"""Verifies get_llm_client() returns a usage-tracked client end to end."""

from __future__ import annotations

from unittest.mock import MagicMock, patch

import pytest

from app.services.llm.llm_factory import LLMFactory, get_llm_client
from app.services.llm.tracked_client import TrackedLLMClient
from app.shared.model_usage_tracker import get_model_usage_tracker


@pytest.fixture(autouse=True)
def _reset_singletons():
    """Clear the two process-wide singletons this test touches, before and after.

    LLMFactory._global_instances and get_model_usage_tracker() both persist
    for the life of the process; without this fixture, tests would leak
    cached clients/usage data into each other and become order-dependent.
    """
    LLMFactory._global_instances.clear()
    get_model_usage_tracker().snapshot()  # no-op read, just documents intent
    get_model_usage_tracker()._entries.clear()
    yield
    LLMFactory._global_instances.clear()
    get_model_usage_tracker()._entries.clear()


def test_get_llm_client_returns_tracked_client():
    """get_llm_client() must return a TrackedLLMClient, not the raw provider client."""
    with patch("app.services.llm.llm_factory.DeepSeekClient") as mock_cls:
        mock_cls.return_value = MagicMock()
        client = get_llm_client(provider="deepseek", model="deepseek-v4-flash", api_key="test-key")
    assert isinstance(client, TrackedLLMClient)


def test_get_llm_client_caches_the_tracked_instance():
    """A second call with the same provider/model must return the same TrackedLLMClient."""
    with patch("app.services.llm.llm_factory.DeepSeekClient") as mock_cls:
        mock_cls.return_value = MagicMock()
        first = get_llm_client(provider="deepseek", model="deepseek-v4-flash", api_key="test-key")
        second = get_llm_client(provider="deepseek", model="deepseek-v4-flash", api_key="test-key")
    assert first is second
