thu nghiem

server/internal/websocket/websocket.go

@@ -57,18 +57,20 @@ type WsHub struct {
 	students        map[int64]*SocketClient
 	teachers        map[string]*SocketClient
 	teachersByStaff map[uint][]string // staffId -> teacher connection addresses
-	subscribers     map[int64][]string // studentId -> list of teacher connection addresses
+	subscribers     map[int64]map[string]string // studentId -> teacher connection address -> mode ("grid" | "focus")
 	grace           map[int64]offlineGrace
 	graceTimers     map[int64]*time.Timer
+	lastRelay       map[string]time.Time        // studentID:event -> last relay time
 }
 
 var Hub = &WsHub{
 	students:        make(map[int64]*SocketClient),
 	teachers:        make(map[string]*SocketClient),
 	teachersByStaff: make(map[uint][]string),
-	subscribers:     make(map[int64][]string),
+	subscribers:     make(map[int64]map[string]string),
 	grace:           make(map[int64]offlineGrace),
 	graceTimers:     make(map[int64]*time.Timer),
+	lastRelay:       make(map[string]time.Time),
 }
 
 func (h *WsHub) IsStudentOnline(studentRkID int64) bool {
@@ -171,7 +173,7 @@ func (h *WsHub) ForceStudentOffline(studentID int64) {
 	log.Printf("[WS] Student %d force offline (intentional quit/violation)", studentID)
 	h.broadcastPresence(studentID, false, classID)
 	if teachers, exists := h.subscribers[studentID]; exists {
-		for _, tAddr := range teachers {
+		for tAddr := range teachers {
 			if t, found := h.teachers[tAddr]; found {
 				_ = t.WriteJSON(SocketMsg{
 					Event: "teacher:stream-stopped",
@@ -207,7 +209,7 @@ func (h *WsHub) finalizeStudentOffline(studentID int64, classID int64) {
 	h.broadcastPresence(studentID, false, classID)
 
 	if teachers, exists := h.subscribers[studentID]; exists {
-		for _, tAddr := range teachers {
+		for tAddr := range teachers {
 			if t, found := h.teachers[tAddr]; found {
 				_ = t.WriteJSON(SocketMsg{
 					Event: "teacher:stream-stopped",
@@ -256,10 +258,8 @@ func (h *WsHub) Register(c *SocketClient) {
 		h.students[c.StudentID] = c
 		log.Printf("[WS] Student %d registered (Address: %s, Class: %d, reconnectGrace=%v)", c.StudentID, c.Addr, c.ClassID, wasInGrace)
 		h.broadcastPresence(c.StudentID, true, c.ClassID)
-		if subs, exists := h.subscribers[c.StudentID]; exists && len(subs) > 0 {
-			_ = c.WriteJSON(SocketMsg{Event: "start_screenshot_stream"})
-			_ = c.WriteJSON(SocketMsg{Event: "start_webcam_stream"})
-			log.Printf("[WS] Student %d has active subscribers. Sent start stream commands.", c.StudentID)
+		if _, exists := h.subscribers[c.StudentID]; exists {
+			h.updateStudentStreamModeLocked(c.StudentID)
 		}
 	} else if c.Role == "teacher" {
 		h.teachers[c.Addr] = c
@@ -310,66 +310,88 @@ func (h *WsHub) Unregister(c *SocketClient) {
 		}
 		log.Printf("[WS] Teacher %s disconnected", c.Addr)
 
-		for sID, teachersList := range h.subscribers {
-			newList := []string{}
-			for _, addr := range teachersList {
-				if addr != c.Addr {
-					newList = append(newList, addr)
-				}
-			}
-			if len(newList) == 0 {
+		for sID, teachersMap := range h.subscribers {
+			delete(teachersMap, c.Addr)
+			if len(teachersMap) == 0 {
 				delete(h.subscribers, sID)
 				if student, exists := h.students[sID]; exists {
 					_ = student.WriteJSON(SocketMsg{Event: "stop_screenshot_stream"})
 					_ = student.WriteJSON(SocketMsg{Event: "stop_webcam_stream"})
 				}
 			} else {
-				h.subscribers[sID] = newList
+				h.updateStudentStreamModeLocked(sID)
 			}
 		}
 	}
 }
 
-func (h *WsHub) Subscribe(teacherAddr string, studentID int64) {
-	h.mu.Lock()
-	defer h.mu.Unlock()
+func (h *WsHub) updateStudentStreamModeLocked(studentID int64) {
+	student, exists := h.students[studentID]
+	if !exists || student == nil {
+		return
+	}
 
