import hashlib
import importlib.machinery
import importlib.util
import json
import os
from pathlib import Path
import subprocess
import tarfile
import tempfile
import unittest
from unittest import mock


SCRIPT_DIR = Path(__file__).resolve().parent
RUNNER_PATH = SCRIPT_DIR / "nodedc-deploy"
BUILDER_PATH = SCRIPT_DIR / "build-engine-provider-rotating-slot-artifact.mjs"
ENGINE_ROOT = SCRIPT_DIR.parent.parent.parent / "NODEDC_ENGINE_INFRA"
PATCH_ID = "engine-provider-rotating-slot-20991231-999"
AUTHORITY_SUCCESSOR_SHA256 = "1a14299167ebe17efd677fa3c59b84c80e12d6846bac6f40f9bcae0729ab22c6"


def load_runner():
    loader = importlib.machinery.SourceFileLoader(
        "nodedc_engine_provider_rotating_slot",
        str(RUNNER_PATH),
    )
    spec = importlib.util.spec_from_loader(loader.name, loader)
    module = importlib.util.module_from_spec(spec)
    loader.exec_module(module)
    return module


RUNNER = load_runner()


class EngineProviderRotatingSlotTest(unittest.TestCase):
    def source_has_advanced(self):
        current_sha256 = {
            relative_path: hashlib.sha256((ENGINE_ROOT / relative_path).read_bytes()).hexdigest()
            for relative_path in RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_ARTIFACT_ENTRIES
        }
        return current_sha256 != RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_TARGET_SHA256

    def build(self, artifact_dir):
        environment = os.environ.copy()
        environment["NODEDC_ENGINE_SOURCE_ROOT"] = str(ENGINE_ROOT)
        environment["NODEDC_DEPLOY_ARTIFACT_DIR"] = str(artifact_dir)
        completed = subprocess.run(
            ["node", str(BUILDER_PATH), PATCH_ID],
            check=True,
            capture_output=True,
            text=True,
            env=environment,
        )
        return json.loads(completed.stdout)

    def test_builder_emits_exact_deterministic_two_file_slice(self):
        if self.source_has_advanced():
            self.skipTest("historical rotating-slot builder source has advanced to its exact successor")
        with tempfile.TemporaryDirectory(prefix="nodedc-provider-rotating-slot-") as directory:
            root = Path(directory)
            first = self.build(root / "first")
            second = self.build(root / "second")
            first_artifact = Path(first["artifact"])
            second_artifact = Path(second["artifact"])
            self.assertEqual(first_artifact.read_bytes(), second_artifact.read_bytes())
            self.assertEqual(
                first["sha256"],
                hashlib.sha256(first_artifact.read_bytes()).hexdigest(),
            )
            self.assertEqual(first["services"], ["nodedc-backend"])
            self.assertEqual(first["credentialSlot"], "ndcProviderRotatingAccessApi")
            self.assertEqual(
                tuple(first["entries"]),
                RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_ARTIFACT_ENTRIES,
            )

            extract = root / "extract"
            with tarfile.open(first_artifact, "r:gz") as archive:
                archive.extractall(extract, filter="data")
            entries = tuple(
                (extract / "files.txt").read_text(encoding="utf-8").splitlines()
            )
            payload = extract / "payload"
            self.assertTrue(RUNNER.is_engine_provider_rotating_slot_slice("engine", entries))
            self.assertEqual(RUNNER.component_services("engine", entries), ("nodedc-backend",))
            self.assertEqual(
                RUNNER.component_healthchecks("engine", entries, ("nodedc-backend",)),
                ("http://127.0.0.1:3001/health",),
            )
            RUNNER.validate_engine_provider_rotating_slot_slice(payload, entries)

    def test_preflight_is_exact_and_rejects_any_drift(self):
        with tempfile.TemporaryDirectory(prefix="nodedc-provider-rotating-preflight-") as directory:
            root = Path(directory)
            for relative_path in RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_ARTIFACT_ENTRIES:
                path = root / relative_path
                path.parent.mkdir(parents=True, exist_ok=True)
                path.write_text("predecessor\n", encoding="utf-8")

