from pathlib import Path
import subprocess
import sys
import tempfile
import unittest


ROOT = Path(__file__).parents[2]
CHECKER = ROOT / "scripts" / "verify_observability_manifests.py"


class ObservabilityManifestTest(unittest.TestCase):
    def run_checker(self, directory=None):
        command = [sys.executable, str(CHECKER)]
        if directory is not None:
            command += ["--directory", str(directory)]
        return subprocess.run(command, cwd=ROOT, text=True, capture_output=True)

    def test_checked_in_resources_match_service_and_metric_contract(self):
        result = self.run_checker()
        self.assertEqual(result.returncode, 0, result.stderr)

    # Every file the checker opens, in the order it opens them. Copying only a
    # subset makes it die on a missing file before it reaches the assertion
    # under test, so the mutation is never actually exercised.
    FIXTURE = (
        "kustomization.yaml",
        "prometheus-service-monitor.yaml",
        "prometheus-allocator-service-monitor.yaml",
        "prometheus-rules.yaml",
    )

    def build_fixture(self, target, mutate=None):
        for name in self.FIXTURE:
            text = (ROOT / "deploy/observability" / name).read_text()
            if mutate is not None and name == "prometheus-service-monitor.yaml":
                text = mutate(text)
            (target / name).write_text(text)

    def test_unmutated_fixture_copy_passes(self):
        # Guards the two mutation tests below: if this fails, their non-zero
        # exit proves nothing, because the fixture itself is broken.
        with tempfile.TemporaryDirectory() as directory:
            target = Path(directory)
            self.build_fixture(target)
            result = self.run_checker(target)
            self.assertEqual(result.returncode, 0, result.stderr)

    def test_checker_rejects_wrong_namespace(self):
        with tempfile.TemporaryDirectory() as directory:
            target = Path(directory)
            # Widen the namespaceSelector only; metadata.namespace stays put so
            # this isolates the scrape-scope check from the placement check.
            self.build_fixture(target, lambda text: text.replace("      - cosmic-clash", "      - default"))
            result = self.run_checker(target)
            self.assertNotEqual(result.returncode, 0)
            self.assertIn("namespace", result.stderr)

    def test_checker_rejects_broad_scrape_path(self):
        with tempfile.TemporaryDirectory() as directory:
            target = Path(directory)
            self.build_fixture(target, lambda text: text.replace("      path: /metrics", "      path: /"))
            result = self.run_checker(target)
            self.assertNotEqual(result.returncode, 0)
            self.assertIn("path", result.stderr)


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