#include <SoftwareSerial.h>
#include <LiquidCrystal_I2C.h>

#define status_led 3
const byte bt_rx = 2, bt_tx = 3, bt_en = 4;
const byte btn_output = 9, btn_input = 10;

LiquidCrystal_I2C lcd_display(0x27, 16, 2);

SoftwareSerial bt_serial(bt_rx, bt_tx);

bool is_led_active = false;  
unsigned long last_btn_press_time = 0; 
const unsigned long debounce_delay = 200; 

void setup() {
  Serial.begin(9600);  
  bt_serial.begin(9600);  
  delay(1000); 

  pinMode(bt_rx, INPUT); 
  pinMode(bt_tx, OUTPUT);  
  pinMode(bt_en, OUTPUT);  
  pinMode(btn_output, OUTPUT); 
  pinMode(btn_input, INPUT_PULLUP);  

  digitalWrite(bt_en, HIGH); 
  delay(500);  

  while (bt_serial.available()) 
    bt_serial.read(); 

  lcd_display.begin(16, 2);  
  lcd_display.print("Initializing...");  
  delay(2000);  
  lcd_display.clear();
}

void loop() {
  if (digitalRead(btn_input) == LOW && (millis() - last_btn_press_time > debounce_delay)) {
    last_btn_press_time = millis();  
    is_led_active = !is_led_active;  
    digitalWrite(status_led, is_led_active ? HIGH : LOW);  

    lcd_display.clear();
    if (is_led_active) {
      lcd_display.print("BT Connected");
      Serial.println("BT Connected");
    } else {
      lcd_display.print("BT Disconnected");
      Serial.println("BT Disconnected");
    }
  }

  if (Serial.available()) {
    char serial_input = Serial.read();
    bt_serial.write(serial_input);  
  }

  if (bt_serial.available()) {
    char bt_data = bt_serial.read();
    lcd_display.setCursor(0, 1);  
    lcd_display.print("Received: ");
    lcd_display.print(bt_data);  
    Serial.print(bt_data);  
  }

  if (Serial.available()) {
    String command_to_bt = "";
    while (Serial.available()) {
      command_to_bt += (char)Serial.read();
    }
    
    if (command_to_bt == "AT") {
      bt_serial.write("OK\n");  
    } else if (command_to_bt == "AT+NAME") {
      bt_serial.write("GuardianNode\n");  
    } else if (command_to_bt == "AT+VERSION") {
      bt_serial.write("V1.9.1\n");  
    } else if (command_to_bt == "AT+BAUD") {
      bt_serial.write("9600\n");  
    }
  }
  delay(1000);
}