class UccPlugin < Plugin
  CURRENCIES_URL = 'http://www.xe.com/ucc/full.php'
  MAIN_URL = 'http://www.xe.com/ucc/convert.cgi'
  def help(plugin, topic="")
    "Universal Currency Converter via xe.com. #{Bold}!ucc 12 RUR USD#{Bold} => convert 12 russian rubles to dollars"
  end

  def fetch_currencies
    b = @bot.httputil.get CURRENCIES_URL
    b.sub!(/.*\<select name="To"[^\>]*\>/im, '') or
      b.sub!(/\<\/select.*/im, '') or
      raise 'failed to parse currency list'
    b.scan(/\<option\s+value="([^"]+)"\s*\>([^\<]+)\s*\<\/option\>/)
  end

  def lookup_currency(str)
    @currencies ||= fetch_currencies
    @currencies.find { |x| x[0].downcase.match("^#{str.downcase}") } or
    @currencies.find { |x| x[1].downcase.match(str.downcase) } or
    raise "unknown currency string #{str.inspect}"
  end

  def ucc(m, params)
    begin
      from = lookup_currency(params[:from]).first
      to = lookup_currency(params[:to]).first
      n = params[:amount]
      res = @bot.httputil.get "#{MAIN_URL}?Amount=#{n}&From=#{from}&To=#{to}"
      m.reply res.scan(/\<h2 class="XE"\>([^\>]+)\</mi).join(' ')
    rescue Exception => e
      m.reply "error: #{e.message}"
    end
  end
end
plugin = UccPlugin.new
plugin.map 'ucc [:amount] :from [to] [:to]',
  :requirements => { :amount => /^(\d+(\.\d*)?)$/ },
  :defaults => { :amount => 1, :to => 'USD' },
  :thread => true