when new user connected should rebroadcast the graph data

web/app/components/workflow/collaboration/core/collaboration-manager.ts

@@ -35,6 +35,7 @@ export class CollaborationManager {
   private nodePanelPresence: NodePanelPresenceMap = {}
   private activeConnections = new Set<string>()
   private isUndoRedoInProgress = false
+  private pendingInitialSync = false
 
   private getNodePanelPresenceSnapshot(): NodePanelPresenceMap {
     const snapshot: NodePanelPresenceMap = {}
@@ -741,6 +742,8 @@ export class CollaborationManager {
               .map(node => node.id),
           )
 
+          this.pendingInitialSync = false
+
           const updatedNodes = Array
             .from(this.nodesMap.values())
             .map((node: Node) => {
@@ -790,6 +793,8 @@ export class CollaborationManager {
           const updatedEdges = Array.from(this.edgesMap.values())
           console.log('Updating React edges from subscription')
 
+          this.pendingInitialSync = false
+
           // Call ReactFlow's native setter directly to avoid triggering collaboration
           state.setEdges(updatedEdges)
         })
@@ -852,6 +857,11 @@ export class CollaborationManager {
           this.eventEmitter.emit('syncRequest', {})
         }
       }
+      else if (update.type === 'graph_resync_request') {
+        console.log('Received graph resync request from collaborator')
+        if (this.isLeader)
+          this.broadcastCurrentGraph()
+      }
     })
 
     socket.on('online_users', (data: { users: OnlineUser[]; leader?: string }) => {
@@ -898,6 +908,11 @@ export class CollaborationManager {
         const wasLeader = this.isLeader
         this.isLeader = data.isLeader
 
+        if (this.isLeader)
+          this.pendingInitialSync = false
+        else
+          this.requestInitialSyncIfNeeded()
+
         if (wasLeader !== this.isLeader)
           this.eventEmitter.emit('leaderChange', this.isLeader)
       }
@@ -912,6 +927,10 @@ export class CollaborationManager {
         console.log(`Collaboration: I am now the ${this.isLeader ? 'Leader' : 'Follower'}.`)
         this.eventEmitter.emit('leaderChange', this.isLeader)
       }
+      if (this.isLeader)
+        this.pendingInitialSync = false
+      else
+        this.requestInitialSyncIfNeeded()
     })
 
     socket.on('status', (data: { isLeader: boolean }) => {
@@ -920,11 +939,16 @@ export class CollaborationManager {
         console.log(`Collaboration: I am now the ${this.isLeader ? 'Leader' : 'Follower'}.`)
         this.eventEmitter.emit('leaderChange', this.isLeader)
       }
+      if (this.isLeader)
+        this.pendingInitialSync = false
+      else
+        this.requestInitialSyncIfNeeded()
     })
 
     socket.on('connect', () => {
       console.log('WebSocket connected successfully')
       this.eventEmitter.emit('stateChange', { isConnected: true })
+      this.pendingInitialSync = true
     })
 
     socket.on('disconnect', (reason: string) => {
@@ -932,6 +956,7 @@ export class CollaborationManager {
       this.cursors = {}
       this.isLeader = false
       this.leaderId = null
+      this.pendingInitialSync = false
       this.eventEmitter.emit('stateChange', { isConnected: false })
       this.eventEmitter.emit('cursors', {})
     })
@@ -945,6 +970,49 @@ export class CollaborationManager {
       console.error('WebSocket error:', error)
     })
   }
+
+  // We currently only relay CRDT updates; the server doesn't persist them.
+  // When a follower joins mid-session, it might miss earlier broadcasts and render stale data.
+  // This lightweight checkpoint asks the leader to rebroadcast the latest graph snapshot once.
+  private requestInitialSyncIfNeeded(): void {
+    if (!this.pendingInitialSync) return
+    if (this.isLeader) {
+      this.pendingInitialSync = false
+      return
+    }
+
+    this.emitGraphResyncRequest()
+    this.pendingInitialSync = false
+  }
+
+  private emitGraphResyncRequest(): void {
+    if (!this.currentAppId || !webSocketClient.isConnected(this.currentAppId)) return
+
+    const socket = webSocketClient.getSocket(this.currentAppId)
+    if (!socket) return
+
+    socket.emit('collaboration_event', {
+      type: 'graph_resync_request',
+      data: { timestamp: Date.now() },
+      timestamp: Date.now(),
+    })
+  }
+
+  private broadcastCurrentGraph(): void {
+    if (!this.currentAppId || !webSocketClient.isConnected(this.currentAppId)) return
+    if (!this.doc) return
+
+    const socket = webSocketClient.getSocket(this.currentAppId)
+    if (!socket) return
+
+    try {
+      const snapshot = this.doc.export({ mode: 'snapshot' })
+      socket.emit('graph_event', snapshot)
+    }
+    catch (error) {
+      console.error('Failed to broadcast graph snapshot:', error)
+    }
+  }
 }
 
 export const collaborationManager = new CollaborationManager()