from __future__ import annotations
from contextlib import contextmanager
from typing import Generator
import pymysql
import pymysql.cursors
from dbutils.pooled_db import PooledDB
from config.settings import settings

_pool = None

def _get_pool() -> PooledDB:
    global _pool
    if _pool is None:
        _pool = PooledDB(
            creator=pymysql,
            maxconnections=10,
            mincached=2,
            blocking=True,
            host=settings.db_host,
            port=settings.db_port,
            user=settings.db_user,
            password=settings.db_password,
            database=settings.db_name,
            charset="utf8mb4",
            cursorclass=pymysql.cursors.DictCursor,
            autocommit=False,
        )
    return _pool

@contextmanager
def get_connection():
    conn = _get_pool().connection()
    try:
        yield conn
        conn.commit()
    except Exception:
        conn.rollback()
        raise
    finally:
        conn.close()