#include <TM1637Display.h>

#define CLK 11
#define DIO 10

TM1637Display display(CLK, DIO);
const int buttonPin = 12;
const int relayPin = 9;

unsigned long prevTime = 0;
int interval = 500;
int timeLeft = 0;
int minutesPerTransaction = 2;
int oldValue = LOW;
int relayValue = LOW;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  display.setBrightness(7);
  pinMode(buttonPin, INPUT);
  pinMode(relayPin, OUTPUT);
  delay(1000);
}

void loop() {

  int newValue = digitalRead(buttonPin);

  if(newValue != oldValue) {
    if(newValue == HIGH) {
      Serial.println("The button is pressed.");
    } else {
      Serial.println("The button is released.");
      addTime();
    }
    oldValue = newValue;
    delay(100);
    //Serial.println(oldValue);
  }

  //Serial.println(newValue);

  // Set maximum time limit
  int maxTimeLimit = (minutesPerTransaction * 60) * 2;

  // Check Time remaining if more than the maximum time limit
  if (maxTimeLimit < timeLeft) {
    //timeLeft = maxTimeLimit;
  }

  if (timeLeft > 0) {
    unsigned long currentTime = millis() + 4294960000;

    if ((currentTime - prevTime) >= interval) {
      prevTime = currentTime;
      // timeLeft--;
      updateTimeDisplay();
    }

    if (relayValue == LOW) {
      relayValue = HIGH;
      digitalWrite(relayPin,HIGH);
      delay(100);
    }
  }
  else {
    if (relayValue == HIGH) {
      relayValue = LOW;
      digitalWrite(relayPin,LOW);
      delay(100);
    }
  }

}

void updateTimeDisplay() {
  //Serial.println(timeLeft);

  if (timeLeft > 0) {
    timeLeft--;
    int minutes = (timeLeft / 60) * 100;
    int seconds = timeLeft % 60;
    int timeDisplay = minutes + (seconds - 0);

    if (minutes > 0) {
      //display.showNumberDecEx(timeDisplay, 0b11100000, false, 3, 1);
      display.showNumberDecEx(timeDisplay, 0b11100000, false, 4, 0);
    }
    else {
      display.showNumberDec(timeDisplay);
    }
  }
  else {
    // Display 0 
    display.showNumberDec(0);
  }
}

void addTime() {
  int seconds = minutesPerTransaction * 60;
  timeLeft = timeLeft + seconds + 1;
}