# frozen_string_literal: true

require_relative "opentelemetry/version"
require_relative "opentelemetry/configurator"
require_relative "opentelemetry/resource/detectors/aspecto"
require_relative "opentelemetry/resource/detectors/deployment"
require_relative "opentelemetry/config/remote_config"

require "opentelemetry/sdk"
require "opentelemetry/exporter/otlp"
require "opentelemetry/instrumentation/all"
require "opentelemetry-instrumentation-aws_sdk"

module Aspecto
  # Aspecto OpenTelemetry Distro
  module OpenTelemetry
    module_function

    class Error < StandardError; end

    def configure # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
      configurator = Configurator.new
      yield configurator if block_given?

      validate_configurator_options(configurator)

      ::OpenTelemetry::SDK.configure do |c|
        c.logger = Logger.new($stdout, level: configurator.log_level)
        c.resource = Aspecto::OpenTelemetry::Resource::Detectors::Aspecto.detect
        c.resource = Aspecto::OpenTelemetry::Resource::Detectors::Deployment.detect
        c.resource = configurator.config_override_resource # must be last
        c.use_all "OpenTelemetry::Instrumentation::ActionPack" => { enable_recognize_route: true },
                  "OpenTelemetry::Instrumentation::AwsSdk" => { suppress_internal_instrumentation: true }

        otlp_exporter = ::OpenTelemetry::Exporter::OTLP::Exporter.new(endpoint: configurator.otel_exporter_otlp_traces_endpoint, headers: {
                                                                        "Authorization" => configurator.aspecto_auth
                                                                      })
        span_processor = ::OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new otlp_exporter
        c.add_span_processor span_processor

        at_exit do
          # at_exit might be call when service terminates
          # but can also be the initiator or the application like with sinatra:
          # https://github.com/sinatra/sinatra/blob/cd503e6c590cd48c2c9bb7869522494bfc62cb14/lib/sinatra/main.rb#L25
          span_processor.force_flush timeout: 2
        end
      end

      fallback_sampler = ::OpenTelemetry::SDK::Trace::Samplers.trace_id_ratio_based(configurator.sampling_ratio)
      # TODO: how to properly extract the data from resource?
      _, service_name = ::OpenTelemetry.tracer_provider.resource.attribute_enumerator.detect { |elem| elem[0] == ::OpenTelemetry::SemanticConventions::Resource::SERVICE_NAME }
      _, env = ::OpenTelemetry.tracer_provider.resource.attribute_enumerator.detect { |elem| elem[0] == ::OpenTelemetry::SemanticConventions::Resource::DEPLOYMENT_ENVIRONMENT }
      @remote_config_service = Config::RemoteConfig.new configurator.aspecto_auth, service_name, env, fallback_sampler
    rescue StandardError => e
      warn "Failed to initialize Aspecto tracing."
      warn e
    end

    def shutdown
      ::OpenTelemetry.logger.info("Aspecto is shuting down. tracing is now stopped")
      ::OpenTelemetry.tracer_provider.shutdown
      @remote_config_service&.shutdown
    end

    def validate_configurator_options(configurator)
      # aspecto_auth
      unless configurator.aspecto_auth.instance_of?(String) && !configurator.aspecto_auth.empty?
        raise "
    Unable to retrieve Aspecto token.
    In order for the Aspecto service to work, it requires an auth token.
    Please provide it through ASPECTO_AUTH env param OR aspecto_auth configure option.
    You can get the token from: https://app.aspecto.io/app/integration/api-key
    For more details please check: https://docs.aspecto.io

"
      end

      # sampling_ratio
      unless (configurator.sampling_ratio.is_a?(Numeric) || configurator.sampling_ratio.is_a?(String)) && Float(configurator.sampling_ratio).between?(0, 1) # rubocop:disable Style/GuardClause
        raise "
        sampling_ratio should be number in range [0.0, 1.0], received #{configurator.sampling_ratio}

"
      end
    end
  end
end