            def exact_sha(path):
                relative_path = Path(path).relative_to(root).as_posix()
                return RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_PREDECESSOR_SHA256[relative_path]

            with (
                mock.patch.object(RUNNER, "component_root", return_value=root),
                mock.patch.object(RUNNER, "sha256_file", side_effect=exact_sha),
                mock.patch.object(
                    RUNNER,
                    "preflight_engine_credential_backend_runtime",
                    return_value={"mode": "verified-derived-retry"},
                ),
            ):
                result = RUNNER.preflight_engine_provider_rotating_slot_predecessor()
            self.assertEqual(result["mode"], "exact-gelios-v4-credential-slot-alignment")
            self.assertEqual(
                result["predecessor_sha256"],
                RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_PREDECESSOR_SHA256,
            )

            drift_path = root / RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_ARTIFACT_ENTRIES[0]

            def drift_sha(path):
                if Path(path) == drift_path:
                    return "0" * 64
                return exact_sha(path)

            with (
                mock.patch.object(RUNNER, "component_root", return_value=root),
                mock.patch.object(RUNNER, "sha256_file", side_effect=drift_sha),
            ):
                with self.assertRaises(RUNNER.DeployError):
                    RUNNER.preflight_engine_provider_rotating_slot_predecessor()

    def test_healthchecks_dispatch_exact_rotating_slot_acceptance(self):
        entries = RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_ARTIFACT_ENTRIES
        root = Path("/engine")

        def installed_sha(path):
            relative_path = Path(path).relative_to(root).as_posix()
            return RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_TARGET_SHA256[relative_path]

        with (
            mock.patch.object(RUNNER, "component_root", return_value=root),
            mock.patch.object(RUNNER, "sha256_file", side_effect=installed_sha),
            mock.patch.object(RUNNER, "healthcheck_compose_service"),
            mock.patch.object(RUNNER, "component_healthchecks", return_value=()),
            mock.patch.object(
                RUNNER,
                "preflight_engine_credential_backend_runtime",
                return_value={"mode": "verified-derived-retry"},
            ),
            mock.patch.object(
                RUNNER,
                "accept_engine_provider_rotating_slot_runtime",
                return_value={"live": "accepted"},
            ) as rotating_acceptance,
            mock.patch.object(RUNNER, "accept_engine_composite_provider_runtime") as composite_acceptance,
            mock.patch.object(RUNNER, "healthcheck_container"),
        ):
            RUNNER.run_healthchecks("engine", entries, ("nodedc-backend",))

        rotating_acceptance.assert_called_once_with()
        composite_acceptance.assert_not_called()

    def test_live_acceptance_uses_the_rotating_slot_target_contract(self):
        if self.source_has_advanced():
            self.skipTest("historical rotating-slot live fixture source has advanced to its exact successor")
        expected_live = (
            "engine-provider-rotating-slot:gelios.provider.v4:"
            "ndcProviderRotatingAccessApi:fleet.positions.current.v3:monitoring,units"
        )
        with (
            mock.patch.object(RUNNER, "component_root", return_value=ENGINE_ROOT),
            mock.patch.object(RUNNER, "engine_backend_container_id", return_value="backend"),
            mock.patch.object(
                RUNNER,
                "run_engine_backend_probe",
                return_value=expected_live,
            ) as backend_probe,
        ):
            result = RUNNER.accept_engine_provider_rotating_slot_runtime()

        self.assertEqual(result["live"], expected_live)
        self.assertEqual(
            result["target_sha256"],
            RUNNER.ENGINE_PROVIDER_ROTATING_SLOT_TARGET_SHA256,
        )
        self.assertEqual(
            backend_probe.call_args.args[1],
            "Engine provider rotating slot authority",
        )


if __name__ == "__main__":
    unittest.main(verbosity=2)
