);
         }
+      } catch (err) {
+        console.error(`Failed to deliver reply via Telegram for ticket ${params.ticketId}:`, err);
+      }
     }
   }