import os
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
from sqlalchemy.orm import declarative_base

DATABASE_URL = os.getenv("DATABASE_URL", "postgresql+asyncpg://postgres:postgres@localhost:5432/pulseguard")

if "sqlite" in DATABASE_URL:
    engine = create_async_engine(
        DATABASE_URL,
        echo=False,
        future=True
    )
else:
    engine = create_async_engine(
        DATABASE_URL,
        echo=False,
        future=True,
        pool_size=10,
        max_overflow=20
    )

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

Base = declarative_base()

async def init_db():
    async with engine.begin() as conn:
        # Import models inside to avoid circular reference
        from models import AuditLog, ReliabilityEvent, BenchmarkResult
        await conn.run_sync(Base.metadata.create_all)