Update src/streamlit_app.py

src/streamlit_app.py

@@ -1,40 +1,808 @@
-import altair as alt
-import numpy as np
-import pandas as pd
 import streamlit as st
+import requests
+import json
+import os
+from datetime import datetime
+import time 
+# For potential small delays to improve UI experience
 
-"""
-# Welcome to Streamlit!
-
-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).
-
-In the meantime, below is an example of what you can do with just a few lines of code:
-"""
-
-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])),
-    ))
+# Import Firebase Admin SDK
+import firebase_admin
+from firebase_admin import credentials, firestore, auth
+from firebase_admin.exceptions import FirebaseError
+
+# --- Constants & Environment Variables ---
+APP_ID = os.getenv('__app_id', 'default-app-id')
+FIREBASE_CONFIG_STR = os.getenv('__firebase_config', '{}')
+INITIAL_AUTH_TOKEN = os.getenv('__initial_auth_token', None)
+
+OLLAMA_API_BASE_URL = os.getenv("OLLAMA_HOST", "http://localhost:11434")
+OLLAMA_MODEL_NAME = 'krishna_choudhary/AI_Assistant_Chatbot'
+# Your specific model name
+
+# --- Firebase Initialization ---
+if not firebase_admin._apps:
+    try:
+        # Use ApplicationDefault credentials which Canvas environment should provide
+        cred = credentials.ApplicationDefault()
+        firebase_admin.initialize_app(cred, name=APP_ID)
+        st.session_state.db = firestore.client()
+        st.session_state.auth = auth
+        st.session_state.firebase_initialized = True
+        print("Firebase Admin SDK initialized successfully.")
+    except Exception as e:
+        st.error(f"Error initializing Firebase Admin SDK: {e}")
+        st.session_state.firebase_initialized = False
+        print(f"Failed to initialize Firebase Admin SDK: {e}")
+
+# --- Session State Initialization ---
+if 'current_page' not in st.session_state:
+    st.session_state.current_page = 'dashboard'
+if 'messages' not in st.session_state:
+    st.session_state.messages = []
+if 'input_message' not in st.session_state:
+    st.session_state.input_message = ''
+if 'is_loading' not in st.session_state:
+    st.session_state.is_loading = False
+if 'current_chat_id' not in st.session_state:
+    st.session_state.current_chat_id = None
+if 'ollama_api_error' not in st.session_state:
+    st.session_state.ollama_api_error = None
+if 'user_id' not in st.session_state:
+    st.session_state.user_id = None # Will be set after login/signup
+if 'user_email' not in st.session_state:
+    st.session_state.user_email = None # Store email for display/auth
+if 'user_name' not in st.session_state:
+    st.session_state.user_name = ""
+if 'loaded_user_name' not in st.session_state:
+    st.session_state.loaded_user_name = False
+if 'raw_ollama_response' not in st.session_state:
+    st.session_state.raw_ollama_response = None # To store full raw response for debug
+
+# --- Custom CSS for "Code Mentor AI" Styling ---
+st.markdown(
+    """
+    <style>
+        /* General Styles */
+        body {
+            color: #E0E0E0;
+            background-color: #0F172A;
+        }
+        .stApp {
+            background-color: #0F172A; /* Main app background */
+        }
+
+        /* Main Content Area */
+        .main .block-container {
+            padding-top: 2rem;
+            padding-bottom: 2rem;
+            padding-left: 5rem;
+            padding-right: 5rem;
+        }
+
+        /* Sidebar Styles */
+        [data-testid="stSidebar"] {
+            background-color: #1E293B;
+            border-right: 1px solid #334155;
+            padding-top: 2rem;
+        }
+        [data-testid="stSidebar"] h2 {
+            color: #FFFFFF;
+            font-weight: bold;
+            text-align: center;
+            margin-bottom: 2rem;
+        }
+        /* Sidebar buttons - selected/active state */
+        [data-testid="stSidebar"] .stButton>button {
+            background-color: transparent;
+            color: #94A3B8;
+            border: none;
+            width: 100%;
+            text-align: left;
+            padding: 0.75rem 1rem;
+            border-radius: 0.5rem;
+            font-size: 1rem;
+            display: flex;
+            align-items: center;
+            gap: 10px; /* Space between icon and text */
+        }
+        [data-testid="stSidebar"] .stButton>button:hover {
+            background-color: #334155;
+            color: #FFFFFF;
+        }
+        /* Streamlit applies an internal class to selected buttons.
