module Longboat
  class Raiders
    def initialize(collector, config)
      @collector = collector
      @raiders = {}
      @config = config

      @config[:raiders_path].each do |dir|
        next unless Dir.exist?(dir)

        Dir.entries(dir).each do |file|
          next unless file =~ /\A(?![._])[a-zA-Z0-9]+(?:_[a-zA-Z0-9]+)*\.rb\Z/

          reqname = File.basename(file, ".rb")
          cname = reqname.split('_').map(&:capitalize).join

          require "#{dir}/#{reqname}"
          @raiders[reqname] = Kernel.const_get(cname).new(@collector, raider_config)
        end
      end
    end

    def raid!
      @raiders.each do |name, raider|
        @collector.begin!

        begin
          start_time = Time.now
          raider.raid
          end_time = Time.now
          time_taken = end_time - start_time

          @collector.report!(
            "longboat_meta_raider_runtime",
            (time_taken.to_f * 1000).to_i,
            help: "Time taken by a raider whilst raiding in ms",
            type: "gauge",
            labels: {raider: name}
          )

          @collector.commit!
        rescue Exception => e
          @collector.abort!

          $stderr.puts "[ERROR] Caught exception from raider: #{name}"
          $stderr.puts "[ERROR] Exception reads: #{e.message}"
          $stderr.puts "[ERROR] Aborted collector transaction"
          $stderr.puts "[ERROR] Backtrace reads: \"#{e.backtrace}\""
        end
      end
    end

    def raid_every(time = @config[:raid_every], async = true)
      if async
        Thread.new do
          loop do
            raid!
            sleep(time)
          end
        end
      else
        loop do
          raid!
          sleep(time)
        end
      end
    end

    private

    def raider_config
      @config.slice(:raid_every, :metric_prefix)
    end
  end
end