Add a backend for the language selection menu

Assuming you're running this at root, immediately when the dropdown box has a changed value, it installs the required language packs, updates the system locale, then kicks off an SDDM reboot.

This needs lots of error handling and UX to ensure the user doesn't just hold down the down arrow and crash their computer.

scripts/change-system-language

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+LANGUAGE_CODE=$1
+COUNTRY_CODE=$2
+LOCALE="${LANGUAGE_CODE}_${COUNTRY_CODE}.UTF-8"
+
+apt-get -y install language-pack-gnome-$LANGUAGE_CODE language-pack-kde-$LANGUAGE_CODE
+update-locale LANGUAGE=$LOCALE LANG=$LOCALE LC_ALL=$LOCALE
+systemctl restart sddm

src/installerprompt.cpp

@@ -50,6 +50,9 @@ InstallerPrompt::InstallerPrompt(QWidget *parent)
     // Set up the language combo box with available languages
     initLanguageComboBox();
 
+    // Connect the language combo box to the onLanguageChanged slot
+    connect(ui->languageComboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(onLanguageChanged(int)));
+
     // Check initial network status and update UI
     updateConnectionStatus();
 
@@ -340,8 +343,11 @@ void InstallerPrompt::refreshNetworkList() {
 }
 
 void InstallerPrompt::initLanguageComboBox() {
+    languageLocaleMap.clear();
     QStringList languages = getAvailableLanguages();
-    ui->languageComboBox->addItems(languages);
+    for (const auto &language : languages) {
+        ui->languageComboBox->addItem(language);
+    }
 
     QString defaultLanguage = "English (United States)";
     int defaultIndex = ui->languageComboBox->findText(defaultLanguage);
@@ -350,7 +356,7 @@ void InstallerPrompt::initLanguageComboBox() {
     }
 }
 
-QStringList InstallerPrompt::getAvailableLanguages() const {
+QStringList InstallerPrompt::getAvailableLanguages() {
     QMap<QString, QString> languageMap; // Default sorting by QString is case-sensitive
 
     auto sanitize = [](QString s) -> QString {
@@ -384,17 +390,38 @@ QStringList InstallerPrompt::getAvailableLanguages() const {
             languageMap.insert(displayName, locale.name());
         }
     }
-
+    // Sort the language display names
     QStringList sortedLanguages = languageMap.keys();
     std::sort(sortedLanguages.begin(), sortedLanguages.end(), [](const QString &a, const QString &b) {
         return a.compare(b, Qt::CaseInsensitive) < 0;
     });
 
+    // Clear the existing languageLocaleMap and repopulate it based on sortedLanguages
+    languageLocaleMap.clear();
+    for (const QString &languageName : sortedLanguages) {
+        languageLocaleMap.insert(languageName, languageMap[languageName]);
+    }
+
     return sortedLanguages;
 }
 
 void InstallerPrompt::onLanguageChanged(int index) {
-    // Placeholder for handling language change
+    QString selectedLanguage = ui->languageComboBox->itemText(index);
+    QString localeName = languageLocaleMap.value(selectedLanguage);
+    qDebug() << selectedLanguage;
+    qDebug() << index << languageLocaleMap;
+
+    // Split the locale name to get language and country code
+    QStringList localeParts = localeName.split('_');
+    QString languageCode = localeParts.value(0);
+    QString countryCode = localeParts.value(1);
+
+    // Construct the command to run the script with parameters
+    QString scriptPath = "/usr/libexec/change-system-language";  // Update with the actual path
+    QStringList arguments;
+    arguments << languageCode << countryCode;
+
+    QProcess::execute(scriptPath, arguments);
 }
 
 void InstallerPrompt::tryLubuntu()

src/installerprompt.h

@@ -40,12 +40,13 @@ private:
     NetworkManager::Connection::Ptr findConnectionBySsid(const QString &ssid);
     bool wifiWrongHandling = false;
     QLineEdit *passwordLineEdit;
+    QMap<QString, QString> languageLocaleMap;
 
     void handleWifiConnection(const QString &ssid, bool recoverFromWrongPassword = false);
     QString promptForWifiPassword(const QString &ssid, bool isWrongPassword = false);
     void connectToWifi(const QString &ssid, const QString &password, bool recoverFromWrongPassword = false);
     void initLanguageComboBox();
-    QStringList getAvailableLanguages() const;
+    QStringList getAvailableLanguages();
     void showWifiOptions();
     NMVariantMapMap createSettingsBySSID(const QString &ssid);
 };