service/cache_test.go

package service

import (
	"context"
	"testing"
	"time"

	"github.com/korap/korap-mcp/config"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestDefaultCacheConfig(t *testing.T) {
	cacheConfig := config.DefaultCacheConfig()

	assert.True(t, cacheConfig.Enabled)
	assert.Equal(t, "5m", cacheConfig.DefaultTTL)
	assert.Equal(t, "2m", cacheConfig.SearchTTL)
	assert.Equal(t, "15m", cacheConfig.MetadataTTL)
	assert.Equal(t, 1000, cacheConfig.MaxSize)
}

func TestNewCache(t *testing.T) {
	tests := []struct {
		name           string
		config         *config.CacheConfig
		expectError    bool
		expectNilCache bool
	}{
		{
			name:           "enabled cache",
			config:         config.DefaultCacheConfig(),
			expectError:    false,
			expectNilCache: false,
		},
		{
			name: "disabled cache",
			config: &config.CacheConfig{
				Enabled: false,
			},
			expectError:    false,
			expectNilCache: true,
		},
		{
			name: "custom configuration",
			config: &config.CacheConfig{
				Enabled:     true,
				DefaultTTL:  "1m",
				SearchTTL:   "30s",
				MetadataTTL: "5m",
				MaxSize:     500,
			},
			expectError:    false,
			expectNilCache: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			cache, err := NewCache(tt.config)

			if tt.expectError {
				assert.Error(t, err)
				return
			}

			require.NoError(t, err)
			assert.NotNil(t, cache)

			if tt.expectNilCache {
				assert.Nil(t, cache.cache)
			} else {
				assert.NotNil(t, cache.cache)
			}

			assert.Equal(t, tt.config, cache.config)
		})
	}
}

func TestCacheGetSet(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	ctx := context.Background()
	key := "test-key"
	data := []byte("test data")
	ttl := 1 * time.Minute

	// Test cache miss
	result, found := cache.Get(ctx, key)
	assert.False(t, found)
	assert.Nil(t, result)

	// Test cache set and hit
	cache.Set(ctx, key, data, ttl)
	result, found = cache.Get(ctx, key)
	assert.True(t, found)
	assert.Equal(t, data, result)
}

func TestCacheExpiry(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	ctx := context.Background()
	key := "test-key"
	data := []byte("test data")
	ttl := 50 * time.Millisecond

	// Set cache entry with short TTL
	cache.Set(ctx, key, data, ttl)

	// Should hit immediately
	result, found := cache.Get(ctx, key)
	assert.True(t, found)
	assert.Equal(t, data, result)

	// Wait for expiry
	time.Sleep(100 * time.Millisecond)

	// Should miss after expiry
	result, found = cache.Get(ctx, key)
	assert.False(t, found)
	assert.Nil(t, result)
}

func TestCacheDelete(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	ctx := context.Background()
	key := "test-key"
	data := []byte("test data")
	ttl := 1 * time.Minute

	// Set and verify
	cache.Set(ctx, key, data, ttl)
	result, found := cache.Get(ctx, key)
	assert.True(t, found)
	assert.Equal(t, data, result)

	// Delete and verify
	cache.Delete(ctx, key)
	result, found = cache.Get(ctx, key)
	assert.False(t, found)
	assert.Nil(t, result)
}

func TestCacheClear(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	ctx := context.Background()
	ttl := 1 * time.Minute

	// Set multiple entries
	cache.Set(ctx, "key1", []byte("data1"), ttl)
	cache.Set(ctx, "key2", []byte("data2"), ttl)
	cache.Set(ctx, "key3", []byte("data3"), ttl)

	// Verify all entries exist
	_, found1 := cache.Get(ctx, "key1")
	_, found2 := cache.Get(ctx, "key2")
	_, found3 := cache.Get(ctx, "key3")
	assert.True(t, found1)
	assert.True(t, found2)
	assert.True(t, found3)

	// Clear cache
	cache.Clear()

	// Verify all entries are gone
	_, found1 = cache.Get(ctx, "key1")
	_, found2 = cache.Get(ctx, "key2")
	_, found3 = cache.Get(ctx, "key3")
	assert.False(t, found1)
	assert.False(t, found2)
	assert.False(t, found3)
}

func TestCacheStats(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	ctx := context.Background()

	// Test stats with empty cache
	stats := cache.Stats()
	assert.True(t, stats["enabled"].(bool))
	assert.Equal(t, 0, stats["size"].(int))

	// Add some data and check stats
	cache.Set(ctx, "key1", []byte("data1"), 1*time.Minute)
	cache.Set(ctx, "key2", []byte("data2"), 1*time.Minute)

	stats = cache.Stats()
	assert.True(t, stats["enabled"].(bool))
	assert.Equal(t, 2, stats["size"].(int))
	assert.Equal(t, 1000, stats["max_size"].(int))
	assert.Contains(t, stats, "hits")
	assert.Contains(t, stats, "misses")
	assert.Contains(t, stats, "hit_ratio")
}

func TestCacheStatsDisabled(t *testing.T) {
	cacheConfig := &config.CacheConfig{Enabled: false}
	cache, err := NewCache(cacheConfig)
	require.NoError(t, err)

	stats := cache.Stats()
	assert.False(t, stats["enabled"].(bool))
	assert.Len(t, stats, 1) // Only "enabled" key should be present
}

func TestCacheDisabled(t *testing.T) {
	cacheConfig := &config.CacheConfig{Enabled: false}
	cache, err := NewCache(cacheConfig)
	require.NoError(t, err)

	ctx := context.Background()
	key := "test-key"
	data := []byte("test data")
	ttl := 1 * time.Minute

