from sqlalchemy import select, text

from fabledassistant.models import async_session
from fabledassistant.models.note_version import NoteVersion

MAX_VERSIONS = 20


async def create_version(user_id: int, note_id: int, body: str, title: str) -> NoteVersion:
    async with async_session() as session:
        version = NoteVersion(note_id=note_id, user_id=user_id, body=body, title=title)
        session.add(version)
        await session.commit()
        await session.refresh(version)

        # Prune versions beyond MAX_VERSIONS
        await session.execute(
            text("""
                DELETE FROM note_versions
                WHERE id IN (
                    SELECT id FROM note_versions
                    WHERE note_id = :note_id AND user_id = :user_id
                    ORDER BY created_at DESC
                    OFFSET :max_versions
                )
            """).bindparams(note_id=note_id, user_id=user_id, max_versions=MAX_VERSIONS)
        )
        await session.commit()
        return version


async def list_versions(user_id: int, note_id: int) -> list[NoteVersion]:
    async with async_session() as session:
        result = await session.execute(
            select(NoteVersion)
            .where(NoteVersion.note_id == note_id, NoteVersion.user_id == user_id)
            .order_by(NoteVersion.created_at.desc())
        )
        return list(result.scalars().all())


async def get_version(user_id: int, note_id: int, version_id: int) -> NoteVersion | None:
    async with async_session() as session:
        result = await session.execute(
            select(NoteVersion).where(
                NoteVersion.id == version_id,
                NoteVersion.note_id == note_id,
                NoteVersion.user_id == user_id,
            )
        )
        return result.scalars().first()