from fastapi import HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.chats.service import ensure_chat_membership
from app.messages import repository
from app.messages.models import Message
from app.messages.schemas import MessageCreateRequest, MessageUpdateRequest


async def create_chat_message(db: AsyncSession, *, sender_id: int, payload: MessageCreateRequest) -> Message:
    await ensure_chat_membership(db, chat_id=payload.chat_id, user_id=sender_id)
    if payload.type.value == "text" and not (payload.text and payload.text.strip()):
        raise HTTPException(status_code=status.HTTP_422_UNPROCESSABLE_ENTITY, detail="Text message cannot be empty")

    message = await repository.create_message(
        db,
        chat_id=payload.chat_id,
        sender_id=sender_id,
        message_type=payload.type,
        text=payload.text,
    )
    await db.commit()
    await db.refresh(message)
    return message


async def get_messages(
    db: AsyncSession,
    *,
    chat_id: int,
    user_id: int,
    limit: int = 50,
    before_id: int | None = None,
) -> list[Message]:
    await ensure_chat_membership(db, chat_id=chat_id, user_id=user_id)
    safe_limit = max(1, min(limit, 100))
    return await repository.list_chat_messages(db, chat_id, limit=safe_limit, before_id=before_id)


async def update_message(
    db: AsyncSession,
    *,
    message_id: int,
    user_id: int,
    payload: MessageUpdateRequest,
) -> Message:
    message = await repository.get_message_by_id(db, message_id)
    if not message:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Message not found")
    await ensure_chat_membership(db, chat_id=message.chat_id, user_id=user_id)
    if message.sender_id != user_id:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="You can edit only your own messages")
    message.text = payload.text
    await db.commit()
    await db.refresh(message)
    return message


async def delete_message(db: AsyncSession, *, message_id: int, user_id: int) -> None:
    message = await repository.get_message_by_id(db, message_id)
    if not message:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Message not found")
    await ensure_chat_membership(db, chat_id=message.chat_id, user_id=user_id)
    if message.sender_id != user_id:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="You can delete only your own messages")
    await repository.delete_message(db, message)
    await db.commit()