quote.rb

class Quote < ApplicationRecord

  belongs_to :user
  belongs_to :speaker,  class_name: "Artist"
  belongs_to :topic,    class_name: "Artist"
  belongs_to :genre

  delegate :medium, to: :genre, allow_nil: true

  accepts_nested_attributes_for :speaker
  accepts_nested_attributes_for :topic

  validates  :user_id,    presence: true
  validates  :text,       presence: true, length: { maximum: 1200 }
  validates  :source,     presence: true, length: { maximum: 420 },
                          url: { no_local: true, message: 'needs to be cited with
                                by linking to a real url. Make sure to use http://
                                or https://.' }
  validates  :speaker_id, presence: true
  validates  :topic_id,   presence: true

  validate   :topic_cant_be_a_speaker
  validate   :text_cannot_have_double_quotes_included
  validate   :check_medium

  private

    def topic_cant_be_a_speaker
      errors.add(:topic, 'can\'t be the same as the speaker. We don\'t allow
        artists to talk about themselves ;)') if speaker == topic
    end

    def text_cannot_have_double_quotes_included
      if text.scan('"').present?
        errors.add(:text, 'for your quote doesn\'t require you to add the
          "double quotes." We\'ll add those for you."')
      end
    end

    def check_medium
      if genre.try(:medium) != medium
        errors.add(:base, 'You need to select a genre that applies to the medium you\'ve selected')
      end
    end
end