"""Async database configuration and initialization."""

import logging
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker

from app.config import settings
from app.memory.models import Base

logger = logging.getLogger(__name__)

# Global engine and session factory
engine = None
async_session_factory = None


async def init_db() -> None:
    """Initialize the database engine and create all tables."""
    global engine, async_session_factory
    
    try:
        engine = create_async_engine(
            settings.DATABASE_URL,
            echo=settings.DEBUG,
            future=True,
        )
        
        async_session_factory = sessionmaker(
            engine,
            class_=AsyncSession,
            expire_on_commit=False,
        )
        
        # Create all tables
        async with engine.begin() as conn:
            await conn.run_sync(Base.metadata.create_all)
        
        logger.info("Database initialized successfully")
    except Exception as e:
        logger.error(f"Failed to initialize database: {e}")
        raise


async def get_session() -> AsyncSession:
    """Get an async database session."""
    if async_session_factory is None:
        raise RuntimeError("Database not initialized. Call init_db() first.")
    
    async with async_session_factory() as session:
        yield session


async def close_db() -> None:
    """Close the database connection."""
    global engine
    if engine:
        await engine.dispose()
        logger.info("Database connection closed")