#!ruby -w

require 'diff/lcs'
require 'diff/lcs/htmldiff'

begin
  require 'text/format'
rescue LoadError
  Diff::LCS::HTMLDiff.can_expand_tabs = false
end

if ARGV.size < 2 or ARGV.size > 3
  $stderr.puts "usage: #{File.basename($0)} old new [output.html]"
  $stderr.puts "       #{File.basename($0)} old new > output.html"
  exit 127
end

left = IO.read(ARGV[0]).split($/)
right = IO.read(ARGV[1]).split($/)

options = { :title => "diff #{ARGV[0]} #{ARGV[1]}" }

htmldiff = Diff::LCS::HTMLDiff.new(left, right, options)

if ARGV[2]
  File.open(ARGV[2], "w") do |f|
    htmldiff.options[:output] = f
    htmldiff.run
  end
else
  htmldiff.run
end