#define PIR_PIN    34
#define RELAY_PIN  5

#define ENC_CLK    18
#define ENC_DT     19

int lastCLK;
int mode = 0;   // 0=15m, 1=30m, 2=1hr

unsigned long lastMotionTime = 0;
bool relayState = false;

unsigned long offDelay = 900000;  // default 15 min

void setup() 
{
  pinMode(PIR_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);

  pinMode(ENC_CLK, INPUT);
  pinMode(ENC_DT, INPUT);

  digitalWrite(RELAY_PIN, LOW);

  lastCLK = digitalRead(ENC_CLK);
}

void loop()
{
  int currentCLK = digitalRead(ENC_CLK);

  if (currentCLK != lastCLK) 
  {
    if (digitalRead(ENC_DT) != currentCLK)
    {
      mode++;
    } 
    else
    {
      mode--;
    }
  
    if (mode > 2) mode = 0;
    if (mode < 0) mode = 2;

    if (mode == 0) offDelay = 900000;      // 15 min
    if (mode == 1) offDelay = 1800000;     // 30 min
    if (mode == 2) offDelay = 3600000;     // 1 hour
  }

  lastCLK = currentCLK;

  int pirState = digitalRead(PIR_PIN);

  if (pirState == HIGH) 
  {
    digitalWrite(RELAY_PIN, HIGH);
    lastMotionTime = millis();
    relayState = true;
  }

  if (relayState && pirState == LOW) 
  {
    if (millis() - lastMotionTime >= offDelay)
    {

      digitalWrite(RELAY_PIN, LOW);
      relayState = false;
    }
  }
}