from sqlalchemy import create_engine
from sqlalchemy.orm import DeclarativeBase, sessionmaker
from sqlalchemy.pool import StaticPool
from config import settings


class Base(DeclarativeBase):
    pass


_connect_args = {}
_pool_class = None

if settings.database_url.startswith("sqlite"):
    _connect_args = {"check_same_thread": False}
    _pool_class = StaticPool

engine = create_engine(
    settings.database_url,
    connect_args=_connect_args,
    **({"poolclass": _pool_class} if _pool_class else {}),
    echo=settings.debug,
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db() -> None:
    from db import models  # noqa: F401 – Modelle müssen importiert sein
    Base.metadata.create_all(bind=engine)
    _create_default_admin()


def _create_default_admin() -> None:
    """Legt beim ersten Start einen Admin-Benutzer an, falls keine User existieren."""
    import bcrypt
    from db.models import User

    db = SessionLocal()
    try:
        if not db.query(User).first():
            pw_hash = bcrypt.hashpw(
                settings.default_admin_password.encode(), bcrypt.gensalt()
            ).decode()
            admin = User(
                username=settings.default_admin_user,
                password_hash=pw_hash,
                role="admin",
                is_active=True,
            )
            db.add(admin)
            db.commit()
    finally:
        db.close()