"""Real-broker smoke test for Audio Router self-echo correlation.

The fake MQTT client used by ``tests/test_mqtt_adapter.py`` delivers a
publish's own echo synchronously, inside the ``publish()`` call itself, so it
cannot exercise the actual ordering risk: a real broker may legally deliver a
Controller-originated Router mode-set message back through the Controller's
own subscription either before or after the PUBACK that already acknowledged
the same publish. This test runs the real ``MqttAdapter`` against a real
Mosquitto broker in Docker to prove that ordering no longer matters.

Skipped automatically when Docker (or a Mosquitto broker container) is not
available, so it never blocks the primary regression suite.
"""

from __future__ import annotations

import queue
import shutil
import socket
import subprocess
import tempfile
import time
import unittest
import uuid
from pathlib import Path

import paho.mqtt.client as mqtt

from controller.config import ControllerConfig, MqttConfig
from controller.mqtt_adapter import MqttAdapter


def _docker_available() -> bool:
    return shutil.which("docker") is not None


def _free_port() -> int:
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
        sock.bind(("127.0.0.1", 0))
        return sock.getsockname()[1]


@unittest.skipUnless(
    _docker_available(), "docker is not available for a real Mosquitto broker"
)
class RouterSelfEchoMosquittoIntegrationTests(unittest.TestCase):
    @classmethod
    def setUpClass(cls) -> None:
        cls.port = _free_port()
        cls.container_name = f"controller-echo-test-{uuid.uuid4().hex[:10]}"
        cls.tempdir = tempfile.TemporaryDirectory()
        conf_path = Path(cls.tempdir.name) / "mosquitto.conf"
        conf_path.write_text("listener 1883\nallow_anonymous true\n", encoding="utf-8")
        try:
            subprocess.run(
                [
                    "docker",
                    "run",
                    "-d",
                    "--rm",
                    "--name",
                    cls.container_name,
                    "-p",
                    f"127.0.0.1:{cls.port}:1883",
                    "-v",
                    f"{conf_path}:/mosquitto/config/mosquitto.conf:ro",
                    "eclipse-mosquitto",
                ],
                check=True,
                capture_output=True,
                text=True,
                timeout=30,
            )
        except (OSError, subprocess.CalledProcessError, subprocess.TimeoutExpired) as exc:
            cls.tempdir.cleanup()
            raise unittest.SkipTest(
                f"could not start a real Mosquitto broker container: {exc}"
            )
        try:
            cls._wait_for_broker(cls.port)
        except AssertionError as exc:
            subprocess.run(
                ["docker", "rm", "-f", cls.container_name],
                capture_output=True,
                timeout=15,
            )
            cls.tempdir.cleanup()
            raise unittest.SkipTest(str(exc))

    @classmethod
    def tearDownClass(cls) -> None:
        subprocess.run(
            ["docker", "rm", "-f", cls.container_name],
            capture_output=True,
            timeout=15,
        )
        cls.tempdir.cleanup()

    @staticmethod
    def _wait_for_broker(port: int, timeout: float = 15.0) -> None:
        deadline = time.monotonic() + timeout
        last_exc: OSError | None = None
        while time.monotonic() < deadline:
            try:
                with socket.create_connection(("127.0.0.1", port), timeout=0.5):
                    return
            except OSError as exc:
                last_exc = exc
                time.sleep(0.2)
        raise AssertionError(f"Mosquitto broker never became reachable: {last_exc}")

    def _config(self) -> ControllerConfig:
        return ControllerConfig(
            mqtt=MqttConfig(
                host="127.0.0.1",
                port=self.port,
                client_id=f"controller-echo-{uuid.uuid4().hex[:10]}",
                reconnect_min_seconds=1,
                reconnect_max_seconds=1,
                command_queue_size=32,
                publish_ack_timeout_seconds=5.0,
                router_echo_grace_seconds=2.0,
            )
        )

    def test_controller_recognizes_its_own_router_echo_over_a_real_broker(self) -> None:
        config = self._config()
        adapter = MqttAdapter(config)
        adapter.start()
        try:
            self._wait_until(
                lambda: adapter.connected,
                "Controller MQTT adapter never connected to the real broker",
            )
            receipt = adapter.publish_router_mode("video")
            self.assertTrue(receipt.accepted, receipt.reason)

            event = self._next_message_event(adapter, timeout=5.0)
            self.assertEqual(event.topic, config.topics.router_mode_set)
            self.assertEqual(event.payload, b"video")
            self.assertTrue(
                event.controller_echo,
                "Controller did not recognize its own Router mode-set echo "
                "delivered by a real broker; the PUBACK-vs-subscription-echo "
                "race was not closed",
            )
        finally:
            adapter.stop()

    def test_genuine_external_router_command_is_not_treated_as_self_echo(self) -> None:
        config = self._config()
        adapter = MqttAdapter(config)
        adapter.start()
        operator = mqtt.Client(
            mqtt.CallbackAPIVersion.VERSION2,
            client_id=f"operator-{uuid.uuid4().hex[:10]}",
        )
        try:
            self._wait_until(
                lambda: adapter.connected,
                "Controller MQTT adapter never connected to the real broker",
            )
            operator.connect(config.mqtt.host, config.mqtt.port, keepalive=30)
            operator.loop_start()
            info = operator.publish(
                config.topics.router_mode_set, "service", qos=1, retain=False
            )
            info.wait_for_publish(timeout=5.0)

            event = self._next_message_event(adapter, timeout=5.0)
            self.assertEqual(event.payload, b"service")
            self.assertFalse(
                event.controller_echo,
                "A genuine external Router command was mistaken for a "
                "Controller echo; automatic restoration ownership would be "
                "incorrectly preserved instead of relinquished",
            )
        finally:
            operator.loop_stop()
            operator.disconnect()
            adapter.stop()

    @staticmethod
    def _wait_until(predicate, message: str, timeout: float = 10.0) -> None:
        deadline = time.monotonic() + timeout
        while time.monotonic() < deadline:
            if predicate():
                return
            time.sleep(0.05)
        raise AssertionError(message)

    @staticmethod
    def _next_message_event(adapter: MqttAdapter, *, timeout: float):
        deadline = time.monotonic() + timeout
        while time.monotonic() < deadline:
            try:
                event = adapter.events.get(timeout=0.2)
            except queue.Empty:
                continue
            if event.kind == "message":
                return event
        raise AssertionError("no MQTT message event was observed within the timeout")


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