/**
 * @typedef Options
 *   Configuration for `stringify`.
 * @property {boolean} [padLeft=true]
 *   Whether to pad a space before a token.
 * @property {boolean} [padRight=false]
 *   Whether to pad a space after a token.
 */

/**
 * @typedef {Options} StringifyOptions
 *   Please use `StringifyOptions` instead.
 */

/**
 * Parse comma-separated tokens to an array.
 *
 * @param {string} value
 *   Comma-separated tokens.
 * @returns {Array<string>}
 *   List of tokens.
 */
export function parse(value) {
  /** @type {Array<string>} */
  const tokens = []
  const input = String(value || '')
  let index = input.indexOf(',')
  let start = 0
  /** @type {boolean} */
  let end = false

  while (!end) {
    if (index === -1) {
      index = input.length
      end = true
    }

    const token = input.slice(start, index).trim()

    if (token || !end) {
      tokens.push(token)
    }

    start = index + 1
    index = input.indexOf(',', start)
  }

  return tokens
}

/**
 * Serialize an array of strings or numbers to comma-separated tokens.
 *
 * @param {Array<string|number>} values
 *   List of tokens.
 * @param {Options} [options]
 *   Configuration for `stringify` (optional).
 * @returns {string}
 *   Comma-separated tokens.
 */
export function stringify(values, options) {
  const settings = options || {}

  // Ensure the last empty entry is seen.
  const input = values[values.length - 1] === '' ? [...values, ''] : values

  return input
    .join(
      (settings.padRight ? ' ' : '') +
        ',' +
        (settings.padLeft === false ? '' : ' ')
    )
    .trim()
}