"""Unit tests for model discovery (SPEC §4.6).

A background poller queries Ollama ``GET /api/tags``, parses the installed model
set, caches it in Redis (TTL) + in-process (:class:`DiscoveryCache`), and **fails
closed**: an empty/expired discovered set means no model resolves (deny). On an
upstream error ``refresh_once`` returns ``False`` and leaves the caches untouched
so they expire on their own TTL (stale-expired ⇒ empty ⇒ deny); discovery never
opens access.

Driven against the in-process ``mock_ollama`` upstream and the real
``redis_client`` testcontainer fixture (skips cleanly without Docker).
"""

from __future__ import annotations

from typing import Any

import httpx
import pytest
import redis.asyncio as aioredis
from fastapi import FastAPI
from fastapi.responses import JSONResponse

from neuronetz_gateway.config import Settings
from neuronetz_gateway.proxy import discovery


def _ollama_client(app: FastAPI) -> httpx.AsyncClient:
    transport = httpx.ASGITransport(app=app)
    return httpx.AsyncClient(transport=transport, base_url="http://ollama")


def _settings() -> Settings:
    return Settings(model_discovery_cache_ttl_s=120, model_discovery_refresh_s=60)


# --- pure parsing ----------------------------------------------------------


def test_names_of_extracts_model_names() -> None:
    models = [
        discovery.DiscoveredModel(name="llama3.1:8b", family="llama"),
        discovery.DiscoveredModel(name="mistral:7b"),
    ]
    assert discovery.names_of(models) == frozenset({"llama3.1:8b", "mistral:7b"})


def test_names_of_empty() -> None:
    assert discovery.names_of([]) == frozenset()


# --- fetch + parse against the mock upstream -------------------------------


@pytest.mark.asyncio
async def test_fetch_tags_parses_mock_catalogue(mock_ollama_app: FastAPI) -> None:
    async with _ollama_client(mock_ollama_app) as ollama:
        models = await discovery.fetch_tags(ollama)
    names = discovery.names_of(models)
    assert {"llama3.1:8b", "mistral:7b", "nomic-embed-text"} <= names
    # Sanitized metadata is captured (family parsed from the mock's details).
    by_name = {m.name: m for m in models}
    assert by_name["llama3.1:8b"].family == "llama3.1"
    assert by_name["llama3.1:8b"].parameter_size == "8B"


@pytest.mark.asyncio
async def test_fetch_tags_raises_on_upstream_error() -> None:
    broken = FastAPI()

    @broken.get("/api/tags")
    async def _tags() -> Any:
        return JSONResponse({"error": "boom"}, status_code=500)

    async with _ollama_client(broken) as ollama:
        with pytest.raises(httpx.HTTPError):
            await discovery.fetch_tags(ollama)


# --- redis cache round-trip ------------------------------------------------


@pytest.mark.asyncio
async def test_redis_cache_roundtrip(redis_client: aioredis.Redis) -> None:
    models = [discovery.DiscoveredModel(name="llama3.1:8b"), discovery.DiscoveredModel(name="x:1b")]
    await discovery.write_discovered_to_redis(redis_client, models, ttl_s=120)
    names = await discovery.read_discovered_from_redis(redis_client)
    assert names == frozenset({"llama3.1:8b", "x:1b"})
    # TTL was applied (staleness expires) per SPEC §4.6.
    assert 0 < await redis_client.ttl(discovery.REDIS_DISCOVERED_KEY) <= 120


@pytest.mark.asyncio
async def test_read_discovered_miss_returns_empty(redis_client: aioredis.Redis) -> None:
    # Cache miss / expiry => empty set => fail-closed deny.
    assert await discovery.read_discovered_from_redis(redis_client) == frozenset()


# --- refresh_once: success and fail-closed ---------------------------------


@pytest.mark.asyncio
async def test_refresh_once_populates_in_process_and_redis(
    redis_client: aioredis.Redis, mock_ollama_app: FastAPI
) -> None:
    cache = discovery.DiscoveryCache()
    async with _ollama_client(mock_ollama_app) as ollama:
        ok = await discovery.refresh_once(ollama, redis_client, cache, _settings())
    assert ok is True
    assert {"llama3.1:8b", "mistral:7b", "nomic-embed-text"} <= cache.names
    # Mirrored into Redis under the SPEC §4.6 key.
    assert {"llama3.1:8b", "mistral:7b"} <= await discovery.read_discovered_from_redis(redis_client)


@pytest.mark.asyncio
async def test_refresh_once_fail_closed_on_upstream_error(
    redis_client: aioredis.Redis,
) -> None:
    broken = FastAPI()

    @broken.get("/api/tags")
    async def _tags() -> Any:
        return JSONResponse({"error": "boom"}, status_code=500)

    cache = discovery.DiscoveryCache()
    async with _ollama_client(broken) as ollama:
        ok = await discovery.refresh_once(ollama, redis_client, cache, _settings())
    # Refresh reports failure; the in-process cache stays empty (no models
    # resolve) — discovery never opens access on error.
    assert ok is False
    assert cache.names == frozenset()


@pytest.mark.asyncio
async def test_refresh_once_tolerates_missing_redis(mock_ollama_app: FastAPI) -> None:
    # redis_client=None must still refresh the in-process cache (best-effort
    # Redis fill), not crash the poller.
    cache = discovery.DiscoveryCache()
    async with _ollama_client(mock_ollama_app) as ollama:
        ok = await discovery.refresh_once(ollama, None, cache, _settings())
    assert ok is True
    assert "llama3.1:8b" in cache.names