"""
Tests for meshbay_node.hub_client — uses httpx.MockTransport to avoid network.
"""

import base64
import json
import os
import time
import pytest
from pathlib import Path
from unittest.mock import AsyncMock, MagicMock, patch

import httpx
import jwt
from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
from cryptography.hazmat.primitives.asymmetric.x25519 import X25519PrivateKey
from cryptography.hazmat.primitives import serialization

from meshbay_common.crypto import generate_gek, pk_to_b64, wrap_gek
from meshbay_node.hub_client import HubClient, HubConfig, HubSession
from meshbay_node.keystore import NodeKeys


# ── Test fixtures ──────────────────────────────────────────────────────────────

@pytest.fixture
def hub_keys():
    """Fake hub Ed25519 keypair for signing test JWTs."""
    sk = Ed25519PrivateKey.generate()
    sk_pem = sk.private_bytes(
        serialization.Encoding.PEM,
        serialization.PrivateFormat.PKCS8,
        serialization.NoEncryption(),
    )
    pk_pem = sk.public_key().public_bytes(
        serialization.Encoding.PEM,
        serialization.PublicFormat.SubjectPublicKeyInfo,
    )
    return sk, sk_pem, pk_pem


@pytest.fixture
def node_keys():
    sk_ed = Ed25519PrivateKey.generate()
    sk_x  = X25519PrivateKey.generate()
    return NodeKeys(sk_ed25519=sk_ed, sk_x25519=sk_x)


@pytest.fixture
def hub_config(tmp_path):
    return HubConfig(
        hub_url="http://fake-hub",
        username="testuser",
        password="testpass99",
        cache_dir=tmp_path,
    )


def make_token(sk_pem, user_id, pk_user_b64, hub_id="fake-hub", ttl=3600):
    now = int(time.time())
    return jwt.encode({
        "iss": hub_id, "sub": user_id, "pk_user": pk_user_b64,
        "hub_id": hub_id, "jti": "test-jti",
        "iat": now, "exp": now + ttl,
    }, sk_pem, algorithm="EdDSA")


# ── Tests ─────────────────────────────────────────────────────────────────────

@pytest.mark.asyncio
async def test_login_verifies_jwt_offline(hub_keys, node_keys, hub_config):
    sk_hub, sk_hub_pem, pk_hub_pem = hub_keys
    user_id = "user-uuid-001"
    token = make_token(sk_hub_pem, user_id, node_keys.pk_ed25519_b64)

    def handler(request):
        if request.url.path == "/v1/hub/pubkey":
            return httpx.Response(200, json={"pk_hub_pem": pk_hub_pem.decode()})
        if request.url.path == "/v1/users/login":
            return httpx.Response(200, json={
                "access_token": token, "refresh_token": "rt-abc", "expires_in": 3600})
        return httpx.Response(404)

    transport = httpx.MockTransport(handler)
    client = HubClient(hub_config, node_keys)
    client._http = httpx.AsyncClient(transport=transport, base_url="http://fake-hub")

    session = await client.login()
    assert session.user_id == user_id
    assert session.access_token == token
    assert session.hub_pk_pem == pk_hub_pem
    assert session.token_expires_in > 3500
    assert not session.token_needs_refresh


@pytest.mark.asyncio
async def test_login_rejects_missing_jti(hub_keys, node_keys, hub_config):
    sk_hub, sk_hub_pem, pk_hub_pem = hub_keys
    # Token without jti
    bad_token = jwt.encode({
        "iss": "fake-hub", "sub": "uid", "pk_user": node_keys.pk_ed25519_b64,
        "hub_id": "fake-hub", "iat": int(time.time()), "exp": int(time.time()) + 3600,
    }, sk_hub_pem, algorithm="EdDSA")

    def handler(request):
        if request.url.path == "/v1/hub/pubkey":
            return httpx.Response(200, json={"pk_hub_pem": pk_hub_pem.decode()})
        if request.url.path == "/v1/users/login":
            return httpx.Response(200, json={
                "access_token": bad_token, "refresh_token": "rt", "expires_in": 3600})
        return httpx.Response(404)

    transport = httpx.MockTransport(handler)
    client = HubClient(hub_config, node_keys)
    client._http = httpx.AsyncClient(transport=transport, base_url="http://fake-hub")

    with pytest.raises(AssertionError, match="jti"):
        await client.login()


