module CanHaz
  module ModelExtensions
    module Object

      # Checks if the model is accessible by a given subject and a given permission
      # This is a proxy to subject.can?(permission, subject)
      #
      # @param subject [ActiveRecord::Base] The subject we are testing
      # @param permission [String, Symbol] The permission we want to test the subject on
      # @return [Boolean] True if the subject has the permission on this object, false otherwise
      def accessible_by?(subject, permission)
        subject.can?(permission, self)
      end

      # Gets the subjects that have the corresponding permission and type on this model
      #
      # @param type [Class] The type of the subjects we're looking for
      # @param permission [String, Symbol] The permission
      def subjects_with_permission(type, permission)
        type.joins("INNER JOIN can_haz_permissions ON can_haz_permissions.csubject_id = #{type.table_name}.id").where('cobject_id = ? AND cobject_type = ?', self.id, self.class.to_s).where('csubject_type = ?', type.to_s).where('permission_name = ?', permission)
      end


      # Removes all rights on this object
      #
      def not_accessible
        CanHazPermission.destroy_all(['cobject_id = ? AND cobject_type = ?', self.id, self.class.to_s])
      end

      def canhaz_object?
        true
      end

      module ClassMethods
        # Gets the subjects that have the corresponding permission and type on this model
        #
        # params objects [Array or Object] The object(s) that you want subjects with permission
        # @param type [Class] The type of the subjects we're looking for
        # @param permission [String, Symbol] The permission
        def subjects_with_permission(objects, type, permission)
          class_name = (objects.is_a?(Array) ? objects.first.try(:class).try(:name) : objects.class.name)

          type.joins("INNER JOIN can_haz_permissions ON can_haz_permissions.csubject_id = #{type.table_name}.id")
          .where(:'can_haz_permissions.cobject_type' => class_name)
          .where(:'can_haz_permissions.cobject_id' => objects)
          .where('csubject_type = ?', type.to_s)
          .where('permission_name = ?', permission)
          .uniq
        end
      end
    end
  end
end