#pragma once
#include<vector>
#include "../inc/glm/glm.hpp"

struct Mesh {
	unsigned offset;	// offset of mesh in indices
	unsigned size;		// number of vertices in mesh
	bool hasUVs = false;
	bool hasVertexColors = false;
	float reflectivity = 0.f;
	std::string texture;
};

struct Scene {
	std::vector<unsigned> indices;		// triangle has three indices pointing to correct vertex
	std::vector<glm::vec3> vertices;	// vertex positions
	std::vector<glm::vec2> uvs;			// vertex texture coordinates
	std::vector<glm::vec3> normals;		// vertex normals
	std::vector<glm::vec3> colors;		// vertex colors (used for example in .ply files)
	std::vector<Mesh> meshes;

	static Scene* merge(const Scene& scene1, const Scene& scene2)
	{
		// Simple merge: append the vertices of the second scene to that of the first scene
		Scene* merged = new Scene;
		merged->indices.resize(scene1.indices.size() + scene2.indices.size());
		std::copy(scene1.indices.begin(), scene1.indices.end(), merged->indices.begin());
		std::copy(scene2.indices.begin(), scene2.indices.end(), merged->indices.begin() + scene1.indices.size());

		merged->vertices.resize(scene1.vertices.size() + scene2.vertices.size());
		std::copy(scene1.vertices.begin(), scene1.vertices.end(), merged->vertices.begin());
		std::copy(scene2.vertices.begin(), scene2.vertices.end(), merged->vertices.begin() + scene1.vertices.size());

		if (!scene1.uvs.empty())
		merged->uvs.resize(scene1.uvs.size() + scene2.uvs.size());
		std::copy(scene1.uvs.begin(), scene1.uvs.end(), merged->uvs.begin());
		std::copy(scene2.uvs.begin(), scene2.uvs.end(), merged->uvs.begin() + scene1.uvs.size());

		merged->normals.resize(scene1.normals.size() + scene2.normals.size());
		std::copy(scene1.normals.begin(), scene1.normals.end(), merged->normals.begin());
		std::copy(scene2.normals.begin(), scene2.normals.end(), merged->normals.begin() + scene1.normals.size());

		// If one of the scene has colors, load the colors for both scenes
		if (!scene1.colors.empty() || !scene2.colors.empty())
		{
			merged->colors.resize(scene1.vertices.size() + scene2.vertices.size(), glm::vec3(1));
			if (!scene1.colors.empty()) std::copy(scene1.colors.begin(), scene1.colors.end(), merged->colors.begin());
			if (!scene2.colors.empty()) std::copy(scene2.colors.begin(), scene2.colors.end(), merged->colors.begin() + scene1.vertices.size());
		}

		merged->meshes.resize(scene1.meshes.size() + scene2.meshes.size());
		for (unsigned i = 0; i < (unsigned)scene1.meshes.size(); i++)
			merged->meshes[i] = scene1.meshes[i];
		for (unsigned i = 0; i < (unsigned)scene2.meshes.size(); i++) {
			merged->meshes[i + scene1.meshes.size()] = scene2.meshes[i];
			merged->meshes[i + scene1.meshes.size()].offset += (unsigned)scene1.indices.size();
		}
		return merged;
	}

	~Scene()
	{
		vertices.clear();
		uvs.clear();
		normals.clear();
		colors.clear();
		indices.clear();
		meshes.clear();
	}
};