/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

const PARSE_TO_PAIRS = /([0-9]+[^0-9]+)/g;
const PAIR_SPLIT = /^([0-9]+)([dhmsu]+)$/;

export function parseDurationToMs(duration: string): number {
  const matches: string[] = [];

  let array: RegExpExecArray | null;
  while ((array = PARSE_TO_PAIRS.exec(duration)) !== null) {
    matches.push(array[0]);
  }
  return matches
    .map((match) => {
      const res = PAIR_SPLIT.exec(match);
      if (res === null) {
        throw new Error(`Not a valid duration: ${match}`);
      }
      let factor: number = 0;
      switch (res[2]) {
        case 'd':
          factor = 86400000;
          break;
        case 'h':
          factor = 3600000;
          break;
        case 'm':
          factor = 60000;
          break;
        case 's':
          factor = 1000;
          break;
        case 'u':
          factor = 1;
          break;
        default:
          throw new Error(`Not a valid duration unit: ${res[2]}`);
      }
      return parseInt(res[1]) * factor;
    })
    .reduce((total, value) => total + value, 0);
}