#include <TM1637.h>

#define Serial Serial1

#define CLK 10
#define DIO 11

#define led 18
#define fan 19
#define hourBtn 20 // 24
#define minBtn 17
#define sw 2

TM1637 tm(CLK, DIO);

uint8_t HH = 0;
uint8_t MM = 0;
int h = 0;
int m = 0;
int s = 60;
unsigned long timeNow = 0;

void setup(){
  Serial.begin(115200);
  Serial.println("Initiate...");
  pinMode(led, OUTPUT);
  pinMode(fan, OUTPUT);
  pinMode(hourBtn, INPUT_PULLUP);
  pinMode(minBtn, INPUT_PULLUP);
  pinMode(sw, INPUT_PULLUP);
  tm.init();
  tm.set(BRIGHT_TYPICAL);
  tm.display(4, 0x39); // :
}

void loop(){
  // reset timer
  if(!digitalRead(hourBtn) && !digitalRead(minBtn)){
    HH = 0;
    MM = 0;
    delay(250);
  }
  // hour adjustment
  if(!digitalRead(hourBtn)){
    HH++;
    if(HH > 99) HH = 0;
    delay(250);
  }
  // minute adjustment
  if(!digitalRead(minBtn)){
    MM++;
    if(MM >= 60) MM = 0;
    delay(250);
  }
  if(millis() - timeNow >= 250){
    timeNow = millis();
    // display time
    tm.display(0, HH/10);
    tm.display(1, HH%10);
    tm.display(2, MM/10);
    tm.display(3, MM%10);

    // turn of fan and light
    digitalWrite(fan,0);
    digitalWrite(led,0);
    
    // sync timer
    m = MM;
    h = HH;
  }

  // when the switch is pressed
  while(!digitalRead(sw)){
    delay(1000);
    s--;
    if(s <= 0){
      s = 59;
      m--;
      if(m < 0){
        if(h > 0) {
          m = 59;
          h--;
        }
        else{
          m = 0;
          h = 0;
        }
      }
    }

    // fan and light will be off when the timer is over
    if(h == 0 && m == 0){
      digitalWrite(fan,0);
      digitalWrite(led,0);
    }
    
    // turn on fan and light
    else{
    digitalWrite(fan,1);
    digitalWrite(led,1);
    }

    // display time
    tm.display(0, h/10);
    tm.display(1, h%10);
    tm.display(2, m/10);
    tm.display(3, m%10);
  }
}