package main

import (
	"embed"
	"encoding/json"
	"fmt"
	"time"

	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/websocket/v2"
	libpack_cache "github.com/lukaszraczylo/graphql-monitoring-proxy/cache"
	libpack_logger "github.com/lukaszraczylo/graphql-monitoring-proxy/logging"
)

//go:embed admin/dashboard.html
var dashboardHTML embed.FS

// AdminDashboard provides monitoring and management interface
type AdminDashboard struct {
	logger *libpack_logger.Logger
}

// NewAdminDashboard creates a new admin dashboard
func NewAdminDashboard(logger *libpack_logger.Logger) *AdminDashboard {
	return &AdminDashboard{
		logger: logger,
	}
}

// RegisterRoutes registers dashboard routes
func (ad *AdminDashboard) RegisterRoutes(app *fiber.App) {
	// Dashboard UI
	app.Get("/admin", ad.serveDashboard)
	app.Get("/admin/dashboard", ad.serveDashboard)

	// API endpoints for dashboard data
	app.Get("/admin/api/stats", ad.getStats)
	app.Get("/admin/api/health", ad.getHealth)
	app.Get("/admin/api/circuit-breaker", ad.getCircuitBreakerStatus)
	app.Get("/admin/api/cache", ad.getCacheStats)
	app.Get("/admin/api/connections", ad.getConnectionStats)
	app.Get("/admin/api/retry-budget", ad.getRetryBudgetStats)
	app.Get("/admin/api/coalescing", ad.getCoalescingStats)
	app.Get("/admin/api/websocket", ad.getWebSocketStats)

	// WebSocket endpoint for streaming statistics
	app.Get("/admin/ws/stats", websocket.New(ad.handleStatsWebSocket))

	// Cluster mode endpoints (when using Redis)
	app.Get("/admin/api/cluster/stats", ad.getClusterStats)
	app.Get("/admin/api/cluster/instances", ad.getClusterInstances)
	app.Get("/admin/api/cluster/debug", ad.getClusterDebug)
	app.Post("/admin/api/cluster/force-publish", ad.forcePublish)

	// Control endpoints
	app.Post("/admin/api/cache/clear", ad.clearCache)
	app.Post("/admin/api/retry-budget/reset", ad.resetRetryBudget)
	app.Post("/admin/api/coalescing/reset", ad.resetCoalescing)

	if ad.logger != nil {
		ad.logger.Info(&libpack_logger.LogMessage{
			Message: "Admin dashboard routes registered",
			Pairs: map[string]interface{}{
				"path": "/admin",
			},
		})
	}
}

// serveDashboard serves the dashboard HTML
func (ad *AdminDashboard) serveDashboard(c *fiber.Ctx) error {
	data, err := dashboardHTML.ReadFile("admin/dashboard.html")
	if err != nil {
		return c.Status(500).SendString("Failed to load dashboard")
	}

	c.Set("Content-Type", "text/html; charset=utf-8")
	return c.Send(data)
}

// getStats returns overall proxy statistics
// In cluster mode (when metrics aggregator is available), returns aggregated stats from all instances
func (ad *AdminDashboard) getStats(c *fiber.Ctx) error {
	// Check if cluster mode is enabled - if so, return aggregated stats
	if aggregator := GetMetricsAggregator(); aggregator != nil {
		metrics, err := aggregator.GetAggregatedMetrics()
		if err != nil {
			if ad.logger != nil {
				ad.logger.Error(&libpack_logger.LogMessage{
					Message: "Failed to get aggregated metrics, falling back to local stats",
					Pairs:   map[string]interface{}{"error": err.Error()},
				})
			}
			// Fall through to local stats on error
		} else {
			// Return aggregated cluster stats
			response := map[string]interface{}{
				"cluster_mode":      true,
				"total_instances":   metrics.TotalInstances,
				"healthy_instances": metrics.HealthyInstances,
				"timestamp":         metrics.LastUpdate.Format(time.RFC3339),
				"version":           "0.27.0",
			}

