from __future__ import annotations

import structlog
from aiogram import Router
from aiogram.exceptions import TelegramBadRequest
from aiogram.filters import CommandStart
from aiogram.types import Message

from adapter.telegram import db

logger = structlog.get_logger(__name__)

router = Router(name="start")


@router.message(CommandStart())
async def cmd_start(message: Message) -> None:
    """
    Bootstrap the user's forum.

    First visit: create Чат #1, hide General topic.
    Returning visit: health-check all active topics, archive stale ones.
    """
    user_id = message.from_user.id
    chat_id = message.chat.id

    try:
        await _check_and_prune_stale_topics(message, user_id, chat_id)
    except Exception:
        logger.exception("prune_stale_topics_error", user_id=user_id)

    active = db.get_active_chats(user_id)

    if not active:
        try:
            topic = await message.bot.create_forum_topic(chat_id=chat_id, name="Чат #1")
            thread_id = topic.message_thread_id
            db.create_chat(user_id=user_id, thread_id=thread_id, chat_name="Чат #1")
            logger.info("start_created_first_topic", user_id=user_id, thread_id=thread_id)
        except TelegramBadRequest as e:
            logger.warning("start_create_topic_failed", error=str(e))
            await message.answer(
                "Не удалось создать топик. Убедись, что в @BotFather включён "
                "Threaded Mode для этого бота."
            )
            return

        try:
            await message.bot.hide_general_forum_topic(chat_id=chat_id)
        except TelegramBadRequest:
            pass  # Not critical

        await message.answer(
            "Привет! Это твоё личное пространство с AI-агентом Lambda. "
            "Каждый топик — отдельный контекст. Напиши что-нибудь."
        )
    else:
        await message.answer(
            f"Снова привет! У тебя {len(active)} активных чатов. "
            "Напиши /new чтобы создать новый."
        )


async def _check_and_prune_stale_topics(
    message: Message, user_id: int, chat_id: int
) -> None:
    """Send typing action to each active topic; archive any that no longer exist."""
    for chat in db.get_active_chats(user_id):
        thread_id = chat["thread_id"]
        try:
            await message.bot.send_chat_action(
                chat_id=chat_id,
                action="typing",
                message_thread_id=thread_id,
            )
        except TelegramBadRequest:
            db.archive_chat(user_id=user_id, thread_id=thread_id)
            logger.info("pruned_stale_topic", user_id=user_id, thread_id=thread_id)