Switch to language_code instead of language _order key

lib/I18n/I18n.cpp

@@ -4,13 +4,15 @@
 #include <HardwareSerial.h>
 #include <Serialization.h>
 
+#include <string>
+
 #include "I18nStrings.h"
 
 using namespace i18n_strings;
 
 // Settings file path
 static constexpr const char* SETTINGS_FILE = "/.crosspoint/language.bin";
-static constexpr uint8_t SETTINGS_VERSION = 1;
+static constexpr uint8_t SETTINGS_VERSION = 2;
 
 I18n& I18n::getInstance() {
   static I18n instance;
@@ -44,6 +46,14 @@ const char* I18n::getLanguageName(Language lang) const {
   return LANGUAGE_NAMES[index];
 }
 
+const char* I18n::getLanguageCode(Language lang) const {
+  const auto index = static_cast<size_t>(lang);
+  if (index >= static_cast<size_t>(Language::_COUNT)) {
+    return LANGUAGE_CODES[0];
+  }
+  return LANGUAGE_CODES[index];
+}
+
 void I18n::saveSettings() {
   Storage.mkdir("/.crosspoint");
 
@@ -54,10 +64,11 @@ void I18n::saveSettings() {
   }
 
   serialization::writePod(file, SETTINGS_VERSION);
-  serialization::writePod(file, static_cast<uint8_t>(_language));
+  serialization::writeString(file, getLanguageCode(_language));
 
   file.close();
-  Serial.printf("[I18N] Settings saved: language=%d\n", static_cast<int>(_language));
+  Serial.printf("[I18N] Settings saved: language=%d code=%s\n", static_cast<int>(_language),
+                getLanguageCode(_language));
 }
 
 void I18n::loadSettings() {
@@ -69,19 +80,48 @@ void I18n::loadSettings() {
 
   uint8_t version;
   serialization::readPod(file, version);
-  if (version != SETTINGS_VERSION) {
-    Serial.printf("[I18N] Settings version mismatch\n");
+
+  if (version == SETTINGS_VERSION) {
+    std::string code;
+    serialization::readString(file, code);
+    bool found = false;
+
+    for (uint8_t i = 0; i < getLanguageCount(); i++) {
+      if (code == LANGUAGE_CODES[i]) {
+        _language = static_cast<Language>(i);
+        found = true;
+        break;
+      }
+    }
+
+    if (found) {
+      Serial.printf("[I18N] Loaded language code: %s (%d)\n", code.c_str(), static_cast<int>(_language));
+    } else {
+      Serial.printf("[I18N] Unknown language code in settings: %s\n", code.c_str());
+    }
     file.close();
     return;
   }
 
-  uint8_t lang;
-  serialization::readPod(file, lang);
-  if (lang < static_cast<size_t>(Language::_COUNT)) {
-    _language = static_cast<Language>(lang);
-    Serial.printf("[I18N] Loaded language: %d\n", static_cast<int>(_language));
+  // Legacy migration path: version 1 stored language enum index directly.
+  if (version == 1) {
+    uint8_t lang;
+    serialization::readPod(file, lang);
+    if (lang < static_cast<size_t>(Language::_COUNT)) {
+      _language = static_cast<Language>(lang);
+      Serial.printf("[I18N] Migrating v1 language index: %d -> %s\n", static_cast<int>(_language),
+                    getLanguageCode(_language));
+      file.close();
+      saveSettings();
+      return;
+    }
+    file.close();
+    Serial.printf("[I18N] Invalid v1 language index: %d\n", static_cast<int>(lang));
+    return;
   }
 
+  Serial.printf("[I18N] Settings version mismatch: %d\n", static_cast<int>(version));
+
   file.close();
 }
 

lib/I18n/I18n.h

@@ -22,6 +22,7 @@ class I18n {
 
   Language getLanguage() const { return _language; }
   void setLanguage(Language lang);
+  const char* getLanguageCode(Language lang) const;
   const char* getLanguageName(Language lang) const;
 
   void saveSettings();

scripts/gen_i18n.py

@@ -471,6 +471,10 @@ def generate_keys_header(
     lines.append("")
 
     # Extern declarations
+    lines.append("// Language codes (defined in I18nStrings.cpp)")
+    lines.append("extern const char* const LANGUAGE_CODES[];")
+    lines.append("")
+
     lines.append("// Language display names (defined in I18nStrings.cpp)")
     lines.append("extern const char* const LANGUAGE_NAMES[];")
     lines.append("")
@@ -592,6 +596,14 @@ def generate_strings_cpp(
         "",
     ]
 
+    # LANGUAGE_NAMES array
+    lines.append("// Language codes")
+    lines.append("const char* const LANGUAGE_CODES[] = {")
+    for code in languages:
+        _append_string_entry(lines, code)
+    lines.append("};")
+    lines.append("")
+
     # LANGUAGE_NAMES array
     lines.append("// Language display names")
     lines.append("const char* const LANGUAGE_NAMES[] = {")