10 files changed, 235 insertions, 84 deletions

diff --git a/src/yuzu/CMakeLists.txt b/src/yuzu/CMakeLists.txt
index a862b2610..7257aa701 100644
--- a/src/yuzu/CMakeLists.txt
+++ b/src/yuzu/CMakeLists.txt
@@ -133,12 +133,45 @@ file(GLOB COMPAT_LIST
 file(GLOB_RECURSE ICONS ${PROJECT_SOURCE_DIR}/dist/icons/*)
 file(GLOB_RECURSE THEMES ${PROJECT_SOURCE_DIR}/dist/qt_themes/*)
 
+if (ENABLE_QT_TRANSLATION)
+    set(YUZU_QT_LANGUAGES "${PROJECT_SOURCE_DIR}/dist/languages" CACHE PATH "Path to the translation bundle for the Qt frontend")
+    option(GENERATE_QT_TRANSLATION "Generate en.ts as the translation source file" OFF)
+
+    # Update source TS file if enabled
+    if (GENERATE_QT_TRANSLATION)
+        get_target_property(SRCS yuzu SOURCES)
+        qt5_create_translation(QM_FILES ${SRCS} ${UIS} ${YUZU_QT_LANGUAGES}/en.ts)
+        add_custom_target(translation ALL DEPENDS ${YUZU_QT_LANGUAGES}/en.ts)
+    endif()
+
+    # Find all TS files except en.ts
+    file(GLOB_RECURSE LANGUAGES_TS ${YUZU_QT_LANGUAGES}/*.ts)
+    list(REMOVE_ITEM LANGUAGES_TS ${YUZU_QT_LANGUAGES}/en.ts)
+
+    # Compile TS files to QM files
+    qt5_add_translation(LANGUAGES_QM ${LANGUAGES_TS})
+
+    # Build a QRC file from the QM file list
+    set(LANGUAGES_QRC ${CMAKE_CURRENT_BINARY_DIR}/languages.qrc)
+    file(WRITE ${LANGUAGES_QRC} "<RCC><qresource prefix=\"languages\">\n")
+    foreach (QM ${LANGUAGES_QM})
+        get_filename_component(QM_FILE ${QM} NAME)
+        file(APPEND ${LANGUAGES_QRC} "<file>${QM_FILE}</file>\n")
+    endforeach (QM)
+    file(APPEND ${LANGUAGES_QRC} "</qresource></RCC>")
+
+    # Add the QRC file to package in all QM files
+    qt5_add_resources(LANGUAGES ${LANGUAGES_QRC})
+else()
+    set(LANGUAGES)
+endif()
 
 target_sources(yuzu
     PRIVATE
         ${COMPAT_LIST}
         ${ICONS}
         ${THEMES}
+        ${LANGUAGES}
 )
 
 if (APPLE)
diff --git a/src/yuzu/configuration/config.cpp b/src/yuzu/configuration/config.cpp
index 805bb954b..59a193edd 100644
--- a/src/yuzu/configuration/config.cpp
+++ b/src/yuzu/configuration/config.cpp
@@ -611,6 +611,7 @@ void Config::ReadPathValues() {
         }
     }
     UISettings::values.recent_files = ReadSetting(QStringLiteral("recentFiles")).toStringList();
+    UISettings::values.language = ReadSetting(QStringLiteral("language"), QString{}).toString();
 
     qt_config->endGroup();
 }
@@ -1095,6 +1096,7 @@ void Config::SavePathValues() {
     }
     qt_config->endArray();
     WriteSetting(QStringLiteral("recentFiles"), UISettings::values.recent_files);
+    WriteSetting(QStringLiteral("language"), UISettings::values.language, QString{});
 
     qt_config->endGroup();
 }
diff --git a/src/yuzu/configuration/configure_dialog.cpp b/src/yuzu/configuration/configure_dialog.cpp
index a5afb354f..4e30dc51e 100644
--- a/src/yuzu/configuration/configure_dialog.cpp
+++ b/src/yuzu/configuration/configure_dialog.cpp
@@ -23,6 +23,7 @@ ConfigureDialog::ConfigureDialog(QWidget* parent, HotkeyRegistry& registry)
     SetConfiguration();
     PopulateSelectionList();
 
