# Shamelessly copied from ActionDispatch::RequestId
require 'securerandom'
require 'active_support/core_ext/string/access'
require 'active_support/core_ext/object/blank'

# rubocop:disable Lint/AssignmentInCondition, Metrics/LineLength, Style/GuardClause
module Loga
  module Rack
    # Makes a unique request id available to the action_dispatch.request_id env variable (which is then accessible through
    # ActionDispatch::Request#uuid) and sends the same id to the client via the X-Request-Id header.
    #
    # The unique request id is either based on the X-Request-Id header in the request, which would typically be generated
    # by a firewall, load balancer, or the web server, or, if this header is not available, a random uuid. If the
    # header is accepted from the outside world, we sanitize it to a max of 255 chars and alphanumeric and dashes only.
    #
    # The unique request id can be used to trace a request end-to-end and would typically end up being part of log files
    # from multiple pieces of the stack.
    class RequestId
      def initialize(app)
        @app = app
      end

      def call(env)
        env['action_dispatch.request_id'] = external_request_id(env) || internal_request_id
        @app.call(env).tap do |_status, headers, _body|
          headers['X-Request-Id'] = env['action_dispatch.request_id']
        end
      end

      private

      def external_request_id(env)
        if request_id = env['HTTP_X_REQUEST_ID'].presence
          request_id.gsub(/[^\w\-]/, '').first(255)
        end
      end

      def internal_request_id
        SecureRandom.uuid
      end
    end
  end
end
# rubocop:enable Lint/AssignmentInCondition, Metrics/LineLength, Style/GuardClause