#include <TM1637Display.h>
#include <EEPROM.h>
#include <OneWire.h>
#include <DallasTemperature.h>

// Pin definitions for TM1637
#define CLK 2
#define DIO 3

// Pin definitions for DS18B20
#define ONE_WIRE_BUS 4    // DS18B20 data pin

// Pin definitions for buttons and LED
#define BUTTON_UP 5       // Increase setpoint
#define BUTTON_DOWN 6     // Decrease setpoint and toggle mode
#define LED_PIN 7

// EEPROM address for setpoint
#define EEPROM_ADDRESS 0

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

// Variables
TM1637Display display(CLK, DIO);

const uint8_t C[] = {
  SEG_B | SEG_A | SEG_F | SEG_G,
  SEG_A | SEG_D | SEG_E | SEG_F
};

float temperature;
int setPoint = 25;  // Default setpoint in Celsius
bool inSetPointMode = false;  // Set to true when setpoint mode is active

// Button state and debouncing
bool upButtonState = false;
bool downButtonState = false;
unsigned long lastDebounceTime = 0;
const long debounceDelay = 50;

void setup() {
  // Initialize serial
  Serial.begin(9600);
  
  // Initialize DS18B20 sensor
  sensors.begin();
  
  // Initialize display
  display.setBrightness(0x0f);
  
  // Button inputs with internal pull-ups
  pinMode(BUTTON_UP, INPUT_PULLUP);
  pinMode(BUTTON_DOWN, INPUT_PULLUP);
  
  // LED pin
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);  // Ensure LED is off initially
  
  // Load setpoint from EEPROM
  int storedSetPoint;
  EEPROM.get(EEPROM_ADDRESS, storedSetPoint);
  if (storedSetPoint >= -9 && storedSetPoint <= 99) {
    setPoint = storedSetPoint;
  } else {
    setPoint = 25;  // Default if EEPROM value is invalid
    EEPROM.put(EEPROM_ADDRESS, setPoint);
  }
}

void loop() {
  // Check for button presses
  checkButtons();

  // Read temperature from DS18B20
  temperature = readTemperature();

  // Display either setpoint or temperature
  if (inSetPointMode) {
    displaySetPoint();
  } else {
    displayTemperature();
  }

  // Control LED based on temperature vs setpoint
  if (temperature > setPoint) {
    digitalWrite(LED_PIN, HIGH);  // Turn LED on if temp > setpoint
  } else {
    digitalWrite(LED_PIN, LOW);   // Turn LED off if temp <= setpoint
  }
}

// Function to read temperature from DS18B20
float readTemperature() {
  sensors.requestTemperatures();
  float tempCelsius = sensors.getTempCByIndex(0);
  if (tempCelsius == DEVICE_DISCONNECTED_C) {
    return -127.0;  // Error value if sensor is disconnected
  }
  return tempCelsius;
}

// Function to display the temperature on the TM1637 display
void displayTemperature() {
  int displayTemp = (int)(temperature * 1);  // Convert to 1 decimal place
 // display.showNumberDecEx(displayTemp, false, 2, 0);  // Display with decimal point
 display.showNumberDecEx(displayTemp, 0b0100, false, 2, 0);
 
  display.setSegments(C, 2, 2);  // Show "C" symbol
}

// Function to display the setpoint
void displaySetPoint() {
  display.showNumberDec(setPoint, false, 2, 0);
  // Flash to indicate setpoint mode
  if (millis() % 1000 < 500) {
    display.clear();
  }
}

// Function to check button presses and adjust setpoint
void checkButtons() {
  unsigned long currentMillis = millis();
  
  // Read button states
  int upReading = digitalRead(BUTTON_UP);
  int downReading = digitalRead(BUTTON_DOWN);
  
  // Debounce UP button (increase setpoint)
  if (upReading != upButtonState) {
    lastDebounceTime = currentMillis;
  }
  if ((currentMillis - lastDebounceTime) > debounceDelay && upReading == LOW) {
    if (!inSetPointMode) {
      inSetPointMode = true;  // Enter setpoint mode
    } else {
      setPoint++;
      if (setPoint > 99) setPoint = 99;  // Max limit
      EEPROM.put(EEPROM_ADDRESS, setPoint);  // Save to EEPROM
    }
  }
  upButtonState = upReading;
  
  // Debounce DOWN button (decrease setpoint or exit mode)
  if (downReading != downButtonState) {
    lastDebounceTime = currentMillis;
  }
  if ((currentMillis - lastDebounceTime) > debounceDelay && downReading == LOW) {
    if (!inSetPointMode) {
      inSetPointMode = true;  // Enter setpoint mode
    } else {
      setPoint--;
      if (setPoint <-9 ) 
      {
        setPoint = 0;  // Min limit
        inSetPointMode = false;  // Exit setpoint mode when reaching 0
      }
      EEPROM.put(EEPROM_ADDRESS, setPoint);  // Save to EEPROM
    }
  }
  downButtonState = downReading;
  
  // Auto-exit setpoint mode after 5 seconds of inactivity
  if (inSetPointMode && (currentMillis - lastDebounceTime) > 2000) {
    inSetPointMode = false;
  }
}