'use strict';

var _moment = require('moment');

var _moment2 = _interopRequireDefault(_moment);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

const d = _moment2.default.duration;

const roundingRules = [[d(500, 'ms'), d(100, 'ms')], [d(5, 'second'), d(1, 'second')], [d(7.5, 'second'), d(5, 'second')], [d(15, 'second'), d(10, 'second')], [d(45, 'second'), d(30, 'second')], [d(3, 'minute'), d(1, 'minute')], [d(9, 'minute'), d(5, 'minute')], [d(20, 'minute'), d(10, 'minute')], [d(45, 'minute'), d(30, 'minute')], [d(2, 'hour'), d(1, 'hour')], [d(6, 'hour'), d(3, 'hour')], [d(24, 'hour'), d(12, 'hour')], [d(1, 'week'), d(1, 'd')], [d(3, 'week'), d(1, 'week')], [d(1, 'year'), d(1, 'month')], [Infinity, d(1, 'year')]];

const revRoundingRules = roundingRules.slice(0).reverse();

function find(rules, check, last) {
  function pick(buckets, duration) {
    const target = duration / buckets;
    let lastResp = null;

    for (let i = 0; i < rules.length; i++) {
      const rule = rules[i];
      const resp = check(rule[0], rule[1], target);

      if (resp == null) {
        if (!last) continue;
        if (lastResp) return lastResp;
        break;
      }

      if (!last) return resp;
      lastResp = resp;
    }

    // fallback to just a number of milliseconds, ensure ms is >= 1
    const ms = Math.max(Math.floor(target), 1);
    return _moment2.default.duration(ms, 'ms');
  }

  return (buckets, duration) => {
    const interval = pick(buckets, duration);
    if (interval) return _moment2.default.duration(interval._data);
  };
}

module.exports = {
  near: find(revRoundingRules, function near(bound, interval, target) {
    if (bound > target) return interval;
  }, true),

  lessThan: find(revRoundingRules, function lessThan(_bound, interval, target) {
    if (interval < target) return interval;
  }),

  atLeast: find(revRoundingRules, function atLeast(_bound, interval, target) {
    if (interval <= target) return interval;
  })
};
