export default function useOptimisticUpdates(action) {
  // old (to pass to other hooks)
  //   update: character, list, options
  //   delete: character, list, options
  //   create: list, options

  // temp (update until settled)
  //   create: character, list

  // new (to update)
  //   update: character, list, options
  //   delete: list, options
  //   create: options

  // error (to rollback)
  //   update: character, list, options
  //   delete: character, list, options
  //   create: list, options

  // success (to re-update with correct id)
  //   create: character, list

  // onMutate
  //   getOld
  //   create new
  //   update caches
  //   cancel queries
  //   return old and new for hooks

  // onSettled
  //   invalidate list, options queries
  //   if newCharacter || delete: invalidate character query

  // onError
  //   if newList: rollback list, options
  //   if newCharacter: rollback character

  // onSuccess
  //   if create: reupdate list

  function getOld(id = null) {
    // save current for rollback
    const oldList = queryCache.getQueryData(characterListQuery.key)
    const oldOptions = queryCache.getQueryData(characterOptionsQuery.key)

    if (id) {
      const index = _findIndex(oldList, { id })

      if (index >= 0) {
        const oldCharacter = oldList[index]

        return { oldCharacter, oldList, oldOptions }
      } else {
        return { oldList, oldOptions }
      }
  }



  function onSettled({ newCharacter }) {
    if (newCharacter) {
      queryCache.invalidateQueries({ key: characterListQuery.key })
      queryCache.invalidateQueries({ key: characterByIdQuery(id).key })
    }
  }

  function onError({ oldCharacter, oldCharacterList, oldOptions, newCharacterList }) {
    // before applying the rollback, check if the values in the cache are the same
    //    in case the cache was updated by another mutation or query
    if (newCharacterList === queryCache.getQueryData(characterListQuery.key)) {
      queryCache.setQueryData(characterListQuery.key, oldCharacterList)
      queryCache.setQueryData(characterOptionsQuery.key, oldOptions)
      queryCache.setQueryData(characterByIdQuery(id).key, oldCharacter)
    }
  }

  function onSuccess() {
    // only create

  }
}