"""POST /display/on-demand/start and /stop: control socket first, mailbox fallback.

The routes hand the request to the display over the control socket
(src/ipc) and get an acknowledgement. On any failure -- no socket (a stopped
display, or one older than the socket), a timeout, a refusal, a bug in the
client -- they write the file mailbox exactly as they did before the socket
existed. These tests pin both paths, that exactly one of them is used, that
the response says which, and that the request id is the same either way (the
display deduplicates on it).

The socket client is patched at the route's module attribute; the last class
runs a real server on a temp socket (Linux/macOS only).
"""

import os
import sys
from pathlib import Path
from unittest.mock import patch

import pytest

sys.path.insert(0, str(Path(__file__).parent.parent))

from test._api_v3_test_helpers import api_v3_client, api_v3_module  # noqa: F401,E402

from src.ipc import client as control_client  # noqa: E402
from src.ipc import contract as c  # noqa: E402

START_URL = "/api/v3/display/on-demand/start"
STOP_URL = "/api/v3/display/on-demand/stop"
MAILBOX = "display_on_demand_request"
CLIENT = "web_interface.blueprints.api_v3.display.control_client"


@pytest.fixture
def service(api_v3_module):
    """A running display service; records systemctl calls and mailbox writes."""
    api_v3_module.api_v3.plugin_catalog = None
    api_v3_module.api_v3.config_manager = None
    state = {"active": True}
    calls = []

    def status():
        return {"active": state["active"]}

    def systemctl(args):
        calls.append(("systemctl", args[-2]))
        if args[-2:] == ["start", "ledmatrix.service"]:
            state["active"] = True
        return {"returncode": 0, "stdout": "", "stderr": ""}

    cache = api_v3_module.api_v3.cache_manager
    cache.set.side_effect = lambda key, value, *a, **kw: calls.append(("cache", key))
    with patch("web_interface.blueprints.api_v3._get_display_service_status",
               side_effect=status), \
         patch("web_interface.blueprints.api_v3.display._get_display_service_status",
               side_effect=status), \
         patch("web_interface.blueprints.api_v3._run_systemctl_command",
               side_effect=systemctl), \
         patch("web_interface.blueprints.api_v3.display._stop_display_service"):
        yield {"state": state, "cache": cache, "calls": calls}


def _mailbox_writes(cache):
    return [call.args[1] for call in cache.set.call_args_list
            if call.args and call.args[0] == MAILBOX]


def _ack(request_id, *a, **kw):
    return {"accepted": True, "request_id": request_id, "queued": 1}


class TestSocketPath:
    def test_start_goes_over_the_socket_and_skips_the_mailbox(self, api_v3_client, service):
        with patch(f"{CLIENT}.on_demand_start", side_effect=_ack) as start:
            resp = api_v3_client.post(START_URL, json={
                "plugin_id": "weather", "mode": "weather_current",
                "duration": 60, "pinned": True})
        assert resp.status_code == 200, resp.get_json()
        data = resp.get_json()["data"]
        assert data["transport"] == "socket"
        assert "socket_error" not in data
        assert _mailbox_writes(service["cache"]) == []
        start.assert_called_once_with(data["request_id"], "weather", "weather_current", 60, True)

    def test_a_callers_request_id_is_passed_through(self, api_v3_client, service):
        with patch(f"{CLIENT}.on_demand_start", side_effect=_ack) as start:
            data = api_v3_client.post(START_URL, json={
                "plugin_id": "weather", "request_id": "ha-123"}).get_json()["data"]
        assert data["request_id"] == "ha-123"
        assert start.call_args.args[0] == "ha-123"

    def test_stop_goes_over_the_socket(self, api_v3_client, service):
        with patch(f"{CLIENT}.on_demand_stop", side_effect=_ack) as stop:
            data = api_v3_client.post(STOP_URL, json={}).get_json()["data"]
        assert data["transport"] == "socket"
        stop.assert_called_once_with(data["request_id"])
        assert _mailbox_writes(service["cache"]) == []


