import os
from pathlib import Path

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, DeclarativeBase

DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///./data/cluedo.db")

engine_options = {"pool_pre_ping": True}

if DATABASE_URL.startswith("sqlite"):
    # SQLite does not allow connections to be used from another thread by
    # default. FastAPI/SQLAlchemy may use a connection across request threads.
    engine_options["connect_args"] = {"check_same_thread": False}

    # Make the parent directory available for the default local database.
    if DATABASE_URL.startswith("sqlite:///"):
        sqlite_path = DATABASE_URL.removeprefix("sqlite:///")
        if sqlite_path not in (":memory:", ""):
            Path(sqlite_path).expanduser().parent.mkdir(parents=True, exist_ok=True)

engine = create_engine(DATABASE_URL, **engine_options)
SessionLocal = sessionmaker(bind=engine, autoflush=False, autocommit=False)

class Base(DeclarativeBase):
    pass

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