//https://lastminuteengineers.com/oled-display-arduino-tutorial/
//http://javl.github.io/image2cpp/
// mcd to magnitude http://unihedron.com/projects/darksky/magconv.php?ACTION=SOLVEMAGS&txtCDM2=0.1
// The HD44780 is a controller for character-based liquid crystal displays (LCDs).  https://www.quinapalus.com/hd44780udg.html

#include <Wire.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>
#include <Fonts/FreeSerif9pt7b.h>
#include "Adafruit_HTU21DF.h"
#include "Adafruit_TSL2591.h"
int counter;


// OLED display TWI address
#define OLED_ADDR   0x3C
Adafruit_SSD1306 display(-1);  // - 1 for restart display with restart button on arduino board

Adafruit_HTU21DF htu = Adafruit_HTU21DF();
Adafruit_TSL2591 tsl = Adafruit_TSL2591(2591); // pass in a number for the sensor identifier (for your use later)

uint32_t lum;
uint16_t ir, full;
int ulux;
float lux;
float temp;
float rel_hum;
float mag_arcsec2; // visual mags/arcsecond² [value in mag/arcsec2]  =   Log10([value in cd/m2]/108000)/-0.4

// symbols
// degree for Celsius
const unsigned char degree [] PROGMEM =
{
  0xe, 0x11, 0x11, 0x11, 0xe, 0x0, 0x0, 0x0
};

// exponent 2
const unsigned char exponent [] PROGMEM =
{
  0xe, 0x1b, 0x3, 0x6, 0xc, 0x18, 0x1f, 0x0
};

// 'moon_logo', 128x64px
const unsigned char intro [] PROGMEM = {
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x01, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x03, 0xff, 0xc0, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xfc, 0x07, 0xff, 0xe0, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x07, 0xff, 0xf8, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x0f, 0xff, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0x0f, 0xff, 0x77, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x1f, 0xbe, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x1f, 0xcc, 0xff, 0xff, 0x8f, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x3f, 0xc0, 0xff, 0xff, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xfe, 0x00, 0x3f, 0xc0, 0xff, 0xff, 0x8f, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xfe, 0x00, 0x3f, 0xe0, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xfc, 0x00, 0x3f, 0x80, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x3f, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x3f, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x3f, 0xf9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x3f, 0xfb, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x18, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x60, 0xff, 0xff, 0xff, 0xff, 0xef, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0xff, 0xff, 0xff, 0xff, 0xe7, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x00, 0xff, 0xff, 0xff, 0xff, 0xe1, 0xe7, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x00, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x07, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x18, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x0f, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x38, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x0f, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x48, 0x7f, 0xff, 0xff, 0xff, 0xc0, 0x1f, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x80, 0x3f, 0xff, 0xff, 0xff, 0x00, 0x1f, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0xc4, 0x1f, 0xff, 0xff, 0xfc, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x60, 0x0f, 0xff, 0xff, 0xff, 0x80, 0x0f, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0xf0, 0x03, 0xff, 0xff, 0xff, 0xf0, 0x07, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x00, 0x00, 0xff, 0xff, 0xff, 0xf0, 0xe3, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x00, 0x00, 0xff, 0xff, 0xff, 0xf0, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xc0, 0x00, 0x01, 0xff, 0xff, 0xff, 0xf1, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x43, 0xff, 0xff, 0xff, 0xfb, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x4f, 0xff, 0xff, 0xff, 0xfb, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x5f, 0xff, 0xff, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x3f, 0xff, 0xff, 0x87, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x03, 0xff, 0xff, 0xcf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x01, 0xff, 0xff, 0xb7, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xfc, 0x01, 0x0f, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xfc, 0x01, 0xfe, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xfe, 0x00, 0x00, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x00, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xc0, 0x00, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x01, 0xff, 0xff, 0xfd, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xf0, 0x00, 0x00, 0x7f, 0xff, 0xf3, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x00, 0x1f, 0xff, 0xc7, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xfc, 0x00, 0x00, 0x00, 0xfc, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x80, 0x00, 0x00, 0x00, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf8, 0x00, 0x00, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe, 0x00, 0x00, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xe0, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};

void setup() {

  // htu21d
  htu.begin();

  // tsl2591
  sensor_t sensor;
  tsl.getSensor(&sensor);
  tsl.setGain(TSL2591_GAIN_MAX);  // MAX, HIGH MED,LOW,
  tsl.setTiming(TSL2591_INTEGRATIONTIME_600MS); // 100MS, 200 MS, 300MS, 400MS,500MS, 600MS

  // setup for oled display
  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.clearDisplay();
  display.display();
  display.drawBitmap(0, 0,  intro, 128, 64, WHITE);
  display.display();
  delay(1000);
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setFont(&FreeSerif9pt7b);
  display.clearDisplay();

}

void loop() {

  lux = 0;
  ulux = 0;
  mag_arcsec2 = 0;
  temp = 0;
  rel_hum = 0;

  delay(100);
  lum = tsl.getFullLuminosity();
  ir = lum >> 16;
  full = lum & 0xFFFF;
  delay(100);
  lux = tsl.calculateLux(full, ir);  // light intensiti in microlux
  ulux = lux * 1000000;
  mag_arcsec2 = log10(lux / 108000) / -0.4; //(log((ulux/108000) ) /(-0.4)

  temp = htu.readTemperature();
  rel_hum = htu.readHumidity();

  display_values();


}

void display_values()
{
  //display.drawPixel(120, 50, WHITE);
  display.clearDisplay();
  display.setCursor(1, 15);
  display.print(temp);
  display.drawBitmap(42, 2,  degree, 8, 5 , WHITE);
  display.setCursor(50, 15);
  display.print("C");
  display.setCursor(70, 15);
  display.print(rel_hum);
  display.setCursor(114, 15);
  display.print("%");
  display.drawLine(1, 20, 127, 20, WHITE);
  display.drawLine(67, 1, 67, 20, WHITE);
  display.setCursor(1, 35);
  display.print("ulux");
  display.setCursor(45, 35);

  if (ulux < 0)
    {
      display.print("saturated");
    }
  else
    {
      display.print(ulux);
    }

  display.setCursor(1, 55);
  display.print("mag/arsec");
  display.drawBitmap(70, 45,  exponent, 8, 8 , WHITE);
  display.setCursor(83, 55);

  if (ulux < 0)
    {
      display.print("n/a");
    }
  else
    {
      display.print(mag_arcsec2);
    }
    
  display.display();
}