# -*- coding: utf-8 -*-
"""数据库后端选择：默认 SQLite，DSN 解析。"""
from __future__ import annotations

import os
import unittest

from _support import IsolatedDataRoot


class TestDbBackend(unittest.TestCase):
    def test_resolve_backend_defaults_to_sqlite(self) -> None:
        with IsolatedDataRoot():
            from db.backend import resolve_backend

            self.assertEqual(resolve_backend(), "sqlite")

    def test_parse_mysql_dsn(self) -> None:
        with IsolatedDataRoot():
            from db.backend import parse_mysql_dsn

            params = parse_mysql_dsn("mysql://root:secret@192.168.0.20:3306/demo_db")
            self.assertEqual(params["host"], "192.168.0.20")
            self.assertEqual(params["port"], 3306)
            self.assertEqual(params["user"], "root")
            self.assertEqual(params["password"], "secret")
            self.assertEqual(params["database"], "demo_db")

    def test_resolve_backend_uses_mysql_dsn_from_env(self) -> None:
        with IsolatedDataRoot():
            from db.backend import resolve_backend

            os.environ["MYSQL_DSN"] = "mysql://u:p@127.0.0.1:3306/t"
            try:
                self.assertEqual(resolve_backend(), "mysql")
            finally:
                os.environ.pop("MYSQL_DSN", None)

    def test_describe_active_store_sqlite(self) -> None:
        with IsolatedDataRoot():
            from db.connection import describe_active_store

            info = describe_active_store()
            self.assertEqual(info["backend"], "sqlite")
            self.assertIn("db_path", info)


if __name__ == "__main__":
    unittest.main()