"""Tests for DS-11: Cache invalidation with key-pattern tracking."""

from unittest.mock import AsyncMock, MagicMock, patch

import pytest


@pytest.fixture
def mock_redis():
    """Patch upstash_redis.Redis so the cache client is usable."""
    with patch("upstash_redis.Redis") as mock_cls:
        mock_instance = MagicMock()
        mock_cls.return_value = mock_instance

        # By default, all Redis operations return something truthy
        mock_instance.get.return_value = None
        mock_instance.set.return_value = "OK"
        mock_instance.sadd.return_value = 1
        mock_instance.smembers.return_value = []
        mock_instance.delete.return_value = 1
        mock_instance.exists.return_value = 0

        yield mock_instance


@pytest.fixture
def cache_with_mock_creds(mock_redis):
    """Return an UpstashRedisCache with mocked credentials and Redis client."""
    from app.core.cache import UpstashRedisCache
    from app.core.config import settings

    with (
        patch.object(settings, "upstash_redis_rest_url", "https://test.upstash.io"),
        patch.object(settings, "upstash_redis_rest_token", "test-token"),
    ):
        cache = UpstashRedisCache()
        # Force client creation so mock_redis is used
        cache._sync_client = mock_redis._mock_new_parent if hasattr(mock_redis, '_mock_new_parent') else mock_redis
        cache._async_client = mock_redis
        yield cache


class TestCacheKeyTracking:
    """DS-11: Cache operations should track keys per user."""

    @patch("app.core.cache.UpstashRedisCache._get_async_client")
    async def test_cache_summary_tracks_key(
        self, mock_get_async, cache_with_mock_creds
    ) -> None:
        """cache_summary should track the cache key under the user's key set."""
        mock_async = AsyncMock()
        mock_async.set.return_value = "OK"
        mock_async.sadd.return_value = 1
        # Setting mock_get_async to return a mock client
        mock_get_async.return_value = mock_async

        from app.core.cache import UpstashRedisCache
        cache = cache_with_mock_creds

        result = await cache.cache_summary(
            user_id="user_abc",
            start_date="2024-01-01",
            end_date="2024-01-31",
            data={"total_runs": 42},
        )

        assert result is True
        # Should have called set AND sadd (for key tracking)
        assert mock_async.set.called
        assert mock_async.sadd.called

    @patch("app.core.cache.UpstashRedisCache._get_async_client")
    async def test_cache_trends_tracks_key(
        self, mock_get_async, cache_with_mock_creds
    ) -> None:
        """cache_trends should track the cache key under the user's key set."""
        mock_async = AsyncMock()
        mock_async.set.return_value = "OK"
        mock_async.sadd.return_value = 1
        mock_get_async.return_value = mock_async

        cache = cache_with_mock_creds
        result = await cache.cache_trends(
            user_id="user_abc",
            period="7d",
            data={"trend": "up"},
        )

        assert result is True
        assert mock_async.set.called
        assert mock_async.sadd.called

    @patch("app.core.cache.UpstashRedisCache._get_async_client")
    async def test_cache_projects_tracks_key(
        self, mock_get_async, cache_with_mock_creds
    ) -> None:
        """cache_projects should track the cache key under the user's key set."""
        mock_async = AsyncMock()
        mock_async.set.return_value = "OK"
        mock_async.sadd.return_value = 1
        mock_get_async.return_value = mock_async

        cache = cache_with_mock_creds
        result = await cache.cache_projects(
            user_id="user_abc",
            data={"projects": []},
        )

        assert result is True
        assert mock_async.set.called
        assert mock_async.sadd.called


class TestCacheInvalidation:
    """DS-11: invalidate_user_cache should clear all keys for a user."""

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_invalidate_user_cache_clears_keys(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """invalidate_user_cache should smembers, delete each key, then delete the set."""
        mock_sync = MagicMock()
        # Return some tracked keys
        mock_sync.smembers.return_value = [
            "cache_key_1",
            "cache_key_2",
            "cache_key_3",
        ]
        mock_sync.delete.return_value = 3
        mock_get_sync.return_value = mock_sync

        cache = cache_with_mock_creds

        await cache.invalidate_user_cache("user_abc")

        # Should have called smembers to get keys
        mock_sync.smembers.assert_called_once()
        # Should have called delete for each key (pipeline or individual)
        assert mock_sync.delete.call_count >= 1

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_invalidate_user_cache_empty_set(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """invalidate_user_cache handles empty key sets gracefully."""
        mock_sync = MagicMock()
        mock_sync.smembers.return_value = []  # No tracked keys
        mock_sync.delete.return_value = 1  # Deleting the set itself
        mock_get_sync.return_value = mock_sync

        cache = cache_with_mock_creds

        # Should not raise
        await cache.invalidate_user_cache("user_xyz")

        mock_sync.smembers.assert_called_once()
        # Should delete the set itself
        mock_sync.delete.assert_called_once()

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_invalidate_user_cache_no_crash_when_redis_unavailable(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """invalidate_user_cache should not crash when Redis client returns None."""
        mock_get_sync.return_value = None

        cache = cache_with_mock_creds

        # Should not raise
        result = await cache.invalidate_user_cache("user_no_redis")
        assert result == 0  # No keys cleared when Redis unavailable

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_invalidate_user_cache_returns_key_count(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """invalidate_user_cache should return the number of keys cleared."""
        mock_sync = MagicMock()
        mock_sync.smembers.return_value = ["key1", "key2"]
        mock_sync.delete.return_value = 2
        mock_get_sync.return_value = mock_sync

        cache = cache_with_mock_creds
        result = await cache.invalidate_user_cache("user_abc")

        assert result == 2
        mock_sync.smembers.assert_called_once()
        assert mock_sync.delete.call_count >= 1


class TestCacheHealth:
    """DS-11: get_cache_health should report cache status."""

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_cache_health_ok(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """get_cache_health returns ok status when Redis is connected."""
        mock_sync = MagicMock()
        mock_sync.exists.return_value = 1
        mock_sync.scard.return_value = 5
        mock_get_sync.return_value = mock_sync

        cache = cache_with_mock_creds
        health = await cache.get_cache_health("user_abc")

        assert health["status"] == "ok"
        assert health["keys_tracked"] == 5
        assert health["ttl_seconds"] > 0

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_cache_health_degraded(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """get_cache_health returns degraded status when Redis is unavailable."""
        mock_get_sync.return_value = None

        cache = cache_with_mock_creds
        health = await cache.get_cache_health("user_abc")

        assert health["status"] == "degraded"
        assert health["keys_tracked"] == 0

    @patch("app.core.cache.UpstashRedisCache._get_sync_client")
    async def test_cache_health_no_keys(
        self, mock_get_sync, cache_with_mock_creds
    ) -> None:
        """get_cache_health returns 0 keys when no key set exists."""
        mock_sync = MagicMock()
        mock_sync.exists.return_value = 0  # Key set doesn't exist
        mock_get_sync.return_value = mock_sync

        cache = cache_with_mock_creds
        health = await cache.get_cache_health("user_abc")

        assert health["status"] == "ok"
        assert health["keys_tracked"] == 0