/* 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 "JavaDownloadDialog.h"

#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QGroupBox>
#include <QMessageBox>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>
#include <QDebug>
#include <QDir>
#include <QHeaderView>
#include <QSplitter>

#include "Application.h"
#include "BuildConfig.h"
#include "FileSystem.h"
#include "Json.h"
#include "java/JavaUtils.h"
#include "net/Download.h"

JavaDownloadDialog::JavaDownloadDialog(QWidget* parent) : QDialog(parent)
{
	setWindowTitle(tr("Download Java"));
	setMinimumSize(700, 450);
	resize(800, 500);
	m_providers = JavaDownload::JavaProviderInfo::availableProviders();
	setupUi();
}

void JavaDownloadDialog::setupUi()
{
	auto* mainLayout = new QVBoxLayout(this);

	// --- Three-column selection area ---
	auto* columnsLayout = new QHBoxLayout();

	// Left: Provider list
	auto* providerGroup = new QGroupBox(tr("Provider"), this);
	auto* providerLayout = new QVBoxLayout(providerGroup);
	m_providerList = new QListWidget(this);
	m_providerList->setIconSize(QSize(24, 24));
	for (const auto& provider : m_providers) {
		auto* item = new QListWidgetItem(
			APPLICATION->getThemedIcon(provider.iconName), provider.name);
		m_providerList->addItem(item);
	}
	providerLayout->addWidget(m_providerList);
	columnsLayout->addWidget(providerGroup, 1);

	// Center: Major version list
	auto* versionGroup = new QGroupBox(tr("Version"), this);
	auto* versionLayout = new QVBoxLayout(versionGroup);
	m_versionList = new QListWidget(this);
	versionLayout->addWidget(m_versionList);
	columnsLayout->addWidget(versionGroup, 1);

	// Right: Sub-version / build list
	auto* subVersionGroup = new QGroupBox(tr("Build"), this);
	auto* subVersionLayout = new QVBoxLayout(subVersionGroup);
	m_subVersionList = new QListWidget(this);
	subVersionLayout->addWidget(m_subVersionList);
	columnsLayout->addWidget(subVersionGroup, 1);

	mainLayout->addLayout(columnsLayout, 1);

	// Info label
	m_infoLabel = new QLabel(this);
	m_infoLabel->setWordWrap(true);
	m_infoLabel->setText(
		tr("Select a Java provider, version, and build to download."));
	mainLayout->addWidget(m_infoLabel);

	// Progress bar
	m_progressBar = new QProgressBar(this);
	m_progressBar->setVisible(false);
	m_progressBar->setRange(0, 100);
	mainLayout->addWidget(m_progressBar);

	// Status label
	m_statusLabel = new QLabel(this);
	m_statusLabel->setVisible(false);
	mainLayout->addWidget(m_statusLabel);

	// Buttons
	auto* buttonLayout = new QHBoxLayout();
	buttonLayout->addStretch();

	m_downloadBtn = new QPushButton(tr("Download"), this);
	m_downloadBtn->setEnabled(false);
	buttonLayout->addWidget(m_downloadBtn);

	m_cancelBtn = new QPushButton(tr("Cancel"), this);
	buttonLayout->addWidget(m_cancelBtn);

	mainLayout->addLayout(buttonLayout);

	// Connections
	connect(m_providerList, &QListWidget::currentRowChanged, this,
			&JavaDownloadDialog::providerChanged);
	connect(m_versionList, &QListWidget::currentRowChanged, this,
			&JavaDownloadDialog::majorVersionChanged);
	connect(m_subVersionList, &QListWidget::currentRowChanged, this,
			&JavaDownloadDialog::subVersionChanged);
	connect(m_downloadBtn, &QPushButton::clicked, this,
			&JavaDownloadDialog::onDownloadClicked);
	connect(m_cancelBtn, &QPushButton::clicked, this,
			&JavaDownloadDialog::onCancelClicked);

