import os
from unittest.mock import patch

from app.core.config import Settings


class TestSettings:
    def test_default_values(self) -> None:
        settings = Settings()
        assert settings.app_name == "Blog API"
        assert settings.debug is False
        assert settings.host == "0.0.0.0"
        assert settings.port == 8000
        assert settings.database_url is None

    def test_custom_values(self) -> None:
        settings = Settings(
            app_name="Test API",
            debug=True,
            host="localhost",
            port=9000,
            database_url="postgresql://test",
        )
        assert settings.app_name == "Test API"
        assert settings.debug is True
        assert settings.host == "localhost"
        assert settings.port == 9000
        assert settings.database_url == "postgresql://test"

    def test_settings_from_env(self) -> None:
        with patch.dict(
            os.environ,
            {
                "APP_NAME": "Env API",
                "DEBUG": "true",
                "HOST": "127.0.0.1",
                "PORT": "8080",
                "DATABASE_URL": "sqlite:///test.db",
            },
        ):
            settings = Settings()
            assert settings.app_name == "Env API"
            assert settings.debug is True
            assert settings.host == "127.0.0.1"
            assert settings.port == 8080
            assert settings.database_url == "sqlite:///test.db"

    def test_global_settings_instance(self) -> None:
        from app.core.config import settings

        assert isinstance(settings, Settings)
        assert settings.app_name == "Blog API"