logistics_support_tool/backend/internal/notifications/ws/ws_handler.go

package ws

import (
	"encoding/json"
	"log"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/gorilla/websocket"
)

type JoinPayload struct {
	Channel  string   `json:"channel"`
	APIKey   string   `json:"apiKey"`
	Services []string `json:"services,omitempty"`
	Levels   []string `json:"levels,omitempty"`
	Labels   []string `json:"labels,omitempty"`
}

var upgrader = websocket.Upgrader{
	CheckOrigin:       func(r *http.Request) bool { return true }, // allow all origins; customize for prod
	HandshakeTimeout:  15 * time.Second,
	ReadBufferSize:    1024,
	WriteBufferSize:   1024,
	EnableCompression: true,
}

func SocketHandler(c *gin.Context, channels map[string]*Channel) {
	// Upgrade HTTP to WebSocket
	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
	if err != nil {
		log.Println("WebSocket upgrade failed:", err)
		return
	}
	//defer conn.Close()

	// Create new client
	client := &Client{
		Conn:      conn,
		APIKey:    "exampleAPIKey",
		Send:      make(chan []byte, 256), // Buffered channel
		Channels:  make(map[string]bool),
		IPAddress: c.ClientIP(),
		UserAgent: c.Request.UserAgent(),
		done:      make(chan struct{}),
	}

	client.isAlive.Store(true)
	// Add to global clients map
	clientsMu.Lock()
	clients[client] = true
	clientsMu.Unlock()

	// Save initial connection to DB
	client.SaveToDB()
	// Save initial connection to DB
	// if err := client.SaveToDB(); err != nil {
	// 	log.Println("Failed to save client to DB:", err)
	// 	conn.Close()
	// 	return
	// }

	// Set handlers
	conn.SetPingHandler(func(string) error {
		return nil // Auto-responds with pong
	})

	conn.SetPongHandler(func(string) error {
		now := time.Now()
		client.markActive() // Track last pong time
		client.lastActive = now
		client.updateHeartbeat()
		return nil
	})

	// Start server-side ping ticker
	go client.startServerPings()

	defer func() {
		// Unregister from all channels
		for channelName := range client.Channels {
			if ch, exists := channels[channelName]; exists {
				ch.Unregister <- client
			}
		}

		// Remove from global clients map
		clientsMu.Lock()
		delete(clients, client)
		clientsMu.Unlock()

		// Mark disconnected in DB
		client.MarkDisconnected()

		// Close connection
		conn.Close()
		log.Printf("Client disconnected: %s", client.ClientID)
	}()

	// Send welcome message immediately
	welcomeMsg := map[string]string{
		"status":  "connected",
		"message": "Welcome to the WebSocket server. Send subscription request to begin.",
	}
	if err := conn.WriteJSON(welcomeMsg); err != nil {
		log.Println("Failed to send welcome message:", err)
		return
	}

	// Message handling goroutine
	go func() {
		defer func() {
			// Cleanup on disconnect
			for channelName := range client.Channels {
				if ch, exists := channels[channelName]; exists {
					ch.Unregister <- client
				}
			}
			close(client.Send)
			client.MarkDisconnected()
		}()

		for {
			_, msg, err := conn.ReadMessage()
			if err != nil {
				if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway) {
					log.Printf("Client disconnected unexpectedly: %v", err)
				}
				break
			}

			var payload struct {
				Channel  string   `json:"channel"`
				APIKey   string   `json:"apiKey"`
				Services []string `json:"services,omitempty"`
				Levels   []string `json:"levels,omitempty"`
				Labels   []string `json:"labels,omitempty"`
			}

			if err := json.Unmarshal(msg, &payload); err != nil {
				conn.WriteJSON(map[string]string{"error": "invalid payload format"})
				continue
			}

			// Validate API key (implement your own validateAPIKey function)
			// if payload.APIKey == "" || !validateAPIKey(payload.APIKey) {
			// 	conn.WriteJSON(map[string]string{"error": "invalid or missing API key"})
			// 	continue
			// }

			if payload.APIKey == "" {
				conn.WriteMessage(websocket.TextMessage, []byte("Missing API Key"))
				continue
			}
			client.APIKey = payload.APIKey

			// Handle channel subscription
			switch payload.Channel {
			case "logServices":
				// Unregister from other channels if needed
				if client.Channels["labels"] {
					channels["labels"].Unregister <- client
					delete(client.Channels, "labels")
				}

				// Update client filters
				client.Services = payload.Services
				client.LogLevels = payload.Levels

				// Register to channel
				channels["logServices"].Register <- client
				client.Channels["logServices"] = true

				conn.WriteJSON(map[string]string{
					"status":  "subscribed",
					"channel": "logServices",
				})

			case "labels":
				// Unregister from other channels if needed
				if client.Channels["logServices"] {
					channels["logServices"].Unregister <- client
					delete(client.Channels, "logServices")
				}

				// Set label filters if provided
				if payload.Labels != nil {
					client.Labels = payload.Labels
				}

				// Register to channel
				channels["labels"].Register <- client
				client.Channels["labels"] = true

				// Update DB record
				client.SaveToDB()
				// if err := client.SaveToDB(); err != nil {
				// 	log.Println("Failed to update client labels:", err)
				// }

				conn.WriteJSON(map[string]interface{}{
					"status":  "subscribed",
					"channel": "labels",
					"filters": client.Labels,
				})

			default:
				conn.WriteJSON(map[string]string{
					"error":              "invalid channel",
					"available_channels": "logServices, labels",
				})
			}
		}
	}()

	// Send messages to client
	for message := range client.Send {
		if err := conn.WriteMessage(websocket.TextMessage, message); err != nil {
			log.Println("Write error:", err)
			break
		}
	}
}