panel/app/jobs/backtrace_job.rb

# frozen_string_literal: true

# Procesa los errores de JavaScript
class BacktraceJob < ApplicationJob
  queue_as :low_priority

  attr_reader :params, :site_id

  def perform(site_id:, params:)
    @site_id = site_id
    @params = params

    return if files.empty?

    params['errors'].each do |error|
      error['backtrace'].each do |backtrace|
        offset = SourceMap::Offset.new(backtrace['line'], backtrace['column'])
        mapping = sourcemap.bsearch(offset)

        next unless mapping

        backtrace['file'] = mapping.source
        backtrace['line'] = mapping.original.line
        backtrace['column'] = mapping.original.column
      end
    end

    begin
      raise NoMethodError
    rescue NoMethodError => e
      ExceptionNotifier.notify_exception(e, data: { site: site.name, params: params })
    end
  end

  private

  def site
    @site ||= Site.find(site_id)
  end

  # Obtiene todos los archivos del backtrace
  def files
    @files ||= params['errors'].map { |x| x['backtrace'] }.flatten.map { |x| x['file'].split('@').last }.uniq.select { |x| x&.start_with?(site.url) }
  end

  # Asume que todos los sourcemaps comparten la misma URL, lo
  # correcto sería buscarlo en sourceMappingURL al final de cada
  # archivo.
  #
  # Descarga los archivos y obtiene el backtrace original.
  def sourcemap
    @sourcemap ||=
      begin
        files.map { |x| "#{x}.map" }.map do |x|
          data = FastJsonparser.parse(Rails.cache.fetch(x, expires_in: 12.hours) do
            Down.open(x).read
          end, symbolize_keys: false)

          SourceMap::Map.from_hash data
        rescue Down::Error, FastJsonparser::Error
          SourceMap::Map.new
        end.reduce(&:+)
      end
  end
end