Fixed choosing preferred language on Windows

The linker could not find _nl_locale_name_default. Maybe it could be
fixed by linking to another library, but it would likely not yield the
preferred behavior. Instead, we now use GetUserPreferredUILanguages to
set the LANG environment variable with one or more languages and let
gettext choose the best fitting available translation.

Also fixed the directory from which the translations are loaded to match
the installation directory,

1 files changed, 32 insertions, 11 deletions

diff --git a/src/main.cpp b/src/main.cpp
index 7b9e921e..68a6b0c3 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -33,6 +33,9 @@
 #ifdef __MINGW32__
 #include <windows.h>
 #endif
+#if ENABLE_NLS && defined(_WIN32)
+#include <winnls.h>
+#endif
 
 static void printHelp()
 {
@@ -178,24 +181,42 @@ static void parseOptions(int argc, char *argv[], Client::Options &options)
     }
 }
 
-#ifdef _WIN32
-//extern "C" char const *_nl_locale_name_default(void);
-#endif
-
 static void initInternationalization()
 {
 #if ENABLE_NLS
 #ifdef _WIN32
-//    SetEnvironmentVariable("LANG", _nl_locale_name_default());
-    // mingw doesn't like LOCALEDIR to be defined for some reason
-    bindtextdomain("mana", "translations/");
-#else
-    bindtextdomain("mana", LOCALEDIR);
-#endif
+    // On Windows we need to set the LANG environment variable to get the
+    // correct translation, because this isn't set by default.
+    ULONG numLanguages = 0;
+    ULONG bufferSize = 0;
+    if (!GetUserPreferredUILanguages(MUI_LANGUAGE_NAME, &numLanguages, nullptr, &bufferSize))
+        return;
+    if (numLanguages == 0 || bufferSize < 2)
+        return;
+
+    std::wstring localeNamesW(bufferSize, L'\0');
+    if (!GetUserPreferredUILanguages(MUI_LANGUAGE_NAME, &numLanguages, localeNamesW.data(), &bufferSize))
+        return;
+
+    // Replace the null characters used as separators with a colon, except for
+    // the last two. Also replace - with _, since gettext expects de_DE rather
+    // than de-DE.
+    for (size_t i = 0; i < localeNamesW.size() - 2; ++i) {
+        auto &c = localeNamesW[i];
+        if (c == L'\0')
+            c = L':';
+        else if (c == L'-')
+            c = L'_';
+    }
+
+    _wputenv_s(L"LANG", localeNamesW.c_str());
+#endif // _WIN32
+
     setlocale(LC_MESSAGES, "");
+    bindtextdomain("mana", LOCALEDIR);
     bind_textdomain_codeset("mana", "UTF-8");
     textdomain("mana");
-#endif
+#endif // ENABLE_NLS
 }