import re

MAX_UTF8_LEN = 2048


def remove_markdown(text: str) -> str:
    text = re.sub(r"```\w*\n?", "", text)
    text = re.sub(r"`([^`]+)`", r"\1", text)
    text = re.sub(r"\*\*([^*]+)\*\*", r"\1", text)
    text = re.sub(r"\*([^*]+)\*", r"\1", text)
    text = re.sub(r"__([^_]+)__", r"\1", text)
    text = re.sub(r"_([^_]+)_", r"\1", text)
    text = re.sub(r"(?m)^#{1,6}\s+", "", text)
    text = re.sub(r"(?m)^[-*_]{3,}\s*$", "", text)
    return text.strip()


def split_utf8(text: str, max_bytes: int = MAX_UTF8_LEN) -> list[str]:
    encoded = text.encode("utf-8")
    if len(encoded) <= max_bytes:
        return [text]
    result: list[str] = []
    remaining = encoded
    while remaining:
        chunk = remaining[:max_bytes]
        for cut in range(len(chunk), 0, -1):
            try:
                result.append(chunk[:cut].decode("utf-8"))
                break
            except UnicodeDecodeError:
                continue
        remaining = remaining[cut:]
    return result


def split_utf8_safe(text: str, max_bytes: int = MAX_UTF8_LEN) -> tuple[str, str | None]:
    encoded = text.encode("utf-8")
    if len(encoded) <= max_bytes:
        return text, None
    hint = "\n【未完待续，回复任意文字以继续】"
    hint_bytes = len(hint.encode("utf-8"))
    limit = max_bytes - hint_bytes
    try:
        cut_point = len(encoded[:limit].decode("utf-8", errors="ignore"))
    except Exception:
        cut_point = limit
    first_part = text[:cut_point] + hint
    remaining = text[cut_point:]
    return first_part, remaining