#include <LiquidCrystal.h> // Library for LCD
#include <SevSeg.h> // Library for 7-segment display

// Pin definitions
const int temperaturePin = A0; // Analog pin for temperature sensor
const int buttonPin = 2; // Digital pin for push button
const int ledPin = 13; // Digital pin for LED
const int shiftDataPin = 3; // Digital pin for shift register data
const int shiftClockPin = 4; // Digital pin for shift register clock
const int shiftLatchPin = 5; // Digital pin for shift register latch

// Variables
float temperature = 0.0; // Variable to store temperature
int mode = 0; // Variable to store current mode
unsigned long previousMillis = 0; // Variable to store previous millis for timing
const long interval = 1000; // Interval for temperature reading

// Initialize LCD and 7-segment display
LiquidCrystal lcd(8, 9, 10, 11, 12, 6, 7); // LCD pins
SevSeg sevSeg; // 7-segment display

void setup() {
  pinMode(buttonPin, INPUT_PULLUP); // Set button pin as input with internal pull-up resistor
  pinMode(ledPin, OUTPUT); // Set LED pin as output
  pinMode(shiftDataPin, OUTPUT); // Set shift register data pin as output
  pinMode(shiftClockPin, OUTPUT); // Set shift register clock pin as output
  pinMode(shiftLatchPin, OUTPUT); // Set shift register latch pin as output

  lcd.begin(16, 2); // Initialize LCD: 16 columns, 2 rows
  sevSeg.begin(HARDWARE, 1, 2, 3, 4, 5, 6, 7, 8); // Initialize 7-segment display
}

void loop() {
  unsigned long currentMillis = millis(); // Get current time

  // Read temperature every interval
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis; // Update previous time
    temperature = readTemperature(); // Read temperature
    updateDisplay(); // Update display with temperature
  }

  // Check for button press
  if (digitalRead(buttonPin) == LOW) {
    mode = (mode + 1) % 3; // Cycle through modes
    updateMode(); // Update mode
  }
}

// Function to read temperature
float readTemperature() {
  int rawValue = analogRead(temperaturePin); // Read analog value
  float voltage = rawValue * (5.0 / 1023.0); // Convert to voltage
  float tempC = (voltage - 0.5) * 100.0; // Convert to temperature in Celsius
  return tempC;
}

// Function to update display
void updateDisplay() {
  lcd.clear(); // Clear LCD
  lcd.setCursor(0, 0); // Set cursor to first row
  lcd.print("Temp: "); // Print temperature label
  lcd.print(temperature); // Print temperature value
  lcd.print(" C"); // Print units
  
  sevSeg.setNumber((int)temperature); // Set 7-segment display value to integer part of temperature
  sevSeg.refreshDisplay(); // Refresh 7-segment display
}

// Function to update mode
void updateMode() {
  switch (mode) {
    case 0:
      digitalWrite(ledPin, LOW); // Turn off LED
      break;
    case 1:
      digitalWrite(ledPin, HIGH); // Turn on LED
      break;
    case 2:
      // Additional mode functionality
      break;
  }
}