			// Add combined stats from aggregation
			if metrics.CombinedStats != nil {
				for k, v := range metrics.CombinedStats {
					response[k] = v
				}
			}

			return c.JSON(response)
		}
	}

	// Local instance stats (fallback or non-cluster mode)
	uptimeSeconds := time.Since(startTime).Seconds()
	stats := map[string]interface{}{
		"cluster_mode":   false,
		"timestamp":      time.Now().Format(time.RFC3339),
		"uptime_seconds": uptimeSeconds,
		"uptime_human":   formatDuration(time.Since(startTime)),
		"version":        "0.27.0", // TODO: Get from build info
	}

	if cfg != nil && cfg.Monitoring != nil {
		succeeded := getAdminMetricValue("requests_succesful")
		failed := getAdminMetricValue("requests_failed")
		skipped := getAdminMetricValue("requests_skipped")
		total := succeeded + failed + skipped

		// Request statistics
		requestStats := map[string]interface{}{
			"total":     total,
			"succeeded": succeeded,
			"failed":    failed,
			"skipped":   skipped,
		}

		// Calculate rates and percentages
		if total > 0 {
			requestStats["success_rate_pct"] = float64(succeeded) / float64(total) * 100
			requestStats["failure_rate_pct"] = float64(failed) / float64(total) * 100
			requestStats["skip_rate_pct"] = float64(skipped) / float64(total) * 100
		} else {
			requestStats["success_rate_pct"] = 0.0
			requestStats["failure_rate_pct"] = 0.0
			requestStats["skip_rate_pct"] = 0.0
		}

		// Calculate average requests per second (lifetime)
		if uptimeSeconds > 0 {
			requestStats["avg_requests_per_second"] = float64(total) / uptimeSeconds
		} else {
			requestStats["avg_requests_per_second"] = 0.0
		}

		// Get current requests per second (last 1 second)
		if rpsTracker := GetRPSTracker(); rpsTracker != nil {
			requestStats["current_requests_per_second"] = rpsTracker.GetCurrentRPS()
		} else {
			requestStats["current_requests_per_second"] = 0.0
		}

		stats["requests"] = requestStats

		// Get cache statistics summary
		cacheStats := libpack_cache.GetCacheStats()
		if cacheStats != nil {
			totalCacheRequests := cacheStats.CacheHits + cacheStats.CacheMisses
			hitRate := 0.0
			if totalCacheRequests > 0 {
				hitRate = float64(cacheStats.CacheHits) / float64(totalCacheRequests) * 100
			}
			stats["cache_summary"] = map[string]interface{}{
				"hits":         cacheStats.CacheHits,
				"misses":       cacheStats.CacheMisses,
				"hit_rate_pct": hitRate,
				"total_cached": cacheStats.CachedQueries,
			}
		}
	}

	return c.JSON(stats)
}

// formatDuration formats a duration into human-readable format
func formatDuration(d time.Duration) string {
	days := int(d.Hours() / 24)
	hours := int(d.Hours()) % 24
	minutes := int(d.Minutes()) % 60
	seconds := int(d.Seconds()) % 60

	if days > 0 {
		return fmt.Sprintf("%dd %dh %dm %ds", days, hours, minutes, seconds)
	} else if hours > 0 {
		return fmt.Sprintf("%dh %dm %ds", hours, minutes, seconds)
	} else if minutes > 0 {
		return fmt.Sprintf("%dm %ds", minutes, seconds)
	}
	return fmt.Sprintf("%ds", seconds)
}

// getHealth returns health status
func (ad *AdminDashboard) getHealth(c *fiber.Ctx) error {
	healthMgr := GetBackendHealthManager()

	health := map[string]interface{}{
		"status": "unknown",
		"backend": map[string]interface{}{
			"healthy": false,
		},
	}

	if healthMgr != nil {
		isHealthy := healthMgr.IsHealthy()
		health["backend"] = map[string]interface{}{
			"healthy":              isHealthy,
			"consecutive_failures": healthMgr.GetConsecutiveFailures(),
			"last_check":           healthMgr.GetLastHealthCheck().Format(time.RFC3339),
		}

		if isHealthy {
			health["status"] = "healthy"
		} else {
			health["status"] = "unhealthy"
		}
	}

	return c.JSON(health)
}

// getCircuitBreakerStatus returns circuit breaker status
func (ad *AdminDashboard) getCircuitBreakerStatus(c *fiber.Ctx) error {
	status := map[string]interface{}{
		"enabled": false,
		"state":   "unknown",
	}

