"""Escape helpers for LaTeX output."""

from __future__ import annotations

import re

_SPECIAL = {
    "\\": r"\textbackslash{}",
    "{": r"\{",
    "}": r"\}",
    "#": r"\#",
    "$": r"\$",
    "%": r"\%",
    "&": r"\&",
    "_": r"\_",
    "~": r"\textasciitilde{}",
    "^": r"\textasciicircum{}",
}


def escape_text(s: str) -> str:
    if not s:
        return ""
    out = []
    for ch in s:
        out.append(_SPECIAL.get(ch, ch))
    return "".join(out)


def escape_verbatim_for_listing(s: str) -> str:
    """lstlisting body — avoid ending the environment accidentally."""
    return s.replace("\\end{lstlisting}", "\\end\\{lstlisting}")


_LABEL_RE = re.compile(r"[^\w\-]+", re.UNICODE)


def latex_label(name: str | None, prefix: str = "obj") -> str:
    if not name:
        return prefix
    cleaned = _LABEL_RE.sub("-", name.strip()).strip("-")
    return f"{prefix}:{cleaned or 'x'}"