#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define S1 A0
#define S2 A1
#define S3 A2
#define S4 A3

int t1 = 0, t2 = 0, t3 = 0, t4 = 0, v1 = 0;
int mode = 1;   // 1 is for vacuume and 2 for temp
int base_vacuume_value = 0;



void setup() {

  Serial.begin(9600);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x32
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever
  }
  display.display();
  delay(200);
  pinMode(A0, INPUT);
  pinMode(A1, INPUT);
  pinMode(A2, INPUT);
  pinMode(A3, INPUT);
  pinMode(A10, INPUT);
  display.clearDisplay();
  if(mode == 1)
  {
    base_vacuume_value = analogRead(A10);
    delay(10);
  }
}

void loop() {

  if (mode == 1)
  {
    v1 = calc_vacuume(analogRead(A10));
    Serial.print(v1);
//    Serial.println(";");
    
    display.clearDisplay();
    display.setTextSize(2);
    display.setTextColor(WHITE);

    display.setCursor(0, 0);
    display.print(v1);
    display.print(" Kpa");
    display.display();
    delay(300);
  }

  else
  {
    t1 = calc_temp(calc_mean(1, 10));
    t2 = calc_temp(calc_mean(2, 10));
    t3 = calc_temp(calc_mean(3, 10));
    t4 = calc_temp(calc_mean(4, 10));

    display.clearDisplay();
    display.setTextSize(2);
    display.setTextColor(WHITE);

    display.setCursor(0, 0);
    display.print(t1);

    display.setCursor(64, 0);
    display.print(t2);

    display.setCursor(0, 16);
    display.print(t3);

    display.setCursor(64, 16);
    display.print(t4);

    display.display();
    
    Serial.print(t1);
    Serial.print(";");

    Serial.print(t2);
    Serial.print(";");

    Serial.print(t3);
    Serial.print(";");

    Serial.print(t4);

    Serial.println("");
    display.display();
    delay(1000);

  }

}

int calc_temp(int voltage)
{
  float temp, logR2, R2, T, R1 = 100000;
  float c1 = 0.001900543448634192, c2 = 0.00004522806498754414, c3 = 6.218570562845963e-7;
  R2 = R1 * (1023.0 / (float)voltage - 1.0);
  logR2 = log(R2);
  T = (1.0 / (c1 + c2 * logR2 + c3 * logR2 * logR2 * logR2));
  temp = T - 273.15;

  if(temp < 0 )
    temp = 0;
  
  return temp;

}

int calc_vacuume(int vacuume)
{
  return (vacuume  = -0.03052503*vacuume + 112.45) ;
}

int calc_mean(int sens_num, int num_of_samples)
{
  int sum = 0;
  
  for(int i = 0 ; i < num_of_samples ; i++)
  {
    
    delay(5);
    if(sens_num == 1)
    {
      sum += analogRead(A0);
    }

    else if(sens_num == 2)
    {
      sum += analogRead(A1);
    }

    else if(sens_num == 3)
    {
      sum += analogRead(A2);
    }

    else if(sens_num == 4)
    {
      sum += analogRead(A3);
    }
      
  }
  return (int)(sum/num_of_samples);
}