package ws

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

// FirmwareProgressHandler — M9-4 hot-fix。
//
// 對稱於 FlashProgressHandler。Client 連 /ws/devices/:id/firmware-progress
// 後會被 join 到 room "firmware:<deviceID>"，由
// firmware_handler.forwardProgressToWS 透過 hub.BroadcastToRoom 推進度。
//
// 行為與 flash 版完全一致：
//   - 共用 package-level upgrader（CheckOrigin = loopback 白名單，見 device_events_ws.go）
//   - 用 RegisterSync 確保 client 已 join room 才回到 read/write loop
//   - 一個 goroutine drain client 端 incoming 訊息（純為觸發斷線偵測）
//   - 主 goroutine 把 client.Send channel 的訊息 WriteMessage 到 conn
//   - conn / unregister 統一由 defer 處理
func FirmwareProgressHandler(hub *Hub) gin.HandlerFunc {
	return func(c *gin.Context) {
		deviceID := c.Param("id")
		conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
		if err != nil {
			return
		}
		defer conn.Close()

		client := &Client{Conn: conn, Send: make(chan []byte, 20)}
		room := "firmware:" + deviceID
		sub := &Subscription{Client: client, Room: room}
		hub.RegisterSync(sub)
		defer hub.Unregister(sub)

		// Read pump — drain incoming messages; close handled by outer defer
		go func() {
			for {
				if _, _, err := conn.ReadMessage(); err != nil {
					break
				}
			}
		}()

		for msg := range client.Send {
			if err := conn.WriteMessage(websocket.TextMessage, msg); err != nil {
				return
			}
		}
	}
}