import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'secondsToTime'
})
export class SecondsToTimePipe implements PipeTransform {
  static factors = {
    year: 31557600,
    month: 2629746,
    day: 86400,
    hour: 3600,
    minute: 60,
    sec: 1
  }

  static showOnly = 3;



  transform(seconds: number) {
    if (seconds == null) return "";

    const { factors } = SecondsToTimePipe;

    let result = '';
    let skippedFirstSpace = false;
    let shown = 0;
    for (const key in factors) {
      if (!factors.hasOwnProperty(key)) continue;

      const factor = factors[key];
      const count = Math.floor(seconds / factor);
      if (count === 0) continue;

      // show only x parameters
      // (i.e. don't show miliseconds if we also display years, keep it concise).
      if (shown++ > SecondsToTimePipe.showOnly) break;

      // only start adding spaces after the first match.
      const space = skippedFirstSpace ? ' ' : '';
      skippedFirstSpace = true;

      // add an s to put words in plural.
      const plural = (count > 1) ? 's' : '';

      // put everything together.
      result += `${space}${count} ${key}${plural}`;
      seconds -= factor * count;
    }
    return result;
  }
}