class ElasticAPM::Metrics::Collector

def collect
  MUTEX.synchronize do
    samplers.each_with_object({}) do |sampler, samples|
      next unless (sample = sampler.collect)
      samples.merge!(sample)
    end
  end
end

def collect_and_send
  metricset = Metricset.new(tags: tags, **collect)
  return if metricset.empty?
  callback.call(metricset)
end

def initialize(config, tags: nil, &block)
  @config = config
  @tags = tags
  @samplers = [CpuMem, VM].map do |kls|
    debug "Adding metrics collector '#{kls}'"
    kls.new(config)
  end
  @callback = block
end

def running?
  !!@running
end

def start
  unless config.collect_metrics?
    debug 'Skipping metrics'
    return
  end
  debug 'Starting metrics'
  @timer_task = Concurrent::TimerTask.execute(
    run_now: true,
    execution_interval: config.metrics_interval,
    timeout_interval: TIMEOUT_INTERVAL
  ) do
    begin
      debug 'Collecting metrics'
      collect_and_send
      true
    rescue StandardError => e
      error 'Error while collecting metrics: %e', e.inspect
      debug { e.backtrace.join("\n") }
      false
    end
  end
  @running = true
end

def stop
  return unless running?
  debug 'Stopping metrics'
  @timer_task.shutdown
  @running = false
end