from pathlib import Path
from typing import AsyncGenerator

from sqlalchemy import create_engine
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker


# Ensure DB directory exists
DB_DIR = Path("/app") / "storage" / "db"
DB_DIR.mkdir(parents=True, exist_ok=True)

# Create SQLite URL (with URI flag for foreign key support)
SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"

# Create engine for synchronous operations (like migrations)
engine = create_engine(
    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)

# For async operations, we need to use a different driver
ASYNC_SQLALCHEMY_DATABASE_URL = f"sqlite+aiosqlite:///{DB_DIR}/db.sqlite"
async_engine = create_async_engine(
    ASYNC_SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)

# Create session factories
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
AsyncSessionLocal = sessionmaker(
    autocommit=False,
    autoflush=False,
    bind=async_engine,
    class_=AsyncSession,
)

# Create a base class for declarative models
Base = declarative_base()


# Dependency function for getting a database session
async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """
    Dependency function that yields an async database session.
    """
    async with AsyncSessionLocal() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()