polyjuice_util

# Copyright 2021 Nicolas Jouanin <nico@beerfactory.org>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
defmodule Polyjuice.Util.Randomizer do
  @moduledoc """
  Random string generator module.
  """

  @doc """
  Generate random string based on the given length. It is also possible to generate certain type of randomise string using the options below:

  * :all - generate alphanumeric random string
  * :alpha - generate nom-numeric random string
  * :numeric - generate numeric random string
  * :upcase - generate upper case non-numeric random string
  * :downcase - generate lower case non-numeric random string
  * :upcase_numeric - generate uppercase alphanumeric random string
  * :downcase_numeric - generate downcase alphanumeric random string

  ## Example
      iex> Randomizer.randomizer(20) //"Je5QaLj982f0Meb0ZBSK"
  """
  def randomize(length, type \\ :all) do
    alphabets = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    numbers = "0123456789"

    lists =
      cond do
        type == :alpha -> alphabets <> String.downcase(alphabets)
        type == :numeric -> numbers
        type == :upcase -> alphabets
        type == :downcase -> String.downcase(alphabets)
        type == :upcase_numeric -> alphabets <> numbers
        type == :downcase_numeric -> String.downcase(alphabets) <> numbers
        true -> alphabets <> String.downcase(alphabets) <> numbers
      end
      |> String.split("", trim: true)

    do_randomizer(length, lists)
  end

  @doc false
  defp get_range(length) when length > 1, do: 1..length
  defp get_range(_length), do: [1]

  @doc false
  defp do_randomizer(length, lists) do
    get_range(length)
    |> Enum.reduce([], fn _, acc -> [Enum.random(lists) | acc] end)
    |> Enum.join("")
  end

  @spec crypto_random_string(non_neg_integer()) :: binary()
  def crypto_random_string(length \\ 30) do
    length |> :crypto.strong_rand_bytes() |> Base.url_encode64(padding: false)
  end

  def unique_id() do
    UUID.uuid4(:hex) |> Base.url_encode64(padding: false)
  end
end