from typing import Any, ClassVar

from gi.repository import GLib, GObject


class ChangeNotifier(GObject.Object):
    __gsignals__: ClassVar[dict[str, Any]] = {
        "changed": (GObject.SignalFlags.RUN_FIRST, None, ())
    }

    def __init__(self):
        super().__init__()
        self._emit_source = 0

    def notify_changed(self):
        if self._emit_source:
            return
        self._emit_source = GLib.idle_add(self._emit_changed)

    def _emit_changed(self):
        self._emit_source = 0
        self.emit("changed")
        return GLib.SOURCE_REMOVE