import os
import psycopg2
from psycopg2.extras import RealDictCursor
from contextlib import contextmanager
import logging

logger = logging.getLogger(__name__)


@contextmanager
def get_cursor():
    """
    New connection per call — psycopg2 is not thread-safe across Gradio workers.
    Commits on clean exit, rolls back on exception.
    """
    url = os.environ.get("DATABASE_URL")
    if not url:
        raise RuntimeError("DATABASE_URL not set — is Docker Compose running?")
    conn = psycopg2.connect(url)
    try:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            yield cur
        conn.commit()
    except Exception:
        conn.rollback()
        raise
    finally:
        conn.close()