#include <TinyWireM.h>
#include <Tiny4kOLED.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <EEPROM.h>

// Pin definitions
#define ONE_WIRE_BUS PB1    // DS18B20 Data (pin 3)
#define SWITCH_UP PB3       // Increase setpoint (pin 2)
#define SWITCH_DOWN PB4     // Decrease setpoint (pin 6)
#define LED_PIN PB5         // LED output (pin 1)
#define EEPROM_ADDRESS 0

// Initialize OneWire and DallasTemperature
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// Global variable for setpoint
float setpoint = 25.0;

void prepareDisplay() {
  oled.clear();
  oled.setCursor(0, 0);
  oled.print(F("Temp:"));
  oled.setCursor(0, 1);
  oled.print(F("Set:"));
}

float getTemperature() {
  sensors.requestTemperatures();
  return sensors.getTempCByIndex(0);
}

void updateSetpoint() {
  static long lastDebounce = 0;
  long currentTime = millis();
  
  if ((currentTime - lastDebounce) > 50) {
    if (!digitalRead(SWITCH_UP)) {
      setpoint += 0.5;
      if (setpoint > 50.0) setpoint = 50.0;
      EEPROM.put(EEPROM_ADDRESS, setpoint);
      lastDebounce = currentTime;
      displaySetpoint();
    }
    if (!digitalRead(SWITCH_DOWN)) {
      setpoint -= 0.5;
      if (setpoint < 0.0) setpoint = 0.0;
      EEPROM.put(EEPROM_ADDRESS, setpoint);
      lastDebounce = currentTime;
      displaySetpoint();
    }
  }
}

void displaySetpoint() {
  oled.setCursor(36, 1);
  oled.print(setpoint, 1);
  oled.print(F("C "));
}

void controlLED(float temperature) {
  if (temperature == DEVICE_DISCONNECTED_C) {
    digitalWrite(LED_PIN, LOW); // LED off if sensor error
  } else {
    digitalWrite(LED_PIN, temperature < setpoint ? HIGH : LOW); // ON if below setpoint, OFF if above
  }
}

void setup() {
  pinMode(SWITCH_UP, INPUT_PULLUP);
  pinMode(SWITCH_DOWN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW); // Initial state off
  
  TinyWireM.begin();
  oled.begin(128, 64, sizeof(tiny4koled_init_128x64br), tiny4koled_init_128x64br);
  oled.setFont(FONT6X8);
  oled.clear();
  oled.on();

  sensors.begin();
  
  EEPROM.get(EEPROM_ADDRESS, setpoint);
  if (setpoint < 0 || setpoint > 50 || isnan(setpoint)) setpoint = 25.0;
  
  prepareDisplay();
  displaySetpoint();
}

void loop() {
  static long startTime = 0;
  long currentTime = millis();

  if ((currentTime - startTime) > 1000) {
    startTime = currentTime;

    float temperature = getTemperature();

    oled.setCursor(36, 0);
    if (temperature == DEVICE_DISCONNECTED_C) {
      oled.print(F("Err "));
    } else {
      oled.print(temperature, 1);
      oled.print(F("C "));
    }

    displaySetpoint();
    controlLED(temperature); // Update LED state
  }

  updateSetpoint();
}