const fs = require('await-file')
const Path = require('path')
const { Snowflake } = require('discord.js')

const storageDirectory = './users'

const userDirectory = user => Path.join(storageDirectory, `${user.id}`)

const userIndexFile = user => Path.join(userDirectory(user), 'index.json')

const userStateFile = (user, snowflake) => Path.join(userDirectory, `${snowflake}.json`)

const ensureUserDirectory = async user => {
  if (!await fs.exists(userDirectory(user))) {
    await fs.createDirectory(userDirectory(user))
  }
}

const getIndex = async user => {
  if (await fs.exists(userIndexFile(user)))
    return JSON.parse(await fs.readFile(userIndexFile(user), 'utf8'))
  return {}
}

const setIndex = async (user, index) => {
  await ensureUserDirectory(user)
  await fs.writeFile(userIndexFile(user), JSON.stringify(index))
}

const get = async (user) => {
  const index = await getIndex(user)
  if (!index.latest) return {}
  return JSON.parse(await fs.readFile(userStateFile(index.latest)))
}

const set = async (user, object) => {
  const json = JSON.stringify(object)
  await ensureUserDirectory(user)
  const index = await getIndex(user)
  index.latest = Snowflake.generate()
  await fs.writeFile(userStateFile(index.latest), json)
  await setIndex(user, index)
}


module.exports = {
  get,
  set,
  getIndex,
  setIndex,
  storageDirectory,
  userDirectory,
  userIndexFile,
  userStateFile,
  ensureUserDirectory
}