From f1b42f871480dec1aff9e8c887125ecd3c7044c7 Mon Sep 17 00:00:00 2001
From: mic <m@micz.it>
Date: Sun, 29 Mar 2026 22:52:47 +0200
Subject: [PATCH] warning on empty lang. see #247 #716

---
 _locales/en/messages.json |  4 ++++
 mzta-background.js        | 34 ++++++++++++++++++++++++++++++++--
 2 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/_locales/en/messages.json b/_locales/en/messages.json
index b456df8d..96064f2a 100644
--- a/_locales/en/messages.json
+++ b/_locales/en/messages.json
@@ -2165,6 +2165,10 @@
     "message": "Translation failed.",
     "description": ""
   },
+  "translate_no_language_configured": {
+    "message": "Translation language is not configured. Please set a language in the Translation settings or set a default language in the General settings.",
+    "description": ""
+  },
   "antispam_by": {
     "message": "Antispam by",
     "description": ""
diff --git a/mzta-background.js b/mzta-background.js
index 5aaad026..24898e05 100644
--- a/mzta-background.js
+++ b/mzta-background.js
@@ -377,6 +377,17 @@ messenger.runtime.onMessage.addListener((message, sender, sendResponse) => {
             case 'triggerTranslationGeneration':
                 async function _triggerTranslationGeneration(message) {
                     let tabId = sender.tab.id;
+                    let prefs_tl = await browser.storage.sync.get({
+                        translate_lang: prefs_default.translate_lang,
+                        default_chatgpt_lang: prefs_default.default_chatgpt_lang
+                    });
+                    const lang_tl = prefs_tl.translate_lang || prefs_tl.default_chatgpt_lang || '';
+                    if (!lang_tl) {
+                        let tabs = await browser.tabs.query({ active: true, currentWindow: true });
+                        browser.tabs.sendMessage(tabId, { command: "sendAlert", curr_tab_type: tabs[0].type, message: browser.i18n.getMessage('translate_no_language_configured') });
+                        browser.tabs.sendMessage(tabId, { command: "showTranslationButton", headerMessageId: message.headerMessageId });
+                        return;
+                    }
                     await _generateTranslationForMessage(message.headerMessageId, tabId);
                 }
                 _triggerTranslationGeneration(message);
@@ -384,6 +395,17 @@ messenger.runtime.onMessage.addListener((message, sender, sendResponse) => {
             case 'triggerTranslationWebchat':
                 async function _triggerTranslationWebchat(message) {
                     let tabId = sender.tab.id;
+                    let prefs_tw = await browser.storage.sync.get({
+                        translate_lang: prefs_default.translate_lang,
+                        default_chatgpt_lang: prefs_default.default_chatgpt_lang
+                    });
+                    const lang_tw = prefs_tw.translate_lang || prefs_tw.default_chatgpt_lang || '';
+                    if (!lang_tw) {
+                        let tabs = await browser.tabs.query({ active: true, currentWindow: true });
+                        browser.tabs.sendMessage(tabId, { command: "sendAlert", curr_tab_type: tabs[0].type, message: browser.i18n.getMessage('translate_no_language_configured') });
+                        browser.tabs.sendMessage(tabId, { command: "showTranslationButton", headerMessageId: message.headerMessageId, webchat: true });
+                        return;
+                    }
                     await _openTranslationWebchat(message.headerMessageId, tabId);
                 }
                 _triggerTranslationWebchat(message);
@@ -716,6 +738,12 @@ async function _generateTranslationForMessage(headerMessageId, tabId = null, opt
             return;
         }
 
+        const lang = prefs.translate_lang || prefs.default_chatgpt_lang || '';
+        if (!lang) {
+            taLog.warn("Translation skipped: no language configured (translate_lang and default_chatgpt_lang are both empty).");
+            return;
+        }
+
         if (await translationStore.isProcessing(headerMessageId)) {
             if (tabId) browser.tabs.sendMessage(tabId, { command: "showTranslationGenerating" });
             return;
@@ -748,8 +776,6 @@ async function _generateTranslationForMessage(headerMessageId, tabId = null, opt
             taWorkingStatus.stopWorking();
             return;
         }
-
-        const lang = prefs.translate_lang || prefs.default_chatgpt_lang || '';
         const { promptText } = await taPromptUtils.buildTranslationPrompt(fullMessage, lang);
 
         const cmd = new mzta_specialCommand({
@@ -951,6 +977,10 @@ async function _openTranslationWebchat(headerMessageId, tabId) {
         }
 
         const lang = prefs.translate_lang || prefs.default_chatgpt_lang || '';
+        if (!lang) {
+            taLog.warn("Translation skipped: no language configured (translate_lang and default_chatgpt_lang are both empty).");
+            return;
+        }
         const { promptText, promptInfo } = await taPromptUtils.buildTranslationPrompt(curr_message_full, lang);
         promptInfo.headerMessageId = headerMessageId;
         promptInfo.translationTabId = tabId;