from datetime import datetime, timedelta, timezone
import copy
import json
from pathlib import Path
import subprocess
import sys
import unittest

ROOT = Path(__file__).resolve().parents[1]
sys.path.insert(0, str(ROOT / 'scripts'))
from prometheus_export import labels, render


class ExportTests(unittest.TestCase):
    def setUp(self):
        self.now = datetime(2026, 9, 28, tzinfo=timezone.utc)
        self.contract = json.loads((ROOT / 'contracts/platform-assurance-2026-09-28.json').read_text())
        self.report = dict(schema='railiance-platform.assurance-signal.v1',
            cluster_uid='a553c742-0115-43d4-99a4-a5ca56fe0786',
            evaluated_at=self.now.isoformat(),
            signals={s: dict(state='healthy', owner='railiance-platform') for s in self.contract['signals']},
            transport='unmonitored', guarantees='unsupported',
            threshold_status='local-diagnostic-only', healthy=True)

    def test_all_states_preserved_including_token_renewal(self):
        for state in ('healthy', 'failed', 'missing', 'unavailable', 'stale'):
            self.report['signals']['eso.token-renewal']['state'] = state
            self.report['healthy'] = state == 'healthy'
            output = render(self.report, self.contract, self.now)
            samples = [line for line in output.splitlines() if line.startswith('railiance_assurance_state')]
            self.assertEqual(len(samples), 120)
            self.assertEqual(sum(line.endswith(' 1') for line in samples), 24)
            self.assertIn(f'signal="eso.token-renewal",state="{state}"}} 1', output)

    def test_retry_preserves_time_and_does_not_mutate_report(self):
        before = copy.deepcopy(self.report)
        self.assertEqual(render(self.report, self.contract, self.now),
                         render(self.report, self.contract, self.now + timedelta(seconds=900)))
        self.assertEqual(self.report, before)
        for delta in (-1, 901):
            with self.assertRaises(ValueError):
                render(self.report, self.contract, self.now + timedelta(seconds=delta))

    def test_scope_drift_is_rejected(self):
        self.report['signals']['unexpected'] = dict(state='healthy', owner='railiance-platform')
        with self.assertRaises(ValueError): render(self.report, self.contract, self.now)

    def test_label_escaping(self):
        self.assertEqual(labels({'signal': 'a"b\\c\nd'}), '{signal="a\\"b\\\\c\\nd"}')

    def test_cli_failure_has_no_metrics_stdout(self):
        result = subprocess.run([sys.executable, str(ROOT / 'scripts/prometheus_export.py'),
            '--contract', str(ROOT / 'contracts/platform-assurance-2026-09-28.json'),
            str(ROOT / 'tests/nonexistent-report.json')], capture_output=True, text=True)
        self.assertEqual(result.returncode, 2)
        self.assertEqual(result.stdout, '')
        self.assertIn('invalid-or-expired-report', result.stderr)