import sys
import weakref

import objgraph
from PySide2 import QtCore, QtGui, QtQml, QtQuick


class TestType(QtCore.QObject):

    instances = weakref.WeakSet()

    def __init__(self):
        super().__init__()
        TestType.instances.add(self)
        self._value = ''
        self.destroy_closure = lambda: self.handle_destroy()
        self.destroyed.connect(self.destroy_closure)

    def handle_destroy(self):
        print('Type destroyed')
        self.destroy_closure = None

    def getValue(self):
        return self._value

    def setValue(self, value):
        print('Set value', value)
        for i, obj in enumerate(TestType.instances):
            print('Refcounts', i, repr(obj.value), sys.getrefcount(obj))
            objgraph.show_backrefs(
                [obj], filename='refs-%s.png' % i, refcounts=True)
        self._value = value

    valueChanged = QtCore.Signal()
    value = QtCore.Property('QVariant', getValue, setValue,
                            notify=valueChanged)


QtQml.qmlRegisterType(TestType, 'Test', 1, 0, 'TestType')


def main():
    app = QtGui.QGuiApplication()
    app.setOrganizationName('Org')

    engine = QtQml.QQmlApplicationEngine()
    engine.load('view.qml')

    app.exec_()


if __name__ == "__main__":
    main()