class RuboCop::Cop::Style::ExpandPathArguments

def arguments_range(node)
  range_between(node.parent.first_argument.source_range.begin_pos,
                node.parent.last_argument.source_range.end_pos)
end

def autocorrect(node)
  lambda do |corrector|
    if (captured_values = file_expand_path(node))
      current_path, default_dir = captured_values
      autocorrect_expand_path(corrector, current_path, default_dir)
    elsif (default_dir = pathname_parent_expand_path(node)) ||
          (default_dir = pathname_new_parent_expand_path(node))
      corrector.replace(default_dir.loc.expression, '__dir__')
      remove_parent_method(corrector, default_dir)
    end
  end
end

def autocorrect_expand_path(corrector, current_path, default_dir)
  stripped_current_path = strip_surrounded_quotes!(current_path.source)
  case depth(stripped_current_path)
  when 0
    range = arguments_range(current_path)
    corrector.replace(range, '__FILE__')
  when 1
    range = arguments_range(current_path)
    corrector.replace(range, '__dir__')
  else
    new_path = "'#{parent_path(stripped_current_path)}'"
    corrector.replace(current_path.loc.expression, new_path)
    corrector.replace(default_dir.loc.expression, '__dir__')
  end
end

def depth(current_path)
  paths = current_path.split(File::SEPARATOR)
  paths.reject { |path| path == '.' }.count
end

def inspect_offense_for_expand_path(node, current_path, default_dir)
  return unless unrecommended_argument?(default_dir) &&
                current_path.str_type?
  current_path = strip_surrounded_quotes!(current_path.source)
  parent_path = parent_path(current_path)
  new_path = parent_path == '' ? '' : "'#{parent_path}', "
  new_default_dir = depth(current_path).zero? ? '__FILE__' : '__dir__'
  message = format(
    MSG,
    new_path: new_path,
    new_default_dir: new_default_dir,
    current_path: "'#{current_path}'"
  )
  add_offense(node, location: :selector, message: message)
end

def on_send(node)
  if (captured_values = file_expand_path(node))
    current_path, default_dir = captured_values
    inspect_offense_for_expand_path(node, current_path, default_dir)
  elsif (default_dir = pathname_parent_expand_path(node))
    return unless unrecommended_argument?(default_dir)
    add_offense(node, message: PATHNAME_MSG)
  elsif (default_dir = pathname_new_parent_expand_path(node))
    return unless unrecommended_argument?(default_dir)
    add_offense(node, message: PATHNAME_NEW_MSG)
  end
end

def parent_path(current_path)
  paths = current_path.split(File::SEPARATOR)
  paths.delete('.')
  paths.each_with_index do |path, index|
    if path == '..'
      paths.delete_at(index)
      break
    end
  end
  paths.join(File::SEPARATOR)
end

def remove_parent_method(corrector, default_dir)
  node = default_dir.parent.parent.parent.children.first
  corrector.remove(node.loc.dot)
  corrector.remove(node.loc.selector)
end

def strip_surrounded_quotes!(path_string)
  path_string.slice!(path_string.length - 1)
  path_string.slice!(0)
  path_string
end

def unrecommended_argument?(default_dir)
  default_dir.source == '__FILE__'
end