	if cfg != nil {
		status["enabled"] = cfg.CircuitBreaker.Enable

		if cb != nil {
			cbMutex.RLock()
			state := cb.State()
			counts := cb.Counts()
			cbMutex.RUnlock()

			status["state"] = state.String()
			status["counts"] = map[string]interface{}{
				"requests":              counts.Requests,
				"total_successes":       counts.TotalSuccesses,
				"total_failures":        counts.TotalFailures,
				"consecutive_successes": counts.ConsecutiveSuccesses,
				"consecutive_failures":  counts.ConsecutiveFailures,
			}
			status["config"] = map[string]interface{}{
				"max_failures":           cfg.CircuitBreaker.MaxFailures,
				"failure_ratio":          cfg.CircuitBreaker.FailureRatio,
				"timeout":                cfg.CircuitBreaker.Timeout,
				"max_requests_half_open": cfg.CircuitBreaker.MaxRequestsInHalfOpen,
				"return_cached_on_open":  cfg.CircuitBreaker.ReturnCachedOnOpen,
			}
		}
	}

	return c.JSON(status)
}

// getCacheStats returns cache statistics
// In cluster mode, returns aggregated cache stats from all instances
func (ad *AdminDashboard) getCacheStats(c *fiber.Ctx) error {
	// Check if cluster mode is enabled - if so, return aggregated cache stats
	if aggregator := GetMetricsAggregator(); aggregator != nil {
		metrics, err := aggregator.GetAggregatedMetrics()
		if err != nil {
			if ad.logger != nil {
				ad.logger.Error(&libpack_logger.LogMessage{
					Message: "Failed to get aggregated cache metrics, falling back to local stats",
					Pairs:   map[string]interface{}{"error": err.Error()},
				})
			}
			// Fall through to local stats on error
		} else {
			// Build aggregated cache stats from combined stats
			response := map[string]interface{}{
				"cluster_mode":    true,
				"total_instances": metrics.TotalInstances,
			}

			// Add cache config from local config
			if cfg != nil {
				response["enabled"] = cfg.Cache.CacheEnable
				response["redis_enabled"] = cfg.Cache.CacheRedisEnable
				response["ttl_seconds"] = cfg.Cache.CacheTTL
				response["max_memory_mb"] = cfg.Cache.CacheMaxMemorySize
				response["max_entries"] = cfg.Cache.CacheMaxEntries
			}

			// Extract aggregated cache stats from combined stats
			if metrics.CombinedStats != nil {
				if cacheHits, ok := metrics.CombinedStats["cache_hits"]; ok {
					response["cache_hits"] = cacheHits
				}
				if cacheMisses, ok := metrics.CombinedStats["cache_misses"]; ok {
					response["cache_misses"] = cacheMisses
				}
				if cachedQueries, ok := metrics.CombinedStats["cached_queries"]; ok {
					response["cached_queries"] = cachedQueries
				}
				if hitRate, ok := metrics.CombinedStats["cache_hit_rate_pct"]; ok {
					response["hit_rate_pct"] = hitRate
				}
				if memoryMB, ok := metrics.CombinedStats["memory_usage_mb"]; ok {
					response["memory_usage_mb"] = memoryMB
				}
			}

			return c.JSON(response)
		}
	}

	// Local instance stats (fallback or non-cluster mode)
	stats := map[string]interface{}{
		"cluster_mode": false,
		"enabled":      false,
	}

	if cfg != nil {
		stats["enabled"] = cfg.Cache.CacheEnable
		stats["redis_enabled"] = cfg.Cache.CacheRedisEnable
		stats["ttl_seconds"] = cfg.Cache.CacheTTL
		stats["max_memory_mb"] = cfg.Cache.CacheMaxMemorySize
		stats["max_entries"] = cfg.Cache.CacheMaxEntries

		// Get runtime cache statistics
		cacheStats := libpack_cache.GetCacheStats()
		if cacheStats != nil {
			stats["cached_queries"] = cacheStats.CachedQueries
			stats["cache_hits"] = cacheStats.CacheHits
			stats["cache_misses"] = cacheStats.CacheMisses

