from __future__ import annotations

from contextlib import contextmanager
from pathlib import Path
from typing import Iterator

from sqlalchemy import create_engine, event, text
from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker

from app.config import get_settings


class Base(DeclarativeBase):
    pass


def _engine_url() -> str:
    url = get_settings().app.database_url
    if url.startswith("sqlite:///") and not url.startswith("sqlite:////"):
        db_path = url.removeprefix("sqlite:///")
        if db_path and db_path != ":memory:":
            Path(db_path).parent.mkdir(parents=True, exist_ok=True)
    return url


def _connect_args(url: str) -> dict:
    if url.startswith("sqlite:"):
        return {"timeout": 60}
    return {}


engine_url = _engine_url()
engine = create_engine(engine_url, future=True, pool_pre_ping=True, connect_args=_connect_args(engine_url))


@event.listens_for(engine, "connect")
def _configure_sqlite(dbapi_connection, connection_record) -> None:
    if engine.url.get_backend_name() != "sqlite":
        return
    cursor = dbapi_connection.cursor()
    cursor.execute("PRAGMA busy_timeout=60000")
    cursor.execute("PRAGMA journal_mode=WAL")
    cursor.close()
SessionLocal = sessionmaker(bind=engine, autoflush=False, autocommit=False, future=True)


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

    Base.metadata.create_all(bind=engine)


def get_db() -> Iterator[Session]:
    with SessionLocal() as session:
        yield session


@contextmanager
def session_scope() -> Iterator[Session]:
    with SessionLocal() as session:
        try:
            yield session
            session.commit()
        except Exception:
            session.rollback()
            raise


def database_ok() -> bool:
    try:
        with engine.connect() as conn:
            conn.execute(text("select 1"))
        return True
    except Exception:
        return False