"""Windows Service wrapper around run_agent_service.run() — reuses it as-is,
does not reimplement any polling/pipeline logic.

Requires pywin32 (`pip install pywin32`), Windows-only.

Commands (run from an elevated/administrator terminal):
    python gti_agent_windows_service.py install     # register the service, Startup=Automatic
    python gti_agent_windows_service.py start
    python gti_agent_windows_service.py stop
    python gti_agent_windows_service.py restart
    python gti_agent_windows_service.py remove       # uninstall
    python gti_agent_windows_service.py --startup=auto --username . --password . install

Recovery (restart on failure) is not set by pywin32's `install` alone; run once
after installing:
    sc.exe failure "GTIFiscalAgent" reset= 86400 actions= restart/60000/restart/60000/restart/60000

This module only wraps agent/scripts/run_agent_service.py's `run()` — the
actual polling/heartbeat/pipeline logic lives there, unchanged.
"""
import sys
import threading
from pathlib import Path

AGENT_ROOT = Path(__file__).resolve().parents[1]
sys.path.insert(0, str(AGENT_ROOT / "scripts"))
sys.path.insert(0, str(AGENT_ROOT / "src"))

import run_agent_service as agent_service  # noqa: E402

try:
    import servicemanager
    import win32event
    import win32service
    import win32serviceutil
except ImportError:  # pragma: no cover — only available on Windows with pywin32 installed
    servicemanager = win32event = win32service = win32serviceutil = None


class _ServiceStopFlag:
    """Plain stop flag (no signal.signal registration) — safe to flip from any
    thread. The Windows Service Control Manager stops the service, not a
    console SIGINT/SIGTERM, so this replaces GracefulStop for this host."""
    def __init__(self):
        self.stop = False


if win32serviceutil is not None:

    class GTIFiscalAgentService(win32serviceutil.ServiceFramework):
        _svc_name_ = "GTIFiscalAgent"
        _svc_display_name_ = "GTI Fiscal Agent"
        _svc_description_ = "Reads the local Firebird ERP, polls the GTI Fiscal Hub for jobs, and applies guarded fiscal updates."

        def __init__(self, args):
            win32serviceutil.ServiceFramework.__init__(self, args)
            self.stop_event = win32event.CreateEvent(None, 0, 0, None)
            self.stop_flag = _ServiceStopFlag()
            self._thread = None

        def SvcStop(self):
            self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING)
            self.stop_flag.stop = True
            win32event.SetEvent(self.stop_event)

        def SvcDoRun(self):
            servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE, servicemanager.PYS_SERVICE_STARTED, (self._svc_name_, ""))
            self._thread = threading.Thread(target=self._run_agent, daemon=True)
            self._thread.start()
            win32event.WaitForSingleObject(self.stop_event, win32event.INFINITE)

        def _run_agent(self):
            import os
            agent_service.load_dotenv(Path(os.environ.get("GTI_AGENT_ENV_FILE") or agent_service.PROJECT_ROOT / ".env"))
            config = agent_service.Config(os.environ)
            agent_service.setup_logging(config.log_path)
            try:
                agent_service.enforce_startup_preflight(os.environ)  # fail closed: a failing preflight stops the service
            except SystemExit:
                self.stop_flag.stop = True
                servicemanager.LogErrorMsg("GTIFiscalAgent: startup preflight failed; see the agent log")
                win32event.SetEvent(self.stop_event)
                return
            agent_service.run(config, os.environ, stopper=self.stop_flag)


def main():
    if win32serviceutil is None:
        raise SystemExit("pywin32 is required: pip install pywin32")
    if len(sys.argv) == 1:
        # SCM launches a service executable without CLI arguments. HandleCommandLine
        # requires a command (install/start/debug) and exits with usage when none
        # is present, which makes SCM report error 1053 for a frozen service host.
        servicemanager.Initialize()
        servicemanager.PrepareToHostSingle(GTIFiscalAgentService)
        servicemanager.StartServiceCtrlDispatcher()
    else:
        win32serviceutil.HandleCommandLine(GTIFiscalAgentService)


if __name__ == "__main__":
    main()