from __future__ import annotations

import pytest

import server_service
from server_service import ServerConfig, ServerService
from transport_server import TransportAwareFalloutTogetherServer


class FakeCoreServer:
    def __init__(self, port: int = 7777):
        self.port = port


class FakeTransport:
    instances = []
    local_port_override = None

    def __init__(self, host, port, *, library_path=None):
        self.host = host
        self.requested_port = port
        self.library_path = library_path
        self.local_port = self.local_port_override or port
        self.closed = False
        self.__class__.instances.append(self)

    def close(self):
        self.closed = True


class FakeAdapter:
    instances = []

    def __init__(self, core, transport):
        self.core = core
        self.transport = transport
        self.started = False
        self.stopped = False
        self.__class__.instances.append(self)

    def start(self):
        self.started = True

    def stop(self):
        self.stopped = True
        self.transport.close()


def reset_fakes():
    FakeTransport.instances.clear()
    FakeTransport.local_port_override = None
    FakeAdapter.instances.clear()


def test_server_service_uses_transport_aware_core_with_gns_disabled_by_default(tmp_path):
    config = ServerConfig(bans_path=str(tmp_path / "bans.json"))
    assert not config.enable_gns_transport
    service = ServerService(config)
    core = service._create_server()
    assert isinstance(core, TransportAwareFalloutTogetherServer)


def test_gns_feature_flag_is_noop_when_disabled(monkeypatch):
    reset_fakes()
    monkeypatch.setattr(server_service, "GnsServerTransport", FakeTransport)
    monkeypatch.setattr(server_service, "GnsGameplayAdapter", FakeAdapter)
    service = ServerService(ServerConfig(enable_gns_transport=False))
    service._server = FakeCoreServer()

    service._start_gns()
    assert service._gns_adapter is None
    assert FakeTransport.instances == []
    assert FakeAdapter.instances == []


def test_gns_feature_flag_starts_udp_on_same_numeric_port_and_stops_cleanly(monkeypatch):
    reset_fakes()
    monkeypatch.setattr(server_service, "GnsServerTransport", FakeTransport)
    monkeypatch.setattr(server_service, "GnsGameplayAdapter", FakeAdapter)
    service = ServerService(
        ServerConfig(
            host="127.0.0.1",
            port=7777,
            enable_gns_transport=True,
            gns_bridge_path="/opt/commonwealth/libcommonwealth_online_gns_bridge.so",
        )
    )
    service._server = FakeCoreServer(7777)

    service._start_gns()
    assert len(FakeTransport.instances) == 1
    transport = FakeTransport.instances[0]
    assert transport.host == "127.0.0.1"
    assert transport.requested_port == 7777
    assert transport.library_path == "/opt/commonwealth/libcommonwealth_online_gns_bridge.so"
    assert len(FakeAdapter.instances) == 1
    adapter = FakeAdapter.instances[0]
    assert adapter.started
    assert service._gns_adapter is adapter

    service._stop_gns()
    assert adapter.stopped
    assert transport.closed
    assert service._gns_adapter is None


def test_gns_start_rejects_native_bridge_bound_to_wrong_udp_port(monkeypatch):
    reset_fakes()
    FakeTransport.local_port_override = 8888
    monkeypatch.setattr(server_service, "GnsServerTransport", FakeTransport)
    monkeypatch.setattr(server_service, "GnsGameplayAdapter", FakeAdapter)
    service = ServerService(ServerConfig(port=7777, enable_gns_transport=True))
    service._server = FakeCoreServer(7777)

    with pytest.raises(RuntimeError, match="expected UDP 7777"):
        service._start_gns()
    assert len(FakeTransport.instances) == 1
    assert FakeTransport.instances[0].closed
    assert FakeAdapter.instances == []
    assert service._gns_adapter is None