import os
import psycopg2
from psycopg2 import sql


def connect():
    """Подключение к БД. Возвращает connection или None."""
    try:
        return psycopg2.connect(
            host=os.getenv("DB_HOST"),
            port=os.getenv("DB_PORT", 5432),
            dbname=os.getenv("DB_NAME"),
            user=os.getenv("DB_USER"),
            password=os.getenv("DB_PASS"),
            sslmode=os.getenv("DB_SSLMODE", "disable"),
        )
    except Exception:
        return None


def query(sql_text, params=None):
    """Выполнить запрос, вернуть (rows, columns) или (None, error)."""
    conn = connect()
    if not conn:
        return None, "no connection"
    try:
        cur = conn.cursor()
        cur.execute(sql_text, params)
        rows = cur.fetchall()
        cols = [desc[0] for desc in cur.description] if cur.description else []
        cur.close()
        conn.close()
        return {"columns": cols, "rows": [list(r) for r in rows]}, None
    except Exception as e:
        conn.close()
        return None, str(e)