"""Text chunking utilities for sending long content within Discord's limit."""

from __future__ import annotations


def split_message(text: str, limit: int = 1900) -> list[str]:
    """Split ``text`` into chunks of at most ``limit`` characters.

    Splits on newlines first so a line is never broken mid-text when
    avoidable; a single line longer than ``limit`` is hard-split by plain
    code-point slicing (Python ``str`` slicing is code-point safe, so no
    lone surrogates are produced). Multi-codepoint grapheme clusters (e.g.
    some emoji) are not protected — this matches the previous behavior and
    keeps the dependency footprint at zero.

    Guarantees ``"".join(split_message(text, limit)) == text``.
    """
    if not text:
        return []
    if limit <= 0:
        raise ValueError("limit must be a positive integer")

    chunks: list[str] = []
    current = ""
    for raw_line in text.splitlines(keepends=True):
        line = raw_line
        while len(line) > limit:
            if current:
                chunks.append(current)
                current = ""
            chunks.append(line[:limit])
            line = line[limit:]
        if len(current) + len(line) <= limit:
            current += line
        else:
            if current:
                chunks.append(current)
            current = line
    if current:
        chunks.append(current)
    return chunks