# frozen_string_literal: true

module MemoryProfiler
  module TopN
    # Fast approach for determining the top_n entries in a Hash of Stat objects.
    # Returns results for both memory (memsize summed) and objects allocated (count) as a tuple.
    def top_n(max, metric_method)

      metric_memsize = Hash.new(0)
      metric_objects_count = Hash.new(0)

      each_value do |value|
        metric = value.send(metric_method)

        metric_memsize[metric] += value.memsize
        metric_objects_count[metric] += 1
      end

      stats_by_memsize =
        metric_memsize
          .to_a
          .sort_by! { |metric, memsize| [-memsize, metric] }
          .take(max)
          .map! { |metric, memsize| { data: metric, count: memsize } }

      stats_by_count =
        metric_objects_count
          .to_a
          .sort_by! { |metric, count| [-count, metric] }
          .take(max)
          .map! { |metric, count| { data: metric, count: count } }

      [stats_by_memsize, stats_by_count]
    end
  end
end