validates input_options based on input type

app/models/question.rb

@@ -4,8 +4,17 @@ class Question < ApplicationRecord
   has_many :answers
   belongs_to :quiz
 
-  validates_presence_of :quiz_id
-  validates_presence_of :question
-  validates_presence_of :category
-  validates_presence_of :input_type
+  before_validation :compact_input_options
+
+  validates :quiz_id, presence: true
+  validates :question, presence: true
+  validates :category, presence: true
+  validates :input_type, presence: true
+  validates :input_options, input_options_presence: true
+
+  private
+
+    def compact_input_options
+      self.input_options = input_options.reject(&:blank?)
+    end
 end

app/validators/input_options_presence_validator.rb

@@ -0,0 +1,11 @@
+class InputOptionsPresenceValidator < ActiveModel::EachValidator
+  def validate_each(record, attribute, value)
+    return true unless record.input_type =~ /radio|check/i
+    return true if value.present? && value.count > 0
+
+    record.errors[attribute] << (options[:message] ||
+                                "You must provide answer options for the selected input type.")
+
+    false
+  end
+end