defmodule CoreUtils.PaginationHelper do
  @moduledoc """
  Utilities for query pagination
  """

  import Ecto.Query

  @doc """
  Implements simple pagination

  Returns query with limit and offset

  ## Examples

    iex> CoreUtils.PaginationHelper.set_pagination(query, limit, page)
    query


  """
  def set_pagination(query, lim, page) when lim >= 0 and page > 0 do
    page = page - 1
    offst = lim * page
    query |> limit(^lim) |> offset(^offst)
  end

  def set_pagination(query, lim, _) when lim >= 0 do
    query |> limit(^lim)
  end

  def set_pagination(query, _, _), do: query
end