AgileVentures/TakeMeAway

class Menu < ActiveRecord::Base
  has_many :menu_items_menus, inverse_of: :menu, dependent: :destroy
  # 'inverse_of' allows access to in-memory representation of menu object for
  # validation of menu_items_menu object (before either are saved and hence access
  # via DB is not possible)
  
  has_many :menu_items, through: :menu_items_menus

  accepts_nested_attributes_for :menu_items_menus, reject_if: :all_blank, allow_destroy: :true

  validates :title, presence: true
  validates :start_date, presence: true
  validates :end_date, presence: true
  
  validate  :end_date_not_earlier_than_start_date
  validate  :items_not_in_overlapping_menu
  
  def end_date_not_earlier_than_start_date
    if end_date && (end_date < start_date)
      errors[:end_date] << 'must be not be earlier than start date'
    end 
  end
  
  validate  :items_not_in_overlapping_menu
  def items_not_in_overlapping_menu
    if self.menu_items_menus
      self.menu_items_menus.each do |mim|
        if (not mim.marked_for_destruction?) && (err_msg = mim.overlapping_menu)
          errors[:item] << err_msg
        end
      end
    end
  end
 
  scope :this_week, -> { where("start_date <= ? AND end_date >= ?",
                          Date.today.end_of_week, Date.today) }
                          
  scope :today,     -> { where("start_date <= ? AND end_date >= ?",
                          Date.today, Date.today).order(:end_date) }                        
                          
  def self.item_in_menu?(item_to_check)
    # Checks whether the input menu_item is included in any current or future menu.

    item_to_check.menus.each do |menu|
      return true if menu.end_date >= Date.today
    end
    false
  end
end