validate presence of first and lastname

app/controllers/volunteers_controller.rb

@@ -21,8 +21,6 @@ class VolunteersController < ApplicationController
 
   def create
     @volunteer = Volunteer.new(volunteer_params)
-    @volunteer.schedules << Schedule.build
-    @volunteer.build_contact
     @volunteer.registrar = current_user
     authorize @volunteer
     if @volunteer.save
@@ -36,7 +34,8 @@ class VolunteersController < ApplicationController
     state_was_registered = @volunteer.registered?
     return render :edit unless @volunteer.update(volunteer_params)
     if state_was_registered && @volunteer.accepted? && invite_volunteer_user
-      redirect_to volunteers_path, notice: t('invite_sent', email: @volunteer.contact.contact_emails.first.body)
+      redirect_to volunteers_path,
+        notice: t('invite_sent', email: @volunteer.contact.contact_emails.first.body)
     else
       redirect_to @volunteer, notice: t('volunteer_updated')
     end

app/models/contact.rb

 class Contact < ApplicationRecord
   belongs_to :contactable, polymorphic: true, optional: true
 
-  validates :last_name, presence: true, if: :department?
-
   has_many :contact_emails
   accepts_nested_attributes_for :contact_emails, allow_destroy: true
   has_many :contact_phones
   accepts_nested_attributes_for :contact_phones, allow_destroy: true
 
+  validates :last_name, presence: true
+  validates :first_name, presence: true, unless: :department?
+
   def to_s
     last_name
   end
 
   def full_name
-    "#{try(:first_name)} #{last_name}"
+    "#{try(:first_name)} #{try(:last_name)}"
   end
 
   def department?
     contactable_type == 'Department'
   end
-
-  def volunteer?
-    contactable_type == 'Volunteer'
-  end
 end

app/models/volunteer.rb

@@ -2,14 +2,20 @@ class Volunteer < ApplicationRecord
   include AssociatableFields
   include GenderCollection
   include FullName
+  acts_as_paranoid
+  before_save :default_state
 
   has_one :contact, as: :contactable
   accepts_nested_attributes_for :contact
+
   has_one :first_language
 
-  acts_as_paranoid
+  belongs_to :user, optional: true
 
-  before_save :default_state
+  belongs_to :registrar, optional: true,
+    class_name: 'User', foreign_key: 'registrar_id'
+
+  has_attached_file :avatar, styles: { thumb: '100x100#' }
 
   REGISTERED = 'registered'.freeze
   ACCEPTED = 'accepted'.freeze
@@ -19,12 +25,7 @@ class Volunteer < ApplicationRecord
   STATES_FOR_REVIEWED = [ACCEPTED, REJECTED, INACTIVE, RESIGNED].freeze
   STATES = [REGISTERED] + STATES_FOR_REVIEWED
 
-  belongs_to :user, optional: true
-  belongs_to :registrar, optional: true,
-    class_name: 'User', foreign_key: 'registrar_id'
-
-  has_attached_file :avatar, styles: { thumb: '100x100#' }
-
+  validates :contact, presence: true
   validates :state, inclusion: { in: STATES }
   validates_attachment :avatar, content_type: {
     content_type: /\Aimage\/.*\z/