blog 2-4

post_form.rb

class PostForm
  include Virtus
  include ActiveModel::Model

  #Post attributes
  attribute :post,  Object
  attribute :title, String
  attribute :body,  String
  #Tag attributes
  attribute :tags, String # first tag,second tag,third tag

  #Validations
  validates :title, :body, presence: true

  def initialize(attributes = {})
    unless attributes[:id].nil?
      @post  = Post.find(attributes[:id])
      @id    = @post.id
      @title = attributes[:title].nil? ? @post.title : attributes[:title]
      @body  = attributes[:body].nil? ? @post.body : attributes[:body]
      @tags  = attributes[:tags].nil? ? @post.tags.map(&:title).join(',') : attributes[:tags]
    else
      super(attributes)
    end
  end


  def save
    if valid?
      persist!
    else
      false
    end
  end

  def update
    if valid?
      update!
    else
      false
    end
  end

  private

  def persist!
    @post = Post.create(title: title, body: body)
    save_tags @post
  end

  def update!
    @post.update_attributes(title: title, body: body)
    @post.tags.clear
    save_tags @post
  end

  def save_tags post
    tags.split(',').each { |title| post.tags << Tag.find_or_create_by(title: title) }
  end
end