Fix race condition in progress tracking EventSource

- Add debugging logs to progress stream endpoint
- Create placeholder session when EventSource connects before API call
- Prevents 404 errors when EventSource tries to connect to non-existent session
- Ensures progress tracking works correctly even with timing issues

This fixes the issue where UI remained stuck on 'TradingView Authentication'
even though backend was correctly progressing through all steps.

app/api/progress/[sessionId]/stream/route.ts

@@ -7,35 +7,50 @@ export async function GET(
 ) {
   const { sessionId } = await params
 
+  console.log(`🔍 [STREAM] Starting EventSource stream for session: ${sessionId}`)
+  console.log(`🔍 [STREAM] Current active sessions:`, progressTracker.getActiveSessions())
+
   // Create a readable stream for Server-Sent Events
   const encoder = new TextEncoder()
   
   const stream = new ReadableStream({
     start(controller) {
-      console.log(`🔍 Starting EventSource stream for session: ${sessionId}`)
+      console.log(`🔍 [STREAM] Stream controller started for session: ${sessionId}`)
       
       // Send initial progress if session exists
       const initialProgress = progressTracker.getProgress(sessionId)
       if (initialProgress) {
-        console.log(`🔍 Sending initial progress for ${sessionId}:`, initialProgress.currentStep)
+        console.log(`🔍 [STREAM] Sending initial progress for ${sessionId}:`, initialProgress.currentStep)
         const data = `data: ${JSON.stringify(initialProgress)}\n\n`
         controller.enqueue(encoder.encode(data))
       } else {
-        // Send a connection established message even if no progress yet
+        console.log(`🔍 [STREAM] No initial progress found for ${sessionId}, creating placeholder session`)
+        // Create a placeholder session if it doesn't exist to handle race condition
+        const placeholderSteps = [
+          { id: 'init', title: 'Initializing Analysis', description: 'Starting AI-powered trading analysis...', status: 'pending' as const },
+          { id: 'auth', title: 'TradingView Authentication', description: 'Logging into TradingView accounts', status: 'pending' as const },
+          { id: 'navigation', title: 'Chart Navigation', description: 'Navigating to chart layouts', status: 'pending' as const },
+          { id: 'loading', title: 'Chart Data Loading', description: 'Waiting for chart data and indicators', status: 'pending' as const },
+          { id: 'capture', title: 'Screenshot Capture', description: 'Capturing high-quality screenshots', status: 'pending' as const },
+          { id: 'analysis', title: 'AI Analysis', description: 'Analyzing screenshots with AI', status: 'pending' as const }
+        ]
+        progressTracker.createSession(sessionId, placeholderSteps)
+        
+        // Send a connection established message
         const connectMsg = `data: ${JSON.stringify({ type: 'connected', sessionId })}\n\n`
         controller.enqueue(encoder.encode(connectMsg))
       }
 
       // Listen for progress updates
       const progressHandler = (progress: any) => {
-        console.log(`🔍 Streaming progress update for ${sessionId}:`, progress.currentStep)
+        console.log(`🔍 [STREAM] Streaming progress update for ${sessionId}:`, progress.currentStep)
         const data = `data: ${JSON.stringify(progress)}\n\n`
         controller.enqueue(encoder.encode(data))
       }
 
       // Listen for completion
       const completeHandler = () => {
-        console.log(`🔍 Streaming completion for ${sessionId}`)
+        console.log(`🔍 [STREAM] Streaming completion for ${sessionId}`)
         const data = `data: ${JSON.stringify({ type: 'complete' })}\n\n`
         controller.enqueue(encoder.encode(data))
         controller.close()
@@ -45,8 +60,11 @@ export async function GET(
       progressTracker.on(`progress:${sessionId}`, progressHandler)
       progressTracker.on(`progress:${sessionId}:complete`, completeHandler)
 
+      console.log(`🔍 [STREAM] Event listeners registered for ${sessionId}`)
+
       // Cleanup on stream close
       request.signal.addEventListener('abort', () => {
+        console.log(`🔍 [STREAM] Stream aborted for ${sessionId}`)
         progressTracker.off(`progress:${sessionId}`, progressHandler)
         progressTracker.off(`progress:${sessionId}:complete`, completeHandler)
         controller.close()