-	teachersList := h.subscribers[studentID]
-	alreadySubscribed := false
-	for _, addr := range teachersList {
-		if addr == teacherAddr {
-			alreadySubscribed = true
+	teachersMap, ok := h.subscribers[studentID]
+	if !ok || len(teachersMap) == 0 {
+		_ = student.WriteJSON(SocketMsg{Event: "stop_screenshot_stream"})
+		_ = student.WriteJSON(SocketMsg{Event: "stop_webcam_stream"})
+		return
+	}
+
+	// Determine effective mode: if any teacher wants "focus", use focus. Otherwise "grid".
+	effectiveMode := "grid"
+	for _, mode := range teachersMap {
+		if mode == "focus" {
+			effectiveMode = "focus"
 			break
 		}
 	}
-	if !alreadySubscribed {
-		h.subscribers[studentID] = append(teachersList, teacherAddr)
-		log.Printf("[WS] Teacher %s subscribed to student %d stream", teacherAddr, studentID)
+
+	intervalMs := 3000 // default for grid
+	if effectiveMode == "focus" {
+		intervalMs = 500 // 500ms for focus view
 	}
 
-	if student, exists := h.students[studentID]; exists {
-		_ = student.WriteJSON(SocketMsg{Event: "start_screenshot_stream"})
-		_ = student.WriteJSON(SocketMsg{Event: "start_webcam_stream"})
+	_ = student.WriteJSON(SocketMsg{
+		Event: "start_screenshot_stream",
+		Data:  map[string]any{"interval": intervalMs},
+	})
+	_ = student.WriteJSON(SocketMsg{
+		Event: "start_webcam_stream",
+		Data:  map[string]any{"interval": intervalMs},
+	})
+	log.Printf("[WS] Updated student %d stream mode to %s (interval: %dms)", studentID, effectiveMode, intervalMs)
+}
+
+func (h *WsHub) Subscribe(teacherAddr string, studentID int64, mode string) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+
+	teachersMap, exists := h.subscribers[studentID]
+	if !exists {
+		teachersMap = make(map[string]string)
+		h.subscribers[studentID] = teachersMap
 	}
+
+	teachersMap[teacherAddr] = mode
+	log.Printf("[WS] Teacher %s subscribed to student %d stream in %s mode", teacherAddr, studentID, mode)
+
+	h.updateStudentStreamModeLocked(studentID)
 }
 
 func (h *WsHub) Unsubscribe(teacherAddr string, studentID int64) {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
-	teachersList, exists := h.subscribers[studentID]
+	teachersMap, exists := h.subscribers[studentID]
 	if !exists {
 		return
 	}
 
-	newList := []string{}
-	for _, addr := range teachersList {
-		if addr != teacherAddr {
-			newList = append(newList, addr)
-		}
-	}
+	delete(teachersMap, teacherAddr)
+	log.Printf("[WS] Teacher %s unsubscribed from student %d stream", teacherAddr, studentID)
 
-	if len(newList) == 0 {
+	if len(teachersMap) == 0 {
 		delete(h.subscribers, studentID)
 		log.Printf("[WS] Student %d has no more proctor subscribers. Stopping streams.", studentID)
 		if student, exists := h.students[studentID]; exists {
@@ -377,20 +399,46 @@ func (h *WsHub) Unsubscribe(teacherAddr string, studentID int64) {
 			_ = student.WriteJSON(SocketMsg{Event: "stop_webcam_stream"})
 		}
 	} else {
-		h.subscribers[studentID] = newList
+		h.updateStudentStreamModeLocked(studentID)
 	}
 }
 
 func (h *WsHub) RelayFrame(studentID int64, event string, data map[string]any) {
-	h.mu.RLock()
-	teachersList, exists := h.subscribers[studentID]
-	if !exists || len(teachersList) == 0 {
-		h.mu.RUnlock()
+	h.mu.Lock()
+	teachersMap, exists := h.subscribers[studentID]
+	if !exists || len(teachersMap) == 0 {
+		h.mu.Unlock()
 		return
 	}
-	addrs := make([]string, len(teachersList))
-	copy(addrs, teachersList)
-	h.mu.RUnlock()
+
+	// Compute effective mode/interval
+	effectiveMode := "grid"
+	for _, mode := range teachersMap {
+		if mode == "focus" {
+			effectiveMode = "focus"
+			break
+		}
+	}
+
+	minInterval := 3000 * time.Millisecond
+	if effectiveMode == "focus" {
+		minInterval = 500 * time.Millisecond
+	}
+
+	relayKey := strconv.FormatInt(studentID, 10) + ":" + event
+	lastTime := h.lastRelay[relayKey]
+	now := time.Now()
+	if now.Sub(lastTime) < minInterval {
+		h.mu.Unlock()
+		return
+	}
+	h.lastRelay[relayKey] = now
+
+	addrs := make([]string, 0, len(teachersMap))
+	for addr := range teachersMap {
+		addrs = append(addrs, addr)
+	}
+	h.mu.Unlock()
 
 	relayEvent := "teacher:screenshot-stream-frame"
 	if event == "webcam_stream_frame" {
@@ -519,8 +567,12 @@ func WebSocketHandler(db *gorm.DB) func(*websocket.Conn) {
 						case string:
 							sID, _ = strconv.ParseInt(v, 10, 64)
 						}
+						mode, _ := msg.Data["mode"].(string)
+						if mode == "" {
+							mode = "focus"
+						}
 						if sID > 0 {
-							Hub.Subscribe(client.Addr, sID)
+							Hub.Subscribe(client.Addr, sID, mode)
 						}
 					}
 				}