defmodule Openmaize.ConfirmEmail do
  @moduledoc """
  Confirm a user's email address.

  ## Options

  There are four options - in most cases you will not need to change
  the `repo` and `user_model` options:

    * repo - the name of the repo
      * the default is MyApp.Repo - using the name of the project
    * user_model - the name of the user model
      * the default is MyApp.User - using the name of the project
    * key_expires_after - the length, in minutes, that the token is valid for
      * the default is 60 minutes (1 hour)
    * mail_function - the emailing function that you need to define

  ## Email function

  Emailing the end user is the developer's responsibility. If you have
  generated files with the `mix openmaize.phx --confirm`
  command, then you will have a template at `lib/your_project_name/mailer.ex`.
  You need to complete this template with the mailing library of your
  choice.

  ## Examples with Phoenix

  Add the following command to the `web/router.ex` file:

      get "/sessions/confirm_email", SessionController, :confirm_email

  Then add the following to the `session_controller.ex` file:

      plug Openmaize.ConfirmEmail, [mail_function: &Mailer.send_receipt/1] when action in [:confirm]

  """

  use Openmaize.Confirm.Base

  @doc """
  Generate a confirmation token and a link containing the email address
  and the token.

  The link is used to create the url that the user needs to follow to
  confirm the email address.

  The user_id is the actual name or email address of the user, and
  unique_id refers to the type of identifier. For example, if you
  want to use `username=fred` in your link, you need to set the
  unique_id to :username. The default unique_id is :email.
  """
  def gen_token_link(user_id, unique_id \\ :email) do
    key = :crypto.strong_rand_bytes(24) |> Base.url_encode64
    {key, "#{unique_id}=#{URI.encode_www_form(user_id)}&key=#{key}"}
  end
end
