"""Vietnamese text normalisation shared by drug and section resolution.

Lives here rather than in `routing.py` because `sections.py` needs it too, and
importing it from `routing` made `service -> sections -> routing -> service` a
cycle. It is a text utility with no knowledge of drugs or sections.
"""
from __future__ import annotations

import re
import unicodedata

WORD_RE = re.compile(r"\w+", re.UNICODE)


def normalize_name(text: str) -> str:
    """Casefold, strip diacritics, collapse to space-separated word tokens.

    `đ` is replaced before decomposition because it is a distinct letter rather
    than a base letter plus a combining mark, so NFKD leaves it intact.
    """
    decomposed = unicodedata.normalize("NFKD", text.casefold()).replace("đ", "d")
    without_marks = "".join(char for char in decomposed if not unicodedata.combining(char))
    return " ".join(WORD_RE.findall(without_marks))