/*
 * Copyright (C) 2017-2019  Christopher J. Howard
 *
 * This file is part of Antkeeper Source Code.
 *
 * Antkeeper Source Code 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.
 *
 * Antkeeper Source Code 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 Antkeeper Source Code.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef CONSOLE_HPP
#define CONSOLE_HPP

#include <functional>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

/**
 * Parses an argument string into a typed value.
 */
template<class T>
class ArgumentParser
{
public:
	static T parse(const std::string& argument);
};

template<>
int ArgumentParser<int>::parse(const std::string& argument);
template<>
unsigned int ArgumentParser<unsigned int>::parse(const std::string& argument);
template<>
long ArgumentParser<long>::parse(const std::string& argument);
template<>
unsigned long ArgumentParser<unsigned long>::parse(const std::string& argument);
template<>
float ArgumentParser<float>::parse(const std::string& argument);
template<>
double ArgumentParser<double>::parse(const std::string& argument);
template<>
std::string ArgumentParser<std::string>::parse(const std::string& argument);

/**
 * Parses an argument vector of strings into a tuple of typed values.
 */
class ArgumentVectorParser
{
public:
	template<class... Args>
	static std::tuple<Args...> parse(const std::vector<std::string>& arguments)
	{
		return parse<Args...>(arguments, std::make_index_sequence<sizeof...(Args)>{});
	}

private:
	template <class... Args, std::size_t... index>
	static std::tuple<Args...> parse(const std::vector<std::string>& arguments, std::index_sequence<index...>)
	{
		return {ArgumentParser<Args>::parse(arguments[index])...};
	}
};

class CommandLinker
{
public:
	/**
	 * Links a function and its arguments together into a single callable object.
	 */
	template<class... Args>
	static std::function<void()> link(const std::function<void(Args...)>& function, const std::vector<std::string>& arguments)
	{
		// Parse argument vectors and store in a tuple
		auto parsedArguments = ArgumentVectorParser::parse<Args...>(arguments);

		// Return callable object which will invoke the function with the parsed arguments
		return std::bind
		(
			[function, parsedArguments]()
			{
				std::apply(function, parsedArguments);
			}
		);
	}
};

/**
 * 
 */
class CommandInterpreter
{
public:
	/**
	 * Registers a command.
	 *
	 * @param name Name used to invoke the command.
	 * @param function Function associated with the command.
	 */
	template <class... Args>
	void registerCommand(const std::string& name, const std::function<void(Args...)>& function);
	template <class... Args>
	void registerCommand(const std::string& name, void(*function)(Args...));

	/**
	 * Interprets a line of text as a function call, returning the interpreted command name, argument vector, and callable function object.
	 *
	 * @param line Line of text to be interpreted.
	 */
	std::tuple<std::string, std::vector<std::string>, std::function<void()>> interpret(const std::string& line);

private:
	template <class Function, class Linker>
	void addCommandLinker(const std::string& name, const Function& function, const Linker& linker);

	// A command name-keyed map of command linkers
	std::unordered_map<std::string, std::function<std::function<void()>(const std::vector<std::string>&)>> linkers;
};

template <class... Args>
void CommandInterpreter::registerCommand(const std::string& name, const std::function<void(Args...)>& function)
{
	addCommandLinker(name, function, CommandLinker::link<Args...>);
}

template <class... Args>
void CommandInterpreter::registerCommand(const std::string& name, void(*function)(Args...))
{
	addCommandLinker(name, function, CommandLinker::link<Args...>);
}

template <class Function, class Linker>
void CommandInterpreter::addCommandLinker(const std::string& name, const Function& function, const Linker& linker)
{
	linkers[name] = std::bind(linker, function, std::placeholders::_1);
}

#endif // CONSOLE_HPP