import importlib.util
import os
import tempfile
import unittest
from pathlib import Path


MODULE_PATH = Path(__file__).parents[2] / "autoinstall/offline/atomic-profile-journal.py"
SPEC = importlib.util.spec_from_file_location("atomic_profile_journal", MODULE_PATH)
MODULE = importlib.util.module_from_spec(SPEC)
assert SPEC.loader
SPEC.loader.exec_module(MODULE)


IDENTITY = {"operation_id": "op-1", "profile": "cpu-only", "manifest_sha256": "a" * 64}


class AtomicProfileJournalTests(unittest.TestCase):
    def test_atomic_sequence_and_permissions(self):
        with tempfile.TemporaryDirectory() as directory:
            path = Path(directory) / "journal.json"
            first = MODULE.update(path, expected_generation=0, state="profile_selected",
                                  checkpoint_id=None, **IDENTITY)
            self.assertEqual(first["generation"], 1)
            self.assertEqual(os.stat(path).st_mode & 0o777, 0o600)
            second = MODULE.update(path, expected_generation=1, state="checkpoint_ready",
                                   checkpoint_id="checkpoint-1", **IDENTITY)
            third = MODULE.update(path, expected_generation=2, state="installing",
                                  checkpoint_id=None, **IDENTITY)
            self.assertEqual(third["checkpoint_id"], "checkpoint-1")
            self.assertEqual(third["previous_record_sha256"], second["record_sha256"])

    def test_stale_generation_and_identity_change_fail(self):
        with tempfile.TemporaryDirectory() as directory:
            path = Path(directory) / "journal.json"
            MODULE.update(path, expected_generation=0, state="profile_selected",
                          checkpoint_id=None, **IDENTITY)
            with self.assertRaisesRegex(MODULE.JournalError, "GENERATION_STALE"):
                MODULE.update(path, expected_generation=0, state="checkpoint_ready",
                              checkpoint_id="checkpoint-1", **IDENTITY)
            with self.assertRaisesRegex(MODULE.JournalError, "IDENTITY_CHANGED"):
                MODULE.update(path, expected_generation=1, state="checkpoint_ready",
                              checkpoint_id="checkpoint-1", **{**IDENTITY, "profile": "nvidia-cu128"})

    def test_checkpoint_required_before_installing(self):
        current = MODULE.next_record(None, 0, "op-1", "cpu-only", "a" * 64,
                                     "profile_selected", None)
        with self.assertRaisesRegex(MODULE.JournalError, "TRANSITION_INVALID"):
            MODULE.next_record(current, 1, "op-1", "cpu-only", "a" * 64, "installing", None)
        with self.assertRaisesRegex(MODULE.JournalError, "CHECKPOINT_ID_REQUIRED"):
            MODULE.next_record(current, 1, "op-1", "cpu-only", "a" * 64,
                               "checkpoint_ready", None)

    def test_tamper_is_detected(self):
        with tempfile.TemporaryDirectory() as directory:
            path = Path(directory) / "journal.json"
            MODULE.update(path, expected_generation=0, state="profile_selected",
                          checkpoint_id=None, **IDENTITY)
            path.write_text(path.read_text().replace("cpu-only", "nvidia-cu128"))
            with self.assertRaisesRegex(MODULE.JournalError, "DIGEST_INVALID"):
                MODULE.read_verified(path)

    def test_rollback_is_terminal(self):
        current = MODULE.next_record(None, 0, "op-1", "cpu-only", "a" * 64,
                                     "profile_selected", None)
        rolled_back = MODULE.next_record(current, 1, "op-1", "cpu-only", "a" * 64,
                                         "rolled_back", None)
        with self.assertRaisesRegex(MODULE.JournalError, "TRANSITION_INVALID"):
            MODULE.next_record(rolled_back, 2, "op-1", "cpu-only", "a" * 64,
                               "profile_selected", None)


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