"""Контракт файлового канала: владение, атомарный ответ и неизвестный итог."""
import json
import os
from pathlib import Path
import sys
import tempfile
import threading
import time
import unittest

ROOT = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(ROOT / 'toolchain'))
from sdbg.build import write_json
from sdbg.transport import BridgeError, FileBridge


class TransportTests(unittest.TestCase):
    def test_owner_lock(self):
        with tempfile.TemporaryDirectory() as directory:
            first = FileBridge(directory, 'one')
            try:
                with self.assertRaisesRegex(BridgeError, 'управляющая'):
                    FileBridge(directory, 'one')
            finally:
                first.close()
            with self.assertRaisesRegex(BridgeError, 'закрыт'):
                first.request('continue')
            second = FileBridge(directory, 'one')
            second.close()

    def test_response_generation_and_session(self):
        with tempfile.TemporaryDirectory() as directory:
            bridge = FileBridge(directory, 'session', timeout=1)
            def backend():
                deadline = time.monotonic() + 1
                while time.monotonic() < deadline:
                    requests = list(Path(directory).glob('req_*.json'))
                    if requests:
                        request = requests[0]
                        data = json.loads(request.read_text())
                        response = request.with_name(request.name.replace('req_', 'resp_'))
                        write_json(response, {'session': data['session'], 'generation': 7,
                                              'ok': True, 'result': {'state': 'stopped'}})
                        request.unlink()
                        return
                    time.sleep(.001)
            thread = threading.Thread(target=backend)
            thread.start()
            try:
                self.assertEqual(bridge.request('snapshot')['state'], 'stopped')
                self.assertEqual(bridge.generation, 7)
            finally:
                thread.join()
                bridge.close()

    def test_timeout_never_retries_mutation(self):
        with tempfile.TemporaryDirectory() as directory:
            bridge = FileBridge(directory, 'session', timeout=.025)
            try:
                with self.assertRaisesRegex(BridgeError, 'Timeout'):
                    bridge.request('continue')
                self.assertTrue(bridge.invalid)
                with self.assertRaisesRegex(BridgeError, 'инвалидирован'):
                    bridge.request('continue')
                self.assertFalse(list(Path(directory).glob('req_*.json')))
            finally:
                bridge.close()


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