# encoding: utf-8

module OneApm
  module Collector
    class ForkedProcessService
      attr_reader :channel_id, :buffer, :pipe
      attr_accessor :request_timeout, :agent_id, :collector

      def initialize(channel_id)
        @channel_id = channel_id
        @collector = OneApm::Support::Server.new(:name => 'parent', :port => 0)
        @pipe = OneApm::Support::ForkedProcessChannel.channels[@channel_id]
        if @pipe && @pipe.parent_pid != $$
          @pipe.after_fork_in_child
        else
          OneApm::Manager.logger.error("No communication channel to parent process.")
        end
      end

      def connect(config)
        nil
      end

      def get_agent_commands
        []
      end

      def analytic_event_data(events)
        write_to_pipe(:analytic_event_data, events) if events
      end

      def custom_event_data(events)
        write_to_pipe(:custom_event_data, events) if events
      end

      def metric_data(unsent_timeslice_data)
        write_to_pipe(:metric_data, unsent_timeslice_data)
        {}
      end

      def transaction_sample_data(transactions)
        write_to_pipe(:transaction_sample_data, transactions) if transactions
      end

      def error_data(errors)
        write_to_pipe(:error_data, errors) if errors
      end

      def sql_trace_data(sql)
        write_to_pipe(:sql_trace_data, sql) if sql
      end

      def shutdown(time)
        @pipe.close if @pipe
      end

      # Invokes the block it is passed.  This is used to implement HTTP
      # keep-alive in the CollectorService, and is a required interface for any
      # Service class.
      def session
        yield
      end

      def reset_metric_id_cache
        # we don't cache metric IDs, so nothing to do
      end

      private

      def marshal_payload(data)
        OneApm::LanguageSupport.with_cautious_gc do
          Marshal.dump(data)
        end
      end

      def write_to_pipe(endpoint, data)
        @pipe.write(marshal_payload([endpoint, data])) if @pipe
      end
    end
  end
end