import json
import socket
import tempfile
import threading
import time
import unittest
from pathlib import Path

from hydra.qmp import QMPClient, QMPError


class QMPServer:
    def __init__(self, path, handler):
        self.socket = socket.socket(socket.AF_UNIX)
        self.socket.bind(str(path))
        self.socket.listen(4)
        self.socket.settimeout(0.1)
        self.handler = handler
        self.stop = threading.Event()
        self.errors = []
        self.thread = threading.Thread(target=self.run, daemon=True)
        self.thread.start()

    def run(self):
        while not self.stop.is_set():
            try:
                conn, _ = self.socket.accept()
            except socket.timeout:
                continue
            except OSError:
                break
            try:
                with conn:
                    conn.settimeout(1)
                    self.handler(conn)
            except (BrokenPipeError, ConnectionResetError, socket.timeout):
                pass
            except Exception as exc:
                self.errors.append(exc)

    def close(self):
        self.stop.set()
        self.socket.close()
        self.thread.join(2)


def send(conn, message):
    conn.sendall(json.dumps(message).encode() + b'\r\n')


def greeting(conn):
    send(conn, {'QMP': {'version': {'qemu': {'major': 10, 'minor': 0, 'micro': 0},
                                   'package': ''}, 'capabilities': []}})


class QMPTests(unittest.TestCase):
    def setUp(self):
        self.tmp = tempfile.TemporaryDirectory(prefix='hq-')
        self.addCleanup(self.tmp.cleanup)
        self.path = Path(self.tmp.name) / 'qmp'

    def server(self, handler):
        srv = QMPServer(self.path, handler)
        self.addCleanup(srv.close)
        return srv

    def test_handshake_ids_events_and_return(self):
        commands = []

        def handler(conn):
            greeting(conn)
            stream = conn.makefile('rb')
            for index in range(2):
                request = json.loads(stream.readline())
                commands.append(request)
                send(conn, {'event': 'STOP', 'data': {}})
                send(conn, {'return': {'ignored': True}, 'id': 'unrelated'})
                send(conn, {'return': {} if index == 0 else {'status': 'running'}, 'id': request['id']})
        self.server(handler)
        with QMPClient(self.path, timeout=0.5) as client:
            self.assertEqual(client.command('query-status'), {'status': 'running'})
        self.assertEqual([cmd['execute'] for cmd in commands], ['qmp_capabilities', 'query-status'])
        self.assertNotEqual(commands[0]['id'], commands[1]['id'])

    def test_command_error(self):
        def handler(conn):
            greeting(conn)
            stream = conn.makefile('rb')
            for index in range(2):
                request = json.loads(stream.readline())
                if index == 0:
                    send(conn, {'return': {}, 'id': request['id']})
                else:
                    send(conn, {'error': {'class': 'CommandNotFound', 'desc': 'unsupported'}, 'id': request['id']})
        self.server(handler)
        with QMPClient(self.path, timeout=0.5) as client, self.assertRaises(QMPError):
            client.command('missing')

    def test_greeting_timeout_is_bounded(self):
        self.server(lambda conn: time.sleep(0.3))
        started = time.monotonic()
        with self.assertRaises(QMPError):
            QMPClient(self.path, timeout=0.08)
        self.assertLess(time.monotonic() - started, 0.25)

    def test_event_stream_cannot_extend_command_deadline(self):
        def handler(conn):
            greeting(conn)
            request = json.loads(conn.makefile('rb').readline())
            while True:
                send(conn, {'event': 'STOP', 'data': {}})
                time.sleep(0.01)
        self.server(handler)
        started = time.monotonic()
        with self.assertRaises(QMPError):
            QMPClient(self.path, timeout=0.08)
        self.assertLess(time.monotonic() - started, 0.25)

    def test_malformed_greeting_rejected(self):
        self.server(lambda conn: send(conn, {'return': {}}))
        with self.assertRaises(QMPError):
            QMPClient(self.path)

    def test_command_timeout_after_successful_handshake(self):
        def handler(conn):
            greeting(conn)
            with conn.makefile('rb') as stream:
                request = json.loads(stream.readline())
                send(conn, {'return': {}, 'id': request['id']})
                stream.readline()
                time.sleep(0.3)
        self.server(handler)
        with QMPClient(self.path, timeout=0.08) as client:
            started = time.monotonic()
            with self.assertRaises(QMPError):
                client.command('query-status')
            self.assertLess(time.monotonic() - started, 0.25)


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