#!/usr/bin/ruby

require 'find'

require 'optparse'

options = {}

OptionParser.new do |opts|

  opts.banner = "Usage: clean-header-guards [options]"

  opts.on("--prefix [PREFIX]", "Append a header prefix to all guards") do |prefix|

    options[:prefix] = prefix

  end

end.parse!

IgnoredFilenamePatterns = [

  # ignore headers which are known not to have guard

  /WebCorePrefix/, 

  /ForwardingHeaders/,

  %r|bindings/objc|, 

  /vcproj/, # anything inside a vcproj is in the windows wasteland

  # we don't own any of these headers

  %r|icu/unicode|,

  %r|platform/graphics/cairo|,

  %r|platform/image-decoders|,

  /config.h/ # changing this one sounds scary

].freeze

IgnoreFileNamesPattern = Regexp.union(*IgnoredFilenamePatterns).freeze

Find::find(".") do |filename|

  next unless filename =~ /\.h$/

  next if filename.match(IgnoreFileNamesPattern)

  File.open(filename, "r+") do |file|

    contents = file.read

    match_results = contents.match(/#ifndef (\S+)\n#define \1/s)

    if match_results

      current_guard = match_results[1]

      new_guard = File.basename(filename).sub('.', '_')

      new_guard = options[:prefix] + '_' + new_guard  if options[:prefix]

      contents.gsub!(/#{current_guard}\b/, new_guard)

    else

      puts "Ignoring #{filename}, failed to find existing header guards."

    end

    tmp_filename = filename + ".tmp"

    File.open(tmp_filename, "w+") do |new_file|

      new_file.write(contents)

    end

    File.rename tmp_filename, filename

  end

end