/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */
#pragma once

#include "Scene/Geometry.hpp"

#include <utility>
#include <string>
#include <sstream>
#include <fmt/core.h>

namespace OpenVulkano::Scene
{
	static constexpr std::string_view DEFAULT_OBJ_MATERIAL_NAME = "Material0";
	static constexpr std::string_view DEFAULT_OBJ_MATERIAL_CONTENTS = R"(newmtl Material0
Ka 1.000 1.000 1.000
Kd 1.000 1.000 1.000
Ks 0.000 0.000 0.000
map_Ka texture.png
map_Kd texture.png
)";

	void WriteObjContents(Geometry* geometry, const std::string_view& materialName, std::ostream& objContent)
	{
		objContent << "# OBJ file generated by OpenVulkanoCpp\n";

		if (materialName.size() != 0)
		{
			std::string_view content = "mtllib material.mtl\n";
			objContent.write(content.data(), content.size());
			
			content = "usemtl ";
			objContent.write(content.data(), content.size());

			objContent.write(materialName.data(), materialName.size());
			objContent.write("\n", 1);
		}

		for (int i = 0; i < geometry->vertexCount; ++i)
		{
			const auto& v = geometry->vertices[i];
			const std::string content = fmt::format("v {} {} {}\n", v.position.x, v.position.y, v.position.z);
			objContent.write(content.data(), content.size());
		}
		for (int i = 0; i < geometry->vertexCount; ++i)
		{
			const auto& v = geometry->vertices[i];
			const std::string content = fmt::format("vn {} {} {}\n", v.normal.x, v.normal.y, v.normal.z);
			objContent.write(content.data(), content.size());
		}
		for (int i = 0; i < geometry->vertexCount; ++i)
		{
			const auto& v = geometry->vertices[i];
			const std::string content = fmt::format("vt {} {}\n", v.textureCoordinates.x, v.textureCoordinates.y);
			objContent.write(content.data(), content.size());
		}
		for (int i = 0; i < geometry->indexCount; i += 3)
		{
			uint32_t i0 = geometry->GetIndex(i + 0) + 1;
			uint32_t i1 = geometry->GetIndex(i + 1) + 1;
			uint32_t i2 = geometry->GetIndex(i + 2) + 1;
			const std::string content = fmt::format("f {0}/{0}/{0} {1}/{1}/{1} {2}/{2}/{2}\n", i0, i1, i2);
			objContent.write(content.data(), content.size());
		}
	}
}