class Appsignal::Hooks::PumaProbe

def call
  puma_stats = fetch_puma_stats
  return unless puma_stats
  stats = JSON.parse puma_stats, :symbolize_names => true
  counts = {}
  count_keys = [:backlog, :running, :pool_capacity, :max_threads]
  if stats[:worker_status] # Multiple workers
    stats[:worker_status].each do |worker|
      stat = worker[:last_status]
      count_keys.each do |key|
        count_if_present counts, key, stat
      end
    end
    gauge(:workers, stats[:workers], :type => :count)
    gauge(:workers, stats[:booted_workers], :type => :booted)
    gauge(:workers, stats[:old_workers], :type => :old)
  else # Single worker
    count_keys.each do |key|
      count_if_present counts, key, stats
    end
  end
  gauge(:connection_backlog, counts[:backlog]) if counts[:backlog]
  gauge(:pool_capacity, counts[:pool_capacity]) if counts[:pool_capacity]
  gauge(:threads, counts[:running], :type => :running) if counts[:running]
  gauge(:threads, counts[:max_threads], :type => :max) if counts[:max_threads]
end

def count_if_present(counts, key, stats)
  stat_value = stats[key]
  return unless stat_value
  counts[key] ||= 0
  counts[key] += stat_value
end

def fetch_puma_stats
  ::Puma.stats
rescue NoMethodError # rubocop:disable Lint/HandleExceptions
end

def gauge(field, count, tags = {})
  Appsignal.set_gauge("puma_#{field}", count, tags.merge(:hostname => hostname))
end

def initialize
  @hostname = Appsignal.config[:hostname] || Socket.gethostname
end