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


Base = declarative_base()

engine = None
AsyncSessionLocal = None


async def init_database(connection_string):
    """راه‌اندازی اولیه دیتابیس PostgreSQL به صورت Async"""
    global engine, AsyncSessionLocal
    
    
    engine = create_async_engine(
        connection_string,
        echo=True,  # برای دیباگ
        future=True,
        pool_pre_ping=True,
        pool_recycle=300
    )
    
    AsyncSessionLocal = async_sessionmaker(
        engine,
        class_=AsyncSession,
        expire_on_commit=False
    )
    
    print("✅ PostgreSQL Async database initialized successfully")

async def get_session() -> AsyncSession:
    if not AsyncSessionLocal:
        raise Exception("Database not initialized. Call init_database() first.")
    
    return AsyncSessionLocal()

async def close_database():
    if engine:
        await engine.dispose()
        print("✅ Database connections closed")