#!/usr/bin/ruby

require 'rubygems'
require 'rest_client'
require 'rexml/document'

class Tracker
  def initialize
    user = 'xxx'
    pass = 'xxx'
    @resource = RestClient::Resource.new("http://#{user}:#{pass}@twitter.com/")
  end

  def diff
    previous = Set.new
    current = Set.new
    
    begin
      input = File.new('followers', 'r')
    
      while (line = input.gets)
        previous.add(line.chomp)
      end

      input.close
    rescue
    end

    document = REXML::Document.new(@resource['followers/ids.xml'].get(:accept => 'text/xml'))
    document.elements.each('//id') { |id| current.add(id.text) }

    log = File.new('log', 'a')
    log.write(`date`)

    previous.subtract(current).each do |id|
      log.write("\n")

      document = REXML::Document.new(@resource["users/#{id}.xml"].get(:accept => 'text/xml'))

      screen_name = document.elements.to_a('//screen_name').first.text
      description = document.elements.to_a('//description').first.text
      name = document.elements.to_a('//name').first.text

      puts name
      puts description
      puts "http://twitter.com/#{screen_name}"
      puts

      log.write("#{name}\n")
      log.write("#{description}\n")
      log.write("http://twitter.com/#{screen_name}\n")

      log.write("\n")
    end

    output = File.new('followers', 'w')
    current.each { |id| output.write("#{id}\n") }
    output.close
  end
end

tracker = Tracker.new
tracker.diff