import os

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


def _db_url() -> str:
    return (
        f"mysql+pymysql://{os.environ['MYSQL_USER']}:{os.environ['MYSQL_PASSWORD']}"
        f"@{os.environ['MYSQL_HOST']}:{os.environ.get('MYSQL_PORT', 3306)}"
        f"/{os.environ['MYSQL_DATABASE']}"
    )


engine = create_engine(_db_url(), pool_pre_ping=True)
SessionLocal = sessionmaker(bind=engine)


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


def check_db() -> tuple[bool, str]:
    try:
        with engine.connect() as conn:
            conn.execute(text("SELECT 1"))
        return True, "ok"
    except Exception as e:
        return False, str(e)