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

// Define the digital pins for sensors and LEDs
#define BUTTON1 18   // Vehicle detection sensor (Road 1)
#define BUTTON2 19   // Vehicle detection sensor (Road 2)

#define RED1 4
#define YELLOW1 5
#define GREEN1 16

#define RED2 17
#define YELLOW2 21
#define GREEN2 22

#define BUZZER 23

// Initialize the LCD with the I2C address and dimensions (16x2)
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
    // Initialize serial communication for debugging
    Serial.begin(115200);

    // Initialize the LCD
    lcd.init();
    // Turn on the backlight of the LCD
    lcd.backlight();
    // Set the cursor to the top-left corner (column 0, row 0)
    lcd.setCursor(0, 0);
    // Print a startup message on the LCD
    lcd.print("Smart Traffic");

    // Configure the button pins as inputs with internal pull-up resistors
    pinMode(BUTTON1, INPUT_PULLUP);
    pinMode(BUTTON2, INPUT_PULLUP);

    // Configure the LED pins as outputs
    pinMode(RED1, OUTPUT);
    pinMode(YELLOW1, OUTPUT);
    pinMode(GREEN1, OUTPUT);

    pinMode(RED2, OUTPUT);
    pinMode(YELLOW2, OUTPUT);
    pinMode(GREEN2, OUTPUT);

    // Configure the buzzer pin as output
    pinMode(BUZZER, OUTPUT);

    // Initialize traffic lights to a safe starting state (Road 1 Red, Road 2 Green)
    digitalWrite(RED1, HIGH);
    digitalWrite(YELLOW1, LOW);
    digitalWrite(GREEN1, LOW);

    digitalWrite(RED2, LOW);
    digitalWrite(YELLOW2, LOW);
    digitalWrite(GREEN2, HIGH);
}

void loop() {
    // Read the state of the vehicle detection sensors
    bool road1_traffic = digitalRead(BUTTON1) == LOW; // LOW indicates vehicle detected (due to pull-up)
    bool road2_traffic = digitalRead(BUTTON2) == LOW;

    // Print the sensor readings to the serial monitor for debugging
    Serial.print("Road 1: ");
    Serial.println(road1_traffic ? "Vehicle Detected" : "Clear");

    Serial.print("Road 2: ");
    Serial.println(road2_traffic ? "Vehicle Detected" : "Clear");

    // Implement a simple priority-based traffic control logic
    if (road1_traffic && !road2_traffic) {
        controlTraffic(1); // Give priority to Road 1 if traffic is detected and Road 2 is clear
    } else if (road2_traffic && !road1_traffic) {
        controlTraffic(2); // Give priority to Road 2 if traffic is detected and Road 1 is clear
    } else {
        controlTraffic(0); // Enter a normal alternating mode if both or neither roads have traffic
    }

    // Introduce a delay for the main loop to avoid excessive readings
    delay(300);
}

// Function to control the traffic lights based on priority
void controlTraffic(int priority) {
    if (priority == 1) {
        // Road 1 has priority
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Road 1 Open");
        lcd.setCursor(0, 1);
        lcd.print("Road 2 Wait");

        // Set Road 1 to Green, Road 2 to Red
        digitalWrite(RED1, LOW);
        digitalWrite(YELLOW1, LOW);
        digitalWrite(GREEN1, HIGH);

        digitalWrite(RED2, HIGH);
        digitalWrite(YELLOW2, LOW);
        digitalWrite(GREEN2, LOW);

        // Keep Road 1 open for a certain duration
        delay(5000);

        // Transition Road 1 to Red through Yellow
        digitalWrite(GREEN1, LOW);
        digitalWrite(YELLOW1, HIGH);
        delay(2000);
        digitalWrite(YELLOW1, LOW);
        digitalWrite(RED1, HIGH);
    }
    else if (priority == 2) {
        // Road 2 has priority
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Road 2 Open");
        lcd.setCursor(0, 1);
        lcd.print("Road 1 Wait");

        // Set Road 2 to Green, Road 1 to Red
        digitalWrite(RED1, HIGH);
        digitalWrite(YELLOW1, LOW);
        digitalWrite(GREEN1, LOW);

        digitalWrite(RED2, LOW);
        digitalWrite(YELLOW2, LOW);
        digitalWrite(GREEN2, HIGH);

        // Keep Road 2 open for a certain duration
        delay(5000);

        // Transition Road 2 to Red through Yellow
        digitalWrite(GREEN2, LOW);
        digitalWrite(YELLOW2, HIGH);
        delay(2000);
        digitalWrite(YELLOW2, LOW);
        digitalWrite(RED2, HIGH);
    }
    else {
        // Normal alternating mode (simplified) - give a short green to Road 2 by default if no clear priority
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Normal Mode");

        // Road 1 Red, Road 2 Green
        digitalWrite(RED1, HIGH);
        digitalWrite(YELLOW1, LOW);
        digitalWrite(GREEN1, LOW);

        digitalWrite(RED2, LOW);
        digitalWrite(YELLOW2, LOW);
        digitalWrite(GREEN2, HIGH);
        delay(3000);

        // Transition Road 2 to Red through Yellow
        digitalWrite(GREEN2, LOW);
        digitalWrite(YELLOW2, HIGH);
        delay(2000);
        digitalWrite(YELLOW2, LOW);
        digitalWrite(RED2, HIGH);

        // Road 2 Red, Road 1 Green
        digitalWrite(RED1, LOW);
        digitalWrite(YELLOW1, LOW);
        digitalWrite(GREEN1, HIGH);

        digitalWrite(RED2, HIGH);
        digitalWrite(YELLOW2, LOW);
        digitalWrite(GREEN2, LOW);
        delay(3000);

        // Transition Road 1 to Red through Yellow
        digitalWrite(GREEN1, LOW);
        digitalWrite(YELLOW1, HIGH);
        delay(2000);
        digitalWrite(YELLOW1, LOW);
        digitalWrite(RED1, HIGH);
    }
}