#pragma once

#include <vector>

#include <gl/glew.h>

#include <glm/glm.hpp>
#include <glm/ext.hpp>

#include "Shader.h"

class DefaultUniform {
private:

public:
	glm::mat4 model;
	glm::mat4 view;
	glm::mat4 projection;
};

template<class TVertexData, class TUniform = DefaultUniform>
class Mesh
{
private:
	TUniform _uniform;

	GLuint _uniformModel;
	GLuint _uniformView;
	GLuint _uniformProjection;
	
protected:
	std::vector<TVertexData> _vertexData;
	
	GLuint _vba;
	GLuint _vbo;
	Shader* shader;

	bool _isVertexDirty;

public:

	TUniform& Uniform() { return _uniform; }

public:
	Mesh(Shader* shader) : shader(shader), _isVertexDirty(true) { 
		shader->Initialize();

		glCreateVertexArrays(1, &_vba);
		glCreateBuffers(1, &_vbo);

		_uniformModel = glGetUniformLocation(shader->Reference(), "model");
		_uniformView = glGetUniformLocation(shader->Reference(), "view");
		_uniformProjection = glGetUniformLocation(shader->Reference(), "projection");
	}

	~Mesh() {
		glDeleteVertexArrays(1, &_vba);
		glDeleteBuffers(1, &_vbo);
	}

	void AddTriangle(const TVertexData& p0, const TVertexData& p1, const TVertexData& p2) {
		_vertexData.push_back(p0);
		_vertexData.push_back(p1);
		_vertexData.push_back(p2);

		_isVertexDirty = true;
	}

	void AddQuad(const TVertexData& p0, const TVertexData& p1, const TVertexData& p2, const TVertexData& p3) {
		AddTriangle(p0, p1, p2);
		AddTriangle(p1, p2, p3);
	}

	virtual void Render(const TUniform& uniform) {
		shader->Use();

		glUniformMatrix4fv(_uniformModel, 1, GL_FALSE, glm::value_ptr(uniform.model));
		glUniformMatrix4fv(_uniformView, 1, GL_FALSE, glm::value_ptr(uniform.view));
		glUniformMatrix4fv(_uniformProjection, 1, GL_FALSE, glm::value_ptr(uniform.projection));

		glBindVertexArray(_vba);
		glBindBuffer(GL_ARRAY_BUFFER, _vbo);

		if (_isVertexDirty) {
			glBufferData(GL_ARRAY_BUFFER, sizeof(TVertexData) * _vertexData.size(), _vertexData.data(), GL_STATIC_DRAW);

			_isVertexDirty = false;
		}

		glDrawArrays(GL_TRIANGLES, 0, _vertexData.size());

		glBindBuffer(GL_ARRAY_BUFFER, 0);
		glBindVertexArray(0);

		shader->Disable();
	}
};