package ws

import (
	"net/http"
	"strconv"
	"sync"

	"github.com/gofiber/fiber/v2"
	"github.com/gorilla/websocket"
	"github.com/valyala/fasthttp"
	"github.com/valyala/fasthttp/fasthttpadaptor"
)

type Client struct {
	Conn        *websocket.Conn
	RecipientID int64
}

type NotificationHub struct {
	Clients    map[*Client]bool
	Broadcast  chan interface{}
	Register   chan *Client
	Unregister chan *Client
	mu         sync.Mutex
}

func NewNotificationHub() *NotificationHub {
	return &NotificationHub{
		Clients:    make(map[*Client]bool),
		Broadcast:  make(chan interface{}, 1000),
		Register:   make(chan *Client),
		Unregister: make(chan *Client),
	}
}

func (h *NotificationHub) Run() {
	for {
		select {
		case client := <-h.Register:
			h.mu.Lock()
			h.Clients[client] = true
			h.mu.Unlock()
		case client := <-h.Unregister:
			h.mu.Lock()
			if _, ok := h.Clients[client]; ok {
				delete(h.Clients, client)
				client.Conn.Close()
			}
			h.mu.Unlock()
		case message := <-h.Broadcast:
			h.mu.Lock()
			for client := range h.Clients {
				if payload, ok := message.(map[string]interface{}); ok {
					if recipient, ok := payload["recipient_id"].(int64); ok && recipient == client.RecipientID {
						err := client.Conn.WriteJSON(payload)
						if err != nil {
							delete(h.Clients, client)
							client.Conn.Close()
						}
					}
				}
			}
			h.mu.Unlock()
		}
	}
}

var Upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

type responseWriterWrapper struct {
	ctx    *fasthttp.RequestCtx
	header http.Header
	wrote  bool
}

func newResponseWriterWrapper(ctx *fasthttp.RequestCtx) *responseWriterWrapper {
	return &responseWriterWrapper{
		ctx:    ctx,
		header: make(http.Header),
	}
}

func (rw *responseWriterWrapper) Header() http.Header {
	return rw.header
}

func (rw *responseWriterWrapper) Write(b []byte) (int, error) {
	rw.writeHeaderIfNeeded(http.StatusOK)
	return rw.ctx.Write(b)
}

func (rw *responseWriterWrapper) WriteHeader(statusCode int) {
	if rw.wrote {
		return
	}
	rw.writeHeaderIfNeeded(statusCode)
}

func (rw *responseWriterWrapper) writeHeaderIfNeeded(statusCode int) {
	if rw.wrote {
		return
	}
	rw.wrote = true

	// Copy headers from rw.header to fasthttp.Response.Header
	for k, vv := range rw.header {
		for _, v := range vv {
			rw.ctx.Response.Header.Add(k, v)
		}
	}

	rw.ctx.SetStatusCode(statusCode)
}

// ✅ WebSocketHandler integrates Gorilla WebSocket with Fiber
func (h *NotificationHub) WebSocketHandler() fiber.Handler {
	return func(c *fiber.Ctx) error {
		userIDStr := c.Params("user_id")
		userID, err := strconv.ParseInt(userIDStr, 10, 64)
		if err != nil {
			return c.Status(fiber.StatusBadRequest).SendString("Invalid user ID")
		}

		// Use your custom responseWriterWrapper here
		rw := newResponseWriterWrapper(c.Context())

		stdReq := new(http.Request)
		if err := fasthttpadaptor.ConvertRequest(c.Context(), stdReq, true); err != nil {
			return err
		}

		conn, err := Upgrader.Upgrade(rw, stdReq, nil)
		if err != nil {
			return err
		}

		client := &Client{
			Conn:        conn,
			RecipientID: userID,
		}

		h.Register <- client
		defer func() {
			h.Unregister <- client
		}()

		for {
			if _, _, err := conn.ReadMessage(); err != nil {
				break
			}
		}

		return nil
	}
}

// func (h *NotificationHub) BroadcastWalletUpdate(userID int64, event event.WalletEvent) {
// 	payload := map[string]interface{}{
// 		"type":         event.EventType,
// 		"wallet_id":    event.WalletID,
// 		"wallet_type":  event.WalletType,
// 		"user_id":      event.UserID,
// 		"balance":      event.Balance,
// 		"trigger":      event.Trigger,
// 		"recipient_id": userID,
// 	}
// 	h.Broadcast <- payload
// }