//Define vars to hold time values
function stopWatch() {
  let seconds = 0;
  a;
  let minutes = 0;
  let hours = 0;

  //Define vars to hold "display" value
  let displaySeconds = 0;
  let displayMinutes = 0;
  let displayHours = 0;

  //Define var to hold setInterval() function
  let interval = null;

  //Define var to hold stopwatch status
  let status = "stopped";

  //Stopwatch function (logic to determine when to increment next value, etc.)
  function stopWatch() {
    seconds++;

    //Logic to determine when to increment next value
    if (seconds / 60 === 1) {
      seconds = 0;
      minutes++;

      if (minutes / 60 === 1) {
        minutes = 0;
        hours++;
      }
    }

    //If seconds/minutes/hours are only one digit, add a leading 0 to the value
    if (seconds < 10) {
      displaySeconds = "0" + seconds.toString();
    } else {
      displaySeconds = seconds;
    }

    if (minutes < 10) {
      displayMinutes = "0" + minutes.toString();
    } else {
      displayMinutes = minutes;
    }

    if (hours < 10) {
      displayHours = "0" + hours.toString();
    } else {
      displayHours = hours;
    }

    //Display updated time values to user
    document.getElementById("display").innerHTML =
      displayHours + ":" + displayMinutes + ":" + displaySeconds;
  }
}

function startStop() {
  if (status === "stopped") {
    //Start the stopwatch (by calling the setInterval() function)
    interval = window.setInterval(stopWatch, 1000);
    document.getElementById("startStop").innerHTML = "Stop";
    status = "started";
  } else {
    window.clearInterval(interval);
    document.getElementById("startStop").innerHTML = "Start";
    status = "stopped";
  }
}

//Function to reset the stopwatch
function reset() {
  window.clearInterval(interval);
  seconds = 0;
  minutes = 0;
  hours = 0;
  document.getElementById("display").innerHTML = "00:00:00";
  document.getElementById("startStop").innerHTML = "Start";
}