module Concernz
  module Country
    extend ActiveSupport::Concern
    included do
      self.primary_key = 'country_id'

      # Diplomat represents Country
      has_many :diplomats, :class_name => 'Diplomat', :foreign_key => :represented_country_id, :dependent => :destroy

      # Diplomat serves in Country
      has_many :diplomats, :class_name => 'Diplomat', :foreign_key => :served_country_id, :dependent => :destroy

      # Country is involved in LanguageUse
      has_many :language_uses, :class_name => 'LanguageUse', :foreign_key => :country_id, :dependent => :destroy
      has_many :languages, :through => :language_uses

      # Country is involved in Representation
      has_many :representations, :class_name => 'Representation', :foreign_key => :country_id, :dependent => :destroy

      # Country is involved in Representation
      has_many :representations, :class_name => 'Representation', :foreign_key => :represented_country_id, :dependent => :destroy

      validates :country_name, :presence => true
    end
  end
end

module Concernz
  module Diplomat
    extend ActiveSupport::Concern
    included do
      self.primary_key = 'diplomat_id'

      # Diplomat represents Country
      belongs_to :represented_country, :class_name => 'Country', :foreign_key => :represented_country_id

      # Diplomat serves in Country
      belongs_to :served_country, :class_name => 'Country', :foreign_key => :served_country_id

      # Diplomat is involved in Fluency
      has_many :fluencies, :class_name => 'Fluency', :foreign_key => :diplomat_id, :dependent => :destroy
      has_many :languages, :through => :fluencies

      # Diplomat is an Ambassador and Ambassador is involved in Representation
      has_many :representations_via_ambassador, :class_name => 'Representation', :foreign_key => :ambassador_id, :dependent => :destroy

      validates :diplomat_name, :presence => true
      validates :represented_country_id, :presence => true
      validates :served_country_id, :presence => true
    end
  end
end

module Concernz
  module Fluency
    extend ActiveSupport::Concern
    included do
      # Fluency involves Diplomat
      belongs_to :diplomat, :foreign_key => :diplomat_id

      # Fluency involves Language
      belongs_to :language, :foreign_key => :language_id

      validates :diplomat_id, :presence => true
      validates :language_id, :presence => true
    end
  end
end

module Concernz
  module Language
    extend ActiveSupport::Concern
    included do
      self.primary_key = 'language_id'

      # Language is involved in Fluency
      has_many :fluencies, :class_name => 'Fluency', :foreign_key => :language_id, :dependent => :destroy
      has_many :diplomats, :through => :fluencies

      # Language is involved in LanguageUse
      has_many :language_uses, :class_name => 'LanguageUse', :foreign_key => :language_id, :dependent => :destroy
      has_many :countries, :through => :language_uses

      validates :language_name, :presence => true
    end
  end
end

module Concernz
  module LanguageUse
    extend ActiveSupport::Concern
    included do
      # LanguageUse involves Country
      belongs_to :country, :foreign_key => :country_id

      # LanguageUse involves Language
      belongs_to :language, :foreign_key => :language_id

      validates :language_id, :presence => true
      validates :country_id, :presence => true
    end
  end
end

module Concernz
  module Representation
    extend ActiveSupport::Concern
    included do
      self.primary_key = 'representation_id'

      # Representation involves Country
      belongs_to :country, :foreign_key => :country_id

      # Representation involves Country
      belongs_to :represented_country, :class_name => 'Country', :foreign_key => :represented_country_id

      # Representation involves Ambassador and Ambassador is a kind of Diplomat
      belongs_to :diplomat_via_ambassador, :class_name => 'Diplomat', :foreign_key => :ambassador_id

      validates :ambassador_id, :presence => true
      validates :country_id, :presence => true
      validates :represented_country_id, :presence => true
    end
  end
end