methods for converting filenames

cengage_convert.rb

require 'fileutils'
require 'securerandom'

#
# all files must match cengage file names
#
def cengagify_files(folder_path)
  Dir.glob("#{folder_path}/**/*").each do |f|
    # skip directories and simple names
    next if File.directory?(f)
    orig_name = File.basename(f)
    basename = File.basename(f, '.*')
    extension = File.extname(f)

    # move html to index for cengage
    if orig_name == 'main.html'
      new_name = 'index.html'
      new_path = f.gsub(orig_name, new_name)
    # skip if the name is otherwise ok
    elsif /^[a-z][a-z_]*$/.match(basename) && basename.size < 20
      next
    # "funny" filenames need to be renamed
    else
      puts "Bad name #{basename}"
      new_name = "#{SecureRandom.hex(10)}#{extension.downcase}"
      new_path = f.gsub(orig_name, new_name)
    end

    FileUtils.mv(f, new_path)
    puts "moving file  file: #{f}"

    referencing_files(folder_path).each do |rf|
      puts "overriting file: #{rf}"
      content = File.open(rf, 'r').read
      content.gsub!(orig_name, new_name)
      File.open(rf, 'w') do |of|
        of.write(content)
      end
    end

    # move main.html
    FileUtils.mv(f, new_path)
  end
end

# return all files that might reference a path
def referencing_files(folder_path)
  Dir.glob("#{folder_path}/**/*.js") +
    Dir.glob("#{folder_path}/**/*.css") +
    Dir.glob("#{folder_path}/**/*.json") +
    Dir.glob("#{folder_path}/**/*.html")
end

rubocopped