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

from app.messages.models import Message, MessageIdempotencyKey, MessageReceipt, 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_client_message_id(
    db: AsyncSession,
    *,
    chat_id: int,
    sender_id: int,
    client_message_id: str,
) -> Message | None:
    result = await db.execute(
        select(Message)
        .join(MessageIdempotencyKey, MessageIdempotencyKey.message_id == Message.id)
        .where(
            MessageIdempotencyKey.chat_id == chat_id,
            MessageIdempotencyKey.sender_id == sender_id,
            MessageIdempotencyKey.client_message_id == client_message_id,
        )
        .limit(1)
    )
    return result.scalar_one_or_none()


async def create_message_idempotency_key(
    db: AsyncSession,
    *,
    chat_id: int,
    sender_id: int,
    client_message_id: str,
    message_id: int,
) -> MessageIdempotencyKey:
    key = MessageIdempotencyKey(
        chat_id=chat_id,
        sender_id=sender_id,
        client_message_id=client_message_id,
        message_id=message_id,
    )
    db.add(key)
    await db.flush()
    return key


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)


async def get_message_receipt(db: AsyncSession, *, chat_id: int, user_id: int) -> MessageReceipt | None:
    result = await db.execute(
        select(MessageReceipt).where(
            MessageReceipt.chat_id == chat_id,
            MessageReceipt.user_id == user_id,
        )
    )
    return result.scalar_one_or_none()


async def create_message_receipt(
    db: AsyncSession,
    *,
    chat_id: int,
    user_id: int,
    last_delivered_message_id: int | None,
    last_read_message_id: int | None,
) -> MessageReceipt:
    receipt = MessageReceipt(
        chat_id=chat_id,
        user_id=user_id,
        last_delivered_message_id=last_delivered_message_id,
        last_read_message_id=last_read_message_id,
    )
    db.add(receipt)
    await db.flush()
    return receipt