import importlib.util
import sys
from pathlib import Path
from types import SimpleNamespace


SERVICE_WRAPPER = Path(__file__).parents[1] / "service" / "gti_agent_windows_service.py"


def load_service_wrapper():
    spec = importlib.util.spec_from_file_location("gti_agent_windows_service_test", SERVICE_WRAPPER)
    module = importlib.util.module_from_spec(spec)
    sys.modules[spec.name] = module
    spec.loader.exec_module(module)
    return module


def test_main_enters_scm_dispatcher_when_started_without_command(monkeypatch):
    service = load_service_wrapper()
    calls = []

    class FakeServiceManager:
        def Initialize(self):
            calls.append("initialize")

        def PrepareToHostSingle(self, service_class):
            calls.append(("prepare", service_class))

        def StartServiceCtrlDispatcher(self):
            calls.append("dispatcher")

    def forbidden_handle_command_line(service_class):
        raise AssertionError("SCM start must not be parsed as a CLI command")

    monkeypatch.setattr(service, "servicemanager", FakeServiceManager())
    monkeypatch.setattr(service, "win32serviceutil", SimpleNamespace(HandleCommandLine=forbidden_handle_command_line))
    monkeypatch.setattr(service.sys, "argv", [str(SERVICE_WRAPPER)])

    service.main()

    assert calls == ["initialize", ("prepare", service.GTIFiscalAgentService), "dispatcher"]


def test_main_preserves_pywin32_cli_commands(monkeypatch):
    service = load_service_wrapper()
    called = []

    class ForbiddenServiceManager:
        def __getattr__(self, name):
            raise AssertionError("CLI commands must not enter the SCM dispatcher")

    monkeypatch.setattr(service, "servicemanager", ForbiddenServiceManager())
    monkeypatch.setattr(service, "win32serviceutil", SimpleNamespace(HandleCommandLine=lambda cls: called.append(cls)))
    monkeypatch.setattr(service.sys, "argv", [str(SERVICE_WRAPPER), "start"])

    service.main()

    assert called == [service.GTIFiscalAgentService]


def test_a_fatal_error_in_the_agent_loop_stops_the_service_instead_of_leaving_a_dead_one_running():
    text = SERVICE_WRAPPER.read_text(encoding="utf-8")
    body = text.split("agent_service.run(config, os.environ, stopper=self.stop_flag)", 1)[1].split("def main", 1)[0]
    assert "except BaseException" in body and "logger" not in body.split("except BaseException")[0][-40:]     # wrapped in try/except
    assert "LogErrorMsg" in body and "self.stop_flag.stop = True" in body and "win32event.SetEvent(self.stop_event)" in body