def index
  @recipe_collection = RecipeCollection.from_params(params)
  render json: @recipe_collection.recipes
end

class RecipeCollection
  attr_accessor :featured, :time_filter

  # Handles the logic of sorting params into a collection
  def self.from_params(params)
    RecipeCollection.new.tap do |recipe_collection|
      recipe_collection.time_filter = params[:time_filter]
      recipe_collection.featured = params[:featured]
    end
  end

  # Should return an ActiveRecord relation
  def recipes
    query = Recipe.scoped
    query.featured if featured.present?
    query.filter_by_time(time_filter)
  end

  def time_filter
  valid_time_filters.include?( @time_filter ) ? @time_filter : default_time_filter
  end

  def default_time_filter
    "today"
  end

  def valid_time_filters
    %w[ today yesterday this-week this-year ]
  end
end