class Aws::S3::Plugins::S3Signer::BucketRegionErrorHandler

def call(context)
  response = @handler.call(context)
  handle_region_errors(response)
end

def fips_region?(resp)
  resp.context.http_request.endpoint.host.include?('fips')
end

def get_region_and_retry(context)
  actual_region = context.http_response.headers['x-amz-bucket-region']
  actual_region ||= region_from_body(context.http_response.body_contents)
  update_bucket_cache(context, actual_region)
  log_warning(context, actual_region)
  resign_with_new_region(context, actual_region)
  @handler.call(context)
end

def handle_region_errors(response)
  if wrong_sigv4_region?(response) && !fips_region?(response)
    get_region_and_retry(response.context)
  else
    response
  end
end

def log_warning(context, actual_region)
  msg = "S3 client configured for #{context.config.region.inspect} " +
    "but the bucket #{context.params[:bucket].inspect} is in " +
    "#{actual_region.inspect}; Please configure the proper region " +
    "to avoid multiple unnecessary redirects and signing attempts\n"
  if logger = context.config.logger
    logger.warn(msg)
  else
    warn(msg)
  end
end

def region_from_body(body)
  region = body.match(/<Region>(.+?)<\/Region>/)[1]
  if region.nil? || region == ""
    raise "couldn't get region from body: #{body}"
  else
    region
  end
end

def resign_with_new_region(context, actual_region)
  context.http_response.body.truncate(0)
  context.http_request.endpoint.host = S3Signer.new_hostname(context, actual_region)
  context.metadata[:redirect_region] = actual_region
  Aws::Plugins::SignatureV4.apply_signature(
    context: context,
    signer: S3Signer.build_v4_signer(
      region: actual_region,
      credentials: context.config.credentials
    )
  )
end

def update_bucket_cache(context, actual_region)
  S3::BUCKET_REGIONS[context.params[:bucket]] = actual_region
end

def wrong_sigv4_region?(resp)
  resp.context.http_response.status_code == 400 &&
  (
    resp.context.http_response.headers['x-amz-bucket-region'] ||
    resp.context.http_response.body_contents.match(/<Region>.+?<\/Region>/)
  )
end