# Copyright (c) 2020 Contrast Security, Inc. See https://www.contrastsecurity.com/enduser-terms-0317a for more details.
# frozen_string_literal: true

require 'contrast/framework/sinatra/support'

module Contrast
  module Framework
    module Sinatra
      module Patch
        # Our patch into the Sinatra::Base Class, allowing for the inventory of the
        # routes called by the application
        module Base
          class << self
            # Use logic copied from Sinatra::Base#process_route to determine which
            # pattern matches the request being invoked by Sinatra::Base#call!
            #
            # @param clazz [Class] the Class that extends Sinatra::Base in
            #   which this route is defined.
            # @param settings [Object] the Sinatra::Base @settings object.
            # @param args [Array<Object>] we rely on the @settings object in
            #   Sinatra::Base and the env variable passed in as args[0].
            def map_route clazz, settings, *args
              context = Contrast::Agent::REQUEST_TRACKER.current
              return unless context

              env = args[0]
              return unless env
              return unless settings

              convert_routes(context, clazz, settings, env)
            rescue StandardError
              # Being careful here since we're directly patching something
            end

            def instrument
              @_instrument ||= begin
                                ::Sinatra::Base.class_eval do
                                  alias_method :cs__patched_sinatra_base_call!, :call!
                                  # publicly available method for Sinatra::Base things -- unfortunately,
                                  # getting the routes appear to require a lookup every time
                                  def call! *args
                                    Contrast::Framework::Sinatra::Patch::Base.map_route(cs__class, settings, *args)
                                    cs__patched_sinatra_base_call!(*args)
                                  end
                                end
                                true
                              end
            end

            private

            # Find the route that matches this request. Since we're using
            # settings, we should resolve in the same precedence as Sinatra
            def convert_routes context, clazz, settings, env
              # There isn't a Request object in the Sinatra::Base yet - it's made
              # during the #call! method, which we're patching - so we need to
              # access the env
              method = env[::Rack::REQUEST_METHOD]
              # get all potential routes for this request type
              routes = settings.routes[method]
              return unless routes

              route = env[::Rack::PATH_INFO]
              route = route.to_s

              # Do some cleanup that matches Sinatra::Base#process_route
              route = '/' if route.empty? && !settings.empty_path_info?
              route = route[0..-2] if !settings.strict_paths? && route != '/' && route.end_with?('/')

              routes.each do |pattern, _, _| # Mustermann::Sinatra
                next unless pattern.params(route)

                dtm = Contrast::Api::Dtm::RouteCoverage.from_sinatra_route(clazz, method, pattern)
                context.append_route_coverage(dtm)
                break
              end
            end
          end
        end
      end
    end
  end
end