			// Calculate hit rate
			totalRequests := cacheStats.CacheHits + cacheStats.CacheMisses
			hitRate := 0.0
			if totalRequests > 0 {
				hitRate = float64(cacheStats.CacheHits) / float64(totalRequests) * 100
			}
			stats["hit_rate_pct"] = hitRate

			// Get memory usage only for in-memory cache
			if cfg.Cache.CacheEnable && !cfg.Cache.CacheRedisEnable {
				memoryUsage := libpack_cache.GetCacheMemoryUsage()
				maxMemory := libpack_cache.GetCacheMaxMemorySize()
				stats["memory_usage_bytes"] = memoryUsage
				stats["memory_usage_mb"] = float64(memoryUsage) / (1024 * 1024)

				// Calculate memory usage percentage
				memoryUsagePct := 0.0
				if maxMemory > 0 {
					memoryUsagePct = float64(memoryUsage) / float64(maxMemory) * 100
				}
				stats["memory_usage_pct"] = memoryUsagePct
			} else {
				// For Redis cache, memory tracking not available per instance
				stats["memory_usage_mb"] = -1 // Sentinel value for "not applicable"
				stats["memory_usage_pct"] = -1
			}
		}
	}

	return c.JSON(stats)
}

// getConnectionStats returns connection pool statistics
func (ad *AdminDashboard) getConnectionStats(c *fiber.Ctx) error {
	poolMgr := GetConnectionPoolManager()

	stats := map[string]interface{}{
		"available": false,
	}

	if poolMgr != nil {
		stats = poolMgr.GetConnectionStats()
		stats["available"] = true
	}

	return c.JSON(stats)
}

// getRetryBudgetStats returns retry budget statistics
func (ad *AdminDashboard) getRetryBudgetStats(c *fiber.Ctx) error {
	rb := GetRetryBudget()

	if rb == nil {
		return c.JSON(map[string]interface{}{
			"enabled": false,
		})
	}

	return c.JSON(rb.GetStats())
}

// getCoalescingStats returns request coalescing statistics
func (ad *AdminDashboard) getCoalescingStats(c *fiber.Ctx) error {
	rc := GetRequestCoalescer()

	if rc == nil {
		return c.JSON(map[string]interface{}{
			"enabled": false,
		})
	}

	return c.JSON(rc.GetStats())
}

// getWebSocketStats returns WebSocket statistics
func (ad *AdminDashboard) getWebSocketStats(c *fiber.Ctx) error {
	wsp := GetWebSocketProxy()

	if wsp == nil {
		return c.JSON(map[string]interface{}{
			"enabled": false,
		})
	}

	return c.JSON(wsp.GetStats())
}

// clearCache clears the cache
func (ad *AdminDashboard) clearCache(c *fiber.Ctx) error {
	libpack_cache.CacheClear()
	return c.JSON(map[string]interface{}{
		"success": true,
		"message": "Cache cleared successfully",
	})
}

// resetRetryBudget resets retry budget statistics
func (ad *AdminDashboard) resetRetryBudget(c *fiber.Ctx) error {
	rb := GetRetryBudget()
	if rb != nil {
		rb.Reset()
	}

	return c.JSON(map[string]interface{}{
		"success": true,
		"message": "Retry budget statistics reset",
	})
}

// resetCoalescing resets coalescing statistics
func (ad *AdminDashboard) resetCoalescing(c *fiber.Ctx) error {
	rc := GetRequestCoalescer()
	if rc != nil {
		rc.Reset()
	}

	return c.JSON(map[string]interface{}{
		"success": true,
		"message": "Coalescing statistics reset",
	})
}

// getClusterStats returns aggregated statistics from all proxy instances
func (ad *AdminDashboard) getClusterStats(c *fiber.Ctx) error {
	aggregator := GetMetricsAggregator()
	if aggregator == nil {
		return c.Status(503).JSON(map[string]interface{}{
			"error":        "Cluster mode not available",
			"message":      "Redis-based metrics aggregation is not enabled",
			"cluster_mode": false,
		})
	}

	metrics, err := aggregator.GetAggregatedMetrics()
	if err != nil {
		if ad.logger != nil {
			ad.logger.Error(&libpack_logger.LogMessage{
				Message: "Failed to get aggregated metrics",
				Pairs:   map[string]interface{}{"error": err.Error()},
			})
		}
		return c.Status(500).JSON(map[string]interface{}{
			"error":   "Failed to retrieve cluster metrics",
			"message": err.Error(),
		})
	}

