"""Unit tests for the database DSN assembly in :mod:`tavolo.config`.

``Settings.from_env`` is called directly with a fully replaced
``os.environ`` so no test leaks its ``DATABASE_*`` overrides into the
suite (``tests/__init__.py`` sets ``DATABASE_URL=sqlite://:memory:``
globally for the application tests).
"""
from __future__ import annotations

import os
import unittest
from unittest.mock import patch

from tavolo.config import Settings


def _settings(env: dict) -> Settings:
    with patch.dict(os.environ, env, clear=True):
        return Settings.from_env()


class DatabaseUrlTests(unittest.TestCase):
    def test_defaults_assemble_from_parts(self):
        settings = _settings({})
        self.assertEqual(
            settings.database_url,
            "postgres://tavolo:password@localhost/tavolo",
        )

    def test_components_override_defaults(self):
        settings = _settings({
            "DATABASE_ENGINE": "postgres",
            "DATABASE_HOST": "db.internal",
            "DATABASE_PORT": "5433",
            "DATABASE_NAME": "cards",
            "DATABASE_USER": "scopa",
            "DATABASE_PASSWORD": "s3cret",
        })
        self.assertEqual(
            settings.database_url,
            "postgres://scopa:s3cret@db.internal:5433/cards",
        )

    def test_options_are_appended_as_query_string(self):
        settings = _settings({"DATABASE_OPTIONS": "ssl=require"})
        self.assertEqual(
            settings.database_url,
            "postgres://tavolo:password@localhost/tavolo?ssl=require",
        )

    def test_options_leading_question_mark_is_stripped(self):
        settings = _settings({"DATABASE_OPTIONS": "?ssl=require"})
        self.assertEqual(
            settings.database_url,
            "postgres://tavolo:password@localhost/tavolo?ssl=require",
        )

    def test_credentials_are_percent_encoded(self):
        settings = _settings({
            "DATABASE_USER": "u@x",
            "DATABASE_PASSWORD": "p@ss/word:1",
        })
        self.assertEqual(
            settings.database_url,
            "postgres://u%40x:p%40ss%2Fword%3A1@localhost/tavolo",
        )

    def test_database_url_takes_precedence_over_parts(self):
        settings = _settings({
            "DATABASE_URL": "sqlite://:memory:",
            "DATABASE_HOST": "db.internal",
            "DATABASE_PASSWORD": "ignored",
        })
        self.assertEqual(settings.database_url, "sqlite://:memory:")

    def test_empty_database_url_falls_back_to_parts(self):
        settings = _settings({"DATABASE_URL": ""})
        self.assertEqual(
            settings.database_url,
            "postgres://tavolo:password@localhost/tavolo",
        )


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