big update: added reactions, groups, media share

server/internal/realtime/hub.go

@@ -84,6 +84,67 @@ func (h *Hub) PublishRead(conversationID, userID, messageID int64) {
 	h.sendToConversation(conversationID, envelope{Type: EventRead, Data: mustMarshal(evt)}, userID)
 }
 
+// Subscribe adds a user to a conversation's subscriber set so they receive its
+// events without reconnecting (used when a member is added to a group).
+func (h *Hub) Subscribe(userID, conversationID int64) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	if h.subs[conversationID] == nil {
+		h.subs[conversationID] = make(map[int64]struct{})
+	}
+	h.subs[conversationID][userID] = struct{}{}
+}
+
+// Unsubscribe removes a user from a conversation's subscriber set.
+func (h *Hub) Unsubscribe(userID, conversationID int64) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	users := h.subs[conversationID]
+	delete(users, userID)
+	if len(users) == 0 {
+		delete(h.subs, conversationID)
+	}
+}
+
+// SendToUser delivers an event to every connection of a single user.
+func (h *Hub) SendToUser(userID int64, evtType string, data any) {
+	payload, err := json.Marshal(envelope{Type: evtType, Data: mustMarshal(data)})
+	if err != nil {
+		slog.Error("ws: marshal direct event", "error", err)
+		return
+	}
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	for c := range h.conns[userID] {
+		c.enqueueRaw(payload)
+	}
+}
+
+// PublishMemberChanged tells a conversation's members that someone joined or left.
+func (h *Hub) PublishMemberChanged(conversationID, userID int64, added bool) {
+	evtType := EventMemberAdded
+	if !added {
+		evtType = EventMemberRemoved
+	}
+	evt := MemberChanged{ConversationID: conversationID, UserID: userID}
+	h.sendToConversation(conversationID, envelope{Type: evtType, Data: mustMarshal(evt)}, 0)
+}
+
+// PublishReactionChanged tells a conversation's members that a reaction changed.
+func (h *Hub) PublishReactionChanged(conversationID, messageID, userID int64, emoji string, added bool) {
+	evtType := EventReactionAdded
+	if !added {
+		evtType = EventReactionRemoved
+	}
+	evt := ReactionChanged{
+		ConversationID: conversationID,
+		MessageID:      messageID,
+		UserID:         userID,
+		Emoji:          emoji,
+	}
+	h.sendToConversation(conversationID, envelope{Type: evtType, Data: mustMarshal(evt)}, 0)
+}
+
 func (h *Hub) register(c *client, conversationIDs []int64) {
 	h.mu.Lock()
 	defer h.mu.Unlock()