/* 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 <exception>
#include <stdexcept>

#include <QString>
#include <QVariant>
#include <QHash>
#include <QStringList>

/**
 * @file libutil/include/cmdutils.h
 * @brief commandline parsing and processing utilities
 */

namespace Commandline
{

	/**
	 * @brief split a string into argv items like a shell would do
	 * @param args the argument string
	 * @return a QStringList containing all arguments
	 */
	QStringList splitArgs(QString args);

	/**
	 * @brief The FlagStyle enum
	 * Specifies how flags are decorated
	 */

	namespace FlagStyle
	{
		enum Enum {
			GNU,	 /**< --option and -o (GNU Style) */
			Unix,	 /**< -option and -o  (Unix Style) */
			Windows, /**< /option and /o  (Windows Style) */
#ifdef Q_OS_WIN32
			Default = Windows
#else
			Default = GNU
#endif
		};
	} // namespace FlagStyle

	/**
	 * @brief The ArgumentStyle enum
	 */
	namespace ArgumentStyle
	{
		enum Enum {
			Space,			/**< --option value */
			Equals,			/**< --option=value */
			SpaceAndEquals, /**< --option[= ]value */
#ifdef Q_OS_WIN32
			Default = Equals
#else
			Default = SpaceAndEquals
#endif
		};
	} // namespace ArgumentStyle

	/**
	 * @brief The ParsingError class
	 */
	class ParsingError : public std::runtime_error
	{
	  public:
		ParsingError(const QString& what);
	};

	/**
	 * @brief The Parser class
	 */
	class Parser
	{
	  public:
		/**
		 * @brief Parser constructor
		 * @param flagStyle the FlagStyle to use in this Parser
		 * @param argStyle the ArgumentStyle to use in this Parser
		 */
		Parser(FlagStyle::Enum flagStyle = FlagStyle::Default,
			   ArgumentStyle::Enum argStyle = ArgumentStyle::Default);

		/**
		 * @brief set the flag style
		 * @param style
		 */
		void setFlagStyle(FlagStyle::Enum style);

		/**
		 * @brief get the flag style
		 * @return
		 */
		FlagStyle::Enum flagStyle();

		/**
		 * @brief set the argument style
		 * @param style
		 */
		void setArgumentStyle(ArgumentStyle::Enum style);

		/**
		 * @brief get the argument style
		 * @return
		 */
		ArgumentStyle::Enum argumentStyle();

		/**
		 * @brief define a boolean switch
		 * @param name the parameter name
		 * @param def the default value
		 */
		void addSwitch(QString name, bool def = false);

		/**
		 * @brief define an option that takes an additional argument
		 * @param name the parameter name
		 * @param def the default value
		 */
		void addOption(QString name, QVariant def = QVariant());

		/**
		 * @brief define a positional argument
		 * @param name the parameter name
		 * @param required wether this argument is required
		 * @param def the default value
		 */
		void addArgument(QString name, bool required = true,
						 QVariant def = QVariant());

		/**
		 * @brief adds a flag to an existing parameter
		 * @param name the (existing) parameter name
		 * @param flag the flag character
		 * @see addSwitch addArgument addOption
		 * Note: any one parameter can only have one flag
		 */
		void addShortOpt(QString name, QChar flag);

		/**
		 * @brief adds documentation to a Parameter
		 * @param name the parameter name
		 * @param metavar a string to be displayed as placeholder for the value
		 * @param doc a QString containing the documentation
		 * Note: on positional arguments, metavar replaces the name as
		 * displayed. on options , metavar replaces the value placeholder
		 */
		void addDocumentation(QString name, QString doc,
							  QString metavar = QString());

		/**
		 * @brief generate a help message
		 * @param progName the program name to use in the help message
		 * @param helpIndent how much the parameter documentation should be
		 * indented
		 * @param flagsInUsage whether we should use flags instead of options in
		 * the usage
		 * @return a help message
		 */
		QString compileHelp(QString progName, int helpIndent = 22,
							bool flagsInUsage = true);

		/**
		 * @brief generate a short usage message
		 * @param progName the program name to use in the usage message
		 * @param useFlags whether we should use flags instead of options
		 * @return a usage message
		 */
		QString compileUsage(QString progName, bool useFlags = true);

		/**
		 * @brief parse
		 * @param argv a QStringList containing the program ARGV
		 * @return a QHash mapping argument names to their values
		 */
		QHash<QString, QVariant> parse(QStringList argv);

		/**
		 * @brief clear all definitions
		 */
		void clear();

		~Parser();

	  private:
		FlagStyle::Enum m_flagStyle;
		ArgumentStyle::Enum m_argStyle;

		enum OptionType { otSwitch, otOption };

		// Important: the common part MUST BE COMMON ON ALL THREE structs
		struct CommonDef {
			QString name;
			QString doc;
			QString metavar;
			QVariant def;
		};

		struct OptionDef {
			// common
			QString name;
			QString doc;
			QString metavar;
			QVariant def;
			// option
			OptionType type;
			QChar flag;
		};

		struct PositionalDef {
			// common
			QString name;
			QString doc;
			QString metavar;
			QVariant def;
			// positional
			bool required;
		};

		QHash<QString, OptionDef*> m_options;
		QHash<QChar, OptionDef*> m_flags;
		QHash<QString, CommonDef*> m_params;
		QList<PositionalDef*> m_positionals;
		QList<OptionDef*> m_optionList;

		void getPrefix(QString& opt, QString& flag);
	};
} // namespace Commandline