import pytest

from teos.gatekeeper import Gatekeeper, IdentificationFailure, NotEnoughSlots

from common.cryptographer import Cryptographer

from test.teos.unit.conftest import get_random_value_hex, generate_keypair

DEFAULT_SLOTS = 42
gatekeeper = Gatekeeper(DEFAULT_SLOTS)


def test_init():
    assert isinstance(gatekeeper.default_slots, int) and gatekeeper.default_slots == DEFAULT_SLOTS
    assert isinstance(gatekeeper.registered_users, dict) and len(gatekeeper.registered_users) == 0


def test_check_user_pk():
    # check_user_pk must only accept values that is not a 33-byte hex string
    for _ in range(100):
        assert gatekeeper.check_user_pk(get_random_value_hex(33))


def test_check_wrong_user_pk():
    wrong_values = [None, 3, 15.23, "", {}, (), object, str, get_random_value_hex(32), get_random_value_hex(34)]

    # check_user_pk must only accept values that is not a 33-byte hex string
    for value in wrong_values:
        assert not gatekeeper.check_user_pk(value)


def test_add_update_user():
    # add_update_user adds DEFAULT_SLOTS to a given user as long as the identifier is a 33-byte hex str
    user_pk = get_random_value_hex(33)

    for _ in range(10):
        current_slots = gatekeeper.registered_users.get(user_pk)
        current_slots = current_slots if current_slots is not None else 0

        gatekeeper.add_update_user(user_pk)

        assert gatekeeper.registered_users.get(user_pk) == current_slots + DEFAULT_SLOTS

    # The same can be checked for multiple users
    for _ in range(10):
        # The user identifier is changed every call
        user_pk = get_random_value_hex(33)

        gatekeeper.add_update_user(user_pk)
        assert gatekeeper.registered_users.get(user_pk) == DEFAULT_SLOTS


def test_add_update_user_wrong_pk():
    # Passing a wrong pk defaults to the errors in check_user_pk. We can try with one.
    wrong_pk = get_random_value_hex(32)

    with pytest.raises(ValueError):
        gatekeeper.add_update_user(wrong_pk)


def test_identify_user():
    # Identify user should return a user_pk for registered users. It raises
    # IdentificationFailure for invalid parameters or non-registered users.

    # Let's first register a user
    sk, pk = generate_keypair()
    compressed_pk = Cryptographer.get_compressed_pk(pk)
    gatekeeper.add_update_user(compressed_pk)

    message = "Hey, it's me"
    signature = Cryptographer.sign(message.encode(), sk)

    assert gatekeeper.identify_user(message.encode(), signature) == compressed_pk


def test_identify_user_non_registered():
    # Non-registered user won't be identified
    sk, pk = generate_keypair()

    message = "Hey, it's me"
    signature = Cryptographer.sign(message.encode(), sk)

    with pytest.raises(IdentificationFailure):
        gatekeeper.identify_user(message.encode(), signature)


def test_identify_user_invalid_signature():
    # If the signature does not match the message given a public key, the user won't be identified
    message = "Hey, it's me"
    signature = get_random_value_hex(72)

    with pytest.raises(IdentificationFailure):
        gatekeeper.identify_user(message.encode(), signature)


def test_identify_user_wrong():
    # Wrong parameters shouldn't verify either
    sk, pk = generate_keypair()

    message = "Hey, it's me"
    signature = Cryptographer.sign(message.encode(), sk)

    # Non-byte message and str sig
    with pytest.raises(IdentificationFailure):
        gatekeeper.identify_user(message, signature)

    # byte message and non-str sig
    with pytest.raises(IdentificationFailure):
        gatekeeper.identify_user(message.encode(), signature.encode())

    # non-byte message and non-str sig
    with pytest.raises(IdentificationFailure):
        gatekeeper.identify_user(message, signature.encode())


def test_fill_slots():
    # Free slots will decrease the slot count of a user as long as he has enough slots, otherwise raise NotEnoughSlots
    user_pk = get_random_value_hex(33)
    gatekeeper.add_update_user(user_pk)

    gatekeeper.fill_slots(user_pk, DEFAULT_SLOTS - 1)
    assert gatekeeper.registered_users.get(user_pk) == 1

    with pytest.raises(NotEnoughSlots):
        gatekeeper.fill_slots(user_pk, 2)

    # NotEnoughSlots is also raised if the user does not exist
    with pytest.raises(NotEnoughSlots):
        gatekeeper.fill_slots(get_random_value_hex(33), 2)


def test_free_slots():
    # Free slots simply adds slots to the user as long as it exists.
    user_pk = get_random_value_hex(33)
    gatekeeper.add_update_user(user_pk)
    gatekeeper.free_slots(user_pk, 33)

    assert gatekeeper.registered_users.get(user_pk) == DEFAULT_SLOTS + 33

    # Just making sure it does not crash for non-registered user
    assert gatekeeper.free_slots(get_random_value_hex(33), 10) is None