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

const byte LED_PIN = 13;
const byte LED_PIN2 = 12;
const byte INTERRUPT_PIN = 2;
const byte SERVO_PIN = 9;

const int SERVO_INTERVAL = 15; // 15 milliseconds interval for servo
const int SERVO_MIN_ANGLE = 0;
const int SERVO_MAX_ANGLE = 180;
const int SERVO_STEP = 5;

const int LCD_INTERVAL = 1000; // 1000 milliseconds interval for LCD
const int MAX_LCD_INDEX = 3;

volatile byte state = LOW;
int angle = 0;
bool isIncreasing = true;

Servo myservo;
LiquidCrystal_I2C lcd(0x27, 16, 2);

unsigned long previousMillisServo = 0;
unsigned long previousMillisLCD = 0;
int lcdIndex = 1;

void setup() {
  pinMode(LED_PIN, OUTPUT);
  pinMode(LED_PIN2, OUTPUT);
  pinMode(INTERRUPT_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(INTERRUPT_PIN), abc, CHANGE);

  lcd.init();
  lcd.backlight();

  myservo.attach(SERVO_PIN);
}

void loop() {
  unsigned long currentMillis = millis();

  // Servo control
  if (currentMillis - previousMillisServo >= SERVO_INTERVAL) {
    previousMillisServo = currentMillis;
    abc();
  }

  // LCD update
  if (currentMillis - previousMillisLCD >= LCD_INTERVAL) {
    previousMillisLCD = currentMillis;
    updateLCD();
  }
}

void abc() {
  if (isIncreasing) {
    angle += SERVO_STEP;
    if (angle >= SERVO_MAX_ANGLE) {
      angle = SERVO_MAX_ANGLE;
      isIncreasing = false;
    }
  } else {
    angle -= SERVO_STEP;
    if (angle <= SERVO_MIN_ANGLE) {
      angle = SERVO_MIN_ANGLE;
      isIncreasing = true;
    }
  }

  myservo.write(angle);
}

void updateLCD() {
  lcd.clear();
  lcd.setCursor(4 * (lcdIndex - 1), 0);
  lcd.print(lcdIndex);
  lcd.setCursor(4 * (lcdIndex - 1), 1);
  lcd.print("hi");

  lcdIndex++;
  if (lcdIndex > MAX_LCD_INDEX) {
    lcdIndex = 1;
  }
}