+           This targets the active button in the sidebar based on session state. */
+        .sidebar-button-active {
+            background-color: #4A5568 !important; /* Brighter background for active */
+            color: #FFFFFF !important;
+            font-weight: bold;
+        }
+        
+        /* Chat Interface Styles */
+        div[data-testid="stVerticalBlock"] > div[data-testid="stVerticalBlock"] > div[data-testid="stVerticalBlock"]:has([data-testid="stChatInput"]) {
+            background-color: #1E293B;
+            border-radius: 0.75rem;
+            padding: 1rem;
+            border-top: 1px solid #334155;
+            margin-top: 1rem;
+        }
+        [data-testid="stChatInput"] {
+            background-color: transparent !important;
+        }
+        [data-testid="stChatInput"] input {
+            background-color: #2D3748 !important;
+            color: #E0E0E0 !important;
+            border: 1px solid #4A5568 !important;
+            border-radius: 0.5rem !important;
+            padding: 0.75rem 1rem;
+        }
+        [data-testid="stChatMessage"] {
+            background-color: #334155;
+            border-radius: 0.5rem;
+            padding: 1rem;
+            margin-bottom: 1rem;
+        }
+        .st-chat-message-user {
+            background-color: #2D3748 !important;
+            border: 1px solid #4A5568;
+        }
+        .st-chat-message-assistant {
+            background-color: #1E293B !important;
+            border: 1px solid #334155;
+        }
+        .stCodeBlock {
+            background-color: #0F172A !important;
+            border: 1px solid #334155 !important;
+            border-radius: 0.5rem;
+            padding: 1rem;
+            overflow-x: auto;
+        }
+
+        /* Custom Cards for Stats */
+        .stat-card {
+            background-color: #1E293B;
+            border-radius: 0.75rem;
+            padding: 1.5rem;
+            text-align: center;
+            border: 1px solid #334155;
+        }
+        .stat-card h3 {
+            color: #94A3B8;
+            font-size: 1rem;
+            margin-bottom: 0.5rem;
+        }
+        .stat-card p {
+            color: #FFFFFF;
+            font-size: 2.5rem;
+            font-weight: bold;
+        }
+
+        /* Popular Topics styling */
+        .popular-topics-card {
+            background-color: #1E293B;
+            border-radius: 0.75rem;
+            padding: 1.5rem;
+            border: 1px solid #334155;
+        }
+        .popular-topics-card h3 {
+            color: #FFFFFF;
+            font-size: 1.2rem;
+            margin-bottom: 1rem;
+        }
+        .popular-topics-card ul {
+            list-style-type: none;
+            padding-left: 0;
+        }
+        .popular-topics-card li {
+            color: #94A3B8;
+            padding: 0.25rem 0;
+            font-size: 0.95rem;
+        }
+        .popular-topics-card li::before {
+            content: "❯ ";
+            color: #69BFF8;
+            font-weight: bold;
+            margin-right: 0.5rem;
+        }
+        
+        /* Info Box for How to Use */
+        .info-box {
+            background-color: #2D3748;
+            border-left: 5px solid #69BFF8;
+            border-radius: 0.5rem;
+            padding: 1rem;
+            margin-bottom: 1rem;
+            color: #E0E0E0;
+        }
+        .info-box strong {
+            color: #FFFFFF;
+        }
+
+        /* Custom Button for "Ask Coding Instructor" */
+        .stButton.coding-instructor-button button {
+            background-color: #69BFF8;
+            color: white;
+            font-size: 1.1rem;
+            padding: 0.8rem 2rem;
+            border-radius: 0.75rem;
+            width: 100%;
+            margin-top: 1.5rem;
+            border: none;
+            transition: background-color 0.3s ease;
+        }
+        .stButton.coding-instructor-button button:hover {
+            background-color: #4CAF50;
+        }
+
+        /* Dark mode toggle and profile button in header */
+        .header-buttons {
+            display: flex;
+            justify-content: flex-end;
+            gap: 10px;
+            margin-bottom: 1rem;
+        }
+        .header-buttons .stButton>button {
+            background-color: #1E293B;
+            border: 1px solid #334155;
+            color: #94A3B8;
+            padding: 0.5rem 1rem;
+            border-radius: 0.5rem;
+        }
+    </style>
+    """,
+    unsafe_allow_html=True
+)
+
+
+# --- Firebase Helpers ---
+def get_user_doc_ref(db_client, user_id):
+    return db_client.collection(f"artifacts/{APP_ID}/users").document(user_id)
+
+def get_chats_collection_ref(db_client, user_id):
+    return get_user_doc_ref(db_client, user_id).collection("chats")
+
+def get_settings_doc_ref(db_client, user_id):
+    return get_user_doc_ref(db_client, user_id).collection("settings").document("userSettings")
+
+# --- Authentication Functions ---
+def login_user(username, password):
+    if not st.session_state.firebase_initialized:
+        st.error("Firebase not initialized.")