@pytest.mark.asyncio
async def test_register_idempotent(hub_keys, node_keys, hub_config):
    def handler(request):
        if request.url.path == "/v1/users/register":
            return httpx.Response(409, json={"detail": "Username already taken"})
        return httpx.Response(404)

    transport = httpx.MockTransport(handler)
    client = HubClient(hub_config, node_keys)
    client._http = httpx.AsyncClient(transport=transport, base_url="http://fake-hub")

    # Should not raise on 409
    result = await client.register()
    assert result == ""


@pytest.mark.asyncio
async def test_token_needs_refresh(hub_keys, node_keys, hub_config):
    sk_hub, sk_hub_pem, pk_hub_pem = hub_keys
    # Token expiring in 60s (< TOKEN_REFRESH_MARGIN of 300s)
    short_token = make_token(sk_hub_pem, "uid", node_keys.pk_ed25519_b64, ttl=60)

    def handler(request):
        if request.url.path == "/v1/hub/pubkey":
            return httpx.Response(200, json={"pk_hub_pem": pk_hub_pem.decode()})
        if request.url.path == "/v1/users/login":
            return httpx.Response(200, json={
                "access_token": short_token, "refresh_token": "rt", "expires_in": 60})
        return httpx.Response(404)

    transport = httpx.MockTransport(handler)
    client = HubClient(hub_config, node_keys)
    client._http = httpx.AsyncClient(transport=transport, base_url="http://fake-hub")

    session = await client.login()
    assert session.token_needs_refresh


@pytest.mark.asyncio
async def test_fetch_gek(hub_keys, node_keys, hub_config):
    """Admin wraps GEK for this node; client fetches and unwraps."""
    sk_hub, sk_hub_pem, pk_hub_pem = hub_keys
    gek = generate_gek()

    # Simulate admin wrapping GEK for this node
    pk_x_raw = base64.b64decode(node_keys.pk_x25519_b64)
    bundle = wrap_gek(gek, pk_x_raw)

    token = make_token(sk_hub_pem, "uid", node_keys.pk_ed25519_b64)

    def handler(request):
        if request.url.path == "/v1/hub/pubkey":
            return httpx.Response(200, json={"pk_hub_pem": pk_hub_pem.decode()})
        if request.url.path == "/v1/users/login":
            return httpx.Response(200, json={
                "access_token": token, "refresh_token": "rt", "expires_in": 3600})
        if "/v1/groups/" in request.url.path and request.url.path.endswith("/gek"):
            return httpx.Response(200, json=bundle)
        return httpx.Response(404)

    transport = httpx.MockTransport(handler)
    client = HubClient(hub_config, node_keys)
    client._http = httpx.AsyncClient(transport=transport, base_url="http://fake-hub")

    await client.login()
    recovered = await client.fetch_gek("group-abc")
    assert recovered == gek


@pytest.mark.asyncio
async def test_hub_pk_cached(hub_keys, node_keys, hub_config, tmp_path):
    _, _, pk_hub_pem = hub_keys
    call_count = {"n": 0}

    def handler(request):
        if request.url.path == "/v1/hub/pubkey":
            call_count["n"] += 1
            return httpx.Response(200, json={"pk_hub_pem": pk_hub_pem.decode()})
        return httpx.Response(404)

    transport = httpx.MockTransport(handler)
    client = HubClient(hub_config, node_keys)
    client._http = httpx.AsyncClient(transport=transport, base_url="http://fake-hub")

    await client._fetch_hub_pk()
    await client._fetch_hub_pk()   # second call should use cache
    assert call_count["n"] == 1, "Hub PK should be fetched only once"