# encoding: utf-8
# This file is distributed under New Relic's license terms.
# See https://github.com/newrelic/rpm/blob/master/LICENSE for complete details.
# frozen_string_literal: true

module NewRelic
  module Agent
    module DistributedTraceMetrics
      extend self

      ALL_SUFFIX = "all"
      ALL_WEB_SUFFIX = "allWeb"
      ALL_OTHER_SUFFIX = "allOther"

      UNKNOWN_CALLER_PREFIX = "%s/Unknown/Unknown/Unknown/%s"

      def transaction_type_suffix
        if Transaction.recording_web_transaction?
          ALL_WEB_SUFFIX
        else
          ALL_OTHER_SUFFIX
        end
      end

      def record_metrics_for_transaction transaction
        return unless Agent.config[:'distributed_tracing.enabled']
        dt = transaction.distributed_tracer
        payload = dt.distributed_trace_payload || dt.trace_state_payload

        record_caller_by_duration_metrics transaction, payload
        record_transport_duration_metrics transaction, payload
        record_errors_by_caller_metrics transaction, payload
      end

      def prefix_for_metric name, transaction, payload
        if payload
          "#{name}/" \
          "#{payload.parent_type}/" \
          "#{payload.parent_account_id}/" \
          "#{payload.parent_app_id}/" \
          "#{transaction.distributed_tracer.caller_transport_type}"
        else
          UNKNOWN_CALLER_PREFIX % [name, transaction.distributed_tracer.caller_transport_type]
        end
      end

      def record_caller_by_duration_metrics transaction, payload
        prefix = prefix_for_metric "DurationByCaller", transaction, payload
        record_unscoped_metric transaction, prefix, transaction.duration
      end

      def record_transport_duration_metrics transaction, payload
        return unless payload

        prefix = prefix_for_metric "TransportDuration", transaction, payload
        duration = transaction.calculate_transport_duration payload
        record_unscoped_metric transaction, prefix, duration
      end

      def record_errors_by_caller_metrics transaction, payload
        return unless transaction.exceptions.size > 0

        prefix = prefix_for_metric "ErrorsByCaller", transaction, payload
        record_unscoped_metric transaction, prefix, 1
      end

      private

      def record_unscoped_metric transaction, prefix, duration
        transaction.metrics.record_unscoped "#{prefix}/#{ALL_SUFFIX}", duration
        transaction.metrics.record_unscoped "#{prefix}/#{transaction_type_suffix}", duration
      end
    end
  end
end