#include <Adafruit_SSD1306.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
#include "Wire.h"



#define LED1 11                     // LED when humidity drops
#define LED2 9                     // LED when temperature drops
#define LED3 10                    // LED when pressure drops   
Adafruit_BME280 Sensor;

float temp;                         // Sensor temperature value
float tempold;

float pressure;                     // Sensor pressure value
float pressureold;

float hum;                          //Sensor humidity value
float humold;

float DisplayTemp;                         // Sensor temperature value
float DisplayHum;
float DisplayPress;

unsigned long previousMillis = 0;
const int interval = 2000;   // interval for time between readings

Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &Wire);



void setup() {
  Serial.begin(115200);

  Sensor.begin(0x76);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.display();
  display.clearDisplay();
  display.setTextSize(3);
  display.setTextColor(WHITE);
  pinMode(11, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
  delay (2000);


  digitalWrite(LED1, LOW);   // turns LED1 off
  digitalWrite(LED2, LOW);   // turns LED2 off
  digitalWrite(LED3, LOW);   // turns LED3 off
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print(1.8 * Sensor.readTemperature() + 32, 0); display.println("F");

  display.setCursor(70, 0);
  display.print(Sensor.readHumidity(), 0); display.println("%");

  display.setCursor(0, 40);
  display.print(Sensor.readPressure() / 100.0F, 0); display.println("hPa");

  display.display();
  Serial.println("Ready..");


}

void loop() {

  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    //read sensors
    temp = Sensor.readTemperature();
    pressure = Sensor.readPressure();
    hum = Sensor.readHumidity();
    //save raw reading for display later..
    DisplayTemp = temp;
    DisplayPress = pressure;
    DisplayHum = hum;
    //check for bad read..
    if (isnan(temp) || isnan(pressure) || isnan(hum)) return;

    pressure = (pressure * 0.0100);
    hum = (hum * 0.1000);

/*
   // ADDED FOR DEBUG
    hum = random (50, 70);
    pressure = random (100, 150);
    temp = random (30, 40);
*/


    //do we need to update display..
    bool UpdateDisplay = false;


    //tempold = tempnow;                        // compares last temperature measurement with the new one
   // tempnow = temp;                           // this maps tempnow to the values of the temperature sensor

//    if (tempold > temp) {             //if temperature drops, turn on LED2
    if (Deviation(tempold, temp) > 1) {             //if temperature drops, turn on LED2
      digitalWrite(LED2, HIGH);
    }
    else {                                  //if temperature is unchanged turn off LED2
      digitalWrite(LED2, LOW);
    }

    if (tempold != temp){
       UpdateDisplay = true;
       tempold = temp;
    }


    //pressureold = pressurenow;                // compares last pressure measurement with the new one
    //pressurenow = pressure;                   // this maps pressurenow to the values of the pressure sensor
//    if (pressureold > pressure) {       // if pressure changes turn on LED3
    if (Deviation(pressureold, pressure) >1) {       // if pressure changes turn on LED3
      digitalWrite(LED3, HIGH);
      Serial.print(pressureold);Serial.print(">");
      Serial.println(pressure);
    }
    else {                                  // if pressure unchanged, keep LED3 off
      digitalWrite(LED3, LOW);
    }

    if (pressureold != pressure){
       UpdateDisplay = true;
       pressureold = pressure;
    }

 //   humdown = humnow;                        // compares last humidity measurement with the new one
  //  humnow = hum;                           // this maps humnow to the values of the humidity sensor
//    if (humold < hum) {                 //if humidity changes turn on LED1
    if (Deviation(humold , hum) < 0) {                 //if humidity changes turn on LED1
      digitalWrite(LED1, HIGH);
    }
    else {                                    //if humidity is unchanged, keep LED1 off
      digitalWrite(LED1, LOW);
    }

    if (humold != hum){
       UpdateDisplay = true;
       humold = hum;
    }

    if (UpdateDisplay)
    {
      display.clearDisplay();
      display.setCursor(0, 0);
      display.print(1.8 * DisplayTemp + 32, 0); display.println("F");
      display.setCursor(70, 0);
      display.print(DisplayHum, 0); display.println("%");
      display.setCursor(0, 40);
      display.print(DisplayPress / 100.0F, 0); display.println("hPa");
      display.display();

    }

  }

}

int Deviation(float a, float b){
  int result = a - b;
   return result;
}