package monitoring

import (
	"encoding/json"
	"sync"
	"time"

	"github.com/atlasos/calypso/internal/common/logger"
	"github.com/gorilla/websocket"
)

// EventType represents the type of event
type EventType string

const (
	EventTypeAlert      EventType = "alert"
	EventTypeTask       EventType = "task"
	EventTypeSystem     EventType = "system"
	EventTypeStorage    EventType = "storage"
	EventTypeSCST       EventType = "scst"
	EventTypeTape       EventType = "tape"
	EventTypeVTL        EventType = "vtl"
	EventTypeMetrics    EventType = "metrics"
)

// Event represents a system event
type Event struct {
	Type      EventType              `json:"type"`
	Timestamp time.Time              `json:"timestamp"`
	Data      map[string]interface{} `json:"data"`
}

// EventHub manages WebSocket connections and broadcasts events
type EventHub struct {
	clients    map[*websocket.Conn]bool
	broadcast  chan *Event
	register   chan *websocket.Conn
	unregister chan *websocket.Conn
	mu         sync.RWMutex
	logger     *logger.Logger
}

// NewEventHub creates a new event hub
func NewEventHub(log *logger.Logger) *EventHub {
	return &EventHub{
		clients:    make(map[*websocket.Conn]bool),
		broadcast:  make(chan *Event, 256),
		register:   make(chan *websocket.Conn),
		unregister: make(chan *websocket.Conn),
		logger:     log,
	}
}

// Run starts the event hub
func (h *EventHub) Run() {
	for {
		select {
		case conn := <-h.register:
			h.mu.Lock()
			h.clients[conn] = true
			h.mu.Unlock()
			h.logger.Info("WebSocket client connected", "total_clients", len(h.clients))

		case conn := <-h.unregister:
			h.mu.Lock()
			if _, ok := h.clients[conn]; ok {
				delete(h.clients, conn)
				conn.Close()
			}
			h.mu.Unlock()
			h.logger.Info("WebSocket client disconnected", "total_clients", len(h.clients))

		case event := <-h.broadcast:
			h.mu.RLock()
			for conn := range h.clients {
				select {
				case <-time.After(5 * time.Second):
					// Timeout - close connection
					h.mu.RUnlock()
					h.mu.Lock()
					delete(h.clients, conn)
					conn.Close()
					h.mu.Unlock()
					h.mu.RLock()
				default:
					conn.SetWriteDeadline(time.Now().Add(10 * time.Second))
					if err := conn.WriteJSON(event); err != nil {
						h.logger.Error("Failed to send event to client", "error", err)
						h.mu.RUnlock()
						h.mu.Lock()
						delete(h.clients, conn)
						conn.Close()
						h.mu.Unlock()
						h.mu.RLock()
					}
				}
			}
			h.mu.RUnlock()
		}
	}
}

// Broadcast broadcasts an event to all connected clients
func (h *EventHub) Broadcast(eventType EventType, data map[string]interface{}) {
	event := &Event{
		Type:      eventType,
		Timestamp: time.Now(),
		Data:      data,
	}

	select {
	case h.broadcast <- event:
	default:
		h.logger.Warn("Event broadcast channel full, dropping event", "type", eventType)
	}
}

// BroadcastAlert broadcasts an alert event
func (h *EventHub) BroadcastAlert(alert *Alert) {
	data := map[string]interface{}{
		"id":             alert.ID,
		"severity":       alert.Severity,
		"source":         alert.Source,
		"title":          alert.Title,
		"message":        alert.Message,
		"resource_type":  alert.ResourceType,
		"resource_id":    alert.ResourceID,
		"is_acknowledged": alert.IsAcknowledged,
		"created_at":     alert.CreatedAt,
	}
	h.Broadcast(EventTypeAlert, data)
}

// BroadcastTaskUpdate broadcasts a task update event
func (h *EventHub) BroadcastTaskUpdate(taskID string, status string, progress int, message string) {
	data := map[string]interface{}{
		"task_id":  taskID,
		"status":   status,
		"progress":  progress,
		"message":  message,
	}
	h.Broadcast(EventTypeTask, data)
}

// BroadcastMetrics broadcasts metrics update
func (h *EventHub) BroadcastMetrics(metrics *Metrics) {
	data := make(map[string]interface{})
	bytes, _ := json.Marshal(metrics)
	json.Unmarshal(bytes, &data)
	h.Broadcast(EventTypeMetrics, data)
}

// GetClientCount returns the number of connected clients
func (h *EventHub) GetClientCount() int {
	h.mu.RLock()
	defer h.mu.RUnlock()
	return len(h.clients)
}