from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import DeclarativeBase
from sqlalchemy import text
import structlog

from .config import settings

logger = structlog.get_logger()

class Base(DeclarativeBase):
    pass

engine = create_async_engine(
    settings.database_url,
    echo=settings.debug,
    pool_pre_ping=True,
    pool_recycle=300
)

AsyncSessionLocal = async_sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False
)

async def get_db():
    async with AsyncSessionLocal() as session:
        try:
            yield session
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()

async def init_db():
    try:
        async with engine.begin() as conn:
            await conn.execute(text("CREATE EXTENSION IF NOT EXISTS vector"))
            logger.info("Database extensions initialized")
            
        from ..models import user, application, job, document
        async with engine.begin() as conn:
            await conn.run_sync(Base.metadata.create_all)
            logger.info("Database tables created")
            
    except Exception as e:
        logger.error("Database initialization failed", error=str(e))
        raise