module Zuul
  module ActiveRecord
    module Permission
      def self.included(base)
        base.send :extend, ClassMethods
        base.send :include, ContextAccessors
        base.send :include, InstanceMethods
      end

      module ClassMethods
        def self.extended(base)
          base.send :attr_accessible, :context, :context_id, :context_type, :slug if ::Zuul.should_whitelist?
          add_validations base
          add_associations base
        end

        def self.add_validations(base)
          base.send :validates_presence_of, :slug
          base.send :validates_uniqueness_of, :slug, :scope => [:context_id, :context_type], :case_sensitive => false
          base.send :validates_format_of, :slug, :with => /\A[a-z0-9_]+\Z/
        end

        def self.add_associations(base)
          base.send :has_many, base.auth_scope.permission_role_plural_key, :class_name => base.auth_scope.permission_role_class_name, :dependent => :destroy
          base.send :has_many, base.auth_scope.role_plural_key, :class_name => base.auth_scope.role_class_name, :through => base.auth_scope.permission_role_plural_key

          base.send :has_many, base.auth_scope.permission_subject_plural_key, :class_name => base.auth_scope.permission_subject_class_name, :dependent => :destroy
          base.send :has_many, base.auth_scope.subject_plural_key, :class_name => base.auth_scope.subject_class_name, :through => base.auth_scope.permission_subject_plural_key
        end
      end

      module InstanceMethods
        # Returns a list of contexts within which the permission has been assigned to roles and/or subjects
        def assigned_contexts
          role_contexts.concat(subject_contexts).uniq
        end

        # Returns a list of contexts within which the permission has been assigned to roles
        def role_contexts
          auth_scope do
            send(permission_role_plural_key).group(:context_type, :context_id).map(&:context)
          end
        end
        
        # Returns a list of contexts within which the permission has been assigned to subjects
        def subject_contexts
          auth_scope do
            send(permission_subject_plural_key).group(:context_type, :context_id).map(&:context)
          end
        end
      end
    end
  end
end