Report OpenAI quota errors in admin

server.js

@@ -479,19 +479,24 @@ async function adminAiTest(res) {
   const apiKey = settings.openaiApiKey;
   if (!apiKey) return json(res, 400, { ok: false, error: "missing_openai_api_key" });
   try {
-    const response = await fetch("https://api.openai.com/v1/models", {
+    const modelsResponse = await fetch("https://api.openai.com/v1/models", {
       headers: { "Authorization": `Bearer ${apiKey}` }
     });
-    if (!response.ok) return json(res, 400, { ok: false, error: `openai_http_${response.status}` });
-    const data = await response.json();
+    if (!modelsResponse.ok) {
+      const openAiError = await openAiErrorFromResponse(modelsResponse);
+      return json(res, 400, { ok: false, error: openAiError.code, message: openAiError.message });
+    }
+    const data = await modelsResponse.json();
+    await translateText("Test", settings.operatorLanguage || "cs", settings.model, apiKey);
     return json(res, 200, {
       ok: true,
       key: maskApiKey(apiKey),
+      model: settings.model,
       modelCount: Array.isArray(data.data) ? data.data.length : 0
     });
   } catch (error) {
     console.error("openai_test_failed", error.message);
-    return json(res, 502, { ok: false, error: "openai_test_failed" });
+    return json(res, 400, { ok: false, error: classifyOpenAiError(error.message), message: error.message });
   }
 }
 
@@ -807,7 +812,7 @@ async function translateStoredMessage(conversationId, messageId, senderType, bod
     markMessageTranslation(messageId, sourceLanguage, translatedText, translatedLanguage, "translated", null);
   } catch (error) {
     console.error("translation_failed", error.message);
-    markMessageTranslation(messageId, null, null, targetLanguage, "failed", error.message);
+    markMessageTranslation(messageId, null, null, targetLanguage, classifyOpenAiError(error.message), error.message);
   }
 }
 
@@ -848,13 +853,38 @@ async function translateText(text, targetLanguage, model, apiKey) {
     })
   });
   if (!response.ok) {
-    const errorBody = await response.text().catch(() => "");
-    throw new Error(`OpenAI HTTP ${response.status}${errorBody ? `: ${errorBody.slice(0, 300)}` : ""}`);
+    const openAiError = await openAiErrorFromResponse(response);
+    throw new Error(openAiError.message);
   }
   const data = await response.json();
   return parseTranslationJson(outputTextFromResponse(data));
 }
 
+async function openAiErrorFromResponse(response) {
+  const errorBody = await response.text().catch(() => "");
+  let message = errorBody;
+  let code = `openai_http_${response.status}`;
+  try {
+    const parsed = JSON.parse(errorBody);
+    message = parsed?.error?.message || message;
+    code = parsed?.error?.code || parsed?.error?.type || code;
+  } catch {}
+  const classifiedCode = classifyOpenAiError(`${code} ${message}`);
+  return {
+    code: classifiedCode,
+    message: `OpenAI HTTP ${response.status}: ${message || response.statusText || classifiedCode}`
+  };
+}
+
+function classifyOpenAiError(value) {
+  const text = String(value || "").toLowerCase();
+  if (text.includes("insufficient_quota") || text.includes("exceeded your current quota") || text.includes("billing")) return "quota_exceeded";
+  if (text.includes("invalid_api_key") || text.includes("incorrect api key") || text.includes("unauthorized") || text.includes("401")) return "invalid_key";
+  if (text.includes("rate_limit") || text.includes("too many requests")) return "rate_limited";
+  if (text.includes("model") && (text.includes("not found") || text.includes("does not exist"))) return "bad_model";
+  return "failed";
+}
+
 function parseTranslationJson(value) {
   try {
     const text = String(value || "").trim().replace(/^```(?:json)?/i, "").replace(/```$/, "").trim();