feat: add --import command-line option

When specified, opens the "Import from zip" dialog as soon as the main
window is shown, with the URL field prefilled with the argument given to
the option.

Closes #2998

application/MultiMC.cpp

@@ -34,6 +34,7 @@
 #include <QNetworkAccessManager>
 #include <QTranslator>
 #include <QLibraryInfo>
+#include <QList>
 #include <QStringList>
 #include <QDebug>
 #include <QStyleFactory>
@@ -174,6 +175,10 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
         parser.addSwitch("alive");
         parser.addDocumentation("alive", "Write a small '" + liveCheckFile + "' file after MultiMC starts");
 
+        parser.addOption("import");
+        parser.addShortOpt("import", 'I');
+        parser.addDocumentation("import", "Import instance from specified zip (local path or URL)");
+
         // parse the arguments
         try
         {
@@ -207,6 +212,7 @@ MultiMC::MultiMC(int &argc, char **argv) : QApplication(argc, argv)
     }
     m_instanceIdToLaunch = args["launch"].toString();
     m_liveCheck = args["alive"].toBool();
+    m_zipToImport = args["import"].toUrl();
 
     QString origcwdPath = QDir::currentPath();
     QString binPath = applicationDirPath();
@@ -812,6 +818,12 @@ void MultiMC::performMainStartupAction()
         showMainWindow(false);
         qDebug() << "<> Main window shown.";
     }
+
+    if (!m_zipToImport.isEmpty()) {
+        qDebug() << "<> Importing instance from zip:" << m_zipToImport.toString();
+        QList<QUrl> urls = { m_zipToImport };
+        m_mainWindow->droppedURLs(urls);
+    }
 }
 
 void MultiMC::showFatalErrorMessage(const QString& title, const QString& content)