"""Unit tests for api/auth.py."""
from datetime import datetime, timedelta, timezone
from unittest.mock import AsyncMock, patch, MagicMock

import jwt as pyjwt
import pytest
from fastapi import HTTPException
from fastapi.security import HTTPAuthorizationCredentials

from api.auth import (
    User,
    _verify_passkey_token,
    _verify_authentik_token,
    get_current_user,
)
from api.config import JWT_SECRET, JWT_ALGORITHM, JWT_ISSUER


def _make_passkey_token(
    sub: str = "user-123",
    email: str = "test@example.com",
    name: str = "Test User",
    issuer: str = JWT_ISSUER,
    secret: str = JWT_SECRET,
    algorithm: str = JWT_ALGORITHM,
    expires_delta: timedelta | None = timedelta(hours=1),
) -> str:
    """Helper to mint a passkey-style HS256 JWT."""
    payload: dict = {"sub": sub, "email": email, "name": name, "iss": issuer}
    if expires_delta is not None:
        payload["exp"] = datetime.now(timezone.utc) + expires_delta
    return pyjwt.encode(payload, secret, algorithm=algorithm)


class TestVerifyPasskeyToken:
    """Tests for _verify_passkey_token()."""

    def test_valid_token_returns_user(self) -> None:
        token = _make_passkey_token()
        user = _verify_passkey_token(token)
        assert isinstance(user, User)
        assert user.sub == "user-123"
        assert user.email == "test@example.com"
        assert user.name == "Test User"

    def test_valid_token_without_name_uses_email(self) -> None:
        payload = {
            "sub": "user-456",
            "email": "noname@example.com",
            "iss": JWT_ISSUER,
            "exp": datetime.now(timezone.utc) + timedelta(hours=1),
        }
        token = pyjwt.encode(payload, JWT_SECRET, algorithm=JWT_ALGORITHM)
        user = _verify_passkey_token(token)
        assert user.name == "noname@example.com"

    def test_rejects_expired_token(self) -> None:
        token = _make_passkey_token(expires_delta=timedelta(hours=-1))
        with pytest.raises(pyjwt.ExpiredSignatureError):
            _verify_passkey_token(token)

    def test_rejects_wrong_secret(self) -> None:
        token = _make_passkey_token(secret="wrong-secret")
        with pytest.raises(pyjwt.InvalidSignatureError):
            _verify_passkey_token(token)

    def test_rejects_wrong_issuer(self) -> None:
        token = _make_passkey_token(issuer="some-other-issuer")
        with pytest.raises(pyjwt.InvalidIssuerError):
            _verify_passkey_token(token)


class TestVerifyAuthentikToken:
    """Tests for _verify_authentik_token() — specifically that expiration is verified."""

    async def test_verifies_expiration_after_fix(self) -> None:
        """After removing verify_exp: False, expired Authentik tokens should be rejected."""
        from cryptography.hazmat.primitives.asymmetric import rsa
        from cryptography.hazmat.primitives import serialization

        private_key = rsa.generate_private_key(public_exponent=65537, key_size=2048)
        public_key = private_key.public_key()
        public_pem = public_key.public_bytes(
            encoding=serialization.Encoding.PEM,
            format=serialization.PublicFormat.SubjectPublicKeyInfo,
        )

        issuer = "https://authentik.viktorbarzin.me/application/o/wrongmove/"
        payload = {
            "sub": "authentik-user",
            "email": "auth@example.com",
            "name": "Auth User",
            "iss": issuer,
            "aud": "5AJKRgcdgVm1OyApBzFkadDFfStW9a555zwv2MOe",
            "exp": datetime.now(timezone.utc) - timedelta(hours=1),  # expired
        }
        token = pyjwt.encode(payload, private_key, algorithm="RS256")

        # Build a real PyJWK-compatible signing key mock so jwt.decode
        # takes the PyJWK code path (uses key.key directly, skips prepare_key)
        mock_signing_key = MagicMock(spec=pyjwt.PyJWK)
        mock_signing_key.key = public_key
        mock_signing_key.algorithm_name = "RS256"
        mock_signing_key.Algorithm = pyjwt.get_algorithm_by_name("RS256")

        mock_jwks_client = MagicMock()
        mock_jwks_client.get_signing_key_from_jwt.return_value = mock_signing_key

        mock_metadata = {
            "issuer": issuer,
            "jwks_uri": f"{issuer}jwks/",
        }

        with patch("api.auth.get_oidc_metadata", new_callable=AsyncMock, return_value=mock_metadata), \
             patch("api.auth.get_cached_jwks_client", new_callable=AsyncMock, return_value=mock_jwks_client):
            with pytest.raises(pyjwt.ExpiredSignatureError):
                await _verify_authentik_token(token)


class TestGetCurrentUser:
    """Tests for get_current_user()."""

    async def test_routes_to_passkey_verifier_for_matching_issuer(self) -> None:
        token = _make_passkey_token()
        credentials = HTTPAuthorizationCredentials(scheme="Bearer", credentials=token)
        user = await get_current_user(credentials)
        assert user.sub == "user-123"
        assert user.email == "test@example.com"

    async def test_routes_to_authentik_for_other_issuer(self) -> None:
        """When issuer != JWT_ISSUER, should route to Authentik verifier."""
        token = _make_passkey_token(issuer="https://authentik.viktorbarzin.me/application/o/wrongmove/")
        credentials = HTTPAuthorizationCredentials(scheme="Bearer", credentials=token)

        mock_user = User(sub="authentik-user", email="auth@example.com", name="Auth User")
        with patch("api.auth._verify_authentik_token", new_callable=AsyncMock, return_value=mock_user):
            user = await get_current_user(credentials)
            assert user.email == "auth@example.com"

    async def test_raises_http_exception_for_invalid_token(self) -> None:
        credentials = HTTPAuthorizationCredentials(scheme="Bearer", credentials="not.a.valid.token")
        with pytest.raises(HTTPException) as exc_info:
            await get_current_user(credentials)
        assert exc_info.value.status_code == 401
        assert "Invalid token" in exc_info.value.detail

    async def test_raises_http_exception_for_garbage_token(self) -> None:
        credentials = HTTPAuthorizationCredentials(scheme="Bearer", credentials="totalgarbage")
        with pytest.raises(HTTPException) as exc_info:
            await get_current_user(credentials)
        assert exc_info.value.status_code == 401