from __future__ import annotations

import logging

from yuxi.channel.extensions.mattermost.format import (
    safe_split_markdown,
    truncate_markdown,
)

logger = logging.getLogger(__name__)


class MattermostDeliveryAdapter:
    def __init__(self, chunk_limit: int = 4000, chunk_mode: str = "length"):
        self.chunk_limit = chunk_limit
        self.chunk_mode = chunk_mode

    def split_for_delivery(self, content: str) -> list[str]:
        if len(content) <= self.chunk_limit:
            return [content]

        if self.chunk_mode == "newline":
            return self._split_by_newline(content)

        return safe_split_markdown(content, self.chunk_limit)

    def _split_by_newline(self, content: str) -> list[str]:
        chunks: list[str] = []
        lines = content.split("\n")
        current = ""
        for line in lines:
            if len(current) + len(line) + 1 > self.chunk_limit:
                if current:
                    chunks.append(current.rstrip())
                current = line
            else:
                if current:
                    current += "\n"
                current += line
        if current:
            chunks.append(current)
        return chunks

    def format_response(self, content: str, prefix: str | None = None) -> str:
        if prefix:
            content = f"{prefix}\n\n{content}"
        return truncate_markdown(content, self.chunk_limit)