module Longboat
  module Metrics
    class << self
      def report!(name, value, help: nil, type: nil, labels: {})
        @metrics ||= {}
        @metrics[name] ||= {help: help, type: type}
        @metrics[name][labels] = value
      end

      def to_s
        timestamp = (Time.now.to_f * 1000).to_i
        res = ""
        (@metrics || {}).each do |name, metric|
          res << "#HELP #{name} #{metric[:help]}\n" unless metric[:help].nil?
          res << "#TYPE #{name} #{metric[:type]}\n" unless metric[:type].nil?

          metric.each do |labels, value|
            next if labels == :help
            next if labels == :type
            labellist = []
            labels.each do |k, v|
              labellist << "#{k}=\"#{v}\""
            end
            labellist = labellist.join(",")
            res << "#{name}{#{labellist}} #{value} #{timestamp}\n"
          end
        end
        res
      end

      def register!(collector)
        @collectors ||= []
        @collectors << collector
      end

      def collect!
        (@collectors || []).each do |collector|
          collector.collect!
        end
      end
    end
  end
end