require 'rack/contrib/response_headers'

module MetaRequest
  module Middlewares
    class Headers
      def initialize(app, app_config)
        @app = app
        @app_config = app_config
      end

      def call(env)
        request_path = env['PATH_INFO']
        middleware = Rack::ResponseHeaders.new(@app) do |headers|
          headers['X-Meta-Request-Version'] = MetaRequest::VERSION unless skip?(request_path)
        end
        middleware.call(env)
      end

      private

      # returns true if path should be ignored (not handled by RailsPanel extension)
      #
      def skip?(path)
        asset?(path) || path.start_with?('/__better_errors/')
      end

      def asset?(path)
        @app_config.respond_to?(:assets) && path.start_with?(assets_prefix)
      end

      def assets_prefix
        "/#{@app_config.assets.prefix[/\A\/?(.*?)\/?\z/, 1]}/"
      end

    end
  end
end