+        return False
+
+    email = f"{username}@app.com" # Map username to email for Firebase Auth
+    try:
+        user = st.session_state.auth.get_user_by_email(email)
+        # In a real app, you'd verify the password here securely.
+        # Firebase Admin SDK doesn't directly verify passwords from client.
+        # This is a SIMULATION for Canvas environment.
+        # A real client-side login would use signInWithEmailAndPassword.
+        
+        # For this server-side simulation, if user exists, we assume success.
+        # This is INSECURE for production.
+        st.session_state.user_id = user.uid
+        st.session_state.user_email = user.email
+        st.session_state.user_name = username
+        st.success(f"Logged in as {username}!")
+        st.rerun() # Rerun to update UI
+        return True
+    except FirebaseError as e:
+        if "user-not-found" in str(e):
+            st.error("User not found. Please sign up or check your username.")
+        else:
+            st.error(f"Login failed: {e}")
+        return False
+    except Exception as e:
+        st.error(f"An unexpected error occurred during login: {e}")
+        return False
+
+def signup_user(username, password):
+    if not st.session_state.firebase_initialized:
+        st.error("Firebase not initialized.")
+        return False
+
+    email = f"{username}@app.com" # Map username to email for Firebase Auth
+    try:
+        user = st.session_state.auth.create_user(email=email, password=password)
+        st.session_state.user_id = user.uid
+        st.session_state.user_email = user.email
+        st.session_state.user_name = username
+        
+        # Store username in Firestore settings for display
+        settings_doc_ref = get_settings_doc_ref(st.session_state.db, user.uid)
+        settings_doc_ref.set({'userName': username}, merge=True)
+
+        st.success(f"Signed up and logged in as {username}!")
+        st.rerun() # Rerun to update UI
+        return True
+    except FirebaseError as e:
+        if "email-already-exists" in str(e):
+            st.error("Username already exists. Please log in.")
+        elif "invalid-password" in str(e):
+            st.error("Password must be at least 6 characters long.")
+        else:
+            st.error(f"Signup failed: {e}")
+        return False
+    except Exception as e:
+        st.error(f"An unexpected error occurred during signup: {e}")
+        return False
+
+def logout_user():
+    st.session_state.user_id = None
+    st.session_state.user_email = None
+    st.session_state.user_name = ""
+    st.session_state.current_chat_id = None
+    st.session_state.messages = []
+    st.session_state.ollama_api_error = None
+    st.session_state.raw_ollama_response = None
+    st.success("Logged out successfully.")
+    st.rerun()
+
+# --- Functions for Chatbot Logic ---
+def load_chat_messages(chat_id):
+    if not st.session_state.firebase_initialized or not st.session_state.user_id or not chat_id:
+        return []
+    try:
+        messages_ref = get_chats_collection_ref(st.session_state.db, st.session_state.user_id).document(chat_id).collection("messages")
+        messages_docs = messages_ref.order_by('timestamp').get()
+        loaded_messages = []
+        for doc in messages_docs:
+            data = doc.to_dict()
+            if 'timestamp' in data and hasattr(data['timestamp'], 'to_datetime'):
+                data['timestamp'] = data['timestamp'].to_datetime()
+            loaded_messages.append({'id': doc.id, **data})
+        return loaded_messages
+    except Exception as e:
+        st.error(f"Error loading chat messages: {e}")
+        return []
+
+def start_new_chat_session():
+    if not st.session_state.firebase_initialized or not st.session_state.user_id:
+        st.session_state.ollama_api_error = "Database not ready. Cannot start new chat."
+        return
+
+    if not st.session_state.is_loading:
+        st.session_state.is_loading = True
+        st.session_state.ollama_api_error = None
+        st.session_state.input_message = ''
+        st.session_state.messages = []
+
+        try:
+            new_chat_ref = get_chats_collection_ref(st.session_state.db, st.session_state.user_id).add({
+                'createdAt': firestore.SERVER_TIMESTAMP,
+                'title': "New Chat"
+            })
+            st.session_state.current_chat_id = new_chat_ref[1].id
+            print(f"New chat session started: {st.session_state.current_chat_id}")
+        except Exception as e:
+            st.session_state.ollama_api_error = f"Failed to start new chat: {e}"
+            print(f"Error starting new chat: {e}")
+        finally:
+            st.session_state.is_loading = False
+            st.rerun()
+
+def send_message():
+    user_message_content = st.session_state.input_message.strip()
+
+    if not user_message_content or st.session_state.is_loading:
+        return
+
+    if not st.session_state.firebase_initialized or not st.session_state.user_id:
+        st.session_state.ollama_api_error = "Database not ready. Cannot send message. Please log in."
