#pragma once
#include <glm/gtc/matrix_transform.hpp>
/*
	ON MOBILE, GLES 3.1 WOULD BE REQUIRED (compute shader support)
*/
#include <GL/glew.h>

#include <string>
#include <iostream>

using namespace std;
using namespace glm;

enum SIM_PRECISION {
	FINE,
	REGULAR,
	ROUGH
};

class CRT_Shader {

private:
	static bool CRT_FLIP_Y;
	string resourceRoot = "C:\\Users\\BoBoBoat\\Desktop\\SCUOLA\\CGI\\GL_STUFF\\GL_STUFF\\SOURCES\\EFFECTS\\CRT_SHADER\\";
	const float CRT_PIXEL_LENGTH = 2e-3;	//value of 1 gets only red (bad bug)
	static const int CRT_PIXEL_SCALE = 1;	//they work together
	const float CRT_DEPTH = 1e0;
	static int CRT_HORIZONTAL_PIXELS;
	static int CRT_VERTICAL_PIXELS;
	static int CRT_WIDTH;
	static int CRT_HEIGHT;
	static int PARTICLE_COUNT;
	static const int GROUP_COUNT = 1024;
	static int PARTICLE_GROUP_COUNT;
	static const unsigned int COLOR_CHANNELS = 4;
	static SIM_PRECISION resolution;
	
	mat4 orthoMat;
	vec3 CS_LTN, CS_RBN, CS_LTF, CS_RBF;
	GLuint dt_location;

	GLuint compute_prog;
	GLuint render_prog;
	GLuint render_vao;
	
	GLuint end_position_buffer, start_position_buffer, velocity_buffer, color_buffer, magnets_buffer;

	float magx;
	float magy;

	vec4 attractors[8];
	
	GLuint velocity_tbo, start_position_tbo, end_position_tbo, color_tbo;


	CRT_Shader();
	vec3 scaleToZOne(vec3 vector);
	vec3 crt_emission_angle(int index);
	void createRenderShader();
	void createComputeShader();
	void buffersSetup();
	void VAOsSetup();

public:
	static void setup(int w, int h, bool flipY, SIM_PRECISION precision) {
		CRT_FLIP_Y = flipY;
		resolution = precision;
		CRT_WIDTH = w;
		CRT_HEIGHT = h;
		CRT_HORIZONTAL_PIXELS = w / CRT_PIXEL_SCALE;
		CRT_VERTICAL_PIXELS = h / CRT_PIXEL_SCALE;
		PARTICLE_COUNT = CRT_HORIZONTAL_PIXELS * CRT_VERTICAL_PIXELS;
		PARTICLE_GROUP_COUNT = (PARTICLE_COUNT / GROUP_COUNT) + ((PARTICLE_COUNT % GROUP_COUNT) ? 1 : 0);
		cout << "HPIX " << CRT_HORIZONTAL_PIXELS << "\n";
		cout << "VPIX " << CRT_VERTICAL_PIXELS << "\n";
	}

	static CRT_Shader& get() {
		static CRT_Shader instance;
		return instance;
	}

	void draw(unsigned int ONE_TICK_MS, unsigned int timePassed);
	void setMagnet(int index, vec4 positionAndMass);
	float getLeftBound();
	float getRightBound();
	float getBottomBound();
	float getTopBound();

	/*Copies H_PIXELS * V_PIXELS from FrameBuffer to internal VAO */
	void loadColorFromFramebuffer(GLuint FBO);
};