import memoizeCapped from './memoizeCapped.js'

/** Used to match property names within property paths. */
const reLeadingDot = /^\./

const rePropName = RegExp([
  // Match anything that isn't a dot or bracket.
  '[^.[\\]]+',
  // Or match property names within brackets.
  '\\[(?:' +
    // Match numbers.
    '(-?\\d+(?:\\.\\d+)?)' + '|' +
    // Or match strings (supports escaping quotation marks).
    '(["\'])((?:(?!\\2)[^\\\\]|\\\\.)*?)\\2' +
  ')\\]',
  // Or match "" as the space between consecutive dots or empty brackets.
  '(?=(?:\\.|\\[\\])(?:\\.|\\[\\]|$))'
].join('|'), 'g')

/** Used to match backslashes in property paths. */
const reEscapeChar = /\\(\\)?/g

/**
 * Converts `string` to a property path array.
 *
 * @private
 * @param {string} string The string to convert.
 * @returns {Array} Returns the property path array.
 */
const stringToPath = memoizeCapped(string => {
  const result = []
  if (reLeadingDot.test(string)) {
    result.push('')
  }
  string.replace(rePropName, (match, number, quote, string) => {
    result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match))
  })
  return result
})

export default stringToPath