require 'rails/configuration'

module Rails
  class Railtie
    class Configuration
      def initialize
        @@options ||= {}
      end

      # Expose the eager_load_namespaces at "module" level for convenience.
      def self.eager_load_namespaces #:nodoc:
        @@eager_load_namespaces ||= []
      end

      # All namespaces that are eager loaded
      def eager_load_namespaces
        @@eager_load_namespaces ||= []
      end

      # Add files that should be watched for change.
      def watchable_files
        @@watchable_files ||= []
      end

      # Add directories that should be watched for change.
      # The key of the hashes should be directories and the values should
      # be an array of extensions to match in each directory.
      def watchable_dirs
        @@watchable_dirs ||= {}
      end

      # This allows you to modify the application's middlewares from Engines.
      #
      # All operations you run on the app_middleware will be replayed on the
      # application once it is defined and the default_middlewares are
      # created
      def app_middleware
        @@app_middleware ||= Rails::Configuration::MiddlewareStackProxy.new
      end

      # This allows you to modify application's generators from Railties.
      #
      # Values set on app_generators will become defaults for application, unless
      # application overwrites them.
      def app_generators
        @@app_generators ||= Rails::Configuration::Generators.new
        yield(@@app_generators) if block_given?
        @@app_generators
      end

      # First configurable block to run. Called before any initializers are run.
      def before_configuration(&block)
        ActiveSupport.on_load(:before_configuration, yield: true, &block)
      end

      # Third configurable block to run. Does not run if +config.cache_classes+
      # set to false.
      def before_eager_load(&block)
        ActiveSupport.on_load(:before_eager_load, yield: true, &block)
      end

      # Second configurable block to run. Called before frameworks initialize.
      def before_initialize(&block)
        ActiveSupport.on_load(:before_initialize, yield: true, &block)
      end

      # Last configurable block to run. Called after frameworks initialize.
      def after_initialize(&block)
        ActiveSupport.on_load(:after_initialize, yield: true, &block)
      end

      # Array of callbacks defined by #to_prepare.
      def to_prepare_blocks
        @@to_prepare_blocks ||= []
      end

      # Defines generic callbacks to run before #after_initialize. Useful for
      # Rails::Railtie subclasses.
      def to_prepare(&blk)
        to_prepare_blocks << blk if blk
      end

      def respond_to?(name, include_private = false)
        super || @@options.key?(name.to_sym)
      end

    private

      def method_missing(name, *args, &blk)
        if name.to_s =~ /=$/
          key = $`.to_sym
          value = args.first

          if value.is_a?(Hash)
            @@options[key] = ChainedConfigurationOptions.new value
          else
            @@options[key] = value
          end
        elsif @@options.key?(name)
          @@options[name]
        else
          @@options[name] = ActiveSupport::OrderedOptions.new
        end
      end

      class ChainedConfigurationOptions < ActiveSupport::OrderedOptions # :nodoc:
        def initialize(value)
          value.each_pair { |k, v| set_value k, v }
        end

        def method_missing(meth, *args)
          if meth =~ /=$/
            key = $`.to_sym
            value = args.first

            set_value key, value
          else
            self.fetch(meth) { super }
          end
        end

        private

        def set_value(key, value)
          if value.is_a?(Hash)
            value = self.class.new(value)
          end

          self[key] = value
        end
      end
    end
  end
end