# -*- encoding: utf-8 -*-
module MusicBrainz
  module Tools
    class Proxy
      @@last_query_time = 0
      @@query_interval = 1.5 # Min: 1.0 Safe: 1.5
      @@tries_limit = 5

      WEB_SERVICE_URL = 'http://musicbrainz.org/ws/2/'
      USER_AGENT = "gem musicbrainz (https://github.com/magnolia-fan/musicbrainz) @ " + Socket.gethostname

      def self.query_interval=(sec)
        @@query_interval = sec.to_f
      end

      def self.tries_limit=(num)
        @@tries_limit = num.to_i
      end

      def self.load(resourse, params = {})
        url = WEB_SERVICE_URL + resourse.to_s.gsub('_', '-') + '/' + (params[:id].to_s || '')
        params.delete(:id) unless params[:id].nil?
        url << '?' + params.map{ |k, v|
          k = k.to_s.gsub('_', '-')
          v = (v.is_a?(Array) ? v.map{ |_| _.to_s.gsub('_', '-') }.join('+') : v.to_s)
          k + '=' + v
        }.join('&') unless params.empty?
        MusicBrainz::Tools::Cache.cache_contents(url) {
          self.get_contents url
        }
      end

      def self.get_contents(url)
        response = nil

        @@tries_limit.times {
          time_passed = Time.now.to_f - @@last_query_time
          sleep(@@query_interval - time_passed) if time_passed < @@query_interval

          begin
            response = open(url, "User-Agent" => USER_AGENT)
            @@last_query_time = Time.now.to_f
          rescue => e
            response = nil if e.io.status[0].to_i == 404
          end

          break unless response.nil?
        }

        response
      end
    end
  end
end