# Copyright (c) 2022 Contrast Security, Inc. See https://www.contrastsecurity.com/enduser-terms-0317a for more details.
# frozen_string_literal: true

require 'contrast/agent/assess/policy/trigger_method'
require 'contrast/components/logger'
require 'contrast/components/scope'

module Contrast
  module Utils
    # This utility allows us to report invalid configurations detected in customer applications, as determined by
    # Configuration Rules at runtime.
    module InvalidConfigurationUtil
      include Contrast::Components::Logger::InstanceMethods
      include Contrast::Components::Scope::InstanceMethods

      CS__PATH = 'path'
      CS__SESSION_ID = 'sessionId'
      CS__SNIPPET = 'snippet'

      # Build and report a finding for the given rule
      #
      # @param rule_id [String] the rule that was violated by the configuration
      # @param user_provided_options [Hash] the configuration value(s) which violated the rule
      # @param call_location [Thread::Backtrace::Location] the location where the bad configuration was set
      def cs__report_finding rule_id, user_provided_options, call_location
        with_contrast_scope do
          finding = build_finding(rule_id, user_provided_options, call_location)
          return unless finding

          Contrast::Agent::Assess::Policy::TriggerMethod.report_finding(finding)
        end
      rescue StandardError => e
        logger.error('Unable to build a finding', e, rule: rule_id)
      end

      private

      # Set the properties needed to report and subsequently render this finding on the finding given.
      #
      # @param rule_id [String] the rule that was violated by the configuration
      # @param user_provided_options [Hash] the configuration value(s) which violated the rule
      # @param call_location [Thread::Backtrace::Location] the location where the bad configuration was set
      # @return [Contrast::Agent::Reporting::Finding]
      def build_finding rule_id, user_provided_options, call_location
        finding = Contrast::Agent::Reporting::Finding.new(rule_id)
        finding.properties[CS__SESSION_ID] = user_provided_options[:key].to_s if user_provided_options
        # just get the file name, not the full path
        finding.properties[CS__PATH] = call_location.path.split(Contrast::Utils::ObjectShare::SLASH).last
        finding.properties[CS__SNIPPET] = file_snippet(call_location.absolute_path, call_location)
        finding.hash_code = Contrast::Utils::HashDigest.generate_config_hash(finding)
        finding
      end

      # @param file_path [String] full path to the file with the property
      # @param call_location [Thread::Backtrace::Location] the location where the bad configuration was set
      def file_snippet file_path, call_location
        idx = call_location&.lineno
        if file_path && idx && File.exist?(file_path)
          idx = idx > 5 ? idx - 5 : 0
          snippet = +''
          File.foreach(file_path).with_index do |line, line_num|
            next unless line_num >= idx
            break if line_num > idx + 10

            snippet << line
            snippet << Contrast::Utils::ObjectShare::NEW_LINE
          end
          return snippet
        end
        call_location&.label&.dup
      end
    end
  end
end