Added thread-based background ingestion worker

app.py

@@ -1,5 +1,6 @@
 """NotebookLM — AI-Powered Study Companion (Gradio)."""
 
+import threading
 import gradio as gr
 
 from state import (
@@ -42,6 +43,9 @@ from pages.artifacts import (
     has_any_summary,
 )
 
+_INGESTION_LOCK = threading.Lock()
+_INGESTION_RUNNING_NOTEBOOKS: set[str] = set()
+
 
 # ── Helpers ──────────────────────────────────────────────────────────────────
 
@@ -514,6 +518,13 @@ with gr.Blocks(css=CUSTOM_CSS, theme=dark_theme, title="NotebookLM") as demo:
     ).then(fn=None, js=MARK_DIRTY_JS)
 
     # ── Sources: Process pending sources ─────────────────────────────────────
+    def _run_ingestion_background(state: UserData, notebook_id: str):
+        try:
+            run_ingestion_pipeline(state)
+        finally:
+            with _INGESTION_LOCK:
+                _INGESTION_RUNNING_NOTEBOOKS.discard(notebook_id)
+
     def handle_process_sources(state):
         nb = get_active_notebook(state)
         if not nb:
@@ -529,13 +540,26 @@ with gr.Blocks(css=CUSTOM_CSS, theme=dark_theme, title="NotebookLM") as demo:
             )
             return refresh_all(state) + (msg,)
 
-        state, _, _, _ = run_ingestion_pipeline(state)
-        nb_after = get_active_notebook(state)
-        ready_count = sum(1 for s in nb_after.sources if s.status == "ready")
-        failed_count = sum(1 for s in nb_after.sources if s.status == "failed")
+        with _INGESTION_LOCK:
+            if nb.id in _INGESTION_RUNNING_NOTEBOOKS:
+                msg = (
+                    '<p style="font-size:0.82rem; color:#9090a8; margin:6px 0 0 0;">'
+                    'Processing already running for this notebook.'
+                    '</p>'
+                )
+                return refresh_all(state) + (msg,)
+            _INGESTION_RUNNING_NOTEBOOKS.add(nb.id)
+
+        worker = threading.Thread(
+            target=_run_ingestion_background,
+            args=(state, nb.id),
+            daemon=True,
+        )
+        worker.start()
+
         msg = (
             '<p style="font-size:0.82rem; color:#22c55e; margin:6px 0 0 0;">'
-            f'Processing complete: {ready_count} ready, {failed_count} failed.'
+            'Processing started in background. You can switch tabs; return to Sources to check status.'
             '</p>'
         )
         return refresh_all(state) + (msg,)