# frozen_string_literal: true

# Copyright The OpenTelemetry Authors
#
# SPDX-License-Identifier: Apache-2.0

module OpenTelemetry
  module Instrumentation
    module Faraday
      module Middlewares
        # TracerMiddleware propagates context and instruments Faraday requests
        # by way of its middlware system
        class TracerMiddleware < ::Faraday::Middleware
          HTTP_METHODS_SYMBOL_TO_STRING = {
            connect: 'CONNECT',
            delete: 'DELETE',
            get: 'GET',
            head: 'HEAD',
            options: 'OPTIONS',
            patch: 'PATCH',
            post: 'POST',
            put: 'PUT',
            trace: 'TRACE'
          }.freeze

          def call(env)
            http_method = HTTP_METHODS_SYMBOL_TO_STRING[env.method]
            config = Faraday::Instrumentation.instance.config

            attributes = span_creation_attributes(
              http_method: http_method, url: env.url, config: config
            )
            tracer.in_span(
              "HTTP #{http_method}", attributes: attributes, kind: config.fetch(:span_kind)
            ) do |span|
              OpenTelemetry.propagation.inject(env.request_headers)

              app.call(env).on_complete { |resp| trace_response(span, resp.status) }
            rescue ::Faraday::Error => e
              trace_response(span, e.response[:status]) if e.response

              raise
            end
          end

          private

          def span_creation_attributes(http_method:, url:, config:)
            instrumentation_attrs = {
              'http.method' => http_method,
              'http.url' => OpenTelemetry::Common::Utilities.cleanse_url(url.to_s),
              'faraday.adapter.name' => app.class.name
            }
            instrumentation_attrs['net.peer.name'] = url.host if url.host
            instrumentation_attrs['peer.service'] = config[:peer_service] if config[:peer_service]

            instrumentation_attrs.merge!(
              OpenTelemetry::Common::HTTP::ClientContext.attributes
            )
          end

          # Versions prior to 1.0 do not define an accessor for app
          attr_reader :app if Gem::Version.new(Faraday::VERSION) < Gem::Version.new('1.0.0')

          def tracer
            Faraday::Instrumentation.instance.tracer
          end

          def trace_response(span, status)
            span.set_attribute('http.status_code', status)
            span.status = OpenTelemetry::Trace::Status.error unless (100..399).cover?(status.to_i)
          end
        end
      end
    end
  end
end