import importlib
import os
import sys
import tempfile
import unittest
from pathlib import Path


class ConfigEnvLoadingTests(unittest.TestCase):
    def setUp(self) -> None:
        self._old_cwd = Path.cwd()
        self._keys = [
            "SCW_ACCESS_KEY",
            "SCW_SECRET_KEY",
            "SCW_DEFAULT_ORGANIZATION_ID",
            "SCW_DEFAULT_PROJECT_ID",
            "SCW_SERVERLESS",
        ]
        self._backup = {k: os.environ.get(k) for k in self._keys}

    def tearDown(self) -> None:
        os.chdir(self._old_cwd)
        for key, value in self._backup.items():
            if value is None:
                os.environ.pop(key, None)
            else:
                os.environ[key] = value

    def _clear_env(self) -> None:
        for key in self._keys:
            os.environ.pop(key, None)

    def test_import_uses_dotenv_fallback(self) -> None:
        self._clear_env()
        with tempfile.TemporaryDirectory() as tmp:
            os.chdir(tmp)
            Path(".env").write_text(
                "SCW_ACCESS_KEY=key0\n"
                "SCW_SECRET_KEY=key1\n"
                "SCW_DEFAULT_ORGANIZATION_ID=key2\n"
                "SCW_DEFAULT_PROJECT_ID=key3\n"
                "SCW_SERVERLESS=key4\n"
            )
            sys.modules.pop("migration_pipeline.config", None)
            config = importlib.import_module("migration_pipeline.config")
            self.assertEqual(config.SCW_SERVERLESS, "key4")
            self.assertEqual(
                config.BASE_URL,
                "https://api.scaleway.ai/key4/v1/chat/completions",
            )

    def test_import_fails_when_required_env_missing(self) -> None:
        self._clear_env()
        with tempfile.TemporaryDirectory() as tmp:
            os.chdir(tmp)
            sys.modules.pop("migration_pipeline.config", None)
            with self.assertRaisesRegex(RuntimeError, "SCW_ACCESS_KEY"):
                importlib.import_module("migration_pipeline.config")