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-composite-provider-v4-artifact.mjs"
ENGINE_ROOT = SCRIPT_DIR.parent.parent.parent / "NODEDC_ENGINE_INFRA"
PATCH_ID = "engine-composite-provider-v4-20991231-999"


def load_runner():
    loader = importlib.machinery.SourceFileLoader(
        "nodedc_engine_composite_provider_v4",
        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 EngineCompositeProviderV4Test(unittest.TestCase):
    def test_predecessor_map_matches_the_applied_release_order(self):
        self.assertEqual(
            RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_PREDECESSOR_SHA256,
            {
                "nodedc-source/server/assets/provider-packages/v1/catalog.json":
                    "992159fc457ec76ce1f45aad337604c8a72b29252d44fbccda515f0fd6ea6428",
                "nodedc-source/server/dataProductPublishGrant/providerCatalog.js":
                    "901b8fad80018ce177b34ced804b39cb140a47e831414057f484296b373c651d",
                "nodedc-source/server/dataProductPublishGrant/service.js":
                    "6a417b25b080c05b40c771df4e2dca163491af2c9083ff73dc7e54ad3b360241",
                "nodedc-source/server/dataProductPublishGrant/store.js":
                    "a92303b2732e21f68c1ac732fa26e4983cbadf3515741cee983b916a283d754c",
            },
        )

    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_is_deterministic_and_emits_exact_backend_only_slice(self):
        current_sha256 = {
            relative_path: hashlib.sha256((ENGINE_ROOT / relative_path).read_bytes()).hexdigest()
            for relative_path in RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_ARTIFACT_ENTRIES
        }
        if current_sha256 != RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_TARGET_SHA256:
            self.skipTest("historical v4 builder source has advanced to its exact successor")
        with tempfile.TemporaryDirectory(prefix="nodedc-engine-composite-v4-") 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["credentialValues"], "preserved")
            self.assertEqual(
                tuple(first["entries"]),
                RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_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_composite_provider_v4_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_composite_provider_v4_slice(payload, entries)
            for relative_path, expected in RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_TARGET_SHA256.items():
                self.assertEqual(
                    hashlib.sha256((payload / relative_path).read_bytes()).hexdigest(),
                    expected,
                )

    def test_preflight_requires_every_exact_predecessor_and_immutable_backend(self):
        with tempfile.TemporaryDirectory(prefix="nodedc-engine-composite-v4-preflight-") as directory:
            root = Path(directory)
            for relative_path in RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_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_COMPOSITE_PROVIDER_V4_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_composite_provider_v4_predecessor()
            self.assertEqual(result["mode"], "exact-composite-provider-v3-to-v4")
            self.assertEqual(
                result["predecessor_sha256"],
                RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_PREDECESSOR_SHA256,
            )
            self.assertEqual(
                result["target_sha256"],
                RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_TARGET_SHA256,
            )

            drift_path = root / RUNNER.ENGINE_COMPOSITE_PROVIDER_V4_ARTIFACT_ENTRIES[1]

            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_composite_provider_v4_predecessor()


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