import os

from sqlmodel import SQLModel

# We used the SQLAlchemy constructs -- e.g., create_async_engine and AsyncSession
# -- since SQLModel 0.0.4 does not have wrappers for them as of writing.
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.orm import sessionmaker

DATABASE_URL = os.environ.get("DATABASE_URL")

# The major differences between SQLModel's create_engine and SQLAlchemy's
# version is that the SQLModel version adds type annotations (for editor support)
# and enables the SQLAlchemy "2.0" style of engines and connections.

# We need the 2.0 style for async support.
# engine = create_engine(DATABASE_URL, echo=True)
engine = create_async_engine(DATABASE_URL, echo=True, future=True)  # Will want a "debug mode where it doesn't echo for prod


async def init_db():
    """
    Our new Async init_db was

    def init_db():
        SQLModel.metadata.create_all(engine)

    metadata.create_all doesn't execute asynchronously,
    so we used run_sync to execute it synchronously within
    the async function.
    """
    async with engine.begin() as conn:
        # await conn.run_sync(SQLModel.metadata.drop_all)
        await conn.run_sync(SQLModel.metadata.create_all)


async def get_session() -> AsyncSession:
    """
    Our new async get_session

    Was

    def get_session():
        with Session(engine) as session:
            yield session

    We disabled expire on commit behavior by passing in expire_on_commit=False.
    I believe this is how flask-sqlalchemy also works
    """
    async_session = sessionmaker(
        engine, class_=AsyncSession, expire_on_commit=False
    )
    async with async_session() as session:
        yield session