#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Define LED pins for traffic lights (Arduino)
#define RED_LED 2
#define YELLOW_LED 3
#define GREEN_LED 4

// IR sensor for vehicle detection
#define IR_SENSOR 7

// Seven-segment display pins (common cathode type)
const int segmentPins[] = {8, 9, 10, 11, 12, 13, A0};  // Seven-segment pins

// Traffic light timings in milliseconds
const long greenLightDuration = 9000;  // 9 seconds for green light
const long yellowLightDuration = 3000;  // 3 seconds for yellow light
const long redLightDuration = 9000;    // 9 seconds for red light

// Initialize the LCD display with I2C address 0x27, 16 columns and 2 rows
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Initialize the LCD
  lcd.init();
  lcd.backlight();
  
  // Setup the traffic light LEDs as output
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);

  // Setup the IR sensor as input
  pinMode(IR_SENSOR, INPUT);

  // Setup seven-segment display pins as output
  for (int i = 0; i < 7; i++) {
    pinMode(segmentPins[i], OUTPUT);
  }

  // Initialize all LEDs and seven-segment display off
  digitalWrite(RED_LED, LOW);
  digitalWrite(YELLOW_LED, LOW);
  digitalWrite(GREEN_LED, LOW);
  clearSevenSegment();
}

void loop() {
  // Green Light - GO
  digitalWrite(GREEN_LED, HIGH);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("GO"); // Display GO message
  displayCountdown(greenLightDuration / 1000);  // Display countdown
  digitalWrite(GREEN_LED, LOW);

  // Yellow Light - GET READY
  digitalWrite(YELLOW_LED, HIGH);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("GET READY"); // Display GET READY message
  displayCountdown(yellowLightDuration / 1000);  // Display countdown
  digitalWrite(YELLOW_LED, LOW);

  // Red Light - STOP
  digitalWrite(RED_LED, HIGH);
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("STOP"); // Display STOP message
  displayCountdown(redLightDuration / 1000);  // Display countdown
  digitalWrite(RED_LED, LOW);
}

// Function to clear the seven-segment display
void clearSevenSegment() {
  for (int i = 0; i < 7; i++) {
    digitalWrite(segmentPins[i], LOW);
  }
}

// Function to display the countdown on seven-segment display
void displayCountdown(int seconds) {
  for (int i = seconds; i >= 0; i--) {  // Display 0 at the end
    showNumberOnSevenSegment(i);
    delay(1000);  // 1-second delay for countdown
  }
  clearSevenSegment();
}

// Function to show a number on the seven-segment display
void showNumberOnSevenSegment(int num) {
  static const byte digits[10][7] = {
    {HIGH, HIGH, HIGH, HIGH, HIGH, HIGH, LOW},   // 0
    {LOW, HIGH, HIGH, LOW, LOW, LOW, LOW},       // 1
    {HIGH, HIGH, LOW, HIGH, HIGH, LOW, HIGH},    // 2
    {HIGH, HIGH, HIGH, HIGH, LOW, LOW, HIGH},    // 3
    {LOW, HIGH, HIGH, LOW, LOW, HIGH, HIGH},     // 4
    {HIGH, LOW, HIGH, HIGH, LOW, HIGH, HIGH},    // 5
    {HIGH, LOW, HIGH, HIGH, HIGH, HIGH, HIGH},   // 6
    {HIGH, HIGH, HIGH, LOW, LOW, LOW, LOW},      // 7
    {HIGH, HIGH, HIGH, HIGH, HIGH, HIGH, HIGH},  // 8
    {HIGH, HIGH, HIGH, HIGH, LOW, HIGH, HIGH}    // 9
  };

  // Show the digit on the seven-segment display
  for (int i = 0; i < 7; i++) {
    digitalWrite(segmentPins[i], digits[num][i]);
  }
}