"""
database/core.py
SQLAlchemy 引擎与 Session 工厂（同步引擎，连接远程 MySQL）。
"""

from __future__ import annotations

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

from config import settings

engine = create_engine(
    settings.DATABASE_URL,
    pool_size=settings.DB_POOL_SIZE,
    max_overflow=settings.DB_MAX_OVERFLOW,
    pool_timeout=settings.DB_POOL_TIMEOUT,
    pool_pre_ping=settings.DB_POOL_PRE_PING,
    pool_recycle=3600,
    connect_args={
        "charset": "utf8mb4",
        "use_unicode": True,
        "init_command": "SET NAMES utf8mb4 COLLATE utf8mb4_unicode_ci",
    },
    echo=False,
)

SessionLocal = sessionmaker(
    bind=engine,
    autocommit=False,
    autoflush=False,
    expire_on_commit=False,
)