+    connect(ui->uiTab, &ConfigureUi::LanguageChanged, this, &ConfigureDialog::OnLanguageChanged);
     connect(ui->selectorList, &QListWidget::itemSelectionChanged, this,
             &ConfigureDialog::UpdateVisibleTabs);
 
@@ -98,6 +99,14 @@ void ConfigureDialog::PopulateSelectionList() {
     }
 }
 
+void ConfigureDialog::OnLanguageChanged(const QString& locale) {
+    emit LanguageChanged(locale);
+    // first apply the configuration, and then restore the display
+    ApplyConfiguration();
+    RetranslateUI();
+    SetConfiguration();
+}
+
 void ConfigureDialog::UpdateVisibleTabs() {
     const auto items = ui->selectorList->selectedItems();
     if (items.isEmpty()) {
diff --git a/src/yuzu/configuration/configure_dialog.h b/src/yuzu/configuration/configure_dialog.h
index 2d3bfc2da..4289bc225 100644
--- a/src/yuzu/configuration/configure_dialog.h
+++ b/src/yuzu/configuration/configure_dialog.h
@@ -22,6 +22,12 @@ public:
 
     void ApplyConfiguration();
 
+private slots:
+    void OnLanguageChanged(const QString& locale);
+
+signals:
+    void LanguageChanged(const QString& locale);
+
 private:
     void changeEvent(QEvent* event) override;
 
diff --git a/src/yuzu/configuration/configure_ui.cpp b/src/yuzu/configuration/configure_ui.cpp
index 94424ee44..3058f2509 100644
--- a/src/yuzu/configuration/configure_ui.cpp
+++ b/src/yuzu/configuration/configure_ui.cpp
@@ -5,6 +5,7 @@
 #include <array>
 #include <utility>
 
+#include <QDirIterator>
 #include "common/common_types.h"
 #include "core/settings.h"
 #include "ui_configure_ui.h"
@@ -28,6 +29,23 @@ constexpr std::array row_text_names{
 
 ConfigureUi::ConfigureUi(QWidget* parent) : QWidget(parent), ui(new Ui::ConfigureUi) {
     ui->setupUi(this);
+    ui->language_combobox->addItem(tr("<System>"), QString{});
+    ui->language_combobox->addItem(tr("English"), QStringLiteral("en"));
+    QDirIterator it(QStringLiteral(":/languages"), QDirIterator::NoIteratorFlags);
+    while (it.hasNext()) {
+        QString locale = it.next();
+        locale.truncate(locale.lastIndexOf(QLatin1Char{'.'}));
+        locale.remove(0, locale.lastIndexOf(QLatin1Char{'/'}) + 1);
+        QString lang = QLocale::languageToString(QLocale(locale).language());
+        ui->language_combobox->addItem(lang, locale);
+    }
+
+    // Unlike other configuration changes, interface language changes need to be reflected on the
+    // interface immediately. This is done by passing a signal to the main window, and then
+    // retranslating when passing back.
+    connect(ui->language_combobox,
+            static_cast<void (QComboBox::*)(int)>(&QComboBox::currentIndexChanged), this,
+            &ConfigureUi::OnLanguageChanged);
 
     for (const auto& theme : UISettings::themes) {
         ui->theme_combobox->addItem(QString::fromUtf8(theme.first),
@@ -72,6 +90,8 @@ void ConfigureUi::RequestGameListUpdate() {
 
