# utils.py
import re
from typing import Optional

def safe_truncate(text: str, max_chars: int = 12000) -> str:
    if not text:
        return ""
    return text if len(text) <= max_chars else text[:max_chars] + "\n\n[[TRUNCATED]]"

def sanitize_text(text: Optional[str]) -> str:
    if not text:
        return ""
    t = re.sub(r"<[^>]+>", " ", text)
    t = re.sub(r"\s+", " ", t).strip()
    return t

def _extract_json_from_text(text: str) -> Optional[str]:
    if not text:
        return None
    start = None
    depth = 0
    for i, ch in enumerate(text):
        if ch == "{":
            if start is None:
                start = i
            depth += 1
        elif ch == "}":
            if depth > 0:
                depth -= 1
                if depth == 0 and start is not None:
                    return text[start:i+1]
    return None