/* 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 "JavaDownloadTask.h"

#include <QDir>
#include <QProcess>
#include <QDebug>
#include <QDirIterator>
#include <QFileInfo>

#include "Application.h"
#include "FileSystem.h"
#include "Json.h"
#include "net/Download.h"
#include "net/ChecksumValidator.h"
#include "MMCZip.h"

JavaDownloadTask::JavaDownloadTask(const JavaDownload::RuntimeEntry& runtime,
								   const QString& targetDir, QObject* parent)
	: Task(parent), m_runtime(runtime), m_targetDir(targetDir)
{
}

void JavaDownloadTask::executeTask()
{
	if (m_runtime.downloadType == "manifest") {
		downloadManifest();
	} else {
		downloadArchive();
	}
}

void JavaDownloadTask::downloadArchive()
{
	setStatus(tr("Downloading %1...").arg(m_runtime.name));

	// Determine archive extension and path
	QUrl url(m_runtime.url);
	QString filename = url.fileName();
	m_archivePath = FS::PathCombine(m_targetDir, filename);

	// Create target directory
	if (!FS::ensureFolderPathExists(m_targetDir)) {
		emitFailed(
			tr("Failed to create target directory: %1").arg(m_targetDir));
		return;
	}

	m_downloadJob = new NetJob(tr("Java download"), APPLICATION->network());

	auto dl = Net::Download::makeFile(m_runtime.url, m_archivePath);

	// Add checksum validation
	if (!m_runtime.checksumHash.isEmpty()) {
		QCryptographicHash::Algorithm algo = QCryptographicHash::Sha256;
		if (m_runtime.checksumType == "sha1")
			algo = QCryptographicHash::Sha1;
		auto validator = new Net::ChecksumValidator(
			algo, QByteArray::fromHex(m_runtime.checksumHash.toLatin1()));
		dl->addValidator(validator);
	}

	m_downloadJob->addNetAction(dl);

	connect(m_downloadJob.get(), &NetJob::succeeded, this,
			&JavaDownloadTask::downloadFinished);
	connect(m_downloadJob.get(), &NetJob::failed, this,
			&JavaDownloadTask::downloadFailed);
	connect(m_downloadJob.get(), &NetJob::progress, this, &Task::setProgress);

	m_downloadJob->start();
}

void JavaDownloadTask::downloadFinished()
{
	m_downloadJob.reset();
	extractArchive();
}

void JavaDownloadTask::downloadFailed(QString reason)
{
	m_downloadJob.reset();
	// Clean up partial download
	if (!m_archivePath.isEmpty() && !QFile::remove(m_archivePath))
		qWarning() << "Failed to remove partial download:" << m_archivePath;
	emitFailed(tr("Failed to download Java: %1").arg(reason));
}

void JavaDownloadTask::extractArchive()
{
	setStatus(tr("Extracting %1...").arg(m_runtime.name));

	bool success = false;

	if (m_archivePath.endsWith(".zip")) {
		// Use QuaZip for zip files
		auto result = MMCZip::extractDir(m_archivePath, m_targetDir);
		success = result.has_value();
	} else if (m_archivePath.endsWith(".tar.gz") ||
			   m_archivePath.endsWith(".tgz")) {
		// Use system tar for tar.gz files
		QProcess tarProcess;
		tarProcess.setWorkingDirectory(m_targetDir);
		tarProcess.start("tar", QStringList() << "xzf" << m_archivePath);
		tarProcess.waitForFinished(300000); // 5 minute timeout
		success = (tarProcess.exitCode() == 0 &&
				   tarProcess.exitStatus() == QProcess::NormalExit);
		if (!success) {
			qWarning() << "tar extraction failed:"
					   << tarProcess.readAllStandardError();
		}
	} else {
		if (!QFile::remove(m_archivePath))
			qWarning() << "Failed to remove archive:" << m_archivePath;
		emitFailed(tr("Unsupported archive format: %1").arg(m_archivePath));
		return;
	}

	// Clean up archive file
	if (!QFile::remove(m_archivePath))
		qWarning() << "Failed to remove archive:" << m_archivePath;

	if (!success) {
		emitFailed(tr("Failed to extract Java archive."));
		return;
	}

	// Fix permissions on extracted files
	QDirIterator it(m_targetDir, QDirIterator::Subdirectories);
	while (it.hasNext()) {
		auto filepath = it.next();
		QFileInfo file(filepath);
		auto permissions = QFile::permissions(filepath);
		if (file.isDir()) {
			permissions |= QFileDevice::ReadUser | QFileDevice::WriteUser |
						   QFileDevice::ExeUser;
		} else {
			permissions |= QFileDevice::ReadUser | QFileDevice::WriteUser;
		}
		QFile::setPermissions(filepath, permissions);
	}

	// Find the java binary
	m_installedJavaPath = findJavaBinary(m_targetDir);
	if (m_installedJavaPath.isEmpty()) {
		emitFailed(tr("Could not find java binary in extracted archive."));
		return;
	}

