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

// Define pins for components
const int redLedPin = 2;     // Pin for the red LED
const int yellowLedPin = 3;  // Pin for the yellow LED
const int buzzerPin = 5;     // Pin for the buzzer
const int trigPin = 6;       // Pin for ultrasonic trigger
const int echoPin = 7;       // Pin for ultrasonic echo
const int pirPin = 8;        // Pin for the PIR sensor
const int buttonPin = 9;     // Pin for the push button

// Initialize the LCD object using the LiquidCrystal_I2C library
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Variable to store the push button state
bool buttonState = false;

void setup() {
  // Configure pin modes
  pinMode(redLedPin, OUTPUT);
  pinMode(yellowLedPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(pirPin, INPUT);
  pinMode(buttonPin, INPUT_PULLUP); // Configure push button with internal pull-up

  // Initialize the LCD
  lcd.begin(16, 2);
  lcd.print("Detection System");
  lcd.setCursor(0, 1);
  lcd.print("Earthquake & Tsunami");
  delay(1000);
  lcd.clear();
}

void loop() {
  // Variables to store time and distance
  long duration, distance;

  // Read the button state
  if (digitalRead(buttonPin) == LOW) { // Button is pressed
    buttonState = !buttonState;       // Toggle the system state
    delay(200);                       // Button debounce
  }

  // If the system is off, turn off all components
  if (!buttonState) {
    lcd.clear();
    lcd.print("System: Inactive");
    digitalWrite(redLedPin, LOW);
    digitalWrite(yellowLedPin, LOW);
    noTone(buzzerPin);
    delay(1000);
    return; // Exit the loop to keep the system off
  }

  // Start measuring distance using the ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  // Read the value from the PIR sensor
  int pirValue = digitalRead(pirPin);

  // Logic to determine the status and actions based on the sensors
  if (pirValue == HIGH) {
    lcd.setCursor(0, 0);
    lcd.print("Status: Earthquake!");
    digitalWrite(redLedPin, HIGH);
    digitalWrite(yellowLedPin, LOW);
    tone(buzzerPin, 1000);
  } else {
    noTone(buzzerPin);

    if (distance > 300) {
      lcd.setCursor(0, 0);
      lcd.print("Status: Danger");
      digitalWrite(redLedPin, HIGH);
      digitalWrite(yellowLedPin, LOW);
      tone(buzzerPin, 1000);
    } else if (distance >= 50 && distance <= 300) {
      lcd.setCursor(0, 0);
      lcd.print("Status: Warning");
      digitalWrite(redLedPin, LOW);
      digitalWrite(yellowLedPin, HIGH);
      noTone(buzzerPin);
    } else {
      lcd.setCursor(0, 0);
      lcd.print("Status: Safe   ");
      digitalWrite(redLedPin, LOW);
      digitalWrite(yellowLedPin, LOW);
      noTone(buzzerPin);
    }
  }

  // Display distance information on the LCD
  lcd.setCursor(0, 1);
  lcd.print("Height: ");
  lcd.print(distance);
  lcd.print(" cm");
  delay(1000);
  lcd.clear();
}

// Function to produce buzzer sound with intervals
void slowBuzzer() {
  for (int i = 0; i < 3; i++) {
    tone(buzzerPin, 500);
    delay(500);
    noTone(buzzerPin);
    delay(1000);
  }
}