/**
	This file is a part of rexy's general purpose library
	Copyright (C) 2022 rexy712

	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 <http://www.gnu.org/licenses/>.
*/

#ifndef REXY_DETAIL_FORMAT_OUTPUT_BUFFER_HPP
#define REXY_DETAIL_FORMAT_OUTPUT_BUFFER_HPP

#include <cstddef> //size_t
#include <cstdio> //fputc, FILE
#include <cwchar> //fputwc

#include "format_error.hpp"

namespace rexy::fmt::detail{
	//polymorphic buffer of which a reference can be passed around to prevent
	//passing around multiple output iterator types
	template<class Char>
	class format_output_buffer_base
	{
	public:
		using value_type = Char;
	protected:
		static constexpr std::size_t s_bufsize = 256;
	protected:
		Char m_data[s_bufsize];
		std::size_t m_size = 0;
		std::size_t m_written_count = 0;
	public:
		format_output_buffer_base(void) = default;
		virtual ~format_output_buffer_base(void) = default;

		virtual std::size_t write_out(void) = 0;
		void clear(void);
		void push_back(Char c);

		constexpr std::size_t count(void)const;
	};

	//Used with the 'formatter' to output a type
	//OutIt is an iterator where the output is written at the end.
	template<class Char, class OutIt>
	class basic_format_output_buffer : public format_output_buffer_base<Char>
	{
	private:
		using base = format_output_buffer_base<Char>;
	private:
		OutIt m_out;
	public:
		basic_format_output_buffer(OutIt out);
		~basic_format_output_buffer(void)override;

		std::size_t write_out(void)override;

		constexpr OutIt out(void);
	private:
		std::size_t write_out_simple(void);
	};
	template<class Char, class OutIt>
	class basic_format_output_n_buffer : public format_output_buffer_base<Char>
	{
	private:
		using base = format_output_buffer_base<Char>;
	private:
		OutIt m_out;
		std::size_t m_max_write = 0;
	public:
		basic_format_output_n_buffer(OutIt out, std::size_t max);
		~basic_format_output_n_buffer(void)override;

		std::size_t write_out(void)override;

		constexpr OutIt out(void);
	};

	template<class Char>
	class basic_format_size_buffer : public format_output_buffer_base<Char>
	{
	public:
		constexpr basic_format_size_buffer(void) = default;
		constexpr ~basic_format_size_buffer(void)override;

		std::size_t write_out(void)override;
	};


	template<class Char>
	struct print_format_buffer : public format_output_buffer_base<Char>
	{
	private:
		FILE* m_stream;
	public:
		constexpr print_format_buffer(FILE* stream):
			m_stream(stream){}
		constexpr ~print_format_buffer(void){
			write_out();
		}

		std::size_t write_out(void)override{
			const auto written = fwrite(this->m_data, sizeof(this->m_data[0]), this->m_size, m_stream);
			if(written != this->m_size){
				REXY_THROW_FORMAT_ERROR("Failed to print data");
			}
		}
	};

}

#endif