export class Time {
  constructor(obj) {
    this.hour = parseInt(obj.hour ?? 0);
    this.minute = parseInt(obj.minute ?? 0);
    this.second = parseInt(obj.second ?? 0);
  }

  static fromInputValue(str) {
    const parts = str.split(':').map(part => parseInt(part));
    return new Time({hour: parts[0], minute: parts[1], second: parts[2]});
  }

  asJsonObject() {
    let res = {}
    if (this.hour !== 0) res.hour = this.hour;
    if (this.minute !== 0) res.minute = this.minute;
    if (this.second !== 0) res.second = this.second;
    return res;
  }

  cmp(other) {
    if (this.hour < other.hour) return -1;
    if (this.hour > other.hour) return 1;
    if (this.minute < other.minute) return -1;
    if (this.minute > other.minute) return 1;
    if (this.second < other.second) return -1;
    if (this.second > other.second) return 1;
    return 0;
  }

  get durationSinceMidnight() {
    return new TimeRange({start_time: new Time({}), end_time: this}).duration;
  }

  plus(duration) {
    const total = this.durationSinceMidnight.total_seconds
                   + duration.total_seconds;
    const second = total % 60;
    const minute = Math.floor(total / 60) % 60;
    const hour = Math.floor(total / 60 / 60) % 24;
    return new Time({hour, minute, second});
  }

  // TODO Just ignoring seconds?
  to12HourString() {
    let hour = this.hour % 12;
    if (hour === 0) hour = 12;
    return hour + ':' + this.minute.toString().padStart(2, '0');
  }

  get inputValue() {
    return this.hour.toString().padStart(2, '0') + ':'
            + this.minute.toString().padStart(2, '0') + ':'
            + this.second.toString().padStart(2, '0');
  }
}

export class Duration {
  constructor(obj) {
    if (obj.total_seconds) {
      this.total_seconds = obj.total_seconds;
      this.hour = Math.floor(obj.total_seconds / 60 / 60);
      this.minute = Math.floor(obj.total_seconds / 60) % 60;
      this.second = obj.total_seconds % 60;
    } else {
      this.hour = obj.hour ?? 0;
      this.minute = obj.minute ?? 0;
      this.second = obj.second ?? 0;
      this.total_seconds = ((this.hour * 60) + this.minute) * 60 + this.second;
    }
  }

  asJsonObject() {
    let res = {}
    if (this.hour !== 0) res.hour = this.hour;
    if (this.minute !== 0) res.minute = this.minute;
    if (this.second !== 0) res.second = this.second;
    return res;
  }

  dividedBy(other) {
    return this.total_seconds / other.total_seconds;
  }

  times(num) {
    const total = this.total_seconds * num;
    const second = total % 60;
    const minute = Math.floor(total / 60) % 60;
    const hour = Math.floor(total / 60 / 60);
    return new Duration({hour, minute, second});
  }

  toString() {
    let res = "";
    if (this.hour) {
      res += this.hour + (this.hour === 1 ? " hour" : " hours ");
    }
    if (this.minute) {
      res += this.minute + (this.minute === 1 ? " minute" : " minutes ");
    }
    if (this.second) {
      res += this.second + (this.second === 1 ? " second" : " seconds");
    }

    return this.total_seconds === 0 ? "0 seconds" : res.trimEnd();
  }

  get inputValue() {
    return new Time({}).plus(this).inputValue;
  }
}

export class TimeRange {
  constructor(args) {
    this.start_time = args.start_time;
    this.end_time = args.end_time;
  }

  get duration() {
    return new Duration({
      'total_seconds': 60 * 60 * (this.end_time.hour - this.start_time.hour)
                        + 60 * (this.end_time.minute - this.start_time.minute)
                        + this.end_time.second - this.start_time.second,
    });
  }

  overlaps(other) {
    return (other.start_time.cmp(this.start_time) <= 0
            && this.start_time.cmp(other.end_time) < 0)
        || (this.start_time.cmp(other.start_time) <= 0
            && other.start_time.cmp(this.end_time) < 0);
  }

  to12HourString() {
    return this.start_time.to12HourString() + '-'
            + this.end_time.to12HourString();
  }
}

const dayDictionary = {
    'M': 'Monday',
    'T': 'Tuesday',
    'W': 'Wednesday',
    'R': 'Thursday',
    'F': 'Friday',
    'S': 'Saturday',
    'U': 'Sunday',
  };

export function DayString(day) {
  return dayDictionary[day];
}

export const allDays = Object.keys(dayDictionary);

export function clearChildren(el) {
  while (el.firstChild) el.removeChild(el.lastChild);
}

// From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
export function setDifference(setA, setB) {
  const _difference = new Set(setA);
  for (const elem of setB) {
    _difference.delete(elem);
  }
  return _difference;
}

export function setIntersection(setA, setB) {
  if (!(setA instanceof Set)) setA = new Set(setA);
  const _intersection = new Set();
  for (const elem of setB) {
    if (setA.has(elem)) {
      _intersection.add(elem);
    }
  }
  return _intersection;
}

export function setEqual(setA, setB) {
  if (!(setA instanceof Set)) setA = new Set(setA);
  if (!(setB instanceof Set)) setB = new Set(setB);

  if (setA.size != setB.size) return false;
  return setDifference(setA, setB).size === 0;
}

// From https://stackoverflow.com/a/68227965
export function debounceAsync(task, ms) {
  function deferred() {
    let cancel, promise = new Promise((resolve, reject) => {
      cancel = reject
      setTimeout(resolve, ms)
    })
    return { promise, cancel }
  }

  let t = { promise: null, cancel: _ => void 0 }
  return async (...args) => {
    try {
      t.cancel()
      t = deferred()
      await t.promise
      await task(...args)
    }
    catch (_) { /* prevent memory leak */ }
  }
}