from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
from sqlalchemy.orm import DeclarativeBase
from app.config import get_settings

settings = get_settings()

engine = create_async_engine(
    settings.database_url,
    echo=False,
    connect_args={"timeout": 30},
)
async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


class Base(DeclarativeBase):
    pass


async def get_db():
    async with async_session() as session:
        try:
            yield session
        finally:
            await session.close()


async def init_db():
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)

    # Migrate existing DBs: add chapter_ids_json to generation_jobs
    async with engine.begin() as conn:
        try:
            await conn.execute(
                __import__("sqlalchemy").text(
                    "ALTER TABLE generation_jobs ADD COLUMN chapter_ids_json TEXT"
                )
            )
        except Exception:
            pass  # Column already exists

    # Migrate existing DBs: add recap_summary to episodes
    async with engine.begin() as conn:
        try:
            await conn.execute(
                __import__("sqlalchemy").text(
                    "ALTER TABLE episodes ADD COLUMN recap_summary TEXT"
                )
            )
        except Exception:
            pass  # Column already exists