 void ConfigureUi::SetConfiguration() {
     ui->theme_combobox->setCurrentIndex(ui->theme_combobox->findData(UISettings::values.theme));
+    ui->language_combobox->setCurrentIndex(
+        ui->language_combobox->findData(UISettings::values.language));
     ui->show_add_ons->setChecked(UISettings::values.show_add_ons);
     ui->icon_size_combobox->setCurrentIndex(
         ui->icon_size_combobox->findData(UISettings::values.icon_size));
@@ -147,3 +167,10 @@ void ConfigureUi::UpdateSecondRowComboBox(bool init) {
     ui->row_2_text_combobox->removeItem(
         ui->row_2_text_combobox->findData(ui->row_1_text_combobox->currentData()));
 }
+
+void ConfigureUi::OnLanguageChanged(int index) {
+    if (index == -1)
+        return;
+
+    emit LanguageChanged(ui->language_combobox->itemData(index).toString());
+}
diff --git a/src/yuzu/configuration/configure_ui.h b/src/yuzu/configuration/configure_ui.h
index d471afe99..3ecbd07c4 100644
--- a/src/yuzu/configuration/configure_ui.h
+++ b/src/yuzu/configuration/configure_ui.h
@@ -20,6 +20,12 @@ public:
 
     void ApplyConfiguration();
 
+private slots:
+    void OnLanguageChanged(int index);
+
+signals:
+    void LanguageChanged(const QString& locale);
+
 private:
     void RequestGameListUpdate();
 
