Meal-Planner/backend/tests/test_swiftly_auth.py

"""Offline tests for swiftly_auth — Firebase REST anon-signUp + cache.

All tests run with ``requests.get``/``requests.post`` patched. No live
network. The live integration check belongs in
``scripts/spike_swiftly_ingest.py --confirm-live``.
"""
from __future__ import annotations

import base64
import json
import sys
import time
from pathlib import Path
from unittest.mock import MagicMock, patch

import pytest
import requests

BACKEND_DIR = Path(__file__).resolve().parent.parent
if str(BACKEND_DIR) not in sys.path:
    sys.path.insert(0, str(BACKEND_DIR))

from app.services import swiftly_auth  # noqa: E402
from app.services.swiftly_auth import (  # noqa: E402
    SwiftlyAuthMintError,
    get_token,
)

API_KEY = "AIzaSy-test-key"
EXPECTED_ISS = "https://securetoken.google.com/swiftly-lu-prod"


@pytest.fixture(autouse=True)
def _clear_cache():
    swiftly_auth._reset_cache_for_tests()
    yield
    swiftly_auth._reset_cache_for_tests()


def _b64url(data: bytes) -> str:
    return base64.urlsafe_b64encode(data).rstrip(b"=").decode("ascii")


def _make_jwt(*, exp: float, iss: str = EXPECTED_ISS) -> str:
    header = _b64url(json.dumps({"alg": "RS256", "typ": "JWT"}).encode())
    payload = _b64url(
        json.dumps({"iss": iss, "aud": "swiftly-lu-prod", "exp": int(exp)}).encode()
    )
    sig = _b64url(b"signature-bytes")
    return f"{header}.{payload}.{sig}"


def _config_response() -> MagicMock:
    resp = MagicMock(spec=requests.Response)
    resp.status_code = 200
    resp.json.return_value = {"firebaseApiKey": API_KEY}
    return resp


def _signup_response(*, id_token: str, status_code: int = 200) -> MagicMock:
    resp = MagicMock(spec=requests.Response)
    resp.status_code = status_code
    resp.text = "ok" if status_code == 200 else "boom"
    if status_code == 200:
        resp.json.return_value = {"idToken": id_token}
    else:
        resp.json.side_effect = ValueError("not json")
    return resp


def test_get_token_mints_fresh_when_cache_empty():
    """First call fetches config.json, posts to Firebase, returns idToken."""
    fresh_exp = time.time() + 3600
    token = _make_jwt(exp=fresh_exp)

    with patch.object(
        swiftly_auth.requests, "get", return_value=_config_response()
    ) as mget, patch.object(
        swiftly_auth.requests,
        "post",
        return_value=_signup_response(id_token=token),
    ) as mpost:
        result = get_token()

    assert result == token
    mget.assert_called_once()
    config_url = mget.call_args.args[0]
    assert config_url == "https://luckysupermarkets.com/config.json"

    mpost.assert_called_once()
    post_url = mpost.call_args.args[0]
    assert post_url == "https://identitytoolkit.googleapis.com/v1/accounts:signUp"
    assert mpost.call_args.kwargs["params"] == {"key": API_KEY}
    headers = mpost.call_args.kwargs["headers"]
    assert headers["Origin"] == "https://luckysupermarkets.com"
    assert headers["Referer"] == "https://luckysupermarkets.com/"


def test_get_token_returns_cached_without_reminting():
    """Second call within the refresh window does NOT re-hit Firebase."""
    fresh_exp = time.time() + 3600  # well above the 300s refresh margin
    token = _make_jwt(exp=fresh_exp)

    with patch.object(
        swiftly_auth.requests, "get", return_value=_config_response()
    ), patch.object(
        swiftly_auth.requests,
        "post",
        return_value=_signup_response(id_token=token),
    ) as mpost:
        first = get_token()
        second = get_token()

    assert first == second == token
    assert mpost.call_count == 1, "expected exactly one signUp call across two get_token() calls"


def test_get_token_remints_when_cached_token_near_expiry():
    """A cached token within the refresh-margin window triggers a re-mint."""
    near_expiry = time.time() + 120  # < 300s margin → must refresh
    fresh_exp = time.time() + 3600
    stale_token = _make_jwt(exp=near_expiry)
    fresh_token = _make_jwt(exp=fresh_exp)

    swiftly_auth._state["api_key"] = API_KEY  # skip the config fetch
    swiftly_auth._state["token"] = stale_token
    swiftly_auth._state["exp"] = near_expiry

    with patch.object(
        swiftly_auth.requests,
        "post",
        return_value=_signup_response(id_token=fresh_token),
    ) as mpost:
        result = get_token()

    assert result == fresh_token
    mpost.assert_called_once()


def test_mint_raises_on_firebase_non_200():
    """Firebase 403/400/etc. surfaces as SwiftlyAuthMintError with status detail."""
    with patch.object(
        swiftly_auth.requests, "get", return_value=_config_response()
    ), patch.object(
        swiftly_auth.requests,
        "post",
        return_value=_signup_response(id_token="ignored", status_code=403),
    ):
        with pytest.raises(SwiftlyAuthMintError) as excinfo:
            get_token()

    assert "403" in str(excinfo.value)