1 files changed, 151 insertions, 0 deletions
diff --git a/meshmc/launcher/minecraft/legacy/LegacyUpgradeTask.cpp b/meshmc/launcher/minecraft/legacy/LegacyUpgradeTask.cpp
new file mode 100644
index 0000000000..89b3506153
--- /dev/null
+++ b/meshmc/launcher/minecraft/legacy/LegacyUpgradeTask.cpp
@@ -0,0 +1,151 @@
+/* SPDX-FileCopyrightText: 2026 Project Tick
+ * SPDX-FileContributor: Project Tick
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *   MeshMC - A Custom Launcher for Minecraft
+ *   Copyright (C) 2026 Project Tick
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "LegacyUpgradeTask.h"
+#include "settings/INISettingsObject.h"
+#include "FileSystem.h"
+#include "NullInstance.h"
+#include "pathmatcher/RegexpMatcher.h"
+#include <QtConcurrentRun>
+#include "LegacyInstance.h"
+#include "minecraft/MinecraftInstance.h"
+#include "minecraft/PackProfile.h"
+#include "LegacyModList.h"
+#include "classparser.h"
+
+LegacyUpgradeTask::LegacyUpgradeTask(InstancePtr origInstance)
+{
+	m_origInstance = origInstance;
+}
+
+void LegacyUpgradeTask::executeTask()
+{
+	setStatus(tr("Copying instance %1").arg(m_origInstance->name()));
+
+	FS::copy folderCopy(m_origInstance->instanceRoot(), m_stagingPath);
+	folderCopy.followSymlinks(true);
+
+	m_copyFuture = QtConcurrent::run(QThreadPool::globalInstance(), folderCopy);
+	connect(&m_copyFutureWatcher, &QFutureWatcher<bool>::finished, this,
+			&LegacyUpgradeTask::copyFinished);
+	connect(&m_copyFutureWatcher, &QFutureWatcher<bool>::canceled, this,
+			&LegacyUpgradeTask::copyAborted);
+	m_copyFutureWatcher.setFuture(m_copyFuture);
+}
+
+static QString decideVersion(const QString& currentVersion,
+							 const QString& intendedVersion)
+{
+	if (intendedVersion != currentVersion) {
+		if (!intendedVersion.isEmpty()) {
+			return intendedVersion;
+		} else if (!currentVersion.isEmpty()) {
+			return currentVersion;
+		}
+	} else {
+		if (!intendedVersion.isEmpty()) {
+			return intendedVersion;
+		}
+	}
+	return QString();
+}
+
+void LegacyUpgradeTask::copyFinished()
+{
+	auto successful = m_copyFuture.result();
+	if (!successful) {
+		emitFailed(tr("Instance folder copy failed."));
+		return;
+	}
+	auto legacyInst = std::dynamic_pointer_cast<LegacyInstance>(m_origInstance);
+
+	auto instanceSettings = std::make_shared<INISettingsObject>(
+		FS::PathCombine(m_stagingPath, "instance.cfg"));
+	instanceSettings->registerSetting("InstanceType", "Legacy");
+	instanceSettings->set("InstanceType", "OneSix");
+	// NOTE: this scope ensures the instance is fully saved before we
+	// emitSucceeded
+	{
+		MinecraftInstance inst(m_globalSettings, instanceSettings,
+							   m_stagingPath);
+		inst.setName(m_instName);
+
+		QString preferredVersionNumber = decideVersion(
+			legacyInst->currentVersionId(), legacyInst->intendedVersionId());
+		if (preferredVersionNumber.isNull()) {
+			// try to decide version based on the jar(s?)
+			preferredVersionNumber =
+				classparser::GetMinecraftJarVersion(legacyInst->baseJar());
+			if (preferredVersionNumber.isNull()) {
+				preferredVersionNumber = classparser::GetMinecraftJarVersion(
+					legacyInst->runnableJar());
+				if (preferredVersionNumber.isNull()) {
+					emitFailed(tr("Could not decide Minecraft version."));
+					return;
+				}
+			}
+		}
+		auto components = inst.getPackProfile();
+		components->buildingFromScratch();
+		components->setComponentVersion("net.minecraft", preferredVersionNumber,
+										true);
+
+		QString jarPath = legacyInst->mainJarToPreserve();
+		if (!jarPath.isNull()) {
+			qDebug() << "Preserving base jar! : " << jarPath;
+			// FIXME: handle case when the jar is unreadable?
+			// TODO: check the hash, if it's the same as the upstream jar, do
+			// not do this
+			components->installCustomJar(jarPath);
+		}
+
+		auto jarMods = legacyInst->jarModList()->allMods();
+		for (auto& jarMod : jarMods) {
+			QString modPath = jarMod.absoluteFilePath();
+			qDebug() << "jarMod: " << modPath;
+			components->installJarMods({modPath});
+		}
+
+		// remove all the extra garbage we no longer need
+		auto removeAll = [&](const QString& root, const QStringList& things) {
+			for (auto& thing : things) {
+				auto removePath = FS::PathCombine(root, thing);
+				QFileInfo stat(removePath);
+				if (stat.isDir()) {
+					FS::deletePath(removePath);
+				} else {
+					QFile::remove(removePath);
+				}
+			}
+		};
+		QStringList rootRemovables = {"modlist", "version", "instMods"};
+		QStringList mcRemovables = {"bin", "MeshMCLauncher.jar", "icon.png"};
+		removeAll(inst.instanceRoot(), rootRemovables);
+		removeAll(inst.gameRoot(), mcRemovables);
+	}
+	emitSucceeded();
+}
+
+void LegacyUpgradeTask::copyAborted()
+{
+	emitFailed(tr("Instance folder copy has been aborted."));
+	return;
+}