# encoding: utf-8

LibraryDetection.defer do
  named :activejob

  depends_on do
    defined?(::ActiveJob::Base)
  end

  executes do
    ::OneApm::Agent.logger.info 'Installing ActiveJob instrumentation'

    ::ActiveJob::Base.around_enqueue do |job, block|
      ::OneApm::Agent::Instrumentation::ActiveJobHelper.enqueue(job, block)
    end

    ::ActiveJob::Base.around_perform do |job, block|
      ::OneApm::Agent::Instrumentation::ActiveJobHelper.perform(job, block)
    end
  end
end

module OneApm
  module Agent
    module Instrumentation
      module ActiveJobHelper
        include ::OneApm::Support::MethodTracer

        def self.enqueue(job, block)
          run_in_trace(job, block, :Produce)
        end

        def self.perform(job, block)
          state = ::OneApm::TransactionState.tl_get

          # Don't nest transactions if we're already in a web transaction.
          # Probably inline processing the job if that happens, so just trace.
          if state.in_web_transaction?
            run_in_trace(job, block, :Consume)
          elsif state.in_background_transaction?
            ::OneApm::Transaction.set_default_transaction_name(
              transaction_name_suffix_for_job(job),
              transaction_category)
            block.call
          else
            run_in_transaction(state, job, block)
          end
        end

        def self.run_in_trace(job, block, event)
          trace_execution_scoped("MessageBroker/#{adapter}/Queue/#{event}/Named/#{job.queue_name}") do
            block.call
          end
        end

        def self.run_in_transaction(state, job, block)
          ::OneApm::Transaction.wrap(state,
                                              transaction_name_for_job(job),
                                              :other,
                                              &block)
        end

        def self.transaction_category
          "OtherTransaction/#{adapter}"
        end

        def self.transaction_name_suffix_for_job(job)
          "#{job.class}/execute"
        end

        def self.transaction_name_for_job(job)
          "#{transaction_category}/#{transaction_name_suffix_for_job(job)}"
        end

        def self.adapter
          clean_adapter_name(::ActiveJob::Base.queue_adapter.name)
        end

        ADAPTER_REGEX = /ActiveJob::QueueAdapters::(.*)Adapter/

        def self.clean_adapter_name(name)
          name = "ActiveJob::#{$1}" if ADAPTER_REGEX =~ name
          name
        end
      end
    end
  end
end