// Adapted from https://github.com/zeit/ms/blob/master/index.js
// Copyright (c) 2016 Zeit, Inc. MIT License
// Copyright (c) 2018 Kevin "Kun" Kassimo Qian. MIT License

const s = 1000;
const m = s * 60;
const h = m * 60;
const d = h * 24;
const w = d * 7;
const y = d * 365.25;

/** Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 */

export function ms(
  val: string | number,
  options?: { [key: string]: any },
): string | number | undefined {
  switch (typeof val) {
    case "string":
      if ((val).length > 0) {
        return parse(val);
      }
      break;
    case "number":
      if (!isNaN(val)) {
        return options && options!.long ? fmtLong(val) : fmtShort(val);
      }
  }
  throw new Error(
    "val is not a non-empty string or a valid number. val=" +
      JSON.stringify(val),
  );
}

/** Parse the given `str` and return milliseconds.
 */

function parse(str: string): number | undefined {
  if (str.length > 100) {
    return;
  }
  const match =
    /^((?:\d+)?-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/i
      .exec(
        str,
      );
  if (!match) {
    return;
  }
  const n = parseFloat(match[1]);
  const type = (match[2] || "ms").toLowerCase();
  switch (type) {
    case "years":
    case "year":
    case "yrs":
    case "yr":
    case "y":
      return n * y;
    case "weeks":
    case "week":
    case "w":
      return n * w;
    case "days":
    case "day":
    case "d":
      return n * d;
    case "hours":
    case "hour":
    case "hrs":
    case "hr":
    case "h":
      return n * h;
    case "minutes":
    case "minute":
    case "mins":
    case "min":
    case "m":
      return n * m;
    case "seconds":
    case "second":
    case "secs":
    case "sec":
    case "s":
      return n * s;
    case "milliseconds":
    case "millisecond":
    case "msecs":
    case "msec":
    case "ms":
      return n;
    default:
      return undefined;
  }
}

/** Short format for `ms`.
 */

function fmtShort(ms: number): string {
  const msAbs = Math.abs(ms);
  if (msAbs >= d) {
    return Math.round(ms / d) + "d";
  }
  if (msAbs >= h) {
    return Math.round(ms / h) + "h";
  }
  if (msAbs >= m) {
    return Math.round(ms / m) + "m";
  }
  if (msAbs >= s) {
    return Math.round(ms / s) + "s";
  }
  return ms + "ms";
}

/** Long format for `ms`.
 */

function fmtLong(ms: number): string {
  const msAbs = Math.abs(ms);
  if (msAbs >= d) {
    return plural(ms, msAbs, d, "day");
  }
  if (msAbs >= h) {
    return plural(ms, msAbs, h, "hour");
  }
  if (msAbs >= m) {
    return plural(ms, msAbs, m, "minute");
  }
  if (msAbs >= s) {
    return plural(ms, msAbs, s, "second");
  }
  return ms + " ms";
}

/** Pluralization helper.
 */

function plural(ms: number, msAbs: number, n: number, name: string) {
  const isPlural = msAbs >= n * 1.5;
  return Math.round(ms / n) + " " + name + (isPlural ? "s" : "");
}