from __future__ import annotations

from collections.abc import Generator
from pathlib import Path

from sqlalchemy import create_engine
from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
from sqlalchemy.pool import StaticPool

from .config import get_settings


class Base(DeclarativeBase):
    pass


def _connect_args(database_url: str) -> dict[str, object]:
    if database_url.startswith("sqlite"):
        return {"check_same_thread": False}
    return {}


def _engine_kwargs(database_url: str) -> dict[str, object]:
    if database_url in {"sqlite://", "sqlite:///:memory:"}:
        return {"poolclass": StaticPool}
    return {}


def _ensure_sqlite_parent(database_url: str) -> None:
    if not database_url.startswith("sqlite:///"):
        return
    db_path = database_url.replace("sqlite:///", "", 1)
    if db_path not in (":memory:", ""):
        Path(db_path).parent.mkdir(parents=True, exist_ok=True)


settings = get_settings()
_ensure_sqlite_parent(settings.database_url)
engine = create_engine(
    settings.database_url,
    connect_args=_connect_args(settings.database_url),
    **_engine_kwargs(settings.database_url),
)
SessionLocal = sessionmaker(bind=engine, autoflush=False, autocommit=False, expire_on_commit=False)


def init_db() -> None:
    from . import models  # noqa: F401

    Base.metadata.create_all(bind=engine)


def get_session() -> Generator[Session, None, None]:
    session = SessionLocal()
    try:
        yield session
    finally:
        session.close()