"""Independent existing SCRAM client/server; synthetic public fixture data only."""
import base64
import json
import sys
from importlib.metadata import version
from pathlib import Path
from scramp import ScramClient, ScramMechanism

assert version("scramp") == "1.4.6"
assert version("asn1crypto") == "1.5.1"
path = Path(__file__).parent / "test" / "scramp-vectors.json"
nonce = "rOprNGfwEbeRWgbNEkqO"
server_nonce = "%hvYDpWUa2RaTCAfuxFIlj)hNlF$k0"
salt = base64.b64decode("W22ZaJ0SNY7soEsUEjb6gQ==")
results = []
for password in ["pencil", "A" * 131, "p\u00e9ncil"]:
    mechanism = ScramMechanism("SCRAM-SHA-512")
    auth = mechanism.make_auth_info(password, iteration_count=4096, salt=salt)
    def auth_fn(username):
        assert username == "user"
        return auth
    server = mechanism.make_server(auth_fn, s_nonce=server_nonce)
    client = ScramClient(["SCRAM-SHA-512"], "user", password, c_nonce=nonce)
    initial = client.get_client_first()
    server.set_client_first(initial)
    first = server.get_server_first()
    client.set_server_first(first)
    proof = client.get_client_final()
    server.set_client_final(proof)  # Independent server verifies proof.
    final = server.get_server_final()
    client.set_server_final(final)  # Independent client verifies server.
    results.append(dict(mechanism="SCRAM-SHA-512", username="user", password=password,
                        nonce=nonce, initial=initial, first=first, proof=proof, final=final))
if sys.argv[1:] == ["--write"]:
    path.write_text(json.dumps(results, indent=2) + "\n")
else:
    assert not sys.argv[1:]
    assert json.loads(path.read_text()) == results
print("scramp 1.4.6: three fixed SHA-512 client/server exchanges verified")