thermograph/tests/notifications/test_discord_interactions.py

"""Discord HTTP-interactions: Ed25519 verification, PING/PONG, /grade dispatch,
and the wired FastAPI route. No live Discord — we hold a test signing key and sign
requests ourselves."""
import datetime
import json

import pytest
from fastapi.testclient import TestClient
from nacl.signing import SigningKey

import app as appmod
import discord_interactions as di
import homepage

B = "/thermograph"

_SK = SigningKey.generate()
_PUBKEY = _SK.verify_key.encode().hex()


def _sign(body: bytes, ts: str = "1700000000") -> tuple[str, str]:
    return _SK.sign(ts.encode() + body).signature.hex(), ts


_CARD = {
    "display": "Tokyo, Japan", "name": "Tokyo", "slug": "tokyo-jp",
    "metric_label": "High temp", "value": 96.0, "normal": 84.0,
    "pct_label": "97th percentile", "grade_label": "Very High",
    "tail": "warm", "date_label": None,
}


# --- signature verification --------------------------------------------------

def test_verify_accepts_a_good_signature():
    body = b'{"type":1}'
    sig, ts = _sign(body)
    assert di.verify(sig, ts, body, _PUBKEY) is True


def test_verify_rejects_tampering_and_bad_inputs():
    body = b'{"type":1}'
    sig, ts = _sign(body)
    assert di.verify(sig, ts, body + b" ", _PUBKEY) is False   # body changed
    assert di.verify(sig, "1700000001", body, _PUBKEY) is False  # timestamp changed
    assert di.verify("00" * 64, ts, body, _PUBKEY) is False       # wrong signature
    assert di.verify("nothex", ts, body, _PUBKEY) is False         # malformed
    assert di.verify(sig, ts, body, "") is False                   # no key configured
    assert di.verify("", ts, body, _PUBKEY) is False               # no signature


# --- handle(): routing -------------------------------------------------------

def test_handle_ping_pongs(monkeypatch):
    monkeypatch.setattr(di, "PUBLIC_KEY", _PUBKEY)
    body = b'{"type":1}'
    sig, ts = _sign(body)
    status, payload = di.handle(body, sig, ts)
    assert status == 200 and payload == {"type": 1}


def test_handle_rejects_bad_signature(monkeypatch):
    monkeypatch.setattr(di, "PUBLIC_KEY", _PUBKEY)
    body = b'{"type":1}'
    status, payload = di.handle(body, "00" * 64, "1700000000")
    assert status == 401


def test_grade_command_returns_the_citys_grade(monkeypatch):
    monkeypatch.setattr(di, "PUBLIC_KEY", _PUBKEY)
    monkeypatch.setattr(homepage, "_grade_city", lambda city, today: dict(_CARD))
    body = json.dumps({"type": 2, "data": {
        "name": "grade", "options": [{"name": "city", "value": "Tokyo"}]}}).encode()
    sig, ts = _sign(body)
    status, payload = di.handle(body, sig, ts)
    assert status == 200 and payload["type"] == 4
    embed = payload["data"]["embeds"][0]
    assert "Tokyo, Japan" in embed["title"]
    assert "96°F" in embed["description"] and "97th percentile" in embed["description"]
    assert embed["url"].endswith("/climate/tokyo-jp")


def test_grade_unknown_city_is_ephemeral(monkeypatch):
    monkeypatch.setattr(di, "PUBLIC_KEY", _PUBKEY)
    data = di._grade_message("Nowherecityville")
    assert data["flags"] == di._EPHEMERAL and "don't track" in data["content"]


def test_grade_city_not_yet_warm_is_ephemeral(monkeypatch):
    monkeypatch.setattr(homepage, "_grade_city", lambda city, today: None)
    data = di._grade_message("Tokyo")           # a real curated city, but no warm cache
    assert data["flags"] == di._EPHEMERAL and "No recent reading" in data["content"]


def test_resolve_city_prefers_exact_then_population():
    # Real cities.json: an exact name resolves, and it's a real curated entry.
    tokyo = di._resolve_city("tokyo")
    assert tokyo is not None and tokyo["name"] == "Tokyo"
    assert di._resolve_city("   ") is None
    assert di._resolve_city("Zzznotacity") is None


# --- the wired FastAPI route -------------------------------------------------

def test_interactions_route_pings_and_rejects(monkeypatch):
    monkeypatch.setattr(di, "PUBLIC_KEY", _PUBKEY)
    client = TestClient(appmod.app)
    body = b'{"type":1}'
    sig, ts = _sign(body)
    # Signed PING -> PONG. Send raw bytes so the signature matches byte-for-byte.
    r = client.post(f"{B}/discord/interactions", content=body,
                    headers={"x-signature-ed25519": sig, "x-signature-timestamp": ts})
    assert r.status_code == 200 and r.json() == {"type": 1}
    # Unsigned -> 401 (Discord's security probe).
    r = client.post(f"{B}/discord/interactions", content=body)
    assert r.status_code == 401