#
# This file is part of Astarte.
#
# Copyright 2017 Ispirata Srl
#
# 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 Astarte.AppEngine.APIWeb.ErrorHelpers do
  @moduledoc """
  Conveniences for translating and building error messages.
  """

  @doc """
  Translates an error message using gettext.
  """
  def translate_error({msg, opts}) do
    # Because error messages were defined within Ecto, we must
    # call the Gettext module passing our Gettext backend. We
    # also use the "errors" domain as translations are placed
    # in the errors.po file.
    # Ecto will pass the :count keyword if the error message is
    # meant to be pluralized.
    # On your own code and templates, depending on whether you
    # need the message to be pluralized or not, this could be
    # written simply as:
    #
    #     dngettext "errors", "1 file", "%{count} files", count
    #     dgettext "errors", "is invalid"
    #
    if count = opts[:count] do
      Gettext.dngettext(Astarte.AppEngine.APIWeb.Gettext, "errors", msg, msg, count, opts)
    else
      Gettext.dgettext(Astarte.AppEngine.APIWeb.Gettext, "errors", msg, opts)
    end
  end
end
