// SPDX-FileCopyrightText: 2013, 2015 ljfa-ag <ljfa-ag@web.de>
//
// SPDX-License-Identifier: LGPL-3.0-or-later

/*
 * libnbt++ - A library for the Minecraft Named Binary Tag format.
 * Copyright (C) 2013, 2015  ljfa-ag
 *
 * This file is part of libnbt++.
 *
 * libnbt++ is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * libnbt++ 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with libnbt++.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "io/stream_reader.h"
#include "make_unique.h"
#include "tag_compound.h"
#include <istream>

namespace nbt
{
	namespace io
	{

		static constexpr int MAX_DEPTH = 1024;

		std::pair<std::string, std::unique_ptr<tag_compound>>
		read_compound(std::istream& is, endian::endian e)
		{
			return stream_reader(is, e).read_compound();
		}

		std::pair<std::string, std::unique_ptr<tag>> read_tag(std::istream& is,
															  endian::endian e)
		{
			return stream_reader(is, e).read_tag();
		}

		stream_reader::stream_reader(std::istream& is,
									 endian::endian e) noexcept
			: is(is), endian(e)
		{
		}

		std::istream& stream_reader::get_istr() const
		{
			return is;
		}

		endian::endian stream_reader::get_endian() const
		{
			return endian;
		}

		std::pair<std::string, std::unique_ptr<tag_compound>>
		stream_reader::read_compound()
		{
			if (read_type() != tag_type::Compound) {
				is.setstate(std::ios::failbit);
				throw input_error("Tag is not a compound");
			}
			std::string key = read_string();
			auto comp = make_unique<tag_compound>();
			comp->read_payload(*this);
			return {std::move(key), std::move(comp)};
		}

		std::pair<std::string, std::unique_ptr<tag>> stream_reader::read_tag()
		{
			tag_type type = read_type();
			std::string key = read_string();
			std::unique_ptr<tag> t = read_payload(type);
			return {std::move(key), std::move(t)};
		}

		std::unique_ptr<tag> stream_reader::read_payload(tag_type type)
		{
			if (++depth > MAX_DEPTH)
				throw input_error("Too deeply nested");
			std::unique_ptr<tag> t = tag::create(type);
			t->read_payload(*this);
			--depth;
			return t;
		}

		tag_type stream_reader::read_type(bool allow_end)
		{
			int type = is.get();
			if (!is)
				throw input_error("Error reading tag type");
			if (!is_valid_type(type, allow_end)) {
				is.setstate(std::ios::failbit);
				throw input_error("Invalid tag type: " + std::to_string(type));
			}
			return static_cast<tag_type>(type);
		}

		std::string stream_reader::read_string()
		{
			uint16_t len;
			read_num(len);
			if (!is)
				throw input_error("Error reading string");

			std::string ret(len, '\0');
			is.read(&ret[0], len); // C++11 allows us to do this
			if (!is)
				throw input_error("Error reading string");
			return ret;
		}

	} // namespace io
} // namespace nbt
