improve locale detection as much as possible

src/engine.cpp

@@ -68,7 +68,7 @@ Engine::Engine(EngineSettings& settings, EnginePaths* paths)
 	Audio::initialize();
 	gui = new gui::GUI();
     if (settings.ui.language == "auto") {
-        settings.ui.language = platform::detect_locale();
+        settings.ui.language = langs::locale_by_envlocale(platform::detect_locale(), paths->getResources());
     }
     setLanguage(settings.ui.language);
 	std::cout << "-- initializing finished" << std::endl;

src/frontend/locale/langs.cpp

@@ -77,6 +77,7 @@ void langs::loadLocalesInfo(const path& resdir, string& fallback) {
 
     auto langs = root->obj("langs");
     if (langs) {
+        std::cout << "locales ";
         for (auto& entry : langs->map) {
             auto langInfo = entry.second;
 
@@ -87,9 +88,31 @@ void langs::loadLocalesInfo(const path& resdir, string& fallback) {
                 continue;
             }
 
-            std::cout << "locale " << entry.first << " (" << name << ") added" << std::endl;
+            std::cout << "[" << entry.first << " (" << name << ")] ";
             langs::locales_info[entry.first] = LocaleInfo {entry.first, name};
         } 
+        std::cout << "added" << std::endl;
+    }
+}
+
+std::string langs::locale_by_envlocale(const std::string& envlocale, const path& resdir){
+    string fallback = FALLBACK_DEFAULT;
+    if (locales_info.size() == 0) {
+        loadLocalesInfo(resdir, fallback);
+    }
+    if (locales_info.find(envlocale) != locales_info.end()) {
+        std::cout << "locale " << envlocale << " is automatically selected" << std::endl;
+        return envlocale;
+    }
+    else {
+        for (const auto& loc : locales_info) {
+            if (loc.first.find(envlocale.substr(0, 2)) != std::string::npos) {
+                std::cout << "locale " << loc.first << " is automatically selected" << std::endl;
+                return loc.first;
+            }
+        }
+        std::cout << "locale " << fallback << " is automatically selected" << std::endl;
+        return fallback;
     }
 }
 

src/frontend/locale/langs.h

@@ -48,6 +48,9 @@ namespace langs {
         const std::filesystem::path& resdir,
         std::string& fallback);
 
+    extern std::string locale_by_envlocale(const std::string& envlocale,
+                                           const std::filesystem::path& resdir);
+
     extern void load(const std::filesystem::path& resdir,
                      const std::string& locale,
                      const std::vector<ContentPack>& packs,

src/util/platform.cpp

@@ -7,18 +7,6 @@
 
 #include "../typedefs.h"
 
-namespace platform {
-    const std::string DEFAULT_LOCALE = "en_EN";
-}
-
-/*System locale to engine locale mapping*/
-std::string platform::get_locale_by_lang(std::string lang) {
-    if (lang == "ru") {
-        return "ru_RU";
-    }
-    return DEFAULT_LOCALE;
-}
-
 #ifdef WIN32
 #include <Windows.h>
 
@@ -32,18 +20,12 @@ void platform::configure_encoding() {
 
 std::string platform::detect_locale() {
     LCID lcid = GetThreadLocale();
-    wchar_t preferredLocaleName[LOCALE_NAME_MAX_LENGTH];
+    wchar_t preferredLocaleName[LOCALE_NAME_MAX_LENGTH];//locale name format: ll-CC
     if (LCIDToLocaleName(lcid, preferredLocaleName, LOCALE_NAME_MAX_LENGTH, 0) == 0) {
-        std::cout << "error in platform::detect_locale! LCIDToLocaleName failed." << std::endl;
+        std::cerr << "error in platform::detect_locale! LCIDToLocaleName failed." << std::endl;
     }
-    wchar_t parentLocaleName[LOCALE_NAME_MAX_LENGTH];
-    if (GetLocaleInfoEx(preferredLocaleName, LOCALE_SPARENT, parentLocaleName, LOCALE_NAME_MAX_LENGTH) == 0){
-        std::cout << "error in platform::detect_locale! GetLocaleInfoEx failed." << std::endl;
-    }
-    std::wcout << "detected environment language locale: " << parentLocaleName << std::endl;
-
-    std::string preferredLang = util::wstr2str_utf8(parentLocaleName);
-    return get_locale_by_lang(preferredLang);
+    //ll_CC format
+    return util::wstr2str_utf8(preferredLocaleName).replace(2, 1, "_").substr(0, 5);
 }
 
 #else
@@ -53,12 +35,10 @@ void platform::configure_encoding(){
 
 std::string platform::detect_locale() {
     std::string programLocaleName = setlocale(LC_ALL, nullptr);
-    std::string preferredLocaleName = setlocale(LC_ALL, "");
-    std::cout << "detected environment locale: " << preferredLocaleName << std::endl;
+    std::string preferredLocaleName = setlocale(LC_ALL, ""); //locale name format: ll_CC.encoding
     setlocale(LC_ALL, programLocaleName.c_str());
 
-    std::string preferredLang = preferredLocaleName.substr(0, 2);
-    return get_locale_by_lang(preferredLang);
+    return preferredLocaleName.substr(0, 5);
 }
 
 #endif

src/util/platform.h

@@ -5,8 +5,8 @@
 
 namespace platform {
     extern void configure_encoding();
+    // @return environment locale in ISO format ll_CC
     extern std::string detect_locale();
-    extern std::string get_locale_by_lang(std::string lang);
 }
 
 #endif // UTIL_PLATFORM_H_