// SPDX-License-Identifier: GPL-3.0-only
// SPDX-FileCopyrightText: 2026 Project Tick
// SPDX-FileContributor: Project Tick Team
/*
 *  ProjT Launcher - Minecraft Launcher
 *  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, version 3.
 *
 *  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, write to the Free Software Foundation,
 *  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
#include "InstanceCopyTask.h"
#include <QDebug>
#include <QtConcurrentRun>
#include <memory>
#include "FileSystem.h"
#include "Filter.h"
#include "NullInstance.h"
#include "minecraft/MinecraftInstance.h"
#include "settings/INISettingsObject.h"
#include "tasks/Task.h"

InstanceCopyTask::InstanceCopyTask(InstancePtr origInstance, const InstanceCopyPrefs& prefs)
{
	m_origInstance	  = origInstance;
	m_keepPlaytime	  = prefs.isKeepPlaytimeEnabled();
	m_useLinks		  = prefs.isUseSymLinksEnabled();
	m_linkRecursively = prefs.isLinkRecursivelyEnabled();
	m_useHardLinks	  = prefs.isLinkRecursivelyEnabled() && prefs.isUseHardLinksEnabled();
	m_copySaves = prefs.isLinkRecursivelyEnabled() && prefs.isDontLinkSavesEnabled() && prefs.isCopySavesEnabled();
	m_useClone	= prefs.isUseCloneEnabled();

	QString filters = prefs.getSelectedFiltersAsRegex();
	if (m_useLinks || m_useHardLinks)
	{
		if (!filters.isEmpty())
			filters += "|";
		filters += "instance.cfg";
	}

	qDebug() << "CopyFilters:" << filters;

	if (!filters.isEmpty())
	{
		// Set regex filter:
		// NOTE: Regex for filtering files during copy.
		QRegularExpression regexp(filters, QRegularExpression::CaseInsensitiveOption);
		m_matcher = Filters::regexp(regexp);
	}

	// Store the original instance type to create the correct instance type during copy
	m_instanceType = m_origInstance->instanceType();
}

void InstanceCopyTask::executeTask()
{
	setStatus(tr("Copying instance %1").arg(m_origInstance->name()));

	m_copyFuture = QtConcurrent::run(
		QThreadPool::globalInstance(),
		[this]
		{
			if (m_useClone)
			{
				FS::clone folderClone(m_origInstance->instanceRoot(), m_stagingPath);
				folderClone.matcher(m_matcher);

				folderClone(true);
				setProgress(0, folderClone.totalCloned());
				connect(&folderClone,
						&FS::clone::fileCloned,
						[this](QString src, QString dst) { setProgress(m_progress + 1, m_progressTotal); });
				return folderClone();
			}
			if (m_useLinks || m_useHardLinks)
			{
				std::unique_ptr<FS::copy> savesCopy;
				if (m_copySaves)
				{
					QFileInfo mcDir(FS::PathCombine(m_stagingPath, "minecraft"));
					QFileInfo dotMCDir(FS::PathCombine(m_stagingPath, ".minecraft"));

					QString staging_mc_dir;
					if (dotMCDir.exists() && !mcDir.exists())
						staging_mc_dir = dotMCDir.filePath();
					else
						staging_mc_dir = mcDir.filePath();

					savesCopy = std::make_unique<FS::copy>(FS::PathCombine(m_origInstance->gameRoot(), "saves"),
														   FS::PathCombine(staging_mc_dir, "saves"));
					savesCopy->followSymlinks(true);
					(*savesCopy)(true);
					setProgress(0, savesCopy->totalCopied());
					connect(savesCopy.get(),
							&FS::copy::fileCopied,
							[this](QString src) { setProgress(m_progress + 1, m_progressTotal); });
				}
				FS::create_link folderLink(m_origInstance->instanceRoot(), m_stagingPath);
				int depth = m_linkRecursively ? -1 : 0; // we need to at least link the top level instead of the
														// instance folder
				folderLink.linkRecursively(true).setMaxDepth(depth).useHardLinks(m_useHardLinks).matcher(m_matcher);

				folderLink(true);
				setProgress(0, m_progressTotal + folderLink.totalToLink());
				connect(&folderLink,
						&FS::create_link::fileLinked,
						[this](QString src, QString dst) { setProgress(m_progress + 1, m_progressTotal); });
				bool there_were_errors = false;

				if (!folderLink())
				{
#if defined Q_OS_WIN32
					if (!m_useHardLinks)
					{
						setProgress(0, m_progressTotal);
						qDebug() << "EXPECTED: Link failure, Windows requires permissions for symlinks";

						qDebug() << "attempting to run with privelage";

