# Copyright (c) 2023 Contrast Security, Inc. See https://www.contrastsecurity.com/enduser-terms-0317a for more details.
# frozen_string_literal: true

require 'contrast/agent/assess/policy/propagator/select'
require 'contrast/utils/duck_utils'

module Contrast
  module Agent
    module Assess
      module Policy
        module Propagator
          # Propagation that results in all the tags of the source being
          # applied to the target at the point of insertion. The target's
          # preexisting tags are shifted to account for this insertion.
          class Response < Contrast::Agent::Assess::Policy::Propagator::Base
            class << self
              # This will path the Net::HTTP.request method. It takes two parameters:
              #  - req: Net::HTTPGenericRequest
              #  - body: String
              # As body may be optional, we need to check if it's nil or not.
              #
              # @param propagation_node [Contrast::Agent::Assess::Policy::PropagationNode]
              # @param preshift [Contrast::Agent::Assess::Preshift]
              # @param ret [Object] Return targer from method invocation.
              # @param _block [nil, {}] block passed.
              def net_response_keep propagation_node, preshift, ret, _block
                return unless Contrast::ASSESS.track_response_as_source?

                # Check to see if the argument is of correct type, and whether the body is tracked or not.
                # if it's tracked and the body is not nil, then copy the properties from the source's body
                # to the target's body.
                source_body = if preshift.args.length == 2
                                preshift.args[1]
                              else
                                preshift.args[0]&.body
                              end
                copy_body_tags(propagation_node, source_body, ret)
              end

              private

              # Copy the properties form source body to the response body, if one is present.
              #
              # @param propagation_node [Contrast::Agent::Assess::Policy::PropagationNode]
              # @param source_body [String] the tracked body to copy from.
              # @param ret [String] the return target from method invocation.
              # @return [String, nil]
              def copy_body_tags propagation_node, source_body, ret
                return if Contrast::Utils::DuckUtils.empty_duck?(source_body)
                return unless ret&.body&.cs__is_a?(String)
                return unless source_body&.cs__is_a?(String)
                return unless (properties = Contrast::Agent::Assess::Tracker.properties!(ret.body))

                # KEEP
                properties.copy_from(source_body, ret.body, 0, propagation_node.untags)
                ret
              end
            end
          end
        end
      end
    end
  end
end