	// Format response similar to regular stats endpoint
	response := map[string]interface{}{
		"cluster_mode":      true,
		"total_instances":   metrics.TotalInstances,
		"healthy_instances": metrics.HealthyInstances,
		"last_update":       metrics.LastUpdate.Format(time.RFC3339),
		"stats":             metrics.CombinedStats,
	}

	return c.JSON(response)
}

// getClusterInstances returns detailed metrics for each proxy instance
func (ad *AdminDashboard) getClusterInstances(c *fiber.Ctx) error {
	aggregator := GetMetricsAggregator()
	if aggregator == nil {
		return c.Status(503).JSON(map[string]interface{}{
			"error":        "Cluster mode not available",
			"message":      "Redis-based metrics aggregation is not enabled",
			"cluster_mode": false,
		})
	}

	metrics, err := aggregator.GetAggregatedMetrics()
	if err != nil {
		if ad.logger != nil {
			ad.logger.Error(&libpack_logger.LogMessage{
				Message: "Failed to get instance metrics",
				Pairs:   map[string]interface{}{"error": err.Error()},
			})
		}
		return c.Status(500).JSON(map[string]interface{}{
			"error":   "Failed to retrieve instance metrics",
			"message": err.Error(),
		})
	}

	return c.JSON(map[string]interface{}{
		"cluster_mode":      true,
		"total_instances":   metrics.TotalInstances,
		"healthy_instances": metrics.HealthyInstances,
		"current_instance":  aggregator.GetInstanceID(),
		"instances":         metrics.Instances,
	})
}

// getClusterDebug returns debug information about cluster mode
func (ad *AdminDashboard) getClusterDebug(c *fiber.Ctx) error {
	aggregator := GetMetricsAggregator()

	debug := map[string]interface{}{
		"aggregator_initialized": aggregator != nil,
		"redis_cache_enabled":    false,
	}

	if cfg != nil {
		debug["redis_cache_enabled"] = cfg.Cache.CacheRedisEnable
		debug["cache_enabled"] = cfg.Cache.CacheEnable
	}

	if aggregator != nil {
		debug["instance_id"] = aggregator.GetInstanceID()
		debug["is_cluster_mode"] = aggregator.IsClusterMode()

		// Try to get metrics
		metrics, err := aggregator.GetAggregatedMetrics()
		if err != nil {
			debug["error"] = err.Error()
		} else {
			debug["total_instances"] = metrics.TotalInstances
			debug["healthy_instances"] = metrics.HealthyInstances

			// Show first instance structure as example
			if len(metrics.Instances) > 0 {
				first := metrics.Instances[0]
				debug["sample_instance"] = map[string]interface{}{
					"instance_id":    first.InstanceID,
					"hostname":       first.Hostname,
					"uptime_seconds": first.UptimeSeconds,
					"stats_keys":     getMapKeys(first.Stats),
					"has_requests":   first.Stats["requests"] != nil,
					"has_cache":      len(first.CacheSummary) > 0,
					"health_status":  first.Health["status"],
				}

				// Show requests structure if it exists
				if requests, ok := first.Stats["requests"].(map[string]interface{}); ok {
					debug["sample_requests"] = requests
				}
			}
		}
	}

	return c.JSON(debug)
}

// Helper to get map keys
func getMapKeys(m map[string]interface{}) []string {
	keys := make([]string, 0, len(m))
	for k := range m {
		keys = append(keys, k)
	}
	return keys
}

// forcePublish forces an immediate metrics publish for testing
func (ad *AdminDashboard) forcePublish(c *fiber.Ctx) error {
	aggregator := GetMetricsAggregator()
	if aggregator == nil {
		return c.Status(503).JSON(map[string]interface{}{
			"error":   "Aggregator not initialized",
			"success": false,
		})
	}