class TestMailboxFallback:
    @pytest.mark.parametrize("reason", [
        "no_socket", "refused", "timeout", "closed", "bad_response", "invalid_request",
        "busy", "unknown_command", "unsupported_version", "disabled", "unsupported",
    ])
    def test_any_socket_failure_writes_the_mailbox_as_before(
            self, api_v3_client, service, reason):
        with patch(f"{CLIENT}.on_demand_start",
                   side_effect=control_client.ControlError(reason, "x")):
            resp = api_v3_client.post(START_URL, json={
                "plugin_id": "weather", "mode": "weather_current",
                "duration": 60, "pinned": True})
        assert resp.status_code == 200
        data = resp.get_json()["data"]
        assert data["transport"] == "mailbox"
        assert data["socket_error"] == reason
        [write] = _mailbox_writes(service["cache"])
        assert write["request_id"] == data["request_id"]
        assert write["action"] == "start"
        assert (write["plugin_id"], write["mode"], write["duration"], write["pinned"]) == \
            ("weather", "weather_current", 60, True)

    def test_a_client_bug_still_falls_back(self, api_v3_client, service):
        with patch(f"{CLIENT}.on_demand_start", side_effect=RuntimeError("boom")):
            resp = api_v3_client.post(START_URL, json={"plugin_id": "weather"})
        assert resp.status_code == 200
        assert resp.get_json()["data"]["socket_error"] == "internal"
        assert len(_mailbox_writes(service["cache"])) == 1

    def test_stop_falls_back(self, api_v3_client, service):
        with patch(f"{CLIENT}.on_demand_stop",
                   side_effect=control_client.ControlError("timeout")):
            data = api_v3_client.post(STOP_URL, json={}).get_json()["data"]
        assert data["transport"] == "mailbox"
        [write] = _mailbox_writes(service["cache"])
        assert write == {"request_id": data["request_id"], "action": "stop",
                         "timestamp": write["timestamp"]}

    def test_a_stopped_display_gets_the_mailbox_before_it_is_started(
            self, api_v3_client, service):
        service["state"]["active"] = False
        with patch(f"{CLIENT}.on_demand_start",
                   side_effect=control_client.ControlError("no_socket")):
            resp = api_v3_client.post(START_URL, json={"plugin_id": "weather"})
        assert resp.status_code == 200
        assert service["calls"] == [("cache", MAILBOX), ("systemctl", "start")]

    def test_the_socket_is_off_in_the_test_suite(self, api_v3_client, service):
        # conftest's _hermetic_control_socket: a suite run on a device must
        # not drive the live display.
        assert os.environ[c.SOCKET_PATH_ENV] == "off"
        data = api_v3_client.post(START_URL, json={"plugin_id": "weather"}).get_json()["data"]
        assert data["transport"] == "mailbox"
        assert data["socket_error"] in ("disabled", "unsupported")   # Linux, Windows


@pytest.mark.skipif(not c.socket_supported(), reason="AF_UNIX sockets are Linux/macOS only")
class TestRealSocket:
    @pytest.fixture
    def live(self, monkeypatch):
        import shutil
        import tempfile
        from src.ipc.server import ControlServer
        d = tempfile.mkdtemp(prefix="lmipc-")
        path = os.path.join(d, "control.sock")
        server = ControlServer(path, status_provider=dict)
        assert server.start()
        monkeypatch.setenv(c.SOCKET_PATH_ENV, path)
        yield server
        server.close()
        shutil.rmtree(d, ignore_errors=True)

    def test_start_is_acked_and_queued(self, api_v3_client, service, live):
        data = api_v3_client.post(START_URL, json={
            "plugin_id": "weather", "duration": "30"}).get_json()["data"]
        assert data["transport"] == "socket"
        [cmd] = live.drain()
        payload = cmd.as_on_demand_request()
        assert payload["request_id"] == data["request_id"]
        assert payload["plugin_id"] == "weather" and payload["duration"] == 30.0
        assert _mailbox_writes(service["cache"]) == []

    def test_stop_is_acked_and_queued(self, api_v3_client, service, live):
        data = api_v3_client.post(STOP_URL, json={}).get_json()["data"]
        assert data["transport"] == "socket"
        assert [x.request_id for x in live.drain()] == [data["request_id"]]

    def test_a_display_that_went_away_falls_back(self, api_v3_client, service, live):
        live.close()
        data = api_v3_client.post(START_URL, json={"plugin_id": "weather"}).get_json()["data"]
        assert data["transport"] == "mailbox" and data["socket_error"] == "no_socket"
        assert len(_mailbox_writes(service["cache"])) == 1