def reload_json():

    global default_json

    global active_json

    with open(default_json_file, encoding='utf-8') as f:

        default_json = json.load(f)

    if os.path.exists(last_state_file) and os.path.isfile(last_state_file):

        with open(last_state_file, encoding='utf-8') as f:

            active_json = json.load(f)

        if os.path.getmtime(last_state_file) \

           < os.path.getmtime(default_json_file):

            backup = copy.deepcopy(active_json)

            active_json.update(default_json)

            active_json['state']['open'] = backup['state']['open']

            active_json['state']['lastchange'] = backup['state']['lastchange']

    else:

        active_json = copy.deepcopy(default_json)

reload_json()

def save_last_state():

    with open(last_state_file, mode='w', encoding='utf-8') as f:

        json.dump(active_json, f, sort_keys=True)