main.py

"""Entry point for Poltergeist."""

from __future__ import annotations

import sys

from PySide6.QtCore import QCoreApplication, Qt
from PySide6.QtWidgets import QApplication, QMessageBox

from services import edition as edition_svc

APP_USER_MODEL_ID_BASE = "Poltergeist.SnippetManager"


def _app_user_model_id() -> str:
    """Admin and user editions get distinct IDs so Windows treats them as
    separate apps in the taskbar / start menu when both are installed."""
    if edition_svc.is_admin():
        return f"{APP_USER_MODEL_ID_BASE}.Admin"
    return APP_USER_MODEL_ID_BASE


def _single_instance_mutex_name() -> str:
    """Parallel to ``_app_user_model_id`` - the two editions run side by
    side so they must not share the single-instance mutex."""
    if edition_svc.is_admin():
        return "Global\\PoltergeistSnippetManager.Admin"
    return "Global\\PoltergeistSnippetManager"


def _set_app_user_model_id() -> None:
    """Tell Windows this is its own app so the taskbar shows our icon.

    Without this, a process launched via ``python.exe`` is grouped under the
    Python interpreter and the taskbar keeps the Python icon. A custom
    AppUserModelID detaches us into our own group and lets Qt's window icon
    show up in the taskbar as well.
    """
    try:
        import ctypes

        ctypes.windll.shell32.SetCurrentProcessExplicitAppUserModelID(
            _app_user_model_id()
        )
    except Exception:
        pass


def _acquire_single_instance():
    """Return a handle that keeps the process as the only running instance.

    Uses a named Windows mutex. If another instance already holds it, this
    function shows a message and terminates the process.
    """
    try:
        import win32api
        import win32event
        import winerror
    except Exception:
        return None

    handle = win32event.CreateMutex(None, False, _single_instance_mutex_name())
    if win32api.GetLastError() == winerror.ERROR_ALREADY_EXISTS:
        QApplication.instance() or QApplication(sys.argv)
        QMessageBox.information(
            None,
            QCoreApplication.translate("Main", "Poltergeist"),
            QCoreApplication.translate(
                "Main",
                "Poltergeist is already running.\n"
                "Look for the icon in the system tray.",
            ),
        )
        sys.exit(0)
    return handle


def main() -> int:
    _set_app_user_model_id()
    QApplication.setAttribute(Qt.ApplicationAttribute.AA_DontCreateNativeWidgetSiblings)
    app = QApplication(sys.argv)
    app.setApplicationName("Poltergeist")
    app.setOrganizationName("Poltergeist")
    app.setQuitOnLastWindowClosed(False)

    import config
    from models.tree import Settings
    from services import i18n

    data = config.load()
    _startup_settings = Settings.from_dict(data.get("settings") or {})
    i18n.install(app, _startup_settings.language)

    _handle = _acquire_single_instance()

    from app import Poltergeist
    from services import icons as icons_svc

    app.setWindowIcon(icons_svc.app_icon())

    controller = Poltergeist(app)
    try:
        return app.exec()
    finally:
        controller.shutdown()


if __name__ == "__main__":
    sys.exit(main())