	// Trigger publish in goroutine to avoid blocking
	go aggregator.publishMetrics()

	return c.JSON(map[string]interface{}{
		"success":   true,
		"triggered": true,
		"message":   "Publish triggered in background",
		"next_steps": []string{
			"Wait 2 seconds",
			"Check GET /admin/api/cluster/debug",
			"Check server logs for ✓ Successfully published or ❌ CRITICAL errors",
		},
	})
}

// Helper to get metric value for admin dashboard
func getAdminMetricValue(name string) int64 {
	if cfg == nil || cfg.Monitoring == nil {
		return 0
	}
	counter := cfg.Monitoring.RegisterMetricsCounter(name, nil)
	if counter == nil {
		return 0
	}
	return int64(counter.Get())
}

// handleStatsWebSocket handles WebSocket connections for streaming statistics
func (ad *AdminDashboard) handleStatsWebSocket(c *websocket.Conn) {
	if ad.logger != nil {
		ad.logger.Info(&libpack_logger.LogMessage{
			Message: "WebSocket client connected to stats stream",
			Pairs: map[string]interface{}{
				"remote_addr": c.RemoteAddr().String(),
			},
		})
	}

	// Cleanup on disconnect
	defer func() {
		if ad.logger != nil {
			ad.logger.Info(&libpack_logger.LogMessage{
				Message: "WebSocket client disconnected from stats stream",
				Pairs: map[string]interface{}{
					"remote_addr": c.RemoteAddr().String(),
				},
			})
		}
		c.Close()
	}()

	// Set up ping/pong handlers
	c.SetReadDeadline(time.Now().Add(60 * time.Second))
	c.SetPongHandler(func(string) error {
		c.SetReadDeadline(time.Now().Add(60 * time.Second))
		return nil
	})

	// Channel to signal when to stop
	done := make(chan struct{})

	// Goroutine to handle incoming messages (for connection keep-alive)
	go func() {
		defer close(done)
		for {
			if _, _, err := c.ReadMessage(); err != nil {
				// Connection closed or error
				return
			}
		}
	}()

	// Stream statistics every 2 seconds
	ticker := time.NewTicker(2 * time.Second)
	defer ticker.Stop()

	// Send initial stats immediately (cluster-aware for dashboard)
	if stats := ad.gatherAllStatsClusterAware(); stats != nil {
		if data, err := json.Marshal(stats); err == nil {
			c.WriteMessage(websocket.TextMessage, data)
		}
	}

	// Stream loop
	for {
		select {
		case <-ticker.C:
			// Gather all stats (cluster-aware for dashboard)
			stats := ad.gatherAllStatsClusterAware()

			// Marshal to JSON
			data, err := json.Marshal(stats)
			if err != nil {
				if ad.logger != nil {
					ad.logger.Error(&libpack_logger.LogMessage{
						Message: "Failed to marshal stats for WebSocket",
						Pairs:   map[string]interface{}{"error": err.Error()},
					})
				}
				return
			}

			// Send to client
			if err := c.WriteMessage(websocket.TextMessage, data); err != nil {
				if ad.logger != nil {
					ad.logger.Debug(&libpack_logger.LogMessage{
						Message: "Failed to write to WebSocket (client likely disconnected)",
						Pairs:   map[string]interface{}{"error": err.Error()},
					})
				}
				return
			}

		case <-done:
			// Client disconnected
			return
		}
	}
}

// gatherAllStats collects all statistics into a single structure
// This always returns LOCAL stats for this instance (used by metrics aggregator)
func (ad *AdminDashboard) gatherAllStats() map[string]interface{} {
	return ad.gatherAllStatsWithMode(false)
}

// gatherAllStatsClusterAware collects statistics with cluster awareness
// If cluster mode is available, returns aggregated stats from all instances
func (ad *AdminDashboard) gatherAllStatsClusterAware() map[string]interface{} {
	return ad.gatherAllStatsWithMode(true)
}

// gatherAllStatsWithMode collects statistics with optional cluster mode
func (ad *AdminDashboard) gatherAllStatsWithMode(useClusterMode bool) map[string]interface{} {
	// Check if cluster mode is requested and available
	if useClusterMode {
		if aggregator := GetMetricsAggregator(); aggregator != nil {
			metrics, err := aggregator.GetAggregatedMetrics()
			if err == nil && metrics != nil {
				// Return aggregated cluster stats
				result := map[string]interface{}{
					"cluster_mode":      true,
					"total_instances":   metrics.TotalInstances,
					"healthy_instances": metrics.HealthyInstances,
				}

