Update src/streamlit_app.py

src/streamlit_app.py

@@ -1,40 +1,217 @@
-import altair as alt
-import numpy as np
-import pandas as pd
 import streamlit as st
+import requests
+import os
 
-"""
-# Welcome to Streamlit!
+# Backend URL (change if deployed)
+BACKEND_URL = "http://localhost:8000"
+
+st.set_page_config(page_title="PDF Assistant", page_icon="📘", layout="wide")
+
+# ---------------- 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; /* Dark gray */
+    padding: 12px;
+    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: var(--primary-color); /* Primary blue */
+    padding: 12px;
+    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)
+
+# ---------------- SESSION STATE ----------------
+if "chat" not in st.session_state:
+    st.session_state.chat = []
+
+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_chat_history():
+    """Clears the chat history in the session state."""
+    st.session_state.chat = []
+
+
+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.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 PDF ----------------
+# Use the dynamic key for the file uploader.
+uploaded = st.file_uploader(
+    "Upload your PDF",
+    type=["pdf"],
+    key=st.session_state.uploader_key # Use the dynamic key
+)
+
+# 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 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 about the loaded PDF:",
+    key="question_input",
+    disabled=disabled_input
+)
+
+if st.button("Send", disabled=disabled_input) and question:
+    # 1. Add user query to chat history
+    st.session_state.chat.append(("user", 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()
+                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()
 
-Edit `/streamlit_app.py` to customize this app to your heart's desire :heart:.
-If you have any questions, checkout our [documentation](https://docs.streamlit.io) and [community
-forums](https://discuss.streamlit.io).
+# ---------------- 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)
 
-In the meantime, below is an example of what you can do with just a few lines of code:
+# ---------------- 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)
 
-num_points = st.slider("Number of points in spiral", 1, 10000, 1100)
-num_turns = st.slider("Number of turns in spiral", 1, 300, 31)
-
-indices = np.linspace(0, 1, num_points)
-theta = 2 * np.pi * num_turns * indices
-radius = indices
-
-x = radius * np.cos(theta)
-y = radius * np.sin(theta)
-
-df = pd.DataFrame({
-    "x": x,
-    "y": y,
-    "idx": indices,
-    "rand": np.random.randn(num_points),
-})
-
-st.altair_chart(alt.Chart(df, height=700, width=700)
-    .mark_point(filled=True)
-    .encode(
-        x=alt.X("x", axis=None),
-        y=alt.Y("y", axis=None),
-        color=alt.Color("idx", legend=None, scale=alt.Scale()),
-        size=alt.Size("rand", legend=None, scale=alt.Scale(range=[1, 150])),
-    ))
+# ---------------- END ----------------