# frozen_string_literal: true

require 'json'

module OpenTracing
  module Instrumentation
    module Redis
      # SpanBuilder create span with tags and logs
      class SpanBuilder
        extend Forwardable

        def initialize(
          config: Config.new,
          error_writer: Common::ErrorWriter.new
        )
          @config = config
          @error_writer = error_writer
        end

        def_delegators :@config,
                       :tracer,
                       :span_name,
                       :component,
                       :log_args,
                       :log_reply

        def_delegators :@error_writer,
                       :write_error

        def start_active_scope(connection_class, peer_addr)
          tags = build_tags(connection_class, peer_addr)
          tracer.start_active_span(
            span_name,
            tags: tags,
          )
        end

        def build_tags(connection_class, peer_addr)
          {
            'span.kind' => 'client',
            'component' => component,
            'peer.address' => peer_addr,
            'peer.service' => 'redis',
            'redis.driver' => connection_class.to_s,
          }.compact
        end

        REDACTED_ARG = ['*'].freeze

        def write_log_command(span, command)
          command_name, *args = command
          args_value = log_args ? JSON.dump(args) : REDACTED_ARG * args.size

          span.log_kv(
            event: EVENT_WRITE,
            'redis.command': command_name,
            'redis.args': args_value,
          )
        end

        def write_error_reply(span, reply)
          return unless reply.is_a?(::Redis::CommandError)

          span.set_tag('error', true)
          span.log_kv(
            'error.kind': 'redis_error',
            message: reply.to_s,
            event: EVENT_READ,
          )
        end

        def write_log_reply(span, reply)
          write_error_reply(span, reply)

          return unless log_reply

          span.log_kv(
            event: EVENT_READ,
            'redis.reply': JSON.dump(reply),
          )
        end
      end
    end
  end
end