1 files changed, 147 insertions, 0 deletions
diff --git a/meshmc/launcher/minecraft/update/FMLLibrariesTask.cpp b/meshmc/launcher/minecraft/update/FMLLibrariesTask.cpp
new file mode 100644
index 0000000000..635af84ef1
--- /dev/null
+++ b/meshmc/launcher/minecraft/update/FMLLibrariesTask.cpp
@@ -0,0 +1,147 @@
+/* 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 "FMLLibrariesTask.h"
+
+#include "FileSystem.h"
+#include "minecraft/VersionFilterData.h"
+#include "minecraft/MinecraftInstance.h"
+#include "minecraft/PackProfile.h"
+
+#include "BuildConfig.h"
+#include "Application.h"
+
+FMLLibrariesTask::FMLLibrariesTask(MinecraftInstance* inst)
+{
+	m_inst = inst;
+}
+void FMLLibrariesTask::executeTask()
+{
+	// Get the mod list
+	MinecraftInstance* inst = (MinecraftInstance*)m_inst;
+	auto components = inst->getPackProfile();
+	auto profile = components->getProfile();
+
+	if (!profile->hasTrait("legacyFML")) {
+		emitSucceeded();
+		return;
+	}
+
+	QString version = components->getComponentVersion("net.minecraft");
+	auto& fmlLibsMapping = g_VersionFilterData.fmlLibsMapping;
+	if (!fmlLibsMapping.contains(version)) {
+		emitSucceeded();
+		return;
+	}
+
+	auto& libList = fmlLibsMapping[version];
+
+	// determine if we need some libs for FML or forge
+	setStatus(tr("Checking for FML libraries..."));
+	if (!components->getComponent("net.minecraftforge")) {
+		emitSucceeded();
+		return;
+	}
+
+	// now check the lib folder inside the instance for files.
+	for (auto& lib : libList) {
+		QFileInfo libInfo(FS::PathCombine(inst->libDir(), lib.filename));
+		if (libInfo.exists())
+			continue;
+		fmlLibsToProcess.append(lib);
+	}
+
+	// if everything is in place, there's nothing to do here...
+	if (fmlLibsToProcess.isEmpty()) {
+		emitSucceeded();
+		return;
+	}
+
+	// download missing libs to our place
+	setStatus(tr("Downloading FML libraries..."));
+	auto dljob = new NetJob("FML libraries", APPLICATION->network());
+	auto metacache = APPLICATION->metacache();
+	for (auto& lib : fmlLibsToProcess) {
+		auto entry = metacache->resolveEntry("fmllibs", lib.filename);
+		QString urlString = BuildConfig.FMLLIBS_BASE_URL + lib.filename;
+		dljob->addNetAction(Net::Download::makeCached(QUrl(urlString), entry));
+	}
+
+	connect(dljob, &NetJob::succeeded, this,
+			&FMLLibrariesTask::fmllibsFinished);
+	connect(dljob, &NetJob::failed, this, &FMLLibrariesTask::fmllibsFailed);
+	connect(dljob, &NetJob::progress, this, &FMLLibrariesTask::progress);
+	downloadJob.reset(dljob);
+	downloadJob->start();
+}
+
+bool FMLLibrariesTask::canAbort() const
+{
+	return true;
+}
+
+void FMLLibrariesTask::fmllibsFinished()
+{
+	downloadJob.reset();
+	if (!fmlLibsToProcess.isEmpty()) {
+		setStatus(tr("Copying FML libraries into the instance..."));
+		MinecraftInstance* inst = (MinecraftInstance*)m_inst;
+		auto metacache = APPLICATION->metacache();
+		int index = 0;
+		for (auto& lib : fmlLibsToProcess) {
+			progress(index, fmlLibsToProcess.size());
+			auto entry = metacache->resolveEntry("fmllibs", lib.filename);
+			auto path = FS::PathCombine(inst->libDir(), lib.filename);
+			if (!FS::ensureFilePathExists(path)) {
+				emitFailed(tr(
+					"Failed creating FML library folder inside the instance."));
+				return;
+			}
+			if (!QFile::copy(entry->getFullPath(),
+							 FS::PathCombine(inst->libDir(), lib.filename))) {
+				emitFailed(tr("Failed copying Forge/FML library: %1.")
+							   .arg(lib.filename));
+				return;
+			}
+			index++;
+		}
+		progress(index, fmlLibsToProcess.size());
+	}
+	emitSucceeded();
+}
+void FMLLibrariesTask::fmllibsFailed(QString reason)
+{
+	QStringList failed = downloadJob->getFailedFiles();
+	QString failed_all = failed.join("\n");
+	emitFailed(tr("Failed to download the following "
+				  "files:\n%1\n\nReason:%2\nPlease try again.")
+				   .arg(failed_all, reason));
+}
+
+bool FMLLibrariesTask::abort()
+{
+	if (downloadJob) {
+		return downloadJob->abort();
+	} else {
+		qWarning() << "Prematurely aborted FMLLibrariesTask";
+	}
+	return true;
+}