	// Select first provider
	if (m_providerList->count() > 0) {
		m_providerList->setCurrentRow(0);
	}
}

void JavaDownloadDialog::providerChanged(int index)
{
	if (index < 0 || index >= m_providers.size())
		return;

	m_versionList->clear();
	m_subVersionList->clear();
	m_downloadBtn->setEnabled(false);
	m_versions.clear();
	m_runtimes.clear();

	const auto& provider = m_providers[index];
	m_infoLabel->setText(tr("Loading versions for %1...").arg(provider.name));

	fetchVersionList(provider.uid);
}

void JavaDownloadDialog::majorVersionChanged(int index)
{
	if (index < 0 || index >= m_versions.size())
		return;

	m_subVersionList->clear();
	m_downloadBtn->setEnabled(false);
	m_runtimes.clear();

	const auto& version = m_versions[index];
	m_infoLabel->setText(tr("Loading builds for %1...").arg(version.versionId));

	fetchRuntimes(version.uid, version.versionId);
}

void JavaDownloadDialog::subVersionChanged(int index)
{
	if (index < 0 || index >= m_runtimes.size()) {
		m_downloadBtn->setEnabled(false);
		return;
	}

	const auto& rt = m_runtimes[index];
	m_infoLabel->setText(tr("Ready to download: %1\n"
							"Version: %2\n"
							"Platform: %3\n"
							"Checksum: %4")
							 .arg(rt.name, rt.version.toString(), rt.runtimeOS,
								  rt.checksumHash.isEmpty()
									  ? tr("None")
									  : tr("Yes (%1)").arg(rt.checksumType)));
	m_downloadBtn->setEnabled(true);
}

void JavaDownloadDialog::fetchVersionList(const QString& uid)
{
	m_fetchJob.reset();
	m_fetchData.clear();

	QString url = QString("%1%2/index.json").arg(BuildConfig.META_URL, uid);
	m_fetchJob = new NetJob(tr("Fetch Java versions"), APPLICATION->network());
	auto dl = Net::Download::makeByteArray(QUrl(url), &m_fetchData);
	m_fetchJob->addNetAction(dl);

	connect(m_fetchJob.get(), &NetJob::succeeded, this, [this, uid]() {
		m_fetchJob.reset();

		QJsonDocument doc;
		try {
			doc = Json::requireDocument(m_fetchData);
		} catch (const Exception& e) {
			m_infoLabel->setText(
				tr("Failed to parse version list: %1").arg(e.cause()));
			return;
		}
		if (!doc.isObject()) {
			m_infoLabel->setText(tr("Failed to parse version list."));
			return;
		}

		m_versions = JavaDownload::parseVersionIndex(doc.object(), uid);
		m_versionList->clear();

		for (const auto& ver : m_versions) {
			QString displayName = ver.versionId;
			if (displayName.startsWith("java")) {
				displayName = "Java " + displayName.mid(4);
			}
			m_versionList->addItem(displayName);
		}

		if (m_versions.size() > 0) {
			m_infoLabel->setText(tr("Select a version."));
		} else {
			m_infoLabel->setText(
				tr("No versions available for this provider."));
		}
	});

	connect(m_fetchJob.get(), &NetJob::failed, this, [this](QString reason) {
		m_fetchJob.reset();
		m_infoLabel->setText(tr("Failed to load versions: %1").arg(reason));
	});

	m_fetchJob->start();
}

void JavaDownloadDialog::fetchRuntimes(const QString& uid,
									   const QString& versionId)
{
	m_fetchJob.reset();
	m_fetchData.clear();

	QString url =
		QString("%1%2/%3.json").arg(BuildConfig.META_URL, uid, versionId);
	m_fetchJob =
		new NetJob(tr("Fetch Java runtime details"), APPLICATION->network());
	auto dl = Net::Download::makeByteArray(QUrl(url), &m_fetchData);
	m_fetchJob->addNetAction(dl);

	connect(m_fetchJob.get(), &NetJob::succeeded, this, [this]() {
		m_fetchJob.reset();

