Update app.py

app.py

@@ -1,23 +1,27 @@
 import gradio as gr
 
-def greet(name):
-    return "Hello " + name + "!!"
+class GUI:
+    def __init__(self, params):
+        with gr.Blocks() as demo:
+            with gr.Row():
+                gr.LoginButton()
+                self.l_o_btn = gr.LogoutButton(visible=False)
+            self.inp = gr.File(file_types=['.epub'], visible=False)
+            self.out = gr.Markdown().attach_load_event(self.hello, None)
+            inp.change(self.hello, self.inp, self.out)
+        
+        demo.launch()
 
+    def greet(self, name):
+        return "Hello " + name + "!!"
 
-def hello(profile: gr.OAuthProfile | None):
-    if profile is None:
-        return gr.Markdown(
-            '# ePub summarization tool  '
-            '<p style="text-align: center;">Login to access the tool.</p>'
-        )
-    return f"Hello {profile.name}"
-
-
-with gr.Blocks() as demo:
-    with gr.Row():
-        gr.LoginButton()
-        gr.LogoutButton()
-    gr.File()
-    gr.Markdown().attach_load_event(hello, None)
-
-demo.launch()
+    def hello(self, profile: gr.OAuthProfile | None):
+        if profile is None:
+            return (
+                '# ePub summarization tool  '
+                '<p style="text-align: center;">Login to access the tool.</p>'
+            )
+        self.l_o_btn.update(visible=True)
+        self.inp.update(visible=True)
+        return self.greet(profile.name)
+