Add "Create desktop shortcut" feature.

This patch adds a way of adding a shortcut to directly start an
instance. How this works is it uses the already existing "-l" command
line option. This, however, has not been implemented for Mac, which is
something that can definetly be improved in the future if anyone wants
to work on it :^)

Signed-off-by: xSlendiX <slendi@socopon.com>

launcher/ui/MainWindow.cpp

@@ -115,6 +115,35 @@
 
 #include "MMCTime.h"
 
+#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
+// For .lnk creation
+#include <windows.h>
+#include <shobjidl.h>
+
+// https://stackoverflow.com/a/63443879
+HRESULT createLink(LPCWSTR target, LPCWSTR shortcut_path, LPCWSTR description, LPCWSTR arguments) {
+    HRESULT hres;
+    IShellLinkW* psl;
+
+    hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&psl));
+    if (SUCCEEDED(hres)) {
+        IPersistFile* ppf;
+        psl->SetPath(target);
+        psl->SetArguments(arguments);
+        psl->SetDescription(description);
+
+        hres = psl->QueryInterface(IID_PPV_ARGS(&ppf));
+        if (SUCCEEDED(hres)) {
+            hres = ppf->Save(shortcut_path, TRUE);
+            ppf->Release();
+        }
+        psl->Release();
+    }
+    return hres;
+}
+
+#endif
+
 namespace {
 QString profileInUseFilter(const QString & profile, bool used)
 {
@@ -230,6 +259,7 @@ class MainWindow::Ui
     TranslatedAction actionRenameInstance;
     TranslatedAction actionChangeInstGroup;
     TranslatedAction actionChangeInstIcon;
+    TranslatedAction actionCreateShortcut;
     TranslatedAction actionEditInstNotes;
     TranslatedAction actionEditInstance;
     TranslatedAction actionWorlds;
@@ -723,6 +753,15 @@ class MainWindow::Ui
         actionChangeInstGroup.setTooltipId(QT_TRANSLATE_NOOP("MainWindow", "Change the selected instance's group."));
         actionChangeInstGroup->setShortcut(QKeySequence(tr("Ctrl+G")));
         all_actions.append(&actionChangeInstGroup);
+
+        // FIXME: Add a way to create shortcuts on Mac.
+#ifndef __APPLE__
+        actionCreateShortcut = TranslatedAction(MainWindow);
+        actionCreateShortcut->setObjectName(QStringLiteral("actionCreateShortcut"));
+        actionCreateShortcut.setTextId(QT_TRANSLATE_NOOP("MainWindow", "Create desktop shortcut"));
+        actionCreateShortcut.setTooltipId(QT_TRANSLATE_NOOP("MainWindow", "Create a desktop shortcut to launch the instance."));
+        all_actions.append(&actionCreateShortcut);
+#endif
 
         actionViewSelectedMCFolder = TranslatedAction(MainWindow);
         actionViewSelectedMCFolder->setObjectName(QStringLiteral("actionViewSelectedMCFolder"));
@@ -803,6 +842,7 @@ class MainWindow::Ui
         instanceToolBar->addAction(actionWorlds);
         instanceToolBar->addAction(actionScreenshots);
         instanceToolBar->addAction(actionChangeInstGroup);
+        instanceToolBar->addAction(actionCreateShortcut);
 
         instanceToolBar->addSeparator();
 
@@ -1861,6 +1901,36 @@ void MainWindow::on_actionChangeInstGroup_triggered()
     }
 }
 
+void MainWindow::on_actionCreateShortcut_triggered()
+{
+    if (!m_selectedInstance)
+        return;
+
+    auto desktop = QStandardPaths::writableLocation(QStandardPaths::DesktopLocation);
+    auto executable_path = APPLICATION->applicationFilePath();
+    auto instId = m_selectedInstance->id();
+    auto icon = APPLICATION->windowIcon();
+    QString name(APPLICATION->instances()->getInstanceGroup(instId));
+#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__NT__)
+    createLink(
+        const_cast<wchar_t *>(executable_path.toStdWString().c_str()),
+        const_cast<wchar_t *>(QString("%1\\Launch %2.lnk").arg(desktop, name).toStdWString().c_str()),
+        const_cast<wchar_t *>(QString("Launch instance %1").arg(name).toStdWString().c_str()),
+        const_cast<wchar_t *>(QString("-l %2").arg(instId).toStdWString().c_str())
+    );
+#else
+    QFile shortcut_file(QString("%1/Launch %2.desktop").arg(desktop, instId));
+    if (shortcut_file.open(QFile::WriteOnly | QFile::Truncate)) {
+      QTextStream out(&shortcut_file);
+      out << "[Desktop Entry]" << endl
+          << "Type=Application" << endl
+          << "Exec=" << executable_path << " -l " << instId << " %U" << endl
+          << "Terminal=false" << endl;
+    }
+    shortcut_file.close();
+#endif
+}
+
 void MainWindow::deleteGroup()
 {
     QObject* obj = sender();

launcher/ui/MainWindow.h

@@ -105,6 +105,9 @@ private slots:
     void on_actionChangeInstGroup_triggered();
 
     void on_actionChangeInstIcon_triggered();
+
+    void on_actionCreateShortcut_triggered();
+
     void on_changeIconButton_clicked(bool)
     {
         on_actionChangeInstIcon_triggered();