import os


def get_data_id():
    data_id_file = 'data_id.txt'
    if not os.path.exists(data_id_file):
        with open(data_id_file, 'w') as f:
            idx = 0
            f.write(f'{idx:0>15d}\n')
            f.write(f'{idx:0>15d}\n')
    with open(data_id_file, 'rb') as f:
        f.seek(-16, 2)
        s = f.read().decode()
        idx = int(s)
        print(idx)

    return idx


def set_data_id(idx: int):
    data_id_file = 'data_id.txt'
    with open(data_id_file, 'a') as f:
        f.write(f'{idx:0>15d}\n')


if __name__ == '__main__':
    get_data_id()