diff --git a/src/yuzu/configuration/configure_ui.ui b/src/yuzu/configuration/configure_ui.ui
index bd5c5d3c2..0b81747d7 100644
--- a/src/yuzu/configuration/configure_ui.ui
+++ b/src/yuzu/configuration/configure_ui.ui
@@ -13,112 +13,132 @@
   <property name="windowTitle">
    <string>Form</string>
   </property>
-  <layout class="QHBoxLayout" name="HorizontalLayout">
+  <layout class="QVBoxLayout" name="verticalLayout">
    <item>
-    <layout class="QVBoxLayout" name="VerticalLayout">
-     <item>
-      <widget class="QGroupBox" name="GeneralGroupBox">
-       <property name="title">
-        <string>General</string>
-       </property>
-       <layout class="QHBoxLayout" name="horizontalLayout">
+    <widget class="QGroupBox" name="general_groupBox">
+     <property name="title">
+      <string>General</string>
+     </property>
+     <layout class="QHBoxLayout" name="horizontalLayout">
+      <item>
+       <layout class="QVBoxLayout" name="verticalLayout_2">
         <item>
-         <layout class="QVBoxLayout" name="verticalLayout">
+         <widget class="QLabel" name="label_change_language_info">
+          <property name="text">
+           <string>Note: Changing language will apply your configuration.</string>
+          </property>
+          <property name="wordWrap">
+           <bool>true</bool>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <layout class="QHBoxLayout" name="horizontalLayout_2">
+          <item>
+           <widget class="QLabel" name="language_label">
+            <property name="text">
+             <string>Interface language:</string>
+            </property>
+           </widget>
+          </item>
+          <item>
+           <widget class="QComboBox" name="language_combobox"/>
+          </item>
+         </layout>
+        </item>
+        <item>
+         <layout class="QHBoxLayout" name="horizontalLayout_3">
+          <item>
+           <widget class="QLabel" name="theme_label">
+            <property name="text">
+             <string>Theme:</string>
+            </property>
+           </widget>
+          </item>
           <item>
-           <layout class="QHBoxLayout" name="horizontalLayout_3">
-            <item>
-             <widget class="QLabel" name="theme_label">
-              <property name="text">
-               <string>Theme:</string>
-              </property>
-             </widget>
-            </item>
-            <item>
-             <widget class="QComboBox" name="theme_combobox"/>
-            </item>
-           </layout>
+           <widget class="QComboBox" name="theme_combobox"/>
           </item>
          </layout>
         </item>
        </layout>
-      </widget>
-     </item>
-     <item>
-      <widget class="QGroupBox" name="GameListGroupBox">
-       <property name="title">
-        <string>Game List</string>
-       </property>
-       <layout class="QHBoxLayout" name="GameListHorizontalLayout">
+      </item>
+     </layout>
+    </widget>
+   </item>
+   <item>
+    <widget class="QGroupBox" name="GameListGroupBox">
+     <property name="title">
+      <string>Game List</string>
+     </property>
+     <layout class="QHBoxLayout" name="GameListHorizontalLayout">
+      <item>
+       <layout class="QVBoxLayout" name="GeneralVerticalLayout">
         <item>
-         <layout class="QVBoxLayout" name="GeneralVerticalLayout">
+         <widget class="QCheckBox" name="show_add_ons">
+          <property name="text">
+           <string>Show Add-Ons Column</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <layout class="QHBoxLayout" name="icon_size_qhbox_layout_2">
           <item>
-           <widget class="QCheckBox" name="show_add_ons">
+           <widget class="QLabel" name="icon_size_label">
             <property name="text">
-             <string>Show Add-Ons Column</string>
+             <string>Icon Size:</string>
             </property>
            </widget>
           </item>
           <item>
-           <layout class="QHBoxLayout" name="icon_size_qhbox_layout_2">
-            <item>
-             <widget class="QLabel" name="icon_size_label">
-              <property name="text">
-               <string>Icon Size:</string>
-              </property>
-             </widget>
-            </item>
-            <item>
-             <widget class="QComboBox" name="icon_size_combobox"/>
-            </item>
-           </layout>
+           <widget class="QComboBox" name="icon_size_combobox"/>
           </item>
+         </layout>
+        </item>
+        <item>
+         <layout class="QHBoxLayout" name="row_1_qhbox_layout">
           <item>
-           <layout class="QHBoxLayout" name="row_1_qhbox_layout">
-            <item>
-             <widget class="QLabel" name="row_1_label">
-              <property name="text">
-               <string>Row 1 Text:</string>
-              </property>
-             </widget>
-            </item>
-            <item>
-             <widget class="QComboBox" name="row_1_text_combobox"/>
-            </item>
-           </layout>
+           <widget class="QLabel" name="row_1_label">
+            <property name="text">
+             <string>Row 1 Text:</string>
+            </property>
+           </widget>
           </item>
           <item>
-           <layout class="QHBoxLayout" name="row_2_qhbox_layout">
-            <item>
-             <widget class="QLabel" name="row_2_label">
-              <property name="text">
-               <string>Row 2 Text:</string>
-              </property>
-             </widget>
-            </item>
-            <item>
-             <widget class="QComboBox" name="row_2_text_combobox"/>
-            </item>
-           </layout>
+           <widget class="QComboBox" name="row_1_text_combobox"/>
+          </item>
+         </layout>
+        </item>
+        <item>
+         <layout class="QHBoxLayout" name="row_2_qhbox_layout">
+          <item>
+           <widget class="QLabel" name="row_2_label">
+            <property name="text">
+             <string>Row 2 Text:</string>
+            </property>
+           </widget>
+          </item>
+          <item>
+           <widget class="QComboBox" name="row_2_text_combobox"/>
           </item>
          </layout>
         </item>
        </layout>
-      </widget>
-     </item>
-     <item>
-      <spacer name="verticalSpacer">
-       <property name="orientation">
-        <enum>Qt::Vertical</enum>
-       </property>
-       <property name="sizeHint" stdset="0">
-        <size>
-         <width>20</width>
-         <height>40</height>
-        </size>
-       </property>
-      </spacer>
-     </item>
-    </layout>
+      </item>
+     </layout>
+    </widget>
+   </item>
+   <item>
+    <spacer name="verticalSpacer">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="sizeHint" stdset="0">
+      <size>
+       <width>20</width>
+       <height>40</height>
+      </size>
+     </property>
+    </spacer>
    </item>
   </layout>
  </widget>
diff --git a/src/yuzu/main.cpp b/src/yuzu/main.cpp
index 6909d65d0..31a635176 100644
--- a/src/yuzu/main.cpp
+++ b/src/yuzu/main.cpp
@@ -191,6 +191,8 @@ GMainWindow::GMainWindow()
       provider(std::make_unique<FileSys::ManualContentProvider>()) {
     InitializeLogging();
 
