#include <LiquidCrystal.h>

// Pin definitions (match JSON connections)
const int trigPin = PA0;
const int echoPin = PA1;
const int ledPin = PA2;
const int buzzerPin = PA3;
const int relayPin = PA4;

// LCD pins (RS, E, D4, D5, D6, D7)
LiquidCrystal lcd(PB0, PB1, PB9, PB3, PB4, PB5);

// Detection threshold in cm
const int detectionDistance = 15;

void setup() {
  // Initialize serial for debugging (optional)
  Serial.begin(9600);

  // Set pins mode
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(relayPin, OUTPUT);

  // Initialize LCD
  lcd.begin(16, 2);
  lcd.print("Smart Appliance");
  lcd.setCursor(0, 1);
  lcd.print("Panel Starting");
  delay(2000);
  lcd.clear();
}

long readDistanceCM() {
  // Clear trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Send 10us pulse to trigPin
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echoPin pulse duration
  long duration = pulseIn(echoPin, HIGH, 30000); // timeout 30ms

  // Calculate distance in cm
  long distance = duration * 0.034 / 2;

  return distance;
}

void loop() {
  long distance = readDistanceCM();

  // Debug serial print
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  lcd.setCursor(0, 0);
  lcd.print("Distance:       "); // clear old data
  lcd.setCursor(10, 0);
  if (distance == 0 || distance > 400) {
    lcd.print("Out of range");
  } else {
    lcd.print(distance);
    lcd.print(" cm");
  }

  if (distance > 0 && distance <= detectionDistance) {
    // Object detected within threshold
    digitalWrite(ledPin, HIGH);     // Turn on LED
    digitalWrite(buzzerPin, HIGH);  // Sound buzzer
    digitalWrite(relayPin, HIGH);   // Activate relay

    lcd.setCursor(0, 1);
    lcd.print("Status: Detected ");
  } else {
    // No object detected
    digitalWrite(ledPin, LOW);
    digitalWrite(buzzerPin, LOW);
    digitalWrite(relayPin, LOW);

    lcd.setCursor(0, 1);
    lcd.print("Status: No Detect");
  }

  delay(500);
}