import pytest
from unittest.mock import MagicMock, patch

# Import the necessary functions from ai_client, including the reset helper
from ai_client import get_gemini_cache_stats, reset_session

def test_get_gemini_cache_stats_with_mock_client():
    """
    Test that get_gemini_cache_stats correctly processes cache lists
    from a mocked client instance.
    """
    # Ensure a clean state before the test by resetting the session
    reset_session()

    # 1. Create a mock for the cache object that the client will return
    mock_cache = MagicMock()
    mock_cache.name = "cachedContents/test-cache"
    mock_cache.display_name = "Test Cache"
    mock_cache.model = "models/gemini-1.5-pro-001"
    mock_cache.size_bytes = 1024

    # 2. Create a mock for the client instance
    mock_client_instance = MagicMock()
    # Configure its `caches.list` method to return our mock cache
    mock_client_instance.caches.list.return_value = [mock_cache]

    # 3. Patch the Client constructor to return our mock instance
    #    This intercepts the `_ensure_gemini_client` call inside the function
    with patch('google.genai.Client', return_value=mock_client_instance) as mock_client_constructor:
        
        # 4. Call the function under test
        stats = get_gemini_cache_stats()

        # 5. Assert that the function behaved as expected
        
        # It should have constructed the client
        mock_client_constructor.assert_called_once()
        # It should have called the `list` method on the `caches` attribute
        mock_client_instance.caches.list.assert_called_once()

        # The returned stats dictionary should be correct
        assert "cache_count" in stats
        assert "total_size_bytes" in stats
        assert stats["cache_count"] == 1
        assert stats["total_size_bytes"] == 1024