"""Classify CP 707 extracted chunks as prosa vs tabel for RAG metadata."""

from __future__ import annotations

import re

_NUMERIC_PIPE_ROW = re.compile(r"^[\d.,]+(\s*\|\s*[\d.,]*)+$")
_CHAPTER_RE = re.compile(
    r"(?:bab|chapter|lampiran)\s*([0-9IVXLC]+)",
    re.IGNORECASE,
)


def classify_chunk_tipe(text: str) -> str:
    """Return 'tabel' if the chunk is mostly headerless numeric rows, else 'prosa'."""
    lines = [ln.strip() for ln in (text or "").splitlines() if ln.strip()]
    if not lines:
        return "prosa"
    numeric = sum(1 for ln in lines if _NUMERIC_PIPE_ROW.match(ln))
    if numeric >= max(2, len(lines) // 2):
        return "tabel"
    return "prosa"


def detect_bab(text: str, source_filename: str = "") -> str:
    """Best-effort chapter / lampiran label from chunk text or filename."""
    haystack = f"{source_filename}\n{text[:800]}"
    match = _CHAPTER_RE.search(haystack)
    if match:
        return match.group(0).strip()
    lower = source_filename.lower()
    if "lampiran" in lower:
        return "lampiran"
    return ""