Group Discussion Creator

creator.rb

class Creator
  class << self
    def create!(*args)
      create(*args).tap do |object|
        raise ActiveRecord::RecordInvalid.new(object) if object.new_record?
      end
    end
  end
end

discussion_creator.rb

class Group::DiscussionCreator < Creator

  class EmailDecoder < ::EmailDecoder
    def title 
      subject
    end

    def group
      descriptor = email.to.first.split("@").first
      group_url = descriptor.gsub(/^group\+/, '')
      Group.where(url: group_url).first
    end
  end

  class << self
    def create(*args)
      new(*args).create
    end

    def create_from_email(email)
      decoder = EmailDecoder.new(email)
      self.new(decoder.group, decoder.user, decoder.title, decoder.content).create
    end
  end

  def initialize(group, user, title, content)
    @group = group
    @user = user
    @title = title
    @content = content
  end

  def create
    @group.discussions.build(started_by: @user, title: @title).tap do |discussion|
      discussion.posts.build(content: @content, user: @user)
      discussion.save
      after_create unless discussion.new_record?
    end
  end
  
  def after_create
    Group::DiscussionNotifier.delay.notify_and_email(discussion.id) 
  end
end

email_decoder.rb

class EmailDecoder
  attr_reader :email

  def initialize(email)
    @email = email
  end

  def user
    user_email = User::EmailAddress.where(email_address: email.from.first).first
    user = user_email ? user_email.user : nil
  end

  def subject
    email.subject
  end

  def content
    body = (email.multipart?? email.text_part : email).body.decoded
    MailExtract.new(body).body
  end
end