// global variables
var work; // work time
var pause; // break time
var timer_status; // 0 if timer is stopped, 1 if it's running
var current_time; // current time on the timer
var timer; // timer itself
var work_status; // 1 if working, 0 if on a break

$(document).ready(function() {

  // set variables in seconds
  work = $("#timer-work-set").text() * 60;
  pause = $("#timer-pause-set").text() * 60;

  timer_status = 0; // timer is not running at the moment
  work_status = 1; // work first

  changeTimer(work);
  current_time = work;

  $("#timer-click").addClass("timer-left-work");

  Notification.requestPermission();

  window.setTimeout(function() {
    $(".timer-hint").fadeOut("slow");
  }, 5000);

  // decrease work time when clicking minus
  $("#timer-work-minus").on("click", function() {
    if (timer_status === 0) { // only allow changes when timer is not running
      if (work > 60) { // don't want to work less than a minute
        work -= 60;
        $("#timer-work-set").text(Math.floor(work / 60)); // change text
        changeTimer(work); // change timer text
        current_time = work;
      }
    }
  });

  // increase work time when clicking plus
  $("#timer-work-plus").on("click", function() {
    if (timer_status === 0) { // only allow changes when timer is not running
      work += 60;
      $("#timer-work-set").text(Math.floor(work / 60));
      changeTimer(work);
      current_time = work;
    }
  });

  // decrease break time when clicking minus
  $("#timer-pause-minus").on("click", function() {
    if (timer_status === 0) { // only allow changes when timer is not running
      if (pause > 60) { // don't want break time less than a minute
        pause -= 60;
        $("#timer-pause-set").text(Math.floor(pause / 60));
        changeTimer(work);
        current_time = work;
      }
    }
  });

  // increase break time when clicking plus
  $("#timer-pause-plus").on("click", function() {
    if (timer_status === 0) { // only allow changes when timer is not running
      pause += 60;
      $("#timer-pause-set").text(Math.floor(pause / 60));
      changeTimer(work);
      current_time = work;
    }
  });

  // pause or start timer
  $("#timer-click").click(function() {
    if (timer_status === 0) { // if timer isn't running, start it
      timer_seconds = window.setInterval(time_update, 1000);

      // adjust CSS classes based on work_status 
      $("#timer-click").removeClass();
      if (work_status === 1) {
        $("#timer-click").addClass("timer-left-work");
      } else if (work_status === 0) {
        $("#timer-click").addClass("timer-left-pause");
      }

      timer_status = 1;

    } else if (timer_status === 1) { // if the timer is running, pause it
      window.clearInterval(timer_seconds);
      timer_status = 0;
    }
  });

});

// adjust text on timer mm:ss
function changeTimer(number) {
  var work_min = Math.floor(number / 60);
  var work_sec = number % 60;
  $("#timer-click").text(work_min + ":" + ('0' + work_sec).slice(-2));
}

// switch from work to break
function switchTimer() {
  // stop current timer
  window.clearInterval(timer_seconds);

  $("#timer-click").removeClass();

  if (work_status === 1) { // if working

    notify("Time to take a break!");
    work_status = 0;
    $("#timer-click").addClass("timer-left-pause");
    current_time = pause;
    timer_seconds = window.setInterval(time_update, 1000); // set new timer

  } else if (work_status === 0) { // if on a break

    notify("Back to work!");
    work_status = 1;
    $("#timer-click").addClass("timer-left-work");
    current_time = work;
    timer_seconds = window.setInterval(time_update, 1000); // set new timer

  }
}

// notify the user that the time is up
function notify(message) {
  if (!("Notification" in window)) {
    alert("This browser does not support desktop notification");
  } else if (Notification.permission === "granted") {
    var notification = new Notification(message);
  } else if (Notification.permission !== 'denied') {
    Notification.requestPermission(function(permission) {
      if (permission === "granted") {
        var notification = new Notification(message);
      }
    });
  }
}

// update timer
var time_update = function timeUpdate() {
  current_time--;
  changeTimer(current_time);
  if (current_time === 0) {
    switchTimer();
  }
};