# Copyright (c) 2015 Sqreen. All Rights Reserved.
# Please refer to our terms for more information: https://www.sqreen.com/terms.html

module Sqreen
  module Dependency
    module Sinatra
      module_function

      def required?
        Sqreen::Dependency.const_exist?('Sinatra::Base')
      end

      def insert_sqreen_middlewares(builder, *args, &block)
        Sqreen.log.debug { 'Inserting Sqreen middlewares for Sinatra' }

        insert_middleware(builder, Sqreen::ErrorHandlingMiddleware, args, block) do |p, u|
          if middlewares(builder).include?(::Sinatra::ShowExceptions)
            Sqreen.log.warn('Sinatra :show_exceptions detected: Sinatra exception handling may prevent the Sqreen error page to display on attacks.')
          end

          if (i = middlewares(builder).index(::Rack::Head))
            u.insert(i, p)
          elsif (i = middlewares(builder).index(::Rack::MethodOverride))
            u.insert(i + 1, p)
          elsif (i = middlewares(builder).index(::Sinatra::ExtendedRack))
            u.insert(i + 1, p)
          else
            u.insert(0, p)
          end
        end

        insert_middleware(builder, Sqreen::Middleware, args, block) do |p, u|
          if (i = middlewares(builder).index(::Sinatra::ExtendedRack))
            u.insert(i, p)
          else
            u.insert(0, p)
          end
        end

        insert_middleware(builder, Sqreen::SinatraMiddleware, args, block) do |p, u|
          if ::Sqreen::Dependency.const_exist?('Rack::PostBodyContentTypeParser') && (i = middlewares(builder).index(::Rack::PostBodyContentTypeParser))
            u.insert(i + 1, p)
          elsif (i = middlewares(builder).index(::Rack::Protection))
            u.insert(i + 1, p)
          else
            u.append(p)
          end
        end
      end

      def wrap_middleware(middleware, *args, &block)
        proc { |app| middleware.new(app, *args, &block) }
      end

      def insert_middleware(builder, middleware, args, block)
        use = builder.instance_variable_get('@use')
        wrapped = wrap_middleware(middleware, *args, &block)

        catch(:skip) do
          throw(:skip) if middlewares(builder).include?(middleware)

          yield(wrapped, use)
        end
      end

      def inspect_middlewares(builder)
        Sqreen.log.debug do
          "Middlewares: " << middlewares(builder).map(&:inspect).inspect
        end
      end

      def middlewares(builder)
        builder.instance_variable_get(:@use).map do |p|
          unless p.respond_to?(:binding) && p.binding.local_variable_defined?(:middleware)
            next :unknown
          end

          p.binding.local_variable_get(:middleware)
        end
      end
    end
  end
end