#include <AccelStepper.h>
#include <LiquidCrystal.h>

const int rs = 7;
const int en = 6;
const int d4 = 5;
const int d5 = 4;
const int d6 = 3;
const int d7 = 2;

LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

const int ldr = 26;
const int step = 15;
const int dir = 14;

const int DT = 12;
const int CLK = 13;
const int SW = 11;

const int light_thrshold = 500;

AccelStepper stepper(AccelStepper::DRIVER, step, dir);
const int stepperrev = 200;
const int stepsopen = stepperrev * 10;
const int stepsclose = -stepperrev * 10;

volatile int encoder_pos = 0;
int last_encoderpos = 0;

int curttainpos = 0;  // 0 for closed, 1 for open

void setup() {
  lcd.begin(16, 2);
  lcd.print("Curtain Control");

  pinMode(ldr, INPUT);
  pinMode(DT, INPUT);
  pinMode(CLK, INPUT);
  pinMode(SW, INPUT_PULLUP);

  attachInterrupt(digitalPinToInterrupt(DT), encoderISR, CHANGE);

  stepper.setMaxSpeed(1000);
  stepper.setAcceleration(500);
  lcd.setCursor(0, 1);
  lcd.print("Light Level: ");
}

void loop() {
  int lightLevel = analogRead(ldr);
  lcd.setCursor(0, 0);
  lcd.print("Curtain Control");
  lcd.setCursor(0, 1);
  lcd.print("Light: ");
  lcd.print(lightLevel);
  lcd.print("  ");

  if (lightLevel > light_thrshold) {
    if (curttainpos == 0) {
      opencurtain();
      curttainpos = 1;  // Mark as open
    }
  } else {
    if (curttainpos == 1) {
      closeCurtain();
      curttainpos = 0;  // Mark as closed
    }
  }

  if (encoder_pos != last_encoderpos) {
    if (encoder_pos > last_encoderpos) {
      stepper.moveTo(stepper.currentPosition() + 100);
    } else {
      stepper.moveTo(stepper.currentPosition() - 100);
    }
    last_encoderpos = encoder_pos;
    stepper.run();
  }
  
  stepper.run();
}

void opencurtain() {
  lcd.setCursor(0, 1);
  lcd.print("Curtain: Opening   ");
  
  stepper.moveTo(stepsopen);
  
  while (stepper.distanceToGo() != 0) {
    stepper.run();
  }lcd.clear();
}

void closeCurtain() {
  lcd.setCursor(0, 1);
  lcd.print("Curtain: Closing   ");
  
  stepper.moveTo(stepsclose);
  
  while (stepper.distanceToGo() != 0) {
    stepper.run();
  }lcd.clear();
}

void encoderISR() {
  if (digitalRead(CLK) == LOW) {
    encoder_pos++;
  } else {
    encoder_pos--;
  }
}