"""SQLite 连接统一配置（WAL + busy_timeout，降低并发锁冲突）。"""
from __future__ import annotations

import os
import sqlite3

DB_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "futures.db")


def connect_db(path: str | None = None) -> sqlite3.Connection:
    db_path = path or DB_PATH
    conn = sqlite3.connect(db_path, timeout=30, check_same_thread=False)
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA busy_timeout=30000")
    try:
        conn.execute("PRAGMA journal_mode=WAL")
    except sqlite3.OperationalError:
        pass
    return conn