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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SSD1306_I2C_ADDRESS 0x3C  // Replace with your SSD1306 display I2C address
#define DHTTYPE DHT22
#define DHTPIN 12 

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
DHT dht(DHTPIN, DHTTYPE);

// classic leds
int redPin = 9,bluePin = 8, greenPin = 7;
// pins for the rgb LED
int rPin = 4, bPin = 3, gPin = 2;
int ButtonUp = 3;
enum ledState {
  goodTemperature,
  hotTemperature,
  coldTemperature
};
ledState state;
int pins[] = {redPin, bluePin, greenPin};
size_t pins_size = sizeof(pins) / sizeof(pins[0]);

void selectLed(int first){
  // there will usually be only 1 pin on at a time, the rest will
  // be off
  for(int i=0; i < pins_size; i++){
    if(pins[i] == first)
      digitalWrite(pins[i], HIGH);
    else
      digitalWrite(pins[i], LOW);
  }
}

void setup() {
  for(int i =0; i < pins_size ; i++){
    pinMode(pins[i], OUTPUT);
  }
  Serial.begin(9600);
  Wire.begin(); // Initialize the Wire library
  if (!display.begin(SSD1306_SWITCHCAPVCC, SSD1306_I2C_ADDRESS)) {  // Initialize the OLED display
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // if the display initialization failed, don't proceed
  }
  display.display();
  dht.begin();
}

void loop() {
  // Wait a few seconds between measurements.
  delay(1000);
  float temp = dht.readTemperature();
  Serial.print("Temp is : ");
  Serial.print(temp);
  Serial.println();
  // Check if any reads failed and exit early (to try again).
  if (isnan(temp) ) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }
  if(temp >= 15 && temp <= 27 )
    state = goodTemperature;
  else if (temp > 27)
    state = hotTemperature;
  else
    state = coldTemperature;

  switch(state){

    case goodTemperature:
      selectLed(greenPin);
      break;

    case hotTemperature:
      selectLed(redPin);
      break;

    case coldTemperature:
      selectLed(bluePin);
      break;

    default:
      break;     
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print(F("Temp is : "));
  display.print(temp);
  display.print(" ");
  display.print(state == goodTemperature? "GOOD" : state == hotTemperature? "HOT" : "COLD");
  display.println();
  display.display();
  
  delay(1000);
}