		QJsonDocument doc;
		try {
			doc = Json::requireDocument(m_fetchData);
		} catch (const Exception& e) {
			m_infoLabel->setText(
				tr("Failed to parse runtime details: %1").arg(e.cause()));
			return;
		}
		if (!doc.isObject()) {
			m_infoLabel->setText(tr("Failed to parse runtime details."));
			return;
		}

		auto allRuntimes = JavaDownload::parseRuntimes(doc.object());
		QString myOS = JavaDownload::currentRuntimeOS();

		m_runtimes.clear();
		m_subVersionList->clear();
		for (const auto& rt : allRuntimes) {
			if (rt.runtimeOS == myOS) {
				m_runtimes.append(rt);
				m_subVersionList->addItem(rt.version.toString());
			}
		}

		if (m_runtimes.isEmpty()) {
			m_infoLabel->setText(
				tr("No builds available for your platform (%1).").arg(myOS));
			m_downloadBtn->setEnabled(false);
		} else {
			m_infoLabel->setText(tr("Select a build to download."));
			m_subVersionList->setCurrentRow(0);
		}
	});

	connect(m_fetchJob.get(), &NetJob::failed, this, [this](QString reason) {
		m_fetchJob.reset();
		m_infoLabel->setText(
			tr("Failed to load runtime details: %1").arg(reason));
	});

	m_fetchJob->start();
}

QString JavaDownloadDialog::javaInstallDir() const
{
	return JavaUtils::managedJavaRoot();
}

void JavaDownloadDialog::onDownloadClicked()
{
	int idx = m_subVersionList->currentRow();
	if (idx < 0 || idx >= m_runtimes.size())
		return;

	const auto& runtime = m_runtimes[idx];

	// Build target directory path: {dataPath}/java/{vendor}/{name}-{version}/
	QString dirName =
		QString("%1-%2").arg(runtime.name, runtime.version.toString());
	QString targetDir =
		FS::PathCombine(javaInstallDir(), runtime.vendor, dirName);

	// Check if already installed
	if (QDir(targetDir).exists()) {
		auto result = QMessageBox::question(
			this, tr("Already Installed"),
			tr("This Java version appears to be already installed at:\n%1\n\n"
			   "Do you want to reinstall it?")
				.arg(targetDir),
			QMessageBox::Yes | QMessageBox::No);
		if (result != QMessageBox::Yes) {
			return;
		}
		// Remove existing installation
		QDir(targetDir).removeRecursively();
	}

	m_downloadBtn->setEnabled(false);
	m_providerList->setEnabled(false);
	m_versionList->setEnabled(false);
	m_subVersionList->setEnabled(false);
	m_progressBar->setVisible(true);
	m_progressBar->setValue(0);
	m_statusLabel->setVisible(true);

	m_downloadTask =
		std::make_unique<JavaDownloadTask>(runtime, targetDir, this);

	connect(m_downloadTask.get(), &Task::progress, this,
			[this](qint64 current, qint64 total) {
				if (total > 0) {
					m_progressBar->setValue(
						static_cast<int>(current * 100 / total));
				}
			});

	connect(m_downloadTask.get(), &Task::status, this,
			[this](const QString& status) { m_statusLabel->setText(status); });

	connect(m_downloadTask.get(), &Task::succeeded, this, [this]() {
		m_installedJavaPath = m_downloadTask->installedJavaPath();
		m_progressBar->setValue(100);
		m_statusLabel->setText(tr("Java installed successfully!"));

		QMessageBox::information(
			this, tr("Download Complete"),
			tr("Java has been downloaded and installed successfully.\n\n"
			   "Java binary: %1")
				.arg(m_installedJavaPath));

		accept();
	});

	connect(m_downloadTask.get(), &Task::failed, this,
			[this](const QString& reason) {
				m_progressBar->setVisible(false);
				m_statusLabel->setText(tr("Download failed: %1").arg(reason));
				m_downloadBtn->setEnabled(true);
				m_providerList->setEnabled(true);
				m_versionList->setEnabled(true);
				m_subVersionList->setEnabled(true);

				QMessageBox::warning(
					this, tr("Download Failed"),
					tr("Failed to download Java:\n%1").arg(reason));
			});

	m_downloadTask->start();
}

void JavaDownloadDialog::onCancelClicked()
{
	if (m_fetchJob) {
		m_fetchJob->abort();
		m_fetchJob.reset();
	}
	if (m_downloadTask) {
		m_downloadTask->abort();
		m_downloadTask.reset();
	}
	reject();
}