module RuboCop::FileFinder

def self.root_level=(level)
  @root_level = level
end

def self.root_level?(path)
  @root_level == path.to_s
end

def find_file_upwards(filename, start_dir, use_home: false)
  traverse_files_upwards(filename, start_dir, use_home) do |file|
    # minimize iteration for performance
    return file if file
  end
end

def find_files_upwards(filename, start_dir, use_home: false)
  files = []
  traverse_files_upwards(filename, start_dir, use_home) do |file|
    files << file
  end
  files
end

def traverse_files_upwards(filename, start_dir, use_home)
  Pathname.new(start_dir).expand_path.ascend do |dir|
    break if FileFinder.root_level?(dir)
    file = dir + filename
    yield(file.to_s) if file.exist?
  end
  return unless use_home && ENV.key?('HOME')
  file = File.join(Dir.home, filename)
  yield(file) if File.exist?(file)
end