#!/usr/bin/env ruby

require 'yaml'
require 'nokogiri'
require 'bigdecimal'
require 'optparse'

options = {}
optparse = OptionParser.new do |opts|
  opts.banner = "Usage: rrd.rb -f rrd_file [options]"

  opts.on('-f', '--file [FILE]', 'RRD File') do |f|
    options[:file] = f
  end
  opts.on('-g', '--removegaps' ) { |g| options[:remove_gaps] = true}
end

optparse.parse!

# Raise an exception when an rrd file is not specified
if options[:file].nil?
  puts 'No rrd file specified'
  exit 1
elsif ooptions[:remove_gaps].nil?
  puts 'Please specify an action'
  exit 1
end

def extract_rra_rows(cf:, pdp_per_row:)
    @doc.css('rra').select do |x|
        if (x.css('cf')[0].inner_text == "#{cf}" && x.css('pdp_per_row')[0].inner_text == "#{pdp_per_row}")
          rra_avg_rows = x.css('database>row')
          # TODO: require timeframe which will then be used to return
          # the rows within the given timeframe
          # Currently, return rows for the last 7 days
          # 464 = 800 - 336 (336 * 30m = 10080 / 60 = 168h / 24 = 7d)
          yield rra_avg_rows[464, 799]
        end
    end
end

def remove_gaps(rows)
  for i in 0..(rows.size-1)
    break if i == rows.size - 1

    current_bits_in = BigDecimal(rows[i].css('v')[0].inner_text)

    if current_bits_in == 'NaN'
      puts "#{rows[i].css('v')[0].content}"
      if BigDecimal(rows[i-1].css('v')[0].inner_text) != 'NaN'
        rows[i].css('v')[0].content = BigDecimal(rows[i-1].css('v')[0].inner_text)
      elsif
        rows[i].css('v')[0].content = BigDecimal(rows[i-2].css('v')[0].inner_text)
      end
    end

    current_bits_out = BigDecimal(rows[i].css('v')[1].inner_text)

    if current_bits_out == 'NaN'
      if BigDecimal(rows[i-1].css('v')[1].inner_text) != 'NaN'
        rows[i].css('v')[1].content = BigDecimal(rows[i-1].css('v')[1].inner_text)
      elsif
        rows[i].css('v')[1].content = BigDecimal(rows[i-2].css('v')[1].inner_text)
      end
    end
  end
end

dump_xml = File.join(__dir__, 'ixp.xml')

`rrdtool dump #{options[:file]} #{dump_xml}`

@doc = Nokogiri::XML(open(dump_xml))

extract_rra_rows(cf: 'AVERAGE', pdp_per_row: '6') do |rows|
    remove_gaps(rows)
end

extract_rra_rows(cf: 'MAX', pdp_per_row: '6') do |rows|
    remove_gaps(rows)
end

File.write(dump_xml, @doc)

`rrdtool restore  #{dump_xml} ixp_normalized.rrd`