Update app.py

app.py

@@ -1,102 +1,217 @@
 import streamlit as st
 import requests
+import os
 
-# ✅ HF-safe same-origin routing
-BACKEND_URL = ""
+# Backend URL (change if deployed)
+BACKEND_URL = "http://localhost:8000"
 
 st.set_page_config(page_title="PDF Assistant", page_icon="📘", layout="wide")
 
-# ---------------- CSS ----------------
+# ---------------- CSS (Dark Theme) ----------------
+# FIX: Added CSS for the footer
 st.markdown("""
 <style>
+/* Streamlit standard setup for dark theme adherence */
+:root {
+    --primary-color: #1e3a8a; /* Blue for highlights */
+    --background-color: #0e1117;
+    --secondary-background-color: #1a1d29;
+    --text-color: #f0f2f6;
+}
+
+/* Custom Chat Bubbles */
 .chat-user {
-    background: #2d3748;
+    background: #2d3748; /* Dark gray */
     padding: 12px;
-    border-radius: 10px;
+    border-radius: 10px 10px 2px 10px; /* Rounded corners for chat bubble */
+    margin: 6px 0 6px auto;
+    max-width: 85%;
     text-align: right;
+    color: var(--text-color);
 }
 .chat-bot {
-    background: #1e3a8a;
+    background: var(--primary-color); /* Primary blue */
     padding: 12px;
-    border-radius: 10px;
-    color: white;
+    border-radius: 10px 10px 10px 2px;
+    margin: 6px auto 6px 0;
+    max-width: 85%;
+    text-align: left;
+    color: #ffffff; /* White text for contrast */
 }
+
+/* Sources section styling */
 .sources {
     font-size: 0.8em;
     opacity: 0.7;
+    margin-top: 10px;
+    border-top: 1px solid rgba(255, 255, 255, 0.1);
+    padding-top: 5px;
+}
+
+/* Footer styling */
+.footer {
+    position: fixed;
+    left: 0;
+    bottom: 0;
+    width: 100%;
+    background-color: var(--secondary-background-color);
+    color: var(--text-color);
+    text-align: center;
+    padding: 10px;
+    font-size: 0.85em;
+    border-top: 1px solid rgba(255, 255, 255, 0.1);
+}
+.footer a {
+    color: var(--primary-color);
+    text-decoration: none;
+    font-weight: bold;
+}
+.footer a:hover {
+    text-decoration: underline;
 }
 </style>
 """, unsafe_allow_html=True)
 
-# ---------------- STATE ----------------
+# ---------------- SESSION STATE ----------------
 if "chat" not in st.session_state:
     st.session_state.chat = []
-if "pdf" not in st.session_state:
-    st.session_state.pdf = None
+
+if "uploaded_file_name" not in st.session_state:
+    st.session_state.uploaded_file_name = None
+
+# Add a key to the file uploader to allow it to be reset.
 if "uploader_key" not in st.session_state:
     st.session_state.uploader_key = 0
 
+# FIX 1: Change application name
 st.title("📘 PDF Assistant")
 
+
 # ---------------- FUNCTIONS ----------------
-def clear_memory():
-    requests.post(f"{BACKEND_URL}/api/clear")
+def clear_chat_history():
+    """Clears the chat history in the session state."""
     st.session_state.chat = []
-    st.session_state.pdf = None
-    st.session_state.uploader_key += 1
-    st.success("Memory cleared")
 
 
-# ---------------- SIDEBAR ----------------
+def clear_memory():
+    """Calls the backend endpoint to clear loaded PDF data and resets UI state."""
+    res = requests.post(f"{BACKEND_URL}/clear")
+    if res.status_code == 200:
+        st.session_state.uploaded_file_name = None
+        # Increment the key of the file uploader to clear its value
+        st.session_state.uploader_key += 1
+        st.success("Memory cleared. Please upload a new PDF.")
+    else:
+        st.error(f"Failed to clear memory: {res.json().get('detail', 'Unknown error')}")
+    # Removed st.rerun() to prevent "no-op" warning
+
+
+# ---------------- SIDEBAR CONTROLS ----------------
 with st.sidebar:
-    st.button("🔥 Clear PDF Memory", on_click=clear_memory)
+    st.header("Controls")
+    st.button("🗑️ Clear Chat History", on_click=clear_chat_history, use_container_width=True)
+    st.button("🔥 Clear PDF Memory", on_click=clear_memory, use_container_width=True)
+
+    st.markdown("---")
+    if st.session_state.uploaded_file_name:
+        st.success(f"✅ **Active PDF:**\n `{st.session_state.uploaded_file_name}`")
+    else:
+        st.warning("⬆️ Upload a PDF to start chatting!")
 
