"""Make the math of article/sim_numerics.md valid LaTeX as well as MathJax: a sub- or
superscript that starts with a bare control word (n_\\max) needs braces in LaTeX (n_{\\max}).
The rendered formula is identical.  Reports what it finds; --apply writes.

    python -u fix_md_for_latex.py [--apply]
"""
from __future__ import annotations

import re
import sys

PATH = "article/sim_numerics.md"
# only argument-less control words (n_\max); a macro with an argument (x_\mathrm{far},
# r_\text{new}) is valid LaTeX as written, and bracing it would detach its argument
PAT = re.compile(r"([_^])(\\[A-Za-z]+)(?![A-Za-z{])")


def main():
    with open(PATH, encoding="utf8") as fh:
        text = fh.read()
    hits = PAT.findall(text)
    print(f"{len(hits)} bare control words in sub/superscripts:", sorted(set(h[1] for h in hits)))
    if "--apply" in sys.argv:
        text = PAT.sub(lambda m: f"{m.group(1)}{{{m.group(2)}}}", text)
        with open(PATH, "w", encoding="utf8") as fh:
            fh.write(text)
        print("braced")


if __name__ == "__main__":
    main()