const milliSecond = 1000;

export class Timer {
  pointer = 0;
  mins = Number(sessionStorage.getItem("mins")) || 12;
  running = Boolean(Number(sessionStorage.getItem("running"))) || false;
  deadline = Number(sessionStorage.getItem("deadline")) || new Date().getTime();

  constructor() {
    this.running ? this.start(false) : this.reset();
    addTimerBehaviour(this);
  }
  store() {
    sessionStorage.setItem("mins", this.mins);
    sessionStorage.setItem("running", Number(this.running));
    sessionStorage.setItem("deadline", this.deadline);
  }
  set(m, s) {
    const timer = document.getElementById("timer-display");
    m = m < 10 ? "0" + m : m;
    s = s < 10 ? "0" + s : s;
    timer.value = `${m}:${s}`;
  }
  reset() {
    clearInterval(this.pointer);
    const mins = Math.floor(this.mins);
    const secs = (this.mins - mins) * 60;
    this.set(mins, secs);
    this.running = false;
    this.store();
  }
  update(ms) {
    const m = Math.floor((ms % (milliSecond * 60 * 60)) / (milliSecond * 60));
    const s = Math.floor((ms % (milliSecond * 60)) / milliSecond);
    this.set(m, s);
  }
  refresh(p) {
    const now = new Date().getTime();
    const msToDeadline = p.deadline - now;
    if (msToDeadline > 0) {
      p.update(msToDeadline);
      return;
    }
    p.reset();
    getNotifier().error("Round completed");
  }
  start(fresh) {
    if (fresh) {
      const now = new Date().getTime();
      const msToDeadline = this.mins * 60 * 1000;
      this.deadline = now + msToDeadline;
    }
    this.running = true;
    this.store();
    this.pointer = setInterval(this.refresh, 1000, this);
  }
  change(value) {
    this.mins += value;
    if (this.mins < 0.5) {
      this.mins = 0.5;
    }
    this.reset();
  }
}

function addTimerBehaviour(t) {
  document.getElementById("timer-start").addEventListener("click", () => {
    if (t.running) return;
    t.start(1);
  });
  document.getElementById("timer-stop").addEventListener("click", () => {
    t.reset();
  });
  document.getElementById("timer-inc").addEventListener("click", () => {
    if (!t.running) {
      t.change(0.5);
    }
  });
  document.getElementById("timer-dec").addEventListener("click", () => {
    if (!t.running) {
      t.change(-0.5);
    }
  });
}