#pragma once
#include <map>
#include <vector>
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
using namespace std;

#include <GL/glew.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>

#include <SOIL.h>

#include <assimp/Importer.hpp>
#include <assimp/scene.h>
#include <assimp/postprocess.h>

#include "Mesh.h"

GLint TextureFromFile(const char* path, string directory);

class Model 
{
public:
 Model(GLchar* path)
 {
 this->loadModel(path);
 }

 void Draw(Shader shader)
 {
		for (auto mesh : meshes)
			mesh.Draw(shader);
 }
 
//private:
 vector<Mesh> meshes;
 string directory;
 vector<Texture> textures_loaded;

	void loadModel(string path);
	void processNode(aiNode* node, const aiScene* scene);
	Mesh processMesh(aiMesh* mesh, const aiScene* scene);
	vector<Texture> loadMaterialTextures(aiMaterial* mat, aiTextureType type, string typeName);
};


void Model::loadModel(string path)
{
 Assimp::Importer importer;
 const aiScene* scene = importer.ReadFile(path, aiProcess_Triangulate | aiProcess_FlipUVs);
 if(!scene || scene->mFlags == AI_SCENE_FLAGS_INCOMPLETE || !scene->mRootNode) // if is Not Zero
 {
 cout << "ERROR::ASSIMP:: " << importer.GetErrorString() << endl;
 return;
 }
 this->directory = path.substr(0, path.find_last_of('/'));

 this->processNode(scene->mRootNode, scene);
}

void Model::processNode(aiNode* node, const aiScene* scene)
{
	for (GLuint i = 0; i < node->mNumMeshes; i++)
	{
		aiMesh* mesh = scene->mMeshes[node->mMeshes[i]];
		this->meshes.push_back(this->processMesh(mesh, scene));
	}
	for (GLuint i = 0; i < node->mNumChildren; i++)
		this->processNode(node->mChildren[i], scene);
}

Mesh Model::processMesh(aiMesh* mesh, const aiScene* scene)
{
	vector<Vertex> vertices;
	vector<GLuint> indices;
	vector<Texture> textures;

	for (GLuint i = 0; i < mesh->mNumVertices; i++)
	{
		Vertex vertex;
		glm::vec3 vector;
		// Positions
		vector.x = mesh->mVertices[i].x;
		vector.y = mesh->mVertices[i].y;
		vector.z = mesh->mVertices[i].z;
		vertex.Position = vector;
		// Normals
		vector.x = mesh->mNormals[i].x;
		vector.y = mesh->mNormals[i].y;
		vector.z = mesh->mNormals[i].z;
		vertex.Normal = vector;
		// Texture Coordinates
		if (mesh->mTextureCoords[0])
		{
			glm::vec2 vec;
			vec.x = mesh->mTextureCoords[0][i].x;
			vec.y = mesh->mTextureCoords[0][i].y;
			vertex.TexCoords = vec;
		}
		else
			vertex.TexCoords = glm::vec2(0.0f, 0.0f);
		vertices.push_back(vertex);
	}
	for (GLuint i = 0; i < mesh->mNumFaces; i++)
	{
		aiFace face = mesh->mFaces[i];
		for (GLuint j = 0; j < face.mNumIndices; j++)
			indices.push_back(face.mIndices[j]);
	}
	if (mesh->mMaterialIndex >= 0)
	{
		aiMaterial* material = scene->mMaterials[mesh->mMaterialIndex];
		// diffuse maps
		vector<Texture> diffuseMaps = this->loadMaterialTextures(material, aiTextureType_DIFFUSE, "texture_diffuse");
		textures.insert(textures.end(), diffuseMaps.begin(), diffuseMaps.end());
		// Specular maps
		vector<Texture> specularMaps = this->loadMaterialTextures(material, aiTextureType_SPECULAR, "texture_specular");
		textures.insert(textures.end(), specularMaps.begin(), specularMaps.end());
	}
	return Mesh(vertices, indices, textures);
}

vector<Texture> Model:: loadMaterialTextures(aiMaterial* mat, aiTextureType type, string typeName)
{
	vector<Texture> textures;
	for (GLuint i = 0; i < mat->GetTextureCount(type); i++)
	{
		aiString str;
		mat->GetTexture(type, i, &str);
		GLboolean skip = false;
		for (GLuint j = 0; j < textures_loaded.size(); j++)
		{
			if (textures_loaded[j].path == str)
			{
				textures.push_back(textures_loaded[j]);
				skip = true;
				break;
			}
		}
		if (!skip)
		{
			Texture texture;
			texture.id = TextureFromFile(str.C_Str(), this->directory);
			texture.type = typeName;
			texture.path = str;
			textures.push_back(texture);
			this->textures_loaded.push_back(texture);
		}
	}
	return textures;
}

GLint TextureFromFile(const char* path, string directory)
{
 string filename = string(path);
 filename = directory + '/' + filename;
 GLuint textureID;
 glGenTextures(1, &textureID);
 glBindTexture(GL_TEXTURE_2D, textureID);

 int width,height;
 unsigned char* image = SOIL_load_image(filename.c_str(), &width, &height, 0, SOIL_LOAD_RGB);
 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
 glGenerateMipmap(GL_TEXTURE_2D);	

 // Parameters
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
 glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 glBindTexture(GL_TEXTURE_2D, 0);
 SOIL_free_image_data(image);
 return textureID;
}