"""Peer authentication (CONTRACT.md section 7, MAS-WP-0011)."""
import hashlib
import hmac
import json

import pytest

from mas_modes import _load
from mas_modes.contract import message, post
from mas_modes.email_mode import EmailMode, RoleConfig
from mas_modes.harness import ROOT, Harness

STATUTE = ROOT / "mas-modes-v0.1-spec/conformance/statute.json"


def test_vectors_match_an_independent_hmac():
    for v in _load("conformance/auth.json")["vectors"]:
        mac = hmac.new(bytes.fromhex(v["key_hex"]), f"{v['timestamp']}.".encode() + v["body"].encode(),
                       hashlib.sha256).hexdigest()
        assert v["signature"] == "v1=" + mac


def test_signed_events_required_when_configured():
    h = Harness(STATUTE, {"ticket": {"role": "master"}}, sign_events=True)
    try:
        assert h.mail("ticket", "hello").status == 201          # the gateway signs
        h.signer = None
        d = h.mail("ticket", "unsigned")
        assert d.status == 401 and d.response["error"] == "unauthenticated-peer"
        h.signer = ("gateway", b"\0" * 32)
        assert h.mail("ticket", "bad key").status == 401
    finally:
        h.close()


def test_unsigned_events_only_without_event_peer():
    h = Harness(STATUTE, {"ticket": {"role": "master"}})
    try:
        assert h.mail("ticket", "loopback, unsigned").status == 201
        h.signer = ("cms-1", h.keys["cms-1"])               # signed, but not by a gateway
        assert h.mail("ticket", "x").status == 403
    finally:
        h.close()


def test_stubs_accept_only_email():
    h = Harness(STATUTE, {"case": {"role": "slave"}})
    try:
        req = message("handoff.request", {"address": "a@b", "key": "a"}, handoff_id="h", mode="callback",
                      details={}, status_url="http://127.0.0.1:9/x")
        url = h.email.roles["case"].master_url
        assert post(url, message("case.intake", intake_ref="i", resource_type="case", event={}))[0] == 401
        assert post(url, message("case.intake", intake_ref="i", resource_type="case", event={}),
                    ("cms-1", h.keys["cms-1"]))[0] == 401   # the master's key is not email's identity
        mode_url = h.callback_url
        assert post(mode_url, req)[0] == 401
        assert post(mode_url, req, ("email", b"\1" * 32))[0] == 401
        assert post(mode_url, req, ("email", h.keys["callback-1"]))[0] == 202
    finally:
        h.close()


def test_email_refuses_config_without_keys():
    with pytest.raises(ValueError, match="no key"):
        EmailMode({"case": RoleConfig("slave", master_url="http://x", master_peer="cms-1")}, keys={})
    with pytest.raises(ValueError, match="no key"):
        EmailMode({"case": RoleConfig("slave", master_url="http://x", master_peer="cms-1",
                                      transfers={"webhook": "http://y", "peer": "nobody"})},
                  keys={"cms-1": b"k" * 32})


def test_status_urls_are_unguessable_and_distinct():
    h = Harness(STATUTE, {"ticket": {"role": "master", "fields": ("phone", "time", "scenario")}},
                scenario="silent")
    try:
        h.mail("ticket!callback", "Phone: 1\nTime: 2")
        h.mail("ticket!callback", "Phone: 1\nTime: 2")
        urls = [m["status_url"] for m in h.callback.received]
        tokens = [u.rsplit("/", 1)[1] for u in urls]
        assert len(set(tokens)) == 2 and all(len(t) >= 22 for t in tokens)   # >= 128 bits
        assert json.dumps(h.callback.received).count(tokens[0]) == 1          # not echoed elsewhere
    finally:
        h.close()