const reserved = require('./reserved.js')

// from https://werxltd.com/wp/2010/05/13/javascript-implementation-of-javas-string-hashcode-method/
function hashCode(str) {
  let hash = 0
  for (let i = 0; i < str.length; ++i) {
    const char = str.charCodeAt(i)
    hash = (hash << 5) - hash + char
    hash |= 0 // Convert to 32bit integer
  }
  return hash
}

function identifier(key, unique) {
  if (unique) key += ' ' + hashCode(key).toString(36)
  const id = key.trim().replace(/\W+/g, '_')
  return reserved.ES3[id] || reserved.ESnext[id] || /^\d/.test(id)
    ? '_' + id
    : id
}

function property(obj, key) {
  if (/^[A-Z_$][0-9A-Z_$]*$/i.test(key) && !reserved.ES3[key]) {
    return obj ? obj + '.' + key : key
  } else {
    const jkey = JSON.stringify(key)
    return obj ? obj + '[' + jkey + ']' : jkey
  }
}

module.exports = { identifier, property }