From fc696fa0b38a070e25b6e0c5ff3be7c349617961 Mon Sep 17 00:00:00 2001
From: Ivan Savenko <saven.ivan@gmail.com>
Date: Tue, 27 Jun 2023 22:33:42 +0300
Subject: [PATCH] Added detection of OS language on first run

---
 launcher/mainwindow_moc.cpp | 32 +++++++++++++++++++++++++++++++-
 launcher/mainwindow_moc.h   |  1 +
 lib/Languages.h             | 27 +++++++++++++++------------
 3 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/launcher/mainwindow_moc.cpp b/launcher/mainwindow_moc.cpp
index 17e01cea0..ccacca57e 100644
--- a/launcher/mainwindow_moc.cpp
+++ b/launcher/mainwindow_moc.cpp
@@ -15,6 +15,7 @@
 
 #include "../lib/CConfigHandler.h"
 #include "../lib/VCMIDirs.h"
+#include "../lib/Languages.h"
 #include "../lib/filesystem/Filesystem.h"
 #include "../lib/logging/CBasicLogConfigurator.h"
 
@@ -74,6 +75,12 @@ MainWindow::MainWindow(QWidget * parent)
 	: QMainWindow(parent), ui(new Ui::MainWindow)
 {
 	load(); // load FS before UI
+
+	bool setupCompleted = settings["launcher"]["setupCompleted"].Bool();
+
+	if (!setupCompleted)
+		detectPreferredLanguage();
+
 	updateTranslation(); // load translation
 
 	ui->setupUi(this);
@@ -103,7 +110,6 @@ MainWindow::MainWindow(QWidget * parent)
 	computeSidePanelSizes();
 
 	bool h3DataFound = CResourceHandler::get()->existsResource(ResourceID("DATA/GENRLTXT.TXT"));
-	bool setupCompleted = settings["launcher"]["setupCompleted"].Bool();
 
 	if (h3DataFound && setupCompleted)
 		ui->tabListWidget->setCurrentIndex(TabRows::MODS);
@@ -116,6 +122,30 @@ MainWindow::MainWindow(QWidget * parent)
 		UpdateDialog::showUpdateDialog(false);
 }
 
+void MainWindow::detectPreferredLanguage()
+{
+	auto preferredLanguages = QLocale::system().uiLanguages();
+
+	std::string selectedLanguage;
+
+	for (auto const & userLang : preferredLanguages)
+	{
+		logGlobal->info("Preferred language: %s", userLang.toStdString());
+
+		for (auto const & vcmiLang : Languages::getLanguageList())
+			if (vcmiLang.tagIETF == userLang.toStdString())
+				selectedLanguage = vcmiLang.identifier;
+	}
+
+	logGlobal->info("Selected language: %s", selectedLanguage);
+
+	if (!selectedLanguage.empty())
+	{
+		Settings node = settings.write["general"]["language"];
+		node->String() = selectedLanguage;
+	}
+}
+
 void MainWindow::enterSetup()
 {
 	ui->startGameButton->setEnabled(false);
diff --git a/launcher/mainwindow_moc.h b/launcher/mainwindow_moc.h
index f16329ee3..bdc766046 100644
--- a/launcher/mainwindow_moc.h
+++ b/launcher/mainwindow_moc.h
@@ -53,6 +53,7 @@ public:
 	void updateTranslation();
 	void computeSidePanelSizes();
 	
+	void detectPreferredLanguage();
 	void enterSetup();
 	void exitSetup();
 	void switchToModsTab();
diff --git a/lib/Languages.h b/lib/Languages.h
index f87ae6e0b..53201463e 100644
--- a/lib/Languages.h
+++ b/lib/Languages.h
@@ -46,6 +46,9 @@ struct Options
 	/// encoding that is used by H3 for this language
 	std::string encoding;
 
+	/// primary IETF language tag
+	std::string tagIETF;
+
 	/// VCMI is capable of detecting H3 install in this language
 	bool hasDetection = false;
 
@@ -57,19 +60,19 @@ inline const auto & getLanguageList()
 {
 	static const std::array<Options, 12> languages
 	{ {
-		{ "chinese",   "Chinese",   "简体中文",       "GBK",    true,  true }, // Note: actually Simplified Chinese
-		{ "english",   "English",   "English",    "CP1252", true,  true },
-		{ "french",    "French",    "Français",   "CP1252", true,  true },
-		{ "german",    "German",    "Deutsch",    "CP1252", true,  true },
-		{ "korean",    "Korean",    "한국어",        "CP949",  false, false },
-		{ "polish",    "Polish",    "Polski",     "CP1250", true,  true },
-		{ "russian",   "Russian",   "Русский",    "CP1251", true,  true },
-		{ "spanish",   "Spanish",   "Español",    "CP1252", false, true },
-		{ "ukrainian", "Ukrainian", "Українська", "CP1251", true,  true },
+		{ "chinese",   "Chinese",   "简体中文",       "GBK",    "zh", true,  true }, // Note: actually Simplified Chinese
+		{ "english",   "English",   "English",    "CP1252", "en", true,  true },
+		{ "french",    "French",    "Français",   "CP1252", "fr", true,  true },
+		{ "german",    "German",    "Deutsch",    "CP1252", "de", true,  true },
+		{ "korean",    "Korean",    "한국어",        "CP949",  "ko", false, false },
+		{ "polish",    "Polish",    "Polski",     "CP1250", "pl", true,  true },
+		{ "russian",   "Russian",   "Русский",    "CP1251", "ru", true,  true },
+		{ "spanish",   "Spanish",   "Español",    "CP1252", "es", false, true },
+		{ "ukrainian", "Ukrainian", "Українська", "CP1251", "uk", true,  true },
 
-		{ "other_cp1250", "Other (East European)",   "", "CP1251", false, false },
-		{ "other_cp1251", "Other (Cyrillic Script)", "", "CP1250", false, false },
-		{ "other_cp1252", "Other (West European)",   "", "CP1252", false, false }
+		{ "other_cp1250", "Other (East European)",   "", "CP1251", "", false, false },
+		{ "other_cp1251", "Other (Cyrillic Script)", "", "CP1250", "", false, false },
+		{ "other_cp1252", "Other (West European)",   "", "CP1252", "", false, false }
 	} };
 	static_assert(languages.size() == static_cast<size_t>(ELanguages::COUNT), "Languages array is missing a value!");