class ElasticAPM::Metrics::Registry

def collect
  sets.each_value.each_with_object([]) do |set, arr|
    samples = set.collect
    next unless samples
    arr.concat(samples)
  end
end

def collect_and_send
  metricsets = collect
  metricsets.compact!
  metricsets.each do |m|
    callback.call(m)
  end
end

def get(key)
  sets.fetch(key)
end

def initialize(config, &block)
  @config = config
  @callback = block
end

def running?
  !!@running
end

def start
  unless config.collect_metrics?
    debug 'Skipping metrics'
    return
  end
  debug 'Starting metrics'
  @sets = {
    system: CpuMemSet,
    vm: VMSet,
    breakdown: BreakdownSet,
    transaction: TransactionSet
  }.each_with_object({}) do |(key, kls), sets|
    debug "Adding metrics collector '#{kls}'"
    sets[key] = kls.new(config)
  end
  @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