class RuboCop::Cop::Layout::ClosingHeredocIndentation

def argument_indentation_correct?(node)
  return false unless node.argument? || node.chained?
  opening_indentation(
    find_node_used_heredoc_argument(node.parent)
  ) == closing_indentation(node)
end

def closing_indentation(node)
  indent_level(heredoc_closing(node))
end

def find_node_used_heredoc_argument(node)
  if node.parent&.send_type?
    find_node_used_heredoc_argument(node.parent)
  else
    node
  end
end

def heredoc_closing(node)
  node.loc.heredoc_end.source_line
end

def heredoc_opening(node)
  node.source_range.source_line
end

def indent_level(source_line)
  source_line[/\A */].length
end

def indented_end(node)
  closing_indent = closing_indentation(node)
  opening_indent = opening_indentation(node)
  closing_text = heredoc_closing(node)
  closing_text.gsub(/^\s{#{closing_indent}}/, ' ' * opening_indent)
end

def message(node)
  format(
    node.argument? ? MSG_ARG : MSG,
    closing: heredoc_closing(node).strip,
    opening: heredoc_opening(node).strip
  )
end

def on_heredoc(node)
  return if heredoc_type(node) == SIMPLE_HEREDOC ||
            opening_indentation(node) == closing_indentation(node) ||
            argument_indentation_correct?(node)
  message = message(node)
  add_offense(node.loc.heredoc_end, message: message) do |corrector|
    corrector.replace(node.loc.heredoc_end, indented_end(node))
  end
end

def opening_indentation(node)
  indent_level(heredoc_opening(node))
end