# encoding: utf-8
# frozen_string_literal: true

module Carbon
  module Compiler
    class Directive
      ATTACHING = %w(doc extern).freeze
      def self.handlers
        @_handlers ||= {}
      end

      def self.handle(name, &block)
        handlers[name.to_s] = block
      end

      require "carbon/compiler/directive/import"

      def initialize(node, file, index)
        @node = node
        @file = file
        @index = index
      end

      def call
        instance_exec(&self.class.handlers.fetch(name.to_s))
      end

      def name
        @node.value
      end

      def attach?
        ATTACHING.include?(name)
      end

    private

      def error_excessive_parameters(node, expected)
        @file.emit("Directive/Parameter/Excessive", node.location,
          [expected, node.parameters.size])
      end

      def error_invalid_parameter(parameter)
        @file.emit("Directive/Parameter/Invalid", parameter.location)
      end
    end
  end
end