/* 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/>.
 *
 *  This file incorporates work covered by the following copyright and
 *  permission notice:
 *
 * Copyright 2013-2021 MultiMC Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <QObject>
#include <QAbstractListModel>
#include <QSet>
#include <QList>

#include "BaseInstance.h"

#include "QObjectPtr.h"

class QFileSystemWatcher;
class InstanceTask;
using InstanceId = QString;
using GroupId = QString;
using InstanceLocator = std::pair<InstancePtr, int>;

enum class InstCreateError {
	NoCreateError = 0,
	NoSuchVersion,
	UnknownCreateError,
	InstExists,
	CantCreateDir
};

enum class GroupsState { NotLoaded, Steady, Dirty };

class InstanceList : public QAbstractListModel
{
	Q_OBJECT

  public:
	explicit InstanceList(SettingsObjectPtr settings, const QString& instDir,
						  QObject* parent = 0);
	virtual ~InstanceList();

  public:
	QModelIndex index(int row, int column = 0,
					  const QModelIndex& parent = QModelIndex()) const override;
	int rowCount(const QModelIndex& parent = QModelIndex()) const override;
	QVariant data(const QModelIndex& index, int role) const override;
	Qt::ItemFlags flags(const QModelIndex& index) const override;

	bool setData(const QModelIndex& index, const QVariant& value,
				 int role) override;

	enum AdditionalRoles {
		GroupRole = Qt::UserRole,
		InstancePointerRole = 0x34B1CB48, ///< Return pointer to real instance
		InstanceIDRole = 0x34B1CB49		  ///< Return id if the instance
	};
	/*!
	 * \brief Error codes returned by functions in the InstanceList class.
	 * NoError Indicates that no error occurred.
	 * UnknownError indicates that an unspecified error occurred.
	 */
	enum InstListError { NoError = 0, UnknownError };

	InstancePtr at(int i) const
	{
		return m_instances.at(i);
	}

	int count() const
	{
		return m_instances.count();
	}

	InstListError loadList();
	void saveNow();

	InstancePtr getInstanceById(QString id) const;
	QModelIndex getInstanceIndexById(const QString& id) const;
	QStringList getGroups();
	bool isGroupCollapsed(const QString& groupName);

	GroupId getInstanceGroup(const InstanceId& id) const;
	void setInstanceGroup(const InstanceId& id, const GroupId& name);

	void deleteGroup(const GroupId& name);
	void deleteInstance(const InstanceId& id);

	// Wrap an instance creation task in some more task machinery and make it
	// ready to be used
	Task* wrapInstanceTask(InstanceTask* task);

	/**
	 * Create a new empty staging area for instance creation and @return a
	 * path/key top commit it later. Used by instance manipulation tasks.
	 */
	QString getStagedInstancePath();

	/**
	 * Commit the staging area given by @keyPath to the provider - used when
	 * creation succeeds. Used by instance manipulation tasks.
	 */
	bool commitStagedInstance(const QString& keyPath,
							  const QString& instanceName,
							  const QString& groupName);

	/**
	 * Destroy a previously created staging area given by @keyPath - used when
	 * creation fails. Used by instance manipulation tasks.
	 */
	bool destroyStagingPath(const QString& keyPath);

	int getTotalPlayTime();

	Qt::DropActions supportedDragActions() const override;

	Qt::DropActions supportedDropActions() const override;

	bool canDropMimeData(const QMimeData* data, Qt::DropAction action, int row,
						 int column, const QModelIndex& parent) const override;

	bool dropMimeData(const QMimeData* data, Qt::DropAction action, int row,
					  int column, const QModelIndex& parent) override;

	QStringList mimeTypes() const override;
	QMimeData* mimeData(const QModelIndexList& indexes) const override;

  signals:
	void dataIsInvalid();
	void instancesChanged();
	void instanceSelectRequest(QString instanceId);
	void groupsChanged(QSet<QString> groups);

  public slots:
	void on_InstFolderChanged(const Setting& setting, QVariant value);
	void on_GroupStateChanged(const QString& group, bool collapsed);

  private slots:
	void propertiesChanged(BaseInstance* inst);
	void providerUpdated();
	void instanceDirContentsChanged(const QString& path);

  private:
	int getInstIndex(BaseInstance* inst) const;
	void updateTotalPlayTime();
	void suspendWatch();
	void resumeWatch();
	void add(const QList<InstancePtr>& list);
	void loadGroupList();
	void saveGroupList();
	QList<InstanceId> discoverInstances();
	InstancePtr loadInstance(const InstanceId& id);

  private:
	int m_watchLevel = 0;
	int totalPlayTime = 0;
	bool m_dirty = false;
	QList<InstancePtr> m_instances;
	QSet<QString> m_groupNameCache;

	SettingsObjectPtr m_globalSettings;
	QString m_instDir;
	QFileSystemWatcher* m_watcher;
	// FIXME: this is so inefficient that looking at it is almost painful.
	QSet<QString> m_collapsedGroups;
	QMap<InstanceId, GroupId> m_instanceGroupIndex;
	QSet<InstanceId> instanceSet;
	bool m_groupsLoaded = false;
	bool m_instancesProbed = false;
};