"""Linux filesystem qualification with isolated temporary data, never appdata."""
import os
from pathlib import Path
import stat
import subprocess
import tempfile
import unittest

from storage import clone_cold, private_write, tree_manifest


@unittest.skipUnless(os.name == "posix", "Linux ownership/fsync qualification")
class StorageTests(unittest.TestCase):
    def test_private_replacement_is_durable_and_private(self):
        with tempfile.TemporaryDirectory(prefix="migration-storage-test-") as directory:
            path = Path(directory) / "journal.json"
            private_write(path, b"first")
            private_write(path, b"second")
            self.assertEqual(path.read_bytes(), b"second")
            self.assertEqual(stat.S_IMODE(path.stat().st_mode), 0o600)
            target = Path(directory) / "linked"
            target.symlink_to(path)
            with self.assertRaises(ValueError):
                private_write(target, b"must not replace")
            self.assertEqual(path.read_bytes(), b"second")

    def test_real_cold_copy_preserves_content_modes_and_hardlinks(self):
        with tempfile.TemporaryDirectory(prefix="migration-storage-test-") as directory:
            source = Path(directory) / "original"
            source.mkdir(mode=0o750)
            payload = source / "database"
            payload.write_bytes(b"representative fixture data")
            payload.chmod(0o640)
            os.link(payload, source / "hardlink")
            destination = Path(directory) / "candidate"

            def runner(command, **kwargs):
                subprocess.run(command, check=True, capture_output=True, **kwargs)

            checksum = clone_cold(source, destination, runner)
            self.assertEqual(tree_manifest(source), tree_manifest(destination))
            self.assertEqual(len(checksum), 64)
            self.assertNotEqual(payload.stat().st_ino, (destination / "database").stat().st_ino)
            (destination / "database").write_bytes(b"candidate mutation")
            self.assertEqual(payload.read_bytes(), b"representative fixture data")
            with self.assertRaises(ValueError):
                clone_cold(source, destination, runner)

    def test_special_files_are_rejected_before_copy(self):
        with tempfile.TemporaryDirectory(prefix="migration-storage-test-") as directory:
            root = Path(directory)
            (root / "link").symlink_to("/tmp")
            with self.assertRaises(ValueError):
                tree_manifest(root)
            (root / "link").unlink()
            os.mkfifo(root / "fifo")
            with self.assertRaises(ValueError):
                tree_manifest(root)


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