#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SDA 23
#define SCL 22
#define CLK 15
#define DT  4
#define SW  5
#define RL  32

bool lastStateCLK;
bool currentStateCLK;


int value = 0;
int oldvalue = 0;

long longclick = 0;
long runtime = 0;
bool  settime = false;
bool startTimer = false;
long t;
Adafruit_SSD1306 oled(128, 64, &Wire, -1);


void setup() {
  // put your setup code here, to run once:
   pinMode(CLK, INPUT_PULLUP);
   pinMode(DT, INPUT_PULLUP);
   pinMode(SW, INPUT_PULLUP);
   pinMode(RL, OUTPUT);
   digitalWrite(RL, 1);

   Serial.begin(115200);
   currentStateCLK = digitalRead(CLK);

   Wire.begin(SDA, SCL);
   if(!oled.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  oled.display();
  delay(2000);
  oled.clearDisplay();
  oled.setTextSize(1);
  oled.setTextColor(WHITE);
  oled.setCursor(0,0);
  oled.print("Hello");
  oled.display();
}

void loop() {
  // put your main code here, to run repeatedly:
  int timer = 0;

  while(digitalRead(SW) == 0 ){
       timer++;
       delay(1);
       if(timer > 1500){

          settime = !settime;
          startTimer = false;
          timer = 0;
          oled.clearDisplay();
          oled.setTextSize(2);
          oled.setCursor(0,25);
          oled.printf("SET :%3d", value);
          oled.display();
           break; 
         }
  }
  
  if (timer > 300) {
    startTimer = true;
    runtime = millis();
  }


  if(settime == true)
  {
    change(value, 0, 120);
    if(oldvalue != value)
    {
    oldvalue = value;
     oled.clearDisplay();
     oled.setTextSize(2);
     oled.setCursor(0,25);
     oled.printf("SET :%3d", value);
     oled.display();
    }
  }
  else {
    if(startTimer == true){
    long t = value - (millis() - runtime)/1000; 
    digitalWrite(RL, 0);
    oled.clearDisplay();
    oled.setTextSize(2);
    oled.setCursor(0,25);
    oled.printf("TIMER:%3d",t);
    oled.display(); 
     if(t == 0){
        digitalWrite(RL, 1);
        startTimer = false;
        }


    }else {
      oled.clearDisplay();
      oled.setTextSize(2);
      oled.setCursor(0,0);
      oled.printf("TIMER=%3d", value);
      oled.display();
    }
     
  } 

}


void change(int &value, int min, int max) {
  currentStateCLK = digitalRead(CLK);
  if (currentStateCLK != lastStateCLK && currentStateCLK == 1) {
    if (digitalRead(DT) == currentStateCLK ) {
      value--;
    } else {
      value++;
    }
  }
  if (value < min) value = min;
  if (value > max) value = max;
  lastStateCLK = currentStateCLK;
}