import functools

from fastapi import status, HTTPException
from sqlalchemy import create_engine, select, delete, update, and_, or_, func
from sqlalchemy.orm import sessionmaker, Session
from sqlalchemy.exc import ProgrammingError

from logger.logger import log
from config.config_loader import ConfigLoader
from models import Platform, Rom, User, Role


class DBHandler:
    def __init__(self) -> None:
        self.engine = create_engine(ConfigLoader.get_db_engine(), pool_pre_ping=True)
        self.session = sessionmaker(bind=self.engine, expire_on_commit=False)

    @staticmethod
    def begin_session(func):
        @functools.wraps(func)
        def wrapper(*args, **kwargs):
            if hasattr(kwargs, 'session'):
                return func(*args, session=kwargs.get('session'))

            try:
                with args[0].session.begin() as s:
                    return func(*args, session=s)
            except ProgrammingError as e:
                log.critical(str(e))
                raise HTTPException(
                    status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(e)
                )

        return wrapper

    # ========= Platforms =========
    @begin_session
    def add_platform(self, platform: Platform, session: Session = None):
        return session.merge(platform)

    @begin_session
    def get_platforms(self, session: Session = None):
        return session.scalars(select(Platform).order_by(Platform.slug.asc())).all()

    @begin_session
    def get_platform(self, slug: str, session: Session = None):
        return session.get(Platform, slug)

    @begin_session
    def purge_platforms(self, platforms: list[str], session: Session = None):
        return session.execute(
            delete(Platform)
            .where(or_(Platform.fs_slug.not_in(platforms), Platform.slug.is_(None)))
            .execution_options(synchronize_session="evaluate")
        )

    # ========= Roms =========
    @begin_session
    def add_rom(self, rom: Rom, session: Session = None):
        return session.merge(rom)

    def get_roms(self, platform_slug: str):
        return (
            select(Rom)
            .filter_by(platform_slug=platform_slug)
            .order_by(func.lower(Rom.name).asc())
        )

    @begin_session
    def get_rom(self, id, session: Session = None):
        return session.get(Rom, id)

    @begin_session
    def get_recent_roms(self, session: Session = None):
        return session.scalars(select(Rom).order_by(Rom.id.desc()).limit(15)).all()

    @begin_session
    def update_rom(self, id: int, data: dict, session: Session = None):
        return session.execute(
            update(Rom)
            .where(Rom.id == id)
            .values(**data)
            .execution_options(synchronize_session="evaluate")
        )

    @begin_session
    def delete_rom(self, id: int, session: Session = None):
        return session.execute(
            delete(Rom)
            .where(Rom.id == id)
            .execution_options(synchronize_session="evaluate")
        )

    @begin_session
    def purge_roms(self, platform_slug: str, roms: list[str], session: Session = None):
        return session.execute(
            delete(Rom)
            .where(and_(Rom.platform_slug == platform_slug, Rom.file_name.not_in(roms)))
            .execution_options(synchronize_session="evaluate")
        )

    @begin_session
    def get_rom_count(self, platform_slug: str, session: Session = None):
        return session.scalar(
            select(func.count()).select_from(Rom).filter_by(platform_slug=platform_slug)
        )

    # ==== Utils ======
    @begin_session
    def get_rom_by_filename(
        self, platform_slug: str, file_name: str, session: Session = None
    ):
        return session.scalars(
            select(Rom)
            .filter_by(platform_slug=platform_slug, file_name=file_name)
            .limit(1)
        ).first()

    # ========= Users =========
    @begin_session
    def add_user(self, user: User, session: Session = None):
        return session.merge(user)

    @begin_session
    def get_user_by_username(self, username: str, session: Session = None):
        return session.scalars(
            select(User).filter_by(username=username).limit(1)
        ).first()

    @begin_session
    def get_user(self, id: int, session: Session = None):
        return session.get(User, id)

    @begin_session
    def update_user(self, id: int, data: dict, session: Session = None):
        session.execute(
            update(User)
            .where(User.id == id)
            .values(**data)
            .execution_options(synchronize_session="evaluate")
        )

    @begin_session
    def delete_user(self, id: int, session: Session = None):
        return session.execute(
            delete(User)
            .where(User.id == id)
            .execution_options(synchronize_session="evaluate")
        )

    @begin_session
    def get_users(self, session: Session = None):
        return session.scalars(select(User)).all()

    @begin_session
    def get_admin_users(self, session: Session = None):
        return session.scalars(select(User).filter_by(role=Role.ADMIN)).all()