Added system language detection

constants.py

@@ -29,7 +29,7 @@ if FORCE_X11:
 # --- CONFIGURATION ---
 PROG_NAME = "Bagheera Image Viewer"
 PROG_ID = "bagheeraview"
-PROG_VERSION = "0.9.14"
+PROG_VERSION = "0.9.15-dev"
 PROG_AUTHOR = "Ignacio Serantes"
 
 # --- CACHE SETTINGS ---
@@ -341,23 +341,16 @@ DEFAULT_VIEWER_SHORTCUTS = {
 
 # Supported languages
 SUPPORTED_LANGUAGES = {
+    "system": "System",
     "en": "English",
     "es": "Español",
     "gl": "Galego"
 }
 
-# Default language
-DEFAULT_LANGUAGE = "en"
-# Determine current language:
-# 1. Environment variable (for debugging/override)
-# 2. Saved configuration
-# 3. Default
-CURRENT_LANGUAGE = os.getenv("BAGHEERA_LANG") or \
-                   APP_CONFIG.get("language", DEFAULT_LANGUAGE)
-
-# Ensure the loaded language is supported, otherwise fallback to default
-if CURRENT_LANGUAGE not in SUPPORTED_LANGUAGES:
-    CURRENT_LANGUAGE = DEFAULT_LANGUAGE
+# Default language for configuration
+DEFAULT_LANGUAGE = "system"
+# Fallback language for translations
+FALLBACK_LANGUAGE = "en"
 
 _UI_TEXTS = {
     "en": {
@@ -1770,6 +1763,26 @@ _UI_TEXTS = {
 }
 
 
+# Determine which language to use for UI strings
+def _get_current_language():
+    lang = os.getenv("BAGHEERA_LANG") or APP_CONFIG.get("language", DEFAULT_LANGUAGE)
+
+    if lang == "system":
+        sys_lang = os.getenv("LANG")
+        if sys_lang:
+            # LANG is usually something like 'en_US.UTF-8'
+            lang = sys_lang[0:2].lower()
+        else:
+            lang = FALLBACK_LANGUAGE
+
+    # If the resolved language is not supported by our translation dictionaries,
+    # fallback to English.
+    return lang if lang in _UI_TEXTS else FALLBACK_LANGUAGE
+
+
+CURRENT_LANGUAGE = _get_current_language()
+
+
 class _UITextsProxy:
     """
     A proxy class to access UI strings from the _UI_TEXTS dictionary.
@@ -1781,12 +1794,12 @@ class _UITextsProxy:
     """
     def __getattr__(self, name):
         # Get the dictionary for the current language, or fallback to the default.
-        lang_texts = _UI_TEXTS.get(CURRENT_LANGUAGE, _UI_TEXTS[DEFAULT_LANGUAGE])
+        lang_texts = _UI_TEXTS.get(CURRENT_LANGUAGE, _UI_TEXTS[FALLBACK_LANGUAGE])
         # Get the specific string. If not found in the current language,
         # try the default language.
         text = lang_texts.get(name)
         if text is None:
-            default_texts = _UI_TEXTS[DEFAULT_LANGUAGE]
+            default_texts = _UI_TEXTS[FALLBACK_LANGUAGE]
             # Return a placeholder if not found anywhere
             text = default_texts.get(name, f"_{name}_")
         return text