package broker

import (
	"context"
	"net"
	"net/http"

	"git.asio.asia/nixevol/NixMsg/internal/listener"
	"github.com/coder/websocket"
)

// WSHandler 返回 /mqtt 的 WebSocket 升级处理。
// Accept 时 InsecureSkipVerify=true；之后检查 Subprotocol==mqtt。
// NetConn 使用 Background 派生的 context，不用请求 Context。
func (b *Broker) WSHandler(proxies *listener.ProxySet) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		c, err := websocket.Accept(w, r, &websocket.AcceptOptions{
			Subprotocols:       []string{"mqtt"},
			InsecureSkipVerify: true,
		})
		if err != nil {
			return
		}
		if c.Subprotocol() != "mqtt" {
			_ = c.Close(websocket.StatusPolicyViolation, "subprotocol must be mqtt")
			return
		}

		ctx, cancel := context.WithCancel(context.Background())
		defer cancel()

		nc := websocket.NetConn(ctx, c, websocket.MessageBinary)
		if proxies != nil {
			ip := proxies.ClientIP(r)
			if ip != "" {
				nc = listener.WithRemoteAddr(nc, &net.TCPAddr{IP: net.ParseIP(ip)})
			}
		}
		_ = b.AttachWS(nc)
	})
}