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

// OLED config
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET    -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// DS18B20 config
#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// Constants
#define MAX_SENSORS 3

DeviceAddress sensorAddresses[MAX_SENSORS];
uint8_t foundSensors = 0;

void setup() {
  Serial.begin(9600);

  // OLED init
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED failed");
    for (;;);
  }

  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("Initializing...");
  display.display();

  // DS18B20 init
  sensors.begin();
  foundSensors = 0;

  // Scan for up to MAX_SENSORS
  DeviceAddress tempAddr;
  for (uint8_t i = 0; i < sensors.getDeviceCount() && foundSensors < MAX_SENSORS; i++) {
    if (sensors.getAddress(tempAddr, i)) {
      memcpy(sensorAddresses[foundSensors], tempAddr, sizeof(DeviceAddress));
      sensors.setResolution(sensorAddresses[foundSensors], 12);
      foundSensors++;
    }
  }

  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Found ");
  display.print(foundSensors);
  display.println(" sensor(s)");
  display.display();
  delay(1500);
}

void loop() {
  sensors.requestTemperatures();

  display.clearDisplay();
  if (foundSensors == 0) {
    display.setCursor(0, 0);
    display.setTextSize(1);
    display.println("No sensors found");
  } else {
    display.setTextSize(1);
    for (uint8_t i = 0; i < foundSensors && i < MAX_SENSORS; i++) {
      float tempC = sensors.getTempC(sensorAddresses[i]);

      display.setCursor(0, i * 20); // Space readings vertically
      display.print("Sensor ");
      display.print(i + 1);
      display.print(": ");

      if (tempC != DEVICE_DISCONNECTED_C) {
        display.print(tempC, 1);
        display.print(" C");
      } else {
        display.print("Error");
      }
    }
  }

  display.display();
  delay(2000);
}