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

from backend.config import settings

# Convert postgres:// to postgresql:// for SQLAlchemy
DATABASE_URL = settings.DATABASE_URL.replace("postgresql://", "postgresql+asyncpg://")

# Create async engine with statement_cache_size=0 for Supabase pgbouncer compatibility
engine = create_async_engine(
    DATABASE_URL,
    echo=True,
    future=True,
    connect_args={
        "statement_cache_size": 0,
        "prepared_statement_cache_size": 0,
        "server_settings": {"jit": "off"},
    },
    pool_pre_ping=True,
    pool_recycle=300,
)

# Create async session factory
async_session = sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)

Base = declarative_base()


async def get_db():
    """Dependency for FastAPI routes to get database session"""
    async with async_session() as session:
        try:
            yield session
            await session.commit()
        except Exception:
            await session.rollback()
            raise
        finally:
            await session.close()


async def init_db():
    """Initialize database tables"""
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)