from deterministic_automaton import DeterministicAutomaton


def three_automaton():
    a = DeterministicAutomaton()

    state_i = a.add_state()
    state_only_0 = a.add_state()
    state_leading_zeroes = a.add_state()
    state_0 = a.add_state()
    state_1 = a.add_state()
    state_2 = a.add_state()

    a.mark_as_initial(state_i)
    a.mark_as_final(state_0)
    a.mark_as_final(state_only_0)

    add_transitions(a, state_i, "0", state_only_0)
    add_transitions(a, state_i, "147", state_1)
    add_transitions(a, state_i, "258", state_2)
    add_transitions(a, state_i, "369", state_0)

    add_transitions(a, state_only_0, "0123456789", state_leading_zeroes)

    add_transitions(a, state_0, "0369", state_0)
    add_transitions(a, state_0, "147", state_1)
    add_transitions(a, state_0, "258", state_2)

    add_transitions(a, state_1, "0369", state_1)
    add_transitions(a, state_1, "147", state_2)
    add_transitions(a, state_1, "258", state_0)

    add_transitions(a, state_2, "0369", state_2)
    add_transitions(a, state_2, "147", state_0)
    add_transitions(a, state_2, "258", state_1)

    return a


def add_transitions(a, state_from, chars, state_to):
    for ch in chars:
        a.add_transition(state_from, ch, state_to)