from bot.models import ChannelMessage

MAX_TOKENS_PER_CHUNK = 25_000
CHARS_PER_TOKEN = 3


def _format_message(msg: ChannelMessage) -> str:
    parts = [f"[{msg.date:%Y-%m-%d %H:%M}]"]
    stats = []
    if msg.views is not None:
        stats.append(f"{msg.views} views")
    if msg.forwards is not None:
        stats.append(f"{msg.forwards} fwd")
    if msg.replies is not None:
        stats.append(f"{msg.replies} replies")
    if stats:
        parts.append(f"({', '.join(stats)})")
    parts.append(f"\n{msg.text}")
    return " ".join(parts)


def chunk_messages(messages: list[ChannelMessage]) -> list[str]:
    """Split messages into token-bounded chunks."""
    max_chars = MAX_TOKENS_PER_CHUNK * CHARS_PER_TOKEN
    chunks: list[str] = []
    current_lines: list[str] = []
    current_len = 0

    for msg in messages:
        formatted = _format_message(msg)
        entry = formatted + "\n---\n"
        entry_len = len(entry)

        if current_len + entry_len > max_chars and current_lines:
            chunks.append("".join(current_lines))
            current_lines = []
            current_len = 0

        current_lines.append(entry)
        current_len += entry_len

    if current_lines:
        chunks.append("".join(current_lines))

    return chunks