"""I2: a broken worker must answer with a named status, never a naked 500.

`_call_worker` mapped a non-200 HTTP response to 502, but let
`httpx.ConnectError` (worker stopped) and `httpx.ReadTimeout` (job past the
120s budget) propagate unhandled - with no exception handler in main.py that
turns those into anything but FastAPI's generic 500. It also read
`report["outputs"]`, `report["failures"]` and `report["engine_version"]`
without checking the response had that shape at all, so a proxy answering 200
with something else (HTML, an empty body) would raise a bare KeyError instead
of a diagnosable error.

The spec's edge-case table: "il worker isola il guasto, l'API resta in
piedi, il task riporta l'errore" - the worker's fault must not become the
API's fault.
"""
import httpx
import pytest
from fastapi import HTTPException

from src.backend.services.vision_service import _call_worker


class _FakeResponse:
    """Stands in for httpx.Response: only what `_call_worker` touches."""

    def __init__(self, status_code: int, body=..., text: str = "", raise_on_json: bool = False):
        self.status_code = status_code
        self._body = body
        self.text = text
        self._raise_on_json = raise_on_json

    def json(self):
        if self._raise_on_json:
            raise ValueError("not JSON")
        return self._body


class _FakeAsyncClient:
    """Stands in for httpx.AsyncClient: post() does whatever the test wants."""

    def __init__(self, *, response=None, raises=None):
        self._response = response
        self._raises = raises

    async def __aenter__(self):
        return self

    async def __aexit__(self, *exc_info):
        return False

    async def post(self, *args, **kwargs):
        if self._raises is not None:
            raise self._raises
        return self._response


def _install(monkeypatch, *, response=None, raises=None):
    monkeypatch.setattr(
        "src.backend.services.vision_service.httpx.AsyncClient",
        lambda *a, **k: _FakeAsyncClient(response=response, raises=raises),
    )


@pytest.mark.asyncio
async def test_a_stopped_worker_answers_502_not_a_naked_500(monkeypatch):
    _install(monkeypatch, raises=httpx.ConnectError("Connection refused"))

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 502
    assert "unreachable" in excinfo.value.detail.lower()


@pytest.mark.asyncio
async def test_a_job_past_the_time_budget_answers_504(monkeypatch):
    _install(monkeypatch, raises=httpx.ReadTimeout("timed out"))

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 504
    assert "time" in excinfo.value.detail.lower()


@pytest.mark.asyncio
async def test_a_response_missing_the_expected_keys_is_reported_not_raised_raw(monkeypatch):
    """A proxy answering 200 with an unexpected shape must not KeyError."""
    _install(monkeypatch, response=_FakeResponse(200, body={"outputs": {}}))

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 502
    assert "malformed" in excinfo.value.detail.lower()


@pytest.mark.asyncio
async def test_a_response_that_is_not_a_json_object_is_reported(monkeypatch):
    """200 with HTML or a bare list, say - not a dict at all."""
    _install(monkeypatch, response=_FakeResponse(200, body=["not", "a", "dict"]))

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 502
    assert "malformed" in excinfo.value.detail.lower()


@pytest.mark.asyncio
async def test_a_well_formed_response_still_passes_through(monkeypatch):
    body = {"outputs": {"t1.diameter": 10.0}, "failures": [], "engine_version": "a" * 40}
    _install(monkeypatch, response=_FakeResponse(200, body=body))

    report = await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert report == body


# ---------------------------------------------------------------------------
# #14: the worker dying mid-response (RemoteProtocolError) or a connect
# timeout (ConnectTimeout, an httpx.TimeoutException) used to fall through
# every except clause here and surface as a naked 500.
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_the_worker_dying_mid_response_answers_502_not_a_naked_500(monkeypatch):
    _install(
        monkeypatch,
        raises=httpx.RemoteProtocolError(
            "Server disconnected without sending a response."
        ),
    )

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 502
    assert "unreachable" in excinfo.value.detail.lower()


@pytest.mark.asyncio
async def test_a_connect_timeout_answers_504(monkeypatch):
    """ConnectTimeout is an httpx.TimeoutException, not caught by name before -
    only httpx.ReadTimeout was."""
    _install(monkeypatch, raises=httpx.ConnectTimeout("connect timed out"))

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 504
    assert "time" in excinfo.value.detail.lower()


# ---------------------------------------------------------------------------
# #15: a 422 from the worker (bad image, malformed graph) must reach the
# Maker as a 422 with the worker's own reason, not a flattened 502.
# ---------------------------------------------------------------------------


@pytest.mark.asyncio
async def test_a_422_from_the_worker_propagates_as_422_with_its_detail(monkeypatch):
    _install(
        monkeypatch,
        response=_FakeResponse(
            422, body={"detail": "image is not decodable: cannot identify image file"},
        ),
    )

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 422
    assert "not decodable" in excinfo.value.detail


@pytest.mark.asyncio
async def test_a_422_from_the_worker_without_json_body_still_propagates(monkeypatch):
    _install(
        monkeypatch,
        response=_FakeResponse(422, text="plain text reason", raise_on_json=True),
    )

    with pytest.raises(HTTPException) as excinfo:
        await _call_worker(b"img", {"schema_version": 1, "tools": []})

    assert excinfo.value.status_code == 422
    assert excinfo.value.detail == "plain text reason"