# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: OpenMDW-1.1
"""Preserve explicit chart subtitles in their existing table-caption context."""
import re
from bs4 import BeautifulSoup,NavigableString
TABLE=re.compile(r'<table\b[^>]*>.*?</table>',re.S|re.I)
CHART=re.compile(r'(<chart\b[^>]*>)(.*?)(</chart>)',re.S|re.I)
def add_native_subtitles(text):
 def chart(match):
  body=match[2]
  labels=[m[1].strip() for m in re.finditer(r'(?m)^subtitle:[ \t]*([^\n]*)',body) if m[1].strip()]
  if not labels:return match[0]
  def table(m):
   soup=BeautifulSoup(m[0],'html.parser');node=soup.find('table');cap=node.find('caption',recursive=False)
   if not cap:return m[0]
   existing=cap.get_text(' ',strip=True);added=[]
   for value in labels:
    if value not in existing and value not in added:added.append(value)
   if not added:return m[0]
   cap.append(NavigableString(' — '+' — '.join(added)));return str(node)
  return match[1]+TABLE.sub(table,body)+match[3]
 return CHART.sub(chart,text)