package realtime

import (
	"log"
	"net/http"
	"sync"

	"github.com/gorilla/websocket"
)

var upgrader = websocket.Upgrader{
	CheckOrigin: func(r *http.Request) bool {
		// TODO: Restrict origins in production
		return true
	},
}

// Client represents a single WebSocket connection.
type Client struct {
	hub  *Hub
	conn *websocket.Conn
	send chan []byte
}

// Hub manages WebSocket connections and broadcasts.
type Hub struct {
	clients    map[*Client]bool
	broadcast  chan []byte
	register   chan *Client
	unregister chan *Client
	mu         sync.RWMutex
}

// NewHub creates a new Hub instance.
func NewHub() *Hub {
	return &Hub{
		clients:    make(map[*Client]bool),
		broadcast:  make(chan []byte),
		register:   make(chan *Client),
		unregister: make(chan *Client),
	}
}

// Run starts the hub event loop.
func (h *Hub) Run() {
	for {
		select {
		case client := <-h.register:
			h.mu.Lock()
			h.clients[client] = true
			h.mu.Unlock()
			log.Printf("Client connected. Total: %d", len(h.clients))

		case client := <-h.unregister:
			h.mu.Lock()
			if _, ok := h.clients[client]; ok {
				delete(h.clients, client)
				close(client.send)
			}
			h.mu.Unlock()
			log.Printf("Client disconnected. Total: %d", len(h.clients))

		case message := <-h.broadcast:
			h.mu.RLock()
			for client := range h.clients {
				select {
				case client.send <- message:
				default:
					close(client.send)
					delete(h.clients, client)
				}
			}
			h.mu.RUnlock()
		}
	}
}

// Broadcast sends a message to all connected clients.
func (h *Hub) Broadcast(message []byte) {
	h.broadcast <- message
}

// HandleWebSocket upgrades an HTTP connection to WebSocket.
func HandleWebSocket(hub *Hub, w http.ResponseWriter, r *http.Request) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		log.Printf("WebSocket upgrade error: %v", err)
		return
	}

	client := &Client{
		hub:  hub,
		conn: conn,
		send: make(chan []byte, 256),
	}
	hub.register <- client

	go client.writePump()
	go client.readPump()
}

func (c *Client) readPump() {
	defer func() {
		c.hub.unregister <- c
		c.conn.Close()
	}()

	for {
		_, message, err := c.conn.ReadMessage()
		if err != nil {
			if websocket.IsUnexpectedCloseError(err, websocket.CloseGoingAway, websocket.CloseNormalClosure) {
				log.Printf("WebSocket read error: %v", err)
			}
			break
		}
		// TODO: Route messages to appropriate handlers
		log.Printf("Received message: %s", message)
	}
}

func (c *Client) writePump() {
	defer c.conn.Close()

	for message := range c.send {
		if err := c.conn.WriteMessage(websocket.TextMessage, message); err != nil {
			log.Printf("WebSocket write error: %v", err)
			return
		}
	}
}