import hashlib
import importlib.util
import io
import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch


PROJECT_ROOT = Path(__file__).resolve().parents[1]


def load_prepare_vendor():
    specification = importlib.util.spec_from_file_location(
        "snapform_prepare_vendor",
        PROJECT_ROOT / "prepare_vendor.py",
    )
    module = importlib.util.module_from_spec(specification)
    specification.loader.exec_module(module)
    return module


class PrepareVendorTest(unittest.TestCase):
    def test_downloads_and_verifies_artifact(self):
        prepare = load_prepare_vendor()
        content = b"locked artifact"
        artifact = {
            "filename": "artifact.tar.gz",
            "url": "https://example.invalid/artifact.tar.gz",
            "sha256": hashlib.sha256(content).hexdigest(),
        }
        with tempfile.TemporaryDirectory() as directory, patch.object(
            prepare.urllib.request,
            "urlopen",
            return_value=io.BytesIO(content),
        ):
            path = prepare.download_artifact(artifact, Path(directory))
            self.assertEqual(path.read_bytes(), content)

    def test_rejects_hash_mismatch_without_leaving_partial_file(self):
        prepare = load_prepare_vendor()
        artifact = {
            "filename": "artifact.tar.gz",
            "url": "https://example.invalid/artifact.tar.gz",
            "sha256": hashlib.sha256(b"expected").hexdigest(),
        }
        with tempfile.TemporaryDirectory() as directory, patch.object(
            prepare.urllib.request,
            "urlopen",
            return_value=io.BytesIO(b"unexpected"),
        ):
            destination = Path(directory)
            with self.assertRaisesRegex(RuntimeError, "SHA-256 mismatch"):
                prepare.download_artifact(artifact, destination)
            self.assertFalse((destination / artifact["filename"]).exists())
            self.assertFalse(
                (destination / f"{artifact['filename']}.part").exists()
            )

    def test_rejects_unknown_platform(self):
        prepare = load_prepare_vendor()
        with self.assertRaisesRegex(ValueError, "Unsupported platform"):
            prepare.prepare(["windows-arm64"])


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