"""Tests for ai_service.py error handling (gitea#36 point 7).

A malformed response from the AI model (missing fields, invalid JSON) must
raise the dedicated AIResponseError, not a bare KeyError/JSONDecodeError —
JSONDecodeError in particular is itself a ValueError subclass, so without
this it was caught by the router's `except ValueError` (meant for our own
config errors) and misreported as a 400 instead of a 502.
"""
import json
from unittest.mock import AsyncMock, patch

import pytest

from src.backend.services import ai_service


class _FakeResponse:
    def __init__(self, json_data):
        self._json_data = json_data

    def raise_for_status(self):
        pass

    def json(self):
        return self._json_data


def _patch_openrouter(monkeypatch, response_json: dict):
    monkeypatch.setattr(ai_service, "extract_text_from_pdf", lambda _b: "some extracted text")
    monkeypatch.setattr(ai_service.settings, "openrouter_api_key", "test-key")
    monkeypatch.setattr(ai_service.settings, "openrouter_model", "test-model")

    fake_client = AsyncMock()
    fake_client.post = AsyncMock(return_value=_FakeResponse(response_json))
    fake_client.__aenter__ = AsyncMock(return_value=fake_client)
    fake_client.__aexit__ = AsyncMock(return_value=False)

    return patch("src.backend.services.ai_service.httpx.AsyncClient", return_value=fake_client)


async def test_missing_choices_key_raises_ai_response_error(monkeypatch):
    with _patch_openrouter(monkeypatch, {"no_choices_here": True}):
        with pytest.raises(ai_service.AIResponseError):
            await ai_service.parse_technical_sheet(b"%PDF-fake")


async def test_invalid_json_content_raises_ai_response_error(monkeypatch):
    bad_content = "not valid json {{{"
    response_json = {"choices": [{"message": {"content": bad_content}}]}
    with _patch_openrouter(monkeypatch, response_json):
        with pytest.raises(ai_service.AIResponseError):
            await ai_service.parse_technical_sheet(b"%PDF-fake")


async def test_valid_json_content_returns_tasks(monkeypatch):
    tasks = [{"title": "MATERIALI", "directive": "Verificare", "description": "..."}]
    response_json = {"choices": [{"message": {"content": json.dumps(tasks)}}]}
    with _patch_openrouter(monkeypatch, response_json):
        result = await ai_service.parse_technical_sheet(b"%PDF-fake")
    assert result == tasks


async def test_empty_extracted_text_returns_empty_list(monkeypatch):
    """No AI call at all when the PDF has no extractable text."""
    monkeypatch.setattr(ai_service, "extract_text_from_pdf", lambda _b: "   ")
    result = await ai_service.parse_technical_sheet(b"%PDF-fake")
    assert result == []