						QEventLoop loop;
						bool got_priv_results = false;

						connect(&folderLink,
								&FS::create_link::finishedPrivileged,
								this,
								[&got_priv_results, &loop](bool gotResults)
								{
									if (!gotResults)
									{
										qDebug() << "Privileged run exited without results!";
									}
									got_priv_results = gotResults;
									loop.quit();
								});
						folderLink.runPrivileged();

						loop.exec(); // wait for the finished signal

						for (auto result : folderLink.getResults())
						{
							if (result.err_value != 0)
							{
								there_were_errors = true;
							}
						}

						if (savesCopy)
						{
							there_were_errors |= !(*savesCopy)();
						}

						return got_priv_results && !there_were_errors;
					}
#else
					qDebug() << "Link Failed!" << folderLink.getOSError().value()
							 << folderLink.getOSError().message().c_str();
#endif
					return false;
				}

				if (savesCopy)
				{
					there_were_errors |= !(*savesCopy)();
				}

				return !there_were_errors;
			}
			FS::copy folderCopy(m_origInstance->instanceRoot(), m_stagingPath);
			folderCopy.followSymlinks(false).matcher(m_matcher);

			folderCopy(true);
			setProgress(0, folderCopy.totalCopied());
			connect(&folderCopy,
					&FS::copy::fileCopied,
					[this](QString src) { setProgress(m_progress + 1, m_progressTotal); });
			return folderCopy();
		});
	connect(&m_copyFutureWatcher, &QFutureWatcher<bool>::finished, this, &InstanceCopyTask::copyFinished);
	connect(&m_copyFutureWatcher, &QFutureWatcher<bool>::canceled, this, &InstanceCopyTask::copyAborted);
	m_copyFutureWatcher.setFuture(m_copyFuture);
}

void InstanceCopyTask::copyFinished()
{
	if (!isRunning())
	{
		return;
	}
	auto successful = m_copyFuture.result();
	if (!successful)
	{
		emitFailed(tr("Instance folder copy failed."));
		return;
	}

	// Load instance settings with error handling
	QString configPath = FS::PathCombine(m_stagingPath, "instance.cfg");
	if (!QFile::exists(configPath))
	{
		emitFailed(tr("Instance configuration file not found: %1").arg(configPath));
		return;
	}

	auto instanceSettings = std::make_shared<INISettingsObject>(configPath);
	if (!instanceSettings->reload())
	{
		emitFailed(tr("Failed to load instance configuration"));
		return;
	}

	instanceSettings->registerSetting("InstanceType", "");
	QString inst_type = instanceSettings->get("InstanceType").toString();

	InstancePtr inst;
	if (inst_type == "OneSix" || inst_type.isEmpty())
	{
		inst.reset(new MinecraftInstance(m_globalSettings, instanceSettings, m_stagingPath));
	}
	else
	{
		inst.reset(new NullInstance(m_globalSettings, instanceSettings, m_stagingPath));
	}
	inst->setName(name());
	inst->setIconKey(m_instIcon);
	if (!m_keepPlaytime)
	{
		inst->resetTimePlayed();
	}
	if (m_useLinks)
	{
		inst->addLinkedInstanceId(m_origInstance->id());
		auto allowed_symlinks_file = QFileInfo(FS::PathCombine(inst->gameRoot(), "allowed_symlinks.txt"));

		QByteArray allowed_symlinks;
		if (allowed_symlinks_file.exists())
		{
			allowed_symlinks.append(FS::read(allowed_symlinks_file.filePath()));
			if (allowed_symlinks.right(1) != "\n")
				allowed_symlinks.append("\n"); // we want to be on a new line
		}
		allowed_symlinks.append(m_origInstance->gameRoot().toUtf8());
		allowed_symlinks.append("\n");
		if (allowed_symlinks_file.isSymLink())
			FS::deletePath(allowed_symlinks_file.filePath()); // we dont want to modify the original. also make sure the
															  // resulting file is not itself a link.

		try
		{
			FS::write(allowed_symlinks_file.filePath(), allowed_symlinks);
		}
		catch (const FS::FileSystemException& e)
		{
			qCritical() << "Failed to write symlink :" << e.cause();
		}
	}

	emitSucceeded();
}

void InstanceCopyTask::copyAborted()
{
	if (!isRunning())
	{
		return;
	}
	emitAborted();
}

bool InstanceCopyTask::abort()
{
	if (m_copyFutureWatcher.isRunning())
	{
		m_copyFutureWatcher.cancel();
		emitAborted();
		return true;
	}
	return false;
}