-# ---------------- UPLOAD ----------------
+# ---------------- UPLOAD PDF ----------------
+# Use the dynamic key for the file uploader.
 uploaded = st.file_uploader(
-    "Upload PDF",
+    "Upload your PDF",
     type=["pdf"],
-    key=st.session_state.uploader_key
+    key=st.session_state.uploader_key # Use the dynamic key
 )
 
-if uploaded and uploaded.name != st.session_state.pdf:
-    with st.spinner("Processing PDF..."):
-        files = {"file": (uploaded.name, uploaded.getvalue(), "application/pdf")}
-        res = requests.post(f"{BACKEND_URL}/api/upload", files=files)
-
-        if res.status_code == 200:
-            st.session_state.pdf = uploaded.name
-            st.success("PDF processed")
-        else:
-            st.error(res.text)
-
+# Only process if a file is uploaded AND it's a NEW file
+if uploaded and uploaded.name != st.session_state.uploaded_file_name:
+    st.session_state.uploaded_file_name = None  # Clear status while processing
+    st.session_state.chat = []  # Clear chat for a new document
+
+    with st.spinner(f"Processing '{uploaded.name}'..."):
+        try:
+            files = {"file": (uploaded.name, uploaded.getvalue(), "application/pdf")}
+            res = requests.post(f"{BACKEND_URL}/upload", files=files)
+
+            if res.status_code == 200:
+                chunks = res.json().get("chunks", 0)
+                st.success(f"PDF processed successfully! {chunks} chunks created.")
+                st.session_state.uploaded_file_name = uploaded.name
+            else:
+                error_msg = res.json().get("detail", "Unknown error during processing.")
+                st.error(f"Upload failed: {error_msg}")
+                st.session_state.uploaded_file_name = None
+
+        except requests.exceptions.ConnectionError:
+            st.error(f"Could not connect to the backend server at {BACKEND_URL}. Ensure it is running.")
+            st.session_state.uploaded_file_name = None
+        except Exception as e:
+            st.error(f"An unexpected error occurred: {e}")
+            st.session_state.uploaded_file_name = None
+
+    # Rerun the app to update the UI status immediately
     st.rerun()
 
-# ---------------- CHAT ----------------
+# ---------------- CHAT INPUT ----------------
+# Disable input field if no PDF is loaded
+disabled_input = st.session_state.uploaded_file_name is None
 question = st.text_input(
-    "Ask a question",
-    disabled=st.session_state.pdf is None
+    "Ask a question about the loaded PDF:",
+    key="question_input",
+    disabled=disabled_input
 )
 
-if st.button("Send") and question:
+if st.button("Send", disabled=disabled_input) and question:
+    # 1. Add user query to chat history
     st.session_state.chat.append(("user", question))
 
-    res = requests.post(
-        f"{BACKEND_URL}/api/ask",
-        json={"question": question}
-    )
+    # 2. Call backend
+    with st.spinner("Thinking..."):
+        try:
+            res = requests.post(f"{BACKEND_URL}/ask", json={"question": question})
 
-    if res.status_code == 200:
-        data = res.json()
-        msg = f"{data['answer']}<div class='sources'>Chunks used: {data['sources']}</div>"
-        st.session_state.chat.append(("bot", msg))
-    else:
-        st.session_state.chat.append(("bot", "Error"))
+            if res.status_code == 200:
+                data = res.json()
+                answer = data.get("answer", "No answer provided.")
+                sources = data.get("sources", 0)
+
+                # Format the bot's response to include source count
+                bot_message = f"{answer}<div class='sources'>Context Chunks Used: {sources}</div>"
+                st.session_state.chat.append(("bot", bot_message))
+
+            else:
+                error_detail = res.json().get("detail", "Error while generating answer.")
+                st.session_state.chat.append(("bot", f"🔴 **Error:** {error_detail}"))
 
+        except requests.exceptions.ConnectionError:
+            st.session_state.chat.append(("bot",
+                                          f"🔴 **Error:** Could not connect to the backend server at {BACKEND_URL}. Ensure it is running."))
+        except Exception as e:
+            st.session_state.chat.append(("bot", f"🔴 **An unexpected error occurred:** {e}"))
+
+    # Rerun to display the updated chat history
     st.rerun()
 
-# ---------------- CHAT HISTORY ----------------
+# ---------------- SHOW CHAT HISTORY ----------------
+st.markdown("## Chat History")
+# Reverse the list to show the latest messages at the bottom
 for role, msg in st.session_state.chat:
     if role == "user":
         st.markdown(f"<div class='chat-user'>{msg}</div>", unsafe_allow_html=True)
     else:
+        # Bot message includes the source count, so use the HTML content
         st.markdown(f"<div class='chat-bot'>{msg}</div>", unsafe_allow_html=True)
+
+# ---------------- FOOTER (Creator Credit) ----------------
+# FIX 2: Add creator credit with LinkedIn link
+footer_html = """
+<div class="footer">
+    Created by <a href="https://www.linkedin.com/in/abhishek-iitr/" target="_blank">Abhishek Saxena</a>
+</div>
+"""
+st.markdown(footer_html, unsafe_allow_html=True)
+
+# ---------------- END ----------------