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

# PostgreSQL connection string
DATABASE_URL = os.environ.get('DATABASE_URL', 'postgresql+asyncpg://techzone_user:techzone_pass@localhost:5432/techzone')
SYNC_DATABASE_URL = DATABASE_URL.replace('+asyncpg', '')

# Async engine for FastAPI
async_engine = create_async_engine(DATABASE_URL, echo=False)
AsyncSessionLocal = async_sessionmaker(async_engine, class_=AsyncSession, expire_on_commit=False)

# Sync engine for migrations and seeding
sync_engine = create_engine(SYNC_DATABASE_URL, echo=False)

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

async def init_db():
    from models import Base
    async with async_engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)