class Listen::Record

def _fast_build_dir(remaining, symlink_detector)
  entry = remaining.pop
  return if @silencer.silenced?(entry.record_dir_key, :dir)
  children = entry.children # NOTE: children() implicitly tests if dir
  symlink_detector.verify_unwatched!(entry)
  children.each { |child| remaining << child }
  add_dir(entry.record_dir_key)
rescue Errno::ENOTDIR
  _fast_try_file(entry)
rescue SystemCallError, SymlinkDetector::Error
  _fast_unset_path(entry.relative, entry.name)
end

def _fast_try_file(entry)
  _fast_update_file(entry.relative, entry.name, entry.meta)
rescue SystemCallError
  _fast_unset_path(entry.relative, entry.name)
end

def _fast_unset_path(dirname, basename)
  # this may need to be reworked to properly remove
  # entries from a tree, without adding non-existing dirs to the record
  if empty_dirname?(dirname.to_s)
    if @tree.key?(basename)
      @tree.delete(basename)
    end
  elsif @tree.key?(dirname)
    @tree[dirname].delete(basename)
  end
end

def _fast_update_file(dirname, basename, data)
  if empty_dirname?(dirname.to_s)
    @tree[basename] = @tree[basename].merge(data)
  else
    @tree[dirname][basename] = (@tree[dirname][basename] || {}).merge(data)
  end
end

def add_dir(rel_path)
  if !empty_dirname?(rel_path.to_s)
    @tree[rel_path.to_s]
  end
end

def build
  reset_tree
  # TODO: test with a file name given
  # TODO: test other permissions
  # TODO: test with mixed encoding
  symlink_detector = SymlinkDetector.new
  remaining = ::Queue.new
  remaining << Entry.new(root, nil, nil)
  _fast_build_dir(remaining, symlink_detector) until remaining.empty?
end

def dir_entries(rel_path)
  rel_path_s = rel_path.to_s
  subtree = if empty_dirname?(rel_path_s)
    @tree
  else
    @tree[rel_path_s]
  end
  subtree.each_with_object({}) do |(key, values), result|
    # only return data for file entries inside the dir (which will each be sub-hashes)
    if values.is_a?(Hash)
      result[key] = values.has_key?(:mtime) ? values : {}
    end
  end
end

def empty_dirname?(dirname)
  dirname == '.' || dirname == ''
end

def file_data(rel_path)
  dirname, basename = Pathname(rel_path).split.map(&:to_s)
  if empty_dirname?(dirname)
    @tree[basename].dup
  else
    @tree[dirname][basename] ||= {}
    @tree[dirname][basename].dup
  end
end

def initialize(directory, silencer)
  reset_tree
  @root = directory.to_s
  @silencer = silencer
end

def reset_tree
  @tree = Hash.new { |h, k| h[k] = {} }
end

def unset_path(rel_path)
  dirname, basename = Pathname(rel_path).split.map(&:to_s)
  _fast_unset_path(dirname, basename)
end

def update_file(rel_path, data)
  dirname, basename = Pathname(rel_path).split.map(&:to_s)
  _fast_update_file(dirname, basename, data)
end