from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.messages.models import Message, MessageType


async def create_message(
    db: AsyncSession,
    *,
    chat_id: int,
    sender_id: int,
    message_type: MessageType,
    text: str | None,
) -> Message:
    message = Message(chat_id=chat_id, sender_id=sender_id, type=message_type, text=text)
    db.add(message)
    await db.flush()
    return message


async def get_message_by_id(db: AsyncSession, message_id: int) -> Message | None:
    result = await db.execute(select(Message).where(Message.id == message_id))
    return result.scalar_one_or_none()


async def list_chat_messages(
    db: AsyncSession,
    chat_id: int,
    *,
    limit: int = 50,
    before_id: int | None = None,
) -> list[Message]:
    query = select(Message).where(Message.chat_id == chat_id)
    if before_id is not None:
        query = query.where(Message.id < before_id)
    result = await db.execute(query.order_by(Message.id.desc()).limit(limit))
    return list(result.scalars().all())


async def delete_message(db: AsyncSession, message: Message) -> None:
    await db.delete(message)