"""Installer ohne Netzwerk; optionaler Smoke-Test mit echten Modellgewichten."""
from contextlib import redirect_stdout
import hashlib
import importlib.util
from io import BytesIO, StringIO
import os
from pathlib import Path
import tempfile
import unittest
from unittest.mock import patch

from PIL import Image

from halloween.detection import NanoDet


class InstallerTest(unittest.TestCase):
    def setUp(self):
        spec = importlib.util.spec_from_file_location('model_installer', Path(__file__).parents[1] / 'tools/install_detection_model.py')
        self.installer = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(self.installer)
        self.folder = tempfile.TemporaryDirectory()
        self.addCleanup(self.folder.cleanup)
        self.data = b'test-model'
        self.manifest = {'file': 'model.onnx', 'sha256': hashlib.sha256(self.data).hexdigest(),
                         'size': len(self.data), 'url': 'https://example.invalid/model'}
        self.target = Path(self.folder.name) / 'models/model.onnx'

    def install(self, data):
        with patch.object(self.installer.json, 'loads', return_value=self.manifest), \
             patch.object(self.installer.urllib.request, 'urlopen', return_value=BytesIO(data)) as download, \
             patch('sys.argv', ['installer', '--state-dir', self.folder.name]), redirect_stdout(StringIO()):
            self.installer.main()
        return download

    def test_verified_download_is_atomic_and_idempotent(self):
        self.assertEqual(self.install(self.data).call_count, 1)
        self.assertEqual(self.target.read_bytes(), self.data)
        self.assertEqual(self.install(self.data).call_count, 0)
        self.assertEqual(list(self.target.parent.iterdir()), [self.target])

    def test_bad_download_keeps_existing_file(self):
        self.target.parent.mkdir()
        self.target.write_bytes(b'old-corrupt-model')
        with self.assertRaises(ValueError):
            self.install(b'bad-model!')
        self.assertEqual(self.target.read_bytes(), b'old-corrupt-model')
        self.assertEqual(list(self.target.parent.iterdir()), [self.target])

    def test_oversized_download_is_rejected_and_cleaned(self):
        with self.assertRaises(ValueError):
            self.install(self.data+b'extra')
        self.assertEqual(list(self.target.parent.iterdir()), [])


@unittest.skipUnless(os.environ.get('HALLOWEEN_TEST_MODEL'), 'Optionales Modell nicht angegeben')
class ModelSmokeTest(unittest.TestCase):
    def test_real_model_outputs_and_empty_frame(self):
        model = NanoDet(Path(os.environ['HALLOWEEN_TEST_MODEL']))
        frame = BytesIO()
        Image.new('RGB', (640,480)).save(frame, format='JPEG')
        self.assertEqual(model.detect(frame.getvalue()), [])


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