Event Model from a Rails project

event.rb

require "iconv"

class Event < ActiveRecord::Base
  belongs_to :event_category
  has_many :line_items
  has_many :region_links, :as => :region_linkable
  has_many :regions, :through => :region_links
  has_many :interest_links, :as => :interest_linkable
  has_many :interests, :through => :interest_links

  mount_uploader :attachment, AttachmentUploader

  before_save :create_title_url, :geolocation

  before_destroy :ensure_not_referenced_by_any_line_items

  validates :title, :datetime_start, :datetime_end, :event_category_id, :presence => true

  acts_as_taggable_on :tags

  scope :past_events, where("datetime_end < ?", Date.today)


  def date
    if self.datetime_start.day == self.datetime_end.day
      self.datetime_start.strftime('%A, %b %d, %Y')
    else
      "#{self.datetime_start.strftime('%A, %b %d')} - #{self.datetime_end.strftime('%A, %b %d, %Y')}"
    end
  end

  def lat_lng
    "#{self.lat}, #{self.lng}"
  end

  def time?
    if self.datetime_start.hour == 0 && self.datetime_end.hour == 0
      return false
    else
      return true
    end
  end


  # ensure that there are no line items referencing this event
  def ensure_not_referenced_by_any_line_items 
    if line_items.empty?
      return true 
    else
      errors.add(:base, 'Line Items present')
      return false
    end
  end

  def create_title_url
    self.title_url = Iconv.conv("ASCII//TRANSLIT//IGNORE","UTF8", self.title).gsub(/\s+/,"_").gsub(/\W/,"").gsub(/(_)+/,"_").downcase
  end

  def geolocation
    if self.address?
      geo = Geokit::Geocoders::GoogleGeocoder.geocode(self.address)
      self.lat = geo.lat
      self.lng = geo.lng
    end
  end

end