// 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 "text/json_formatter.h"
#include "nbt_tags.h"
#include "nbt_visitor.h"
#include <cmath>
#include <iomanip>
#include <limits>

namespace nbt
{
	namespace text
	{

		namespace // anonymous
		{
			/// Helper class which uses the Visitor pattern to pretty-print tags
			class json_fmt_visitor : public const_nbt_visitor
			{
			  public:
				json_fmt_visitor(std::ostream& os) : os(os) {}

				void visit(const tag_byte& b) override
				{
					os << static_cast<int>(b.get()) << "b";
				} // We don't want to print a character

				void visit(const tag_short& s) override
				{
					os << s.get() << "s";
				}

				void visit(const tag_int& i) override
				{
					os << i.get();
				}

				void visit(const tag_long& l) override
				{
					os << l.get() << "l";
				}

				void visit(const tag_float& f) override
				{
					write_float(f.get());
					os << "f";
				}

				void visit(const tag_double& d) override
				{
					write_float(d.get());
					os << "d";
				}

				void visit(const tag_byte_array& ba) override
				{
					os << "[" << ba.size() << " bytes]";
				}

				void visit(const tag_string& s) override
				{
					os << '"';
					write_escaped_string(s.get());
					os << '"';
				}

				void visit(const tag_list& l) override
				{
					// Wrap lines for lists of lists or compounds.
					// Lists of other types can usually be on one line without
					// problem.
					const bool break_lines =
						l.size() > 0 && (l.el_type() == tag_type::List ||
										 l.el_type() == tag_type::Compound);

					os << "[";
					if (break_lines) {
						os << "\n";
						++indent_lvl;
						for (unsigned int i = 0; i < l.size(); ++i) {
							indent();
							if (l[i])
								l[i].get().accept(*this);
							else
								write_null();
							if (i != l.size() - 1)
								os << ",";
							os << "\n";
						}
						--indent_lvl;
						indent();
					} else {
						for (unsigned int i = 0; i < l.size(); ++i) {
							if (l[i])
								l[i].get().accept(*this);
							else
								write_null();
							if (i != l.size() - 1)
								os << ", ";
						}
					}
					os << "]";
				}

				void visit(const tag_compound& c) override
				{
					if (c.size() ==
						0) // No line breaks inside empty compounds please
					{
						os << "{}";
						return;
					}

					os << "{\n";
					++indent_lvl;
					unsigned int i = 0;
					for (const auto& kv : c) {
						indent();
						os << kv.first << ": ";
						if (kv.second)
							kv.second.get().accept(*this);
						else
							write_null();
						if (i != c.size() - 1)
							os << ",";
						os << "\n";
						++i;
					}
					--indent_lvl;
					indent();
					os << "}";
				}

				void visit(const tag_int_array& ia) override
				{
					os << "[";
					for (unsigned int i = 0; i < ia.size(); ++i) {
						os << ia[i];
						if (i != ia.size() - 1)
							os << ", ";
					}
					os << "]";
				}

				void visit(const tag_long_array& la) override
				{
					os << "[";
					for (unsigned int i = 0; i < la.size(); ++i) {
						os << la[i];
						if (i != la.size() - 1)
							os << ", ";
					}
					os << "]";
				}

			  private:
				const std::string indent_str = "  ";

				std::ostream& os;
				int indent_lvl = 0;

				void indent()
				{
					for (int i = 0; i < indent_lvl; ++i)
						os << indent_str;
				}

				template <class T>
				void write_float(
					T val, int precision = std::numeric_limits<T>::max_digits10)
				{
					if (std::isfinite(val))
						os << std::setprecision(precision) << val;
					else if (std::isinf(val)) {
						if (std::signbit(val))
							os << "-";
						os << "Infinity";
					} else
						os << "NaN";
				}

				void write_null()
				{
					os << "null";
				}

				void write_escaped_string(const std::string& str)
				{
					for (char c : str) {
						switch (c) {
							case '"':
								os << "\\\"";
								break;
							case '\\':
								os << "\\\\";
								break;
							case '\b':
								os << "\\b";
								break;
							case '\f':
								os << "\\f";
								break;
							case '\n':
								os << "\\n";
								break;
							case '\r':
								os << "\\r";
								break;
							case '\t':
								os << "\\t";
								break;
							default:
								if (c < 32 || c == 127) {
									// Control characters, escape as \u00XX
									os << "\\u00" << std::hex << std::setw(2)
									   << std::setfill('0')
									   << static_cast<int>(c);
								} else {
									os << c;
								}
								break;
						}
					}
				}
			};
		} // namespace

		void json_formatter::print(std::ostream& os, const tag& t) const
		{
			json_fmt_visitor v(os);
			t.accept(v);
		}

	} // namespace text
} // namespace nbt
