#!/usr/bin/env ruby

require 'zipf'
require 'trollop'

def main
  conf = Trollop::options do
    opt :inputs, "inputs, comma separated", :type => :string, :short => "-i", :required => true
    opt :output_suffix, "output suffix", :type => :string, :default => ".out", :short => "-S"
    opt :min_len, "minimum length", :type => :int, :default => 1, :short => "-m"
    opt :max_len, "maximum length", :type => :int, :default => 1000, :short => "-M"
    opt :ignore_below, "minimum length to apply ratio test", :type => :int, :default => 7, :short => "-I"
    opt :ratio_mean, "length ratio average", :type => :float, :required => true, :short => "-A"
    opt :ratio_stddev, "length ratio standard deviation", :type => :float, :required => true, :short => "-T"
  end

  fna,fnb = conf[:inputs].split ','
  a = ReadFile.new fna 
  b = ReadFile.new fnb
  a_out = WriteFile.new fna+conf[:output_suffix]
  b_out = WriteFile.new fnb+conf[:output_suffix]

  ratio_lower = conf[:ratio_mean] - conf[:ratio_stddev]
  ratio_upper = conf[:ratio_mean] + conf[:ratio_stddev]

  while linea = a.gets
    lineb = b.gets
    sza = linea.strip.split.size
    szb = lineb.strip.split.size
    ratio = sza.to_f/szb.to_f
    if sza <= conf[:ignore_below] and szb <= conf[:ignore_below] or
        (sza >= conf[:min_len] and szb >= conf[:min_len] and
         sza <= conf[:max_len] and szb <= conf[:max_len] and
         ratio >= ratio_lower and
       ratio <= ratio_upper)
      a_out.write linea
      b_out.write lineb
    end
  end

  a.close
  b.close
  a_out.close
  b_out.close
end

main