#!/usr/bin/env ruby

require 'optparse'
require 'ostruct'

options = OpenStruct.new

op = OptionParser.new do |opts|
  opts.banner = "Usage: random_ranges [options]"
  opts.on("-r", "--range START:END", "range") do |range|
    s, e = range.split(':')
    options.start = s.to_i
    options.end = e.to_i
  end
  opts.on("-l", "--length LEN", "block length") do |len|
    options.length = len.to_i
  end
  opts.on("-n", "--number NUM", "number of blocks") do |num|
    options.num = num.to_i
  end
  opts.on("-s", "--sequence SEQ", "sequence") do |seq|
    options.seq = seq
  end
end.parse!(ARGV)

rand = Random.new
range = options.end - options.start
block_range = range / options.num
block_start_range = block_range - options.length
(0...options.num).each do |n|
  block_offset = rand.rand(block_start_range)
  b_start = options.start + (block_range * n) + block_offset
  b_end = b_start + options.length
  puts "#{options.seq}\t#{b_start}\t#{b_end}\tx"
end