+    LoadTranslation();
+
     setAcceptDrops(true);
     ui.setupUi(this);
     statusBar()->hide();
@@ -2048,6 +2050,9 @@ void GMainWindow::OnConfigure() {
     const bool old_discord_presence = UISettings::values.enable_discord_presence;
 
     ConfigureDialog configure_dialog(this, hotkey_registry);
+    connect(&configure_dialog, &ConfigureDialog::LanguageChanged, this,
+            &GMainWindow::OnLanguageChanged);
+
     const auto result = configure_dialog.exec();
     if (result != QDialog::Accepted) {
         return;
@@ -2620,6 +2625,43 @@ void GMainWindow::UpdateUITheme() {
     QIcon::setThemeSearchPaths(theme_paths);
 }
 
+void GMainWindow::LoadTranslation() {
+    // If the selected language is English, no need to install any translation
+    if (UISettings::values.language == QStringLiteral("en")) {
+        return;
+    }
+
+    bool loaded;
+
+    if (UISettings::values.language.isEmpty()) {
+        // If the selected language is empty, use system locale
+        loaded = translator.load(QLocale(), {}, {}, QStringLiteral(":/languages/"));
+    } else {
+        // Otherwise load from the specified file
+        loaded = translator.load(UISettings::values.language, QStringLiteral(":/languages/"));
+    }
+
+    if (loaded) {
+        qApp->installTranslator(&translator);
+    } else {
+        UISettings::values.language = QStringLiteral("en");
+    }
+}
+
+void GMainWindow::OnLanguageChanged(const QString& locale) {
+    if (UISettings::values.language != QStringLiteral("en")) {
+        qApp->removeTranslator(&translator);
+    }
+
+    UISettings::values.language = locale;
+    LoadTranslation();
+    ui.retranslateUi(this);
+    UpdateWindowTitle();
+
+    if (emulation_running)
+        ui.action_Start->setText(tr("Continue"));
+}
+
 void GMainWindow::SetDiscordEnabled([[maybe_unused]] bool state) {
 #ifdef USE_DISCORD_PRESENCE
     if (state) {
diff --git a/src/yuzu/main.h b/src/yuzu/main.h
index 59d9073ae..db573d606 100644
--- a/src/yuzu/main.h
+++ b/src/yuzu/main.h
@@ -10,6 +10,7 @@
 
 #include <QMainWindow>
 #include <QTimer>
+#include <QTranslator>
 
 #include "common/common_types.h"
 #include "core/core.h"
@@ -225,6 +226,7 @@ private slots:
     void OnCaptureScreenshot();
     void OnCoreError(Core::System::ResultStatus, std::string);
     void OnReinitializeKeys(ReinitializeKeyBehavior behavior);
+    void OnLanguageChanged(const QString& locale);
 
 private:
     std::optional<u64> SelectRomFSDumpTarget(const FileSys::ContentProvider&, u64 program_id);
@@ -237,6 +239,7 @@ private:
     void HideMouseCursor();
     void ShowMouseCursor();
     void OpenURL(const QUrl& url);
+    void LoadTranslation();
 
     Ui::MainWindow ui;
 
@@ -285,6 +288,8 @@ private:
 
     HotkeyRegistry hotkey_registry;
 
+    QTranslator translator;
+
     // Install progress dialog
     QProgressDialog* install_progress;
 
diff --git a/src/yuzu/uisettings.h b/src/yuzu/uisettings.h
index 830932d45..6cc65736d 100644
--- a/src/yuzu/uisettings.h
+++ b/src/yuzu/uisettings.h
@@ -75,6 +75,7 @@ struct Values {
     bool game_dir_deprecated_deepscan;
     QVector<UISettings::GameDir> game_dirs;
     QStringList recent_files;
+    QString language;
 
     QString theme;