	// Make java binary executable
	auto perms = QFile::permissions(m_installedJavaPath) |
				 QFileDevice::ExeUser | QFileDevice::ExeGroup |
				 QFileDevice::ExeOther;
	QFile::setPermissions(m_installedJavaPath, perms);

	qDebug() << "Java installed successfully at:" << m_installedJavaPath;
	emitSucceeded();
}

void JavaDownloadTask::downloadManifest()
{
	setStatus(tr("Downloading manifest for %1...").arg(m_runtime.name));

	if (!FS::ensureFolderPathExists(m_targetDir)) {
		emitFailed(
			tr("Failed to create target directory: %1").arg(m_targetDir));
		return;
	}

	m_downloadJob =
		new NetJob(tr("Java manifest download"), APPLICATION->network());
	auto dl =
		Net::Download::makeByteArray(QUrl(m_runtime.url), &m_manifestData);

	if (m_runtime.checksumType == "sha1" && !m_runtime.checksumHash.isEmpty()) {
		dl->addValidator(new Net::ChecksumValidator(
			QCryptographicHash::Sha1,
			QByteArray::fromHex(m_runtime.checksumHash.toLatin1())));
	}

	m_downloadJob->addNetAction(dl);

	connect(m_downloadJob.get(), &NetJob::succeeded, this,
			&JavaDownloadTask::manifestDownloaded);
	connect(m_downloadJob.get(), &NetJob::failed, this,
			&JavaDownloadTask::downloadFailed);

	m_downloadJob->start();
}

void JavaDownloadTask::manifestDownloaded()
{
	m_downloadJob.reset();

	QJsonDocument doc;
	try {
		doc = Json::requireDocument(m_manifestData);
	} catch (const Exception& e) {
		m_manifestData.clear();
		emitFailed(tr("Failed to parse Java manifest: %1").arg(e.cause()));
		return;
	}
	m_manifestData.clear();

	if (!doc.isObject()) {
		emitFailed(tr("Failed to parse Java manifest."));
		return;
	}

	auto files = doc.object()["files"].toObject();
	m_executableFiles.clear();
	m_linkEntries.clear();

	// Create directories first
	for (auto it = files.begin(); it != files.end(); ++it) {
		auto entry = it.value().toObject();
		if (entry["type"].toString() == "directory") {
			QDir().mkpath(FS::PathCombine(m_targetDir, it.key()));
		}
	}

	// Queue file downloads
	setStatus(tr("Downloading %1 files...").arg(m_runtime.name));
	m_downloadJob =
		new NetJob(tr("Java runtime files"), APPLICATION->network());

	for (auto it = files.begin(); it != files.end(); ++it) {
		auto entry = it.value().toObject();

		if (entry["type"].toString() == "file") {
			auto downloads = entry["downloads"].toObject();
			auto raw = downloads["raw"].toObject();

			QString url = raw["url"].toString();
			QString sha1 = raw["sha1"].toString();
			QString filePath = FS::PathCombine(m_targetDir, it.key());

			// Ensure parent directory exists
			QFileInfo fi(filePath);
			QDir().mkpath(fi.absolutePath());

			auto dl = Net::Download::makeFile(QUrl(url), filePath);
			if (!sha1.isEmpty()) {
				dl->addValidator(new Net::ChecksumValidator(
					QCryptographicHash::Sha1,
					QByteArray::fromHex(sha1.toLatin1())));
			}
			m_downloadJob->addNetAction(dl);

			if (entry["executable"].toBool()) {
				m_executableFiles.append(filePath);
			}
		} else if (entry["type"].toString() == "link") {
			m_linkEntries.append({it.key(), entry["target"].toString()});
		}
	}

	connect(m_downloadJob.get(), &NetJob::succeeded, this,
			&JavaDownloadTask::manifestFilesDownloaded);
	connect(m_downloadJob.get(), &NetJob::failed, this,
			&JavaDownloadTask::downloadFailed);
	connect(m_downloadJob.get(), &NetJob::progress, this, &Task::setProgress);

	m_downloadJob->start();
}

void JavaDownloadTask::manifestFilesDownloaded()
{
	m_downloadJob.reset();

	// Create symlinks
	for (const auto& link : m_linkEntries) {
		QString linkPath = FS::PathCombine(m_targetDir, link.first);
		QFileInfo fi(linkPath);
		QDir().mkpath(fi.absolutePath());
		QFile::link(link.second, linkPath);
	}

	// Set executable permissions
	for (const auto& path : m_executableFiles) {
		QFile::setPermissions(
			path, QFile::permissions(path) | QFileDevice::ExeUser |
					  QFileDevice::ExeGroup | QFileDevice::ExeOther);
	}

	// Find java binary
	m_installedJavaPath = findJavaBinary(m_targetDir);
	if (m_installedJavaPath.isEmpty()) {
		emitFailed(tr("Could not find java binary in downloaded runtime."));
		return;
	}

	qDebug() << "Java installed successfully at:" << m_installedJavaPath;
	emitSucceeded();
}

QString JavaDownloadTask::findJavaBinary(const QString& dir) const
{
#if defined(Q_OS_WIN)
	QString binaryName = "javaw.exe";
#else
	QString binaryName = "java";
#endif

	// Search for java binary in bin/ subdirectories
	QDirIterator it(dir, QStringList() << binaryName, QDir::Files,
					QDirIterator::Subdirectories);
	while (it.hasNext()) {
		it.next();
		QString path = it.filePath();
		if (path.contains("/bin/")) {
			return path;
		}
	}

	// Fallback: any match
	QDirIterator it2(dir, QStringList() << binaryName, QDir::Files,
					 QDirIterator::Subdirectories);
	if (it2.hasNext()) {
		it2.next();
		return it2.filePath();
	}

	return QString();
}