#include <OneWire.h>
#include <DallasTemperature.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// Pin Definitions
#define ONE_WIRE_BUS 12      // DS18B20 data wire connected to pin 2
#define BUZZER_PIN 11        // Buzzer pin
#define SCREEN_WIDTH 128    // OLED display width
#define SCREEN_HEIGHT 32    // OLED display height
#define OLED_RESET -1       // Reset pin (or -1 if sharing Arduino reset pin)
#define TEMP_THRESHOLD 30   // Temperature threshold in Celsius

// Calibration offset (adjustable)
float calibrationOffset = 0.0;

// Create OneWire and DallasTemperature objects
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// Create Adafruit SSD1306 OLED display object
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

void setup() {
  Serial.begin(9600);
  
  // Initialize DS18B20 temperature sensor
  sensors.begin();

  // Initialize OLED display
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3C for 128x32
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  
  // Perform calibration if necessary
  calibrationRoutine();
  
  // Clear the display buffer
  display.clearDisplay();
  display.display();
}

void loop() {
  // Read temperature from DS18B20 sensor
  sensors.requestTemperatures();
  float tempC = sensors.getTempCByIndex(0) + calibrationOffset;
  
  // Display temperature on OLED display
  display.clearDisplay();
  display.setTextSize(1);      
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0,0);
  display.print(F("Temp: "));
  display.print(tempC);
  display.print(F("C"));
  display.display();
  
  // Check if temperature exceeds threshold
  if (tempC > TEMP_THRESHOLD) {
    highTone();
  } else {
    lowTone();
  }
  
  delay(1000); // Update temperature every second
}

void highTone() {
    tone(11, 500, 25);
    delay(25);
    noTone(11);
}

void lowTone() {
    noTone(11);
}

void calibrationRoutine() {
  Serial.println("Starting calibration routine...");
  Serial.println("Current calibration offset: " + String(calibrationOffset, 2));
  Serial.println("Enter the calibration offset (e.g., -0.1 for -0.1°C or 1.0 for +1.0°C):");
  while (!Serial.available()) {} // Wait for user input
  float offset = Serial.parseFloat();
  calibrationOffset = offset;
  Serial.println("Calibration successful. New offset: " + String(calibrationOffset, 2) + "°C");
  }