				// Build stats section from combined stats
				stats := map[string]interface{}{
					"timestamp": metrics.LastUpdate.Format(time.RFC3339),
					"version":   "0.27.0",
				}

				// Copy all combined stats
				if metrics.CombinedStats != nil {
					for k, v := range metrics.CombinedStats {
						stats[k] = v
					}
				}
				result["stats"] = stats

				// Add per-instance details
				result["instances"] = metrics.Instances

				return result
			}
		}
	}

	// Fall back to local stats
	result := make(map[string]interface{})
	result["cluster_mode"] = false

	// Main stats
	uptimeSeconds := time.Since(startTime).Seconds()
	stats := map[string]interface{}{
		"timestamp":      time.Now().Format(time.RFC3339),
		"uptime_seconds": uptimeSeconds,
		"uptime_human":   formatDuration(time.Since(startTime)),
		"version":        "0.27.0",
	}

	if cfg != nil && cfg.Monitoring != nil {
		succeeded := getAdminMetricValue("requests_succesful")
		failed := getAdminMetricValue("requests_failed")
		skipped := getAdminMetricValue("requests_skipped")
		total := succeeded + failed + skipped

		requestStats := map[string]interface{}{
			"total":     total,
			"succeeded": succeeded,
			"failed":    failed,
			"skipped":   skipped,
		}

		if total > 0 {
			requestStats["success_rate_pct"] = float64(succeeded) / float64(total) * 100
			requestStats["failure_rate_pct"] = float64(failed) / float64(total) * 100
			requestStats["skip_rate_pct"] = float64(skipped) / float64(total) * 100
		} else {
			requestStats["success_rate_pct"] = 0.0
			requestStats["failure_rate_pct"] = 0.0
			requestStats["skip_rate_pct"] = 0.0
		}

		if uptimeSeconds > 0 {
			requestStats["avg_requests_per_second"] = float64(total) / uptimeSeconds
		} else {
			requestStats["avg_requests_per_second"] = 0.0
		}

		if rpsTracker := GetRPSTracker(); rpsTracker != nil {
			requestStats["current_requests_per_second"] = rpsTracker.GetCurrentRPS()
		} else {
			requestStats["current_requests_per_second"] = 0.0
		}

		stats["requests"] = requestStats

		// Cache summary
		cacheStats := libpack_cache.GetCacheStats()
		if cacheStats != nil {
			totalCacheRequests := cacheStats.CacheHits + cacheStats.CacheMisses
			hitRate := 0.0
			if totalCacheRequests > 0 {
				hitRate = float64(cacheStats.CacheHits) / float64(totalCacheRequests) * 100
			}
			stats["cache_summary"] = map[string]interface{}{
				"hits":         cacheStats.CacheHits,
				"misses":       cacheStats.CacheMisses,
				"hit_rate_pct": hitRate,
				"total_cached": cacheStats.CachedQueries,
			}
		}
	}

	result["stats"] = stats

	// Health
	healthMgr := GetBackendHealthManager()
	health := map[string]interface{}{
		"status": "unknown",
		"backend": map[string]interface{}{
			"healthy": false,
		},
	}

	if healthMgr != nil {
		isHealthy := healthMgr.IsHealthy()
		health["backend"] = map[string]interface{}{
			"healthy":              isHealthy,
			"consecutive_failures": healthMgr.GetConsecutiveFailures(),
			"last_check":           healthMgr.GetLastHealthCheck().Format(time.RFC3339),
		}

		if isHealthy {
			health["status"] = "healthy"
		} else {
			health["status"] = "unhealthy"
		}
	}
	result["health"] = health

