mirego/emotions

module Emotions
  module Emotion
    extend ActiveSupport::Concern

    included do
      # Validations
      validates :emotional, presence: true
      validates :emotive, presence: true

      # Custom validations
      validate :ensure_valid_emotion_name
      validate { ensure_valid_associated_record :emotional }
      validate { ensure_valid_associated_record :emotive }

      # Associations
      belongs_to :emotional, polymorphic: true
      belongs_to :emotive, polymorphic: true

      # Callbacks
      after_create :update_emotion_counter
      after_destroy :update_emotion_counter
    end

  protected

    # Update the `<emotion>_emotions_counter` for the emotive record
    def update_emotion_counter
      emotive.update_emotion_counter(emotion)
      emotional.update_emotion_counter(emotion)
    end

    # Make sure we're using an allowed emotion name
    def ensure_valid_emotion_name
      unless Emotions.emotions.include?(emotion.try(:to_sym))
        errors.add :emotion, I18n.t(:invalid, scope: [:errors, :messages])
      end
    end

    # Make sure that both emotive and emotional records are actually able to
    # express and/or receive emotions
    def ensure_valid_associated_record(association)
      value = send(association)
      predicate = :"#{association}?"

      if !value.class.respond_to?(predicate) || !value.class.send(predicate)
        errors.add association, I18n.t(:invalid, scope: [:errors, :messages])
      end
    end
  end
end