# encoding: utf-8

LibraryDetection.defer do
  named :typhoeus

  depends_on do
    defined?(Typhoeus) && defined?(Typhoeus::VERSION)
  end

  depends_on do
    OneApm::Agent::Instrumentation::TyphoeusTracing.is_supported_version?
  end

  executes do
    OneApm::Manager.logger.info 'Installing Typhoeus instrumentation'
    require 'one_apm/agent/cross_app/cross_app_tracing'
    require 'one_apm/support/http_clients/typhoeus_wrappers'
  end

  # Basic request tracing
  executes do
    Typhoeus.before do |request|
      OneApm::Agent::Instrumentation::TyphoeusTracing.trace(request)

      # Ensure that we always return a truthy value from the before block,
      # otherwise Typhoeus will bail out of the instrumentation.
      true
    end
  end

  # Apply single TT node for Hydra requests until async support
  executes do
    class Typhoeus::Hydra
      include OneApm::Support::MethodTracer

      def run_with_oneapm(*args)
        trace_execution_scoped("External/Multiple/Typhoeus::Hydra/run") do
          run_without_oneapm(*args)
        end
      end

      alias run_without_oneapm run
      alias run run_with_oneapm
    end
  end
end


module OneApm::Agent::Instrumentation::TyphoeusTracing

  OA_EARLIEST_VERSION = OneApm::VersionNumber.new("0.5.3")

  def self.is_supported_version?
    OneApm::VersionNumber.new(Typhoeus::VERSION) >= OneApm::Agent::Instrumentation::TyphoeusTracing::OA_EARLIEST_VERSION
  end

  def self.request_is_hydra_enabled?(request)
    request.respond_to?(:hydra) && request.hydra
  end

  def self.trace(request)
    state = OneApm::TransactionState.tl_get
    if state.is_execution_traced? && !request_is_hydra_enabled?(request)
      wrapped_request = ::OneApm::Support::HTTPClients::TyphoeusHTTPRequest.new(request)
      t0 = Time.now
      segment = ::OneApm::Agent::CrossAppTracing.start_trace(state, t0, wrapped_request)
      callback = Proc.new do
        wrapped_response = ::OneApm::Support::HTTPClients::TyphoeusHTTPResponse.new(request.response)
        ::OneApm::Agent::CrossAppTracing.finish_trace(state, t0, segment, wrapped_request, wrapped_response)
      end
      request.on_complete.unshift(callback)
    end
  rescue => e
    OneApm::Manager.logger.error("Exception during trace setup for Typhoeus request", e)
  end
end