	// Circuit breaker
	cbStatus := map[string]interface{}{
		"enabled": false,
		"state":   "unknown",
	}

	if cfg != nil {
		cbStatus["enabled"] = cfg.CircuitBreaker.Enable

		if cb != nil {
			cbMutex.RLock()
			state := cb.State()
			counts := cb.Counts()
			cbMutex.RUnlock()

			cbStatus["state"] = state.String()
			cbStatus["counts"] = map[string]interface{}{
				"requests":              counts.Requests,
				"total_successes":       counts.TotalSuccesses,
				"total_failures":        counts.TotalFailures,
				"consecutive_successes": counts.ConsecutiveSuccesses,
				"consecutive_failures":  counts.ConsecutiveFailures,
			}
			cbStatus["config"] = map[string]interface{}{
				"max_failures":           cfg.CircuitBreaker.MaxFailures,
				"failure_ratio":          cfg.CircuitBreaker.FailureRatio,
				"timeout":                cfg.CircuitBreaker.Timeout,
				"max_requests_half_open": cfg.CircuitBreaker.MaxRequestsInHalfOpen,
				"return_cached_on_open":  cfg.CircuitBreaker.ReturnCachedOnOpen,
			}
		}
	}
	result["circuit_breaker"] = cbStatus

	// Cache stats
	cacheStats := map[string]interface{}{
		"enabled": false,
	}

	if cfg != nil {
		cacheStats["enabled"] = cfg.Cache.CacheEnable
		cacheStats["redis_enabled"] = cfg.Cache.CacheRedisEnable
		cacheStats["ttl_seconds"] = cfg.Cache.CacheTTL
		cacheStats["max_memory_mb"] = cfg.Cache.CacheMaxMemorySize
		cacheStats["max_entries"] = cfg.Cache.CacheMaxEntries

		runtimeCacheStats := libpack_cache.GetCacheStats()
		if runtimeCacheStats != nil {
			cacheStats["cached_queries"] = runtimeCacheStats.CachedQueries
			cacheStats["cache_hits"] = runtimeCacheStats.CacheHits
			cacheStats["cache_misses"] = runtimeCacheStats.CacheMisses

			totalRequests := runtimeCacheStats.CacheHits + runtimeCacheStats.CacheMisses
			hitRate := 0.0
			if totalRequests > 0 {
				hitRate = float64(runtimeCacheStats.CacheHits) / float64(totalRequests) * 100
			}
			cacheStats["hit_rate_pct"] = hitRate

			// Only get memory usage for in-memory cache (not Redis)
			if cfg.Cache.CacheEnable && !cfg.Cache.CacheRedisEnable {
				memoryUsage := libpack_cache.GetCacheMemoryUsage()
				maxMemory := libpack_cache.GetCacheMaxMemorySize()
				cacheStats["memory_usage_bytes"] = memoryUsage
				cacheStats["memory_usage_mb"] = float64(memoryUsage) / (1024 * 1024)

				memoryUsagePct := 0.0
				if maxMemory > 0 {
					memoryUsagePct = float64(memoryUsage) / float64(maxMemory) * 100
				}
				cacheStats["memory_usage_pct"] = memoryUsagePct
			} else {
				// For Redis cache, memory tracking is not available per instance
				cacheStats["memory_usage_bytes"] = int64(-1)
				cacheStats["memory_usage_mb"] = float64(-1)
				cacheStats["memory_usage_pct"] = float64(-1)
			}
		}
	}
	result["cache"] = cacheStats

	// Connection stats
	poolMgr := GetConnectionPoolManager()
	connStats := map[string]interface{}{
		"available": false,
	}

	if poolMgr != nil {
		connStats = poolMgr.GetConnectionStats()
		connStats["available"] = true
	}
	result["connections"] = connStats

	// Retry budget
	rb := GetRetryBudget()
	if rb == nil {
		result["retry_budget"] = map[string]interface{}{"enabled": false}
	} else {
		result["retry_budget"] = rb.GetStats()
	}

	// Coalescing
	rc := GetRequestCoalescer()
	if rc == nil {
		result["coalescing"] = map[string]interface{}{"enabled": false}
	} else {
		result["coalescing"] = rc.GetStats()
	}

	// WebSocket
	wsp := GetWebSocketProxy()
	if wsp == nil {
		result["websocket"] = map[string]interface{}{"enabled": false}
	} else {
		result["websocket"] = wsp.GetStats()
	}

	return result
}

var startTime = time.Now()