	// All operations should be no-ops
	cache.Set(ctx, key, data, ttl)
	result, found := cache.Get(ctx, key)
	assert.False(t, found)
	assert.Nil(t, result)

	cache.Delete(ctx, key)
	cache.Clear()

	// Should not panic
	assert.NotPanics(t, func() {
		cache.Close()
	})
}

func TestGenerateCacheKey(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	tests := []struct {
		name     string
		method   string
		endpoint string
		params   map[string]any
		wantSame bool
	}{
		{
			name:     "same parameters",
			method:   "GET",
			endpoint: "/search",
			params:   map[string]any{"q": "test", "count": 10},
			wantSame: true,
		},
		{
			name:     "different method",
			method:   "POST",
			endpoint: "/search",
			params:   map[string]any{"q": "test", "count": 10},
			wantSame: false,
		},
		{
			name:     "different endpoint",
			method:   "GET",
			endpoint: "/corpus",
			params:   map[string]any{"q": "test", "count": 10},
			wantSame: false,
		},
		{
			name:     "different parameters",
			method:   "GET",
			endpoint: "/search",
			params:   map[string]any{"q": "different", "count": 10},
			wantSame: false,
		},
		{
			name:     "nil parameters",
			method:   "GET",
			endpoint: "/search",
			params:   nil,
			wantSame: false,
		},
	}

	baseKey := cache.generateCacheKey("GET", "/search", map[string]any{"q": "test", "count": 10})

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			key := cache.generateCacheKey(tt.method, tt.endpoint, tt.params)

			assert.NotEmpty(t, key)
			assert.Len(t, key, 32) // MD5 hash length

			if tt.wantSame {
				assert.Equal(t, baseKey, key)
			} else {
				assert.NotEqual(t, baseKey, key)
			}
		})
	}
}

func TestCacheKeyDeterministic(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	// Test that map parameter order doesn't affect cache key generation
	// This verifies that json.Marshal provides deterministic ordering
	params1 := map[string]any{
		"query":    "test search",
		"count":    50,
		"offset":   0,
		"corpus":   "news-corpus",
		"language": "poliqarp",
	}

	params2 := map[string]any{
		"language": "poliqarp",
		"corpus":   "news-corpus",
		"offset":   0,
		"count":    50,
		"query":    "test search",
	}

	// Same parameters in different map creation order should produce same cache key
	key1 := cache.generateCacheKey("GET", "/search", params1)
	key2 := cache.generateCacheKey("GET", "/search", params2)

	assert.Equal(t, key1, key2, "Cache keys should be identical regardless of map parameter order")
	assert.Len(t, key1, 32, "Cache key should be MD5 hash length")
	assert.Len(t, key2, 32, "Cache key should be MD5 hash length")

	// Generate keys multiple times to ensure consistency
	for i := 0; i < 10; i++ {
		keyN := cache.generateCacheKey("GET", "/search", params1)
		assert.Equal(t, key1, keyN, "Cache key should be consistent across multiple generations")
	}
}

func TestGetTTLForEndpoint(t *testing.T) {
	cacheConfig := config.DefaultCacheConfig()
	cache, err := NewCache(cacheConfig)
	require.NoError(t, err)

	tests := []struct {
		name     string
		endpoint string
		expected time.Duration
	}{
		{
			name:     "search endpoint",
			endpoint: "/api/v1/search",
			expected: cacheConfig.GetSearchTTL(),
		},
		{
			name:     "query endpoint",
			endpoint: "/query",
			expected: cacheConfig.GetSearchTTL(),
		},
		{
			name:     "corpus endpoint",
			endpoint: "/corpus",
			expected: cacheConfig.GetMetadataTTL(),
		},
		{
			name:     "metadata endpoint",
			endpoint: "/metadata",
			expected: cacheConfig.GetMetadataTTL(),
		},
		{
			name:     "statistics endpoint",
			endpoint: "/statistics",
			expected: cacheConfig.GetMetadataTTL(),
		},
		{
			name:     "info endpoint",
			endpoint: "/info",
			expected: cacheConfig.GetMetadataTTL(),
		},
		{
			name:     "other endpoint",
			endpoint: "/other",
			expected: cacheConfig.GetDefaultTTL(),
		},
		{
			name:     "case insensitive",
			endpoint: "/API/V1/SEARCH",
			expected: cacheConfig.GetSearchTTL(),
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			ttl := cache.GetTTLForEndpoint(tt.endpoint)
			assert.Equal(t, tt.expected, ttl)
		})
	}
}

func TestCacheEntry(t *testing.T) {
	t.Run("not expired", func(t *testing.T) {
		entry := &CacheEntry{
			Data:      []byte("test"),
			Timestamp: time.Now(),
			TTL:       1 * time.Minute,
		}

		assert.False(t, entry.IsExpired())
	})

	t.Run("expired", func(t *testing.T) {
		entry := &CacheEntry{
			Data:      []byte("test"),
			Timestamp: time.Now().Add(-2 * time.Minute),
			TTL:       1 * time.Minute,
		}

		assert.True(t, entry.IsExpired())
	})
}

func TestCacheClose(t *testing.T) {
	cache, err := NewCache(config.DefaultCacheConfig())
	require.NoError(t, err)

	// Add some data
	ctx := context.Background()
	cache.Set(ctx, "key1", []byte("data1"), 1*time.Minute)

	// Close should not error
	err = cache.Close()
	assert.NoError(t, err)

	// Disabled cache close should also not error
	disabledCache, err := NewCache(&config.CacheConfig{Enabled: false})
	require.NoError(t, err)

	err = disabledCache.Close()
	assert.NoError(t, err)
}