module TzuStats

# File lib/tzu_stats.rb, line 4
def self.extended(base)
  base.send :extend, StatsD::Instrument

  # measures time taken
  base.statsd_measure :run!, ->(obj, args) { "#{obj.class.to_s}.run" }

  # count success, invalid & failure
  base.statsd_count_outcomes :run!, ->(obj, args) { "#{obj.class.to_s}.run" }
end

# File lib/tzu_stats.rb, line 14
def statsd_count_outcomes(method, name, *metric_options)
  add_to_method(method, name, :count_outcomes) do |old_method, new_method, metric_name|
    define_method(new_method) do |*args, &block|
      begin
        truthiness = result = send(old_method, *args, &block)
      rescue => e
        truthiness, exception = false, e
        raise
      else
        result
      ensure
        if truthiness
          suffix = 'success'
        else
          suffix = exception && exception.is_a?(Tzu::Invalid) ? 'invalid' : 'failure'
        end

        key = "#{StatsD::Instrument.generate_metric_name(metric_name, self, *args)}.#{suffix}"
        StatsD.increment(key, 1, *metric_options)
      end
    end
  end
end