#define BLYNK_TEMPLATE_ID "TMPL5jE9tzQIO"
#define BLYNK_TEMPLATE_NAME "traindistanceIOT"
#define BLYNK_AUTH_TOKEN "ctoi6u_sXsBQxV1_GYMVkH4dMft1edGz"

#include <Wire.h>
#include <WiFi.h>
#include <WiFiClient.h>
#include <BlynkSimpleEsp32.h>
#include <LiquidCrystal_I2C.h>

// Define the Wi-Fi credentials
char auth[] = BLYNK_AUTH_TOKEN;
char ssid[] = "wokwi-GUEST";
char pass[] = "";

// Define the pins for the ultrasonic sensor, LED, relay module, and push button 
#define TRIG_PIN 26
#define ECHO_PIN 25
#define LED_PIN 27
#define RELAY_PIN 27
#define BUTTON_PIN 32

// Define the I2C address of the LCD display
#define LCD_ADDR 0x27

// Initialize the LCD display
LiquidCrystal_I2C lcd(LCD_ADDR, 16, 2);

int pinValue = 0;
bool blink_mode = false;
bool motor_work = false;
bool enter_state = false;
float current_distance = 0.0;

void setup() {
  Serial.begin(115200);

  // Initialize Blynk
  Blynk.begin(auth, ssid, pass);
  if (Blynk.connected()) {
    Serial.println("Connected to Blynk server");
  } else {
    Serial.println("Failed to connect to Blynk server");
  }

  // Initialize pins
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(RELAY_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT_PULLUP);

  // Initialize the LCD
  Serial.println("Initializing LCD...");
  lcd.init();
  lcd.backlight();
  lcd.print("Train Distance");
  lcd.setCursor(0, 1);
  lcd.print("Management");
  delay(2000);
  lcd.clear();
}

BLYNK_WRITE(V2) {
  pinValue = param.asInt();
  Serial.print("Received value: ");
  Serial.println(pinValue);
}

void loop() {
  Blynk.run();

  // Read the push button state with debounce
  bool reading = digitalRead(BUTTON_PIN);

  // Send a trigger pulse to the ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Measure the time it takes for the echo pulse to return
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance to the water surface
  float distance = duration * 0.034 / 2;

  // Push the water level % to Blynk
  float dist_percent = ((400 - distance) / 400) * 100;
  Blynk.virtualWrite(V0, dist_percent);

  // Update the LCD with the current distance
  lcd.clear();
  lcd.print("Dist: ");
  lcd.print(distance, 1);
  lcd.print(" cm");

  // Auto mode conditions check
  if (abs(current_distance - distance) >= 5 && !blink_mode) {
    if (distance > 100) {
      motor_work = true;
      digitalWrite(RELAY_PIN, LOW);
      lcd.setCursor(0, 1);
      lcd.print("Motor ON");
    } else {
      motor_work = false;
      digitalWrite(RELAY_PIN, HIGH);
      lcd.setCursor(0, 1);
      lcd.print("Motor OFF");
    }
  }
}