/**
 * Basic string formatting, akin to `sprintf` or `util.format`, but limited.
 * Only supports `%o` for arrays, `%j` for objects, `%s` for strings and `%d` for numbers.
 *
 * You should really be using template literals instead (developer's note to self, lol).
 * @param fmt Input
 * @param args Arguments
 * @returns Formatted string
 */
export function formatstr(fmt: string, ...args: any[]) {
  const re = /(%?)(%([ojds]))/g;
  if (args.length) {
    fmt = fmt.replace(re, function (match, escaped, ptn, flag) {
      let arg = args.shift();
      switch (flag) {
        case 'o':
          if (Array.isArray(arg)) {
            arg = JSON.stringify(arg);
            break;
          }
        case 's':
          arg = '' + arg;
          break;
        case 'd':
          arg = Number(arg);
          break;
        case 'j':
          arg = JSON.stringify(arg);
          break;
      }
      if (!escaped) {
        return arg;
      }
      args.unshift(arg);
      return match;
    });
  }

  // arguments remain after formatting
  if (args.length) {
    fmt += ' ' + args.join(' ');
  }

  fmt = fmt.replace('%%', '%');

  return '' + fmt;
}