import asyncio
from sqlalchemy import event, select
from orm.author import Author, AuthorFollower
from orm.reaction import Reaction
from orm.shout import Shout, ShoutAuthor
from orm.topic import Topic, TopicFollower
from resolvers.stat import get_with_stat
from services.cache import cache_author, cache_follows, cache_topic, get_cached_author
from services.logger import root_logger as logger

# Инициализация семафора для ограничения одновременных задач
semaphore = asyncio.Semaphore(10)


async def run_background_task(coro):
    """Запуск фоновой асинхронной задачи с контролем одновременности."""
    async with semaphore:
        try:
            await coro
        except Exception as e:
            logger.error(f"Error in background task: {e}")


async def batch_cache_updates(authors, topics, followers):
    """Обновление кэша для авторов, тем и подписчиков."""
    tasks = (
        [cache_author(author) for author in authors]
        + [cache_topic(topic) for topic in topics]
        + [
            cache_follows(follower["id"], follower["type"], follower["item_id"], follower["is_insert"])
            for follower in followers
        ]
    )
    await asyncio.gather(*tasks)


async def handle_author_follower_change(author_id: int, follower_id: int, is_insert: bool):
    """Обработка изменений в подписках авторов."""
    # Получение данных с кэша или через запрос, если необходимо
    author = await get_cached_author(author_id)
    follower = await get_cached_author(follower_id)
    if author and follower:
        authors = [author.dict()]
        followers = [{"id": follower.id, "type": "author", "item_id": author.id, "is_insert": is_insert}]
        await batch_cache_updates(authors, [], followers)


async def after_shout_update(_mapper, _connection, shout: Shout):
    """После обновления shout, обновить информацию об авторах в кэше."""
    authors_updated = await get_with_stat(
        select(Author).join(ShoutAuthor, ShoutAuthor.author == Author.id).filter(ShoutAuthor.shout == shout.id)
    )
    if authors_updated:
        await batch_cache_updates([author.dict() for author in authors_updated], [], [])


async def handle_topic_follower_change(topic_id: int, follower_id: int, is_insert: bool):
    queries = [select(Topic).filter(Topic.id == topic_id), select(Author).filter(Author.id == follower_id)]
    topic_result, follower_result = await asyncio.gather(*(get_with_stat(query) for query in queries))

    if topic_result and follower_result:
        topics = [topic_result[0].dict()]
        followers = [
            {"id": follower_result[0].id, "type": "topic", "item_id": topic_result[0].id, "is_insert": is_insert}
        ]
        await batch_cache_updates([], topics, followers)


async def after_author_update(_mapper, _connection, author: Author):
    # Обновление кэша для автора
    author_dict = author.dict()
    await cache_author(author_dict)
    logger.info(f"Author updated and cached: {author.id}")


async def after_author_follower_insert(_mapper, _connection, target: AuthorFollower):
    logger.info(f"Author follower inserted: {target}")
    await handle_author_follower_change(target.author, target.follower, True)


async def after_author_follower_delete(_mapper, _connection, target: AuthorFollower):
    logger.info(f"Author follower deleted: {target}")
    await handle_author_follower_change(target.author, target.follower, False)


async def after_topic_follower_insert(_mapper, _connection, target: TopicFollower):
    logger.info(f"Topic follower inserted: {target}")
    await handle_topic_follower_change(target.topic, target.follower, True)


async def after_topic_follower_delete(_mapper, _connection, target: TopicFollower):
    logger.info(f"Topic follower deleted: {target}")
    await handle_topic_follower_change(target.topic, target.follower, False)


async def after_reaction_update(mapper, connection, reaction: Reaction):
    # Получение данных автора реакции и автора, на чью реакцию было отвечено, одновременно
    author_query = select(Author).where(Author.id == reaction.created_by)
    replied_author_query = (
        select(Author).join(Reaction, Author.id == Reaction.created_by).where(Reaction.id == reaction.reply_to)
    )
    results = await asyncio.gather(get_with_stat(author_query), get_with_stat(replied_author_query))
    authors = [result[0].dict() for result in results if result]

    # Кэширование данных авторов
    if authors:
        await asyncio.gather(*(cache_author(author) for author in authors))

    # Обновление информации о shout, если связанный с реакцией
    if reaction.shout:
        shout_query = select(Shout).where(Shout.id == reaction.shout)
        shout_result = await connection.execute(shout_query)
        shout = shout_result.scalar_one_or_none()
        if shout:
            await after_shout_update(mapper, connection, shout)


def events_register():
    """Регистрация обработчиков событий SQLAlchemy."""
    event.listen(Shout, "after_insert", after_shout_update)
    event.listen(Shout, "after_update", after_shout_update)
    event.listen(Reaction, "after_insert", after_reaction_update)
    event.listen(Reaction, "after_update", after_reaction_update)
    event.listen(Author, "after_insert", after_author_update)
    event.listen(Author, "after_update", after_author_update)
    event.listen(AuthorFollower, "after_insert", after_author_follower_insert)
    event.listen(AuthorFollower, "after_delete", after_author_follower_delete)
    event.listen(TopicFollower, "after_insert", after_topic_follower_insert)
    event.listen(TopicFollower, "after_delete", after_topic_follower_delete)
    logger.info("Event handlers registered successfully.")