class GraphQL::StaticValidation::DirectivesAreDefined
  include GraphQL::StaticValidation::Message::MessageHelper

  def validate(context)
    directive_names = context.schema.directives.keys
    context.visitor[GraphQL::Language::Nodes::Directive] << -> (node, parent) {
      validate_directive(node, directive_names, context.errors)
    }
  end

  private

  def validate_directive(ast_directive, directive_names, errors)
     if !directive_names.include?(ast_directive.name)
       errors << message("Directive @#{ast_directive.name} is not defined", ast_directive)
    end
  end
end