"""Database configuration and session management."""
from typing import AsyncGenerator
from sqlalchemy.ext.asyncio import (
    AsyncSession,
    create_async_engine,
    async_sessionmaker,
)
from sqlalchemy.orm import DeclarativeBase

from app.core.config import settings


class Base(DeclarativeBase):
    """Base class for all database models."""
    pass


# Create async engine
engine = create_async_engine(
    settings.DATABASE_URL,
    echo=settings.DEBUG,
    future=True,
)

# Create async session factory
async_session_maker = async_sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False,
)


async def get_db() -> AsyncGenerator[AsyncSession, None]:
    """Dependency for getting async database sessions."""
    async with async_session_maker() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise


async def init_db() -> None:
    """Initialize database tables."""
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)