+        return
+
+    st.session_state.is_loading = True
+    st.session_state.ollama_api_error = None
+
+    if not st.session_state.current_chat_id:
+        st.session_state.is_loading = False
+        start_new_chat_session()
+        return
+
+    chat_messages_ref = get_chats_collection_ref(st.session_state.db, st.session_state.user_id).document(st.session_state.current_chat_id).collection("messages")
+
+    user_message_data = {
+        'role': 'user',
+        'content': user_message_content,
+        'timestamp': firestore.SERVER_TIMESTAMP,
+    }
+    try:
+        chat_messages_ref.add(user_message_data)
+        st.session_state.messages.append({'id': 'temp_user', 'role': 'user', 'content': user_message_content, 'timestamp': datetime.now()})
+        st.session_state.input_message = ''
+    except Exception as e:
+        st.session_state.ollama_api_error = f"Failed to save user message: {e}"
+        st.session_state.is_loading = False
+        st.rerun()
+        return
+
+    if st.session_state.current_chat_id and st.session_state.messages and len(st.session_state.messages) == 1:
+        try:
+            get_chats_collection_ref(st.session_state.db, st.session_state.user_id).document(st.session_state.current_chat_id).update({
+                'title': user_message_content[:50] + "..." if len(user_message_content) > 50 else user_message_content
+            })
+        except Exception as e:
+            print(f"Warning: Could not update new chat title: {e}")
+
+    ollama_messages = [{'role': msg['role'], 'content': msg['content']} for msg in st.session_state.messages]
+
+    try:
+        response = requests.post(
+            f'{OLLAMA_API_BASE_URL}/api/chat',
+            json={
+                'model': OLLAMA_MODEL_NAME,
+                'messages': ollama_messages,
+                'stream': False,
+                'options': {
+                    'temperature': 0.7,
+                    'num_predict': 2048, # CRUCIAL: Increased max tokens for full responses
+                    'top_p': 0.9,
+                },
+            },
+            timeout=120
+        )
+        response.raise_for_status()
+        result = response.json()
+        st.session_state.raw_ollama_response = json.dumps(result, indent=2) # Store raw response
+
+        assistant_response_content = result.get('message', {}).get('content', "No response from model.")
+
+        chat_messages_ref.add({
+            'role': 'assistant',
+            'content': assistant_response_content,
+            'timestamp': firestore.SERVER_TIMESTAMP,
+        })
+        st.session_state.messages.append({'id': 'temp_assistant', 'role': 'assistant', 'content': assistant_response_content, 'timestamp': datetime.now()})
+
+    except requests.exceptions.Timeout:
+        st.session_state.ollama_api_error = "Ollama connection timed out."
+        print("Ollama connection timed out.")
+    except requests.exceptions.RequestException as e:
+        st.session_state.ollama_api_error = f"Ollama connection error: {e}. Is the Ollama server running and accessible?"
+        print(f"Ollama connection error: {e}")
+    except json.JSONDecodeError:
+        st.session_state.ollama_api_error = "Ollama returned an unreadable response. Check server logs."
+        print(f"Ollama JSON decode error: {response.text if 'response' in locals() else 'No response'}")
+    except Exception as e:
+        st.session_state.ollama_api_error = f"An unexpected error occurred: {e}"
+        print(f"General Ollama error: {e}")
+    finally:
+        st.session_state.is_loading = False
+        st.rerun()
+
+# --- UI Page Components ---
+
+def auth_ui():
+    st.title("Welcome to Code Mentor AI")
+    st.markdown("---")
+    st.warning("""
+    **Security Warning:** For demonstration purposes, this app uses a simplified username/password login.
+    In a production environment, user-facing authentication should be handled by Firebase Client SDK
+    or a secure backend API, not directly via Admin SDK in the frontend.
+    """)
+
+    auth_tab = st.tabs(["Login", "Sign Up"])
+
+    with auth_tab[0]:
+        st.subheader("Login")
+        with st.form("login_form"):
+            login_username = st.text_input("Username", key="login_username_input")
+            login_password = st.text_input("Password", type="password", key="login_password_input")
+            login_submitted = st.form_submit_button("Login")
+
+            if login_submitted:
+                if login_username and login_password:
+                    login_user(login_username, login_password)
+                else:
+                    st.error("Please enter both username and password.")
+
+    with auth_tab[1]:
+        st.subheader("Sign Up")
+        with st.form("signup_form"):
+            signup_username = st.text_input("New Username", key="signup_username_input")
+            signup_password = st.text_input("New Password", type="password", key="signup_password_input")
+            signup_submitted = st.form_submit_button("Sign Up")
+
+            if signup_submitted:
+                if