require 'rubygems'
require 'mechanize'
require 'nokogiri'
require 'logger'
require 'open-uri'
require 'pp'
require 'bencode'
require 'json'


class Example

  def initialize()
    #create the agent to search in the code
    @agent = Mechanize.new do |a|
      a.history.max_size = 1
      a.user_agent_alias = 'Mac Safari'
      a.read_timeout = 60
    end
  end

  def run
    time = Time.now
    logfile = "log_" + time.strftime("%Y-%m-%d") + ".txt"
    log = Logger.new(logfile)
    log.debug "***** Begin : " + time.inspect
    log.debug "-------------------------------------------------------------------------"

    torrent_info = {'68a5df15d2ac9b2f14ffe35ff907dd4ec5092264' => ["h%A5%DF%15%D2%AC%9B%2F%14%FF%E3_%F9%07%DDN%C5%09%22d", "[[\"http://tracker.publicbt.com/announce\"],[\"http://tracker.torrent.to:2710/announce\"],[\"http://tracker.istole.it/announce\"],[\"http://tracker2.istole.it:6969/announce\"],[\"http://announce.torrentsmd.com:8080/announce\"],[\"http://tracker.prq.to/announce\"],[\"http://exodus.1337x.org/announce\"],[\"http://genesis.1337x.org:1337/announce\"],[\"http://tracker.torrent.to:2710/announce\"],[\"http://tracker.torrentbay.to:6969/announce\"],[\"http://inferno.demonoid.com:3407/announce\"],[\"http://tracker.ex.ua/announce\"],[\"http://tracker.ilibr.org:6969/announce\"],[\"http://10.rarbg.com/announce\"],[\"http://tracker.ilibr.org:6969/announce\"],[\"udp://denis.stalker.h3q.com:6969/announce\"],[\"udp://tracker.publicbt.com:80/announce\"],[\"udp://tracker.openbittorrent.com:80/announce\"],[\"http://tracker4.finalgear.com/announce\"]]"] }

    if(torrent_info.size > 0)

      torrent_trackers = Array.new

      torrent_info.each { |hashcode, details|

        #clear all the lists
        torrent_trackers.clear

        binary_infohash = details[0]

        torrent_trackers = JSON.parse(details[1])

        seeds = 0
        peers = 0

        #at this point I have the complete list of trackers for a specific torrent
        #and the next step is to send to each one of them a request with the infohash
        if(torrent_trackers.length > 0)
          torrent_trackers.each { |t|
            if(!t[0].eql?(''))
              url = t[0].to_s + '?info_hash=' + details[0].to_s
              if(url.include?("http://"))#http trackers
		#pp url
                tracker_seeds = -1
                tracker_peers = -1
                begin
                  Timeout::timeout(50) do
                    tracker_seeds, tracker_peers = extract_information(url, log)
                  end
                rescue SystemCallError => e
                  log.error 'Fail saving the file '+url+': SystemCallError'
                rescue Timeout::Error => e
                  log.error 'Fail saving the file '+url+': Timeout'
                rescue  Exception => e
                  log.error 'General exception for url ' + url
                  log.error e
                end

                if(tracker_seeds > -1 && !tracker_seeds.nil? && tracker_peers > -1 && !tracker_peers.nil?)

                  seeds = seeds + tracker_seeds
                  peers = peers + tracker_peers

                else
                  log.debug 'The torrent is not present in ' + t[0]
                end
              else#udp trackers
                
              end
            end
          }
          log.debug 'Were found ' + seeds.to_s + ' seeds and ' + peers.to_s + ' peers for torrent ' + hashcode
        end
      }
    end
  log.debug "-------------------------------------------------------------------------"
  log.debug "***** End : " + Time.now.inspect
end
#end



  ##############################################################################
  ## send a request to the tracker, save the file and extract the information ##
  ##############################################################################
  def extract_information(url, log)
    seeds = -1
    peers = -1

    retries = 1
    path = 'announce'

    begin
      Timeout::timeout(5) do
	log.debug 'calling ' + url
        res = @agent.get(url).save_as(path)
        if(res != nil && res != '' )
	  log.debug 'DONE'
          info = BEncode.load_file(path)

          seeds = info['complete']
          peers = info['incomplete']

          #delete the announce file, after extracting the information
          File.delete(path)
	else
          log.debug 'FAIL'
        end
      end
    rescue Exception => e
      log.error 'Fail saving the file '+url+': General exception'
      retries -= 1
      if(retries > 0)
        retry
      else
        log.error 'Fail saving the file '+url+' (General Exception).'
        log.error e
      end
    rescue Timeout::Error => e
      log.error 'Fail saving the file '+url+': Timeout'
      retries -= 1
      if(retries > 0)
        retry
      else
        log.error 'Fail saving the file '+url+' (Timeout::Error).'
        log.error e
      end
    end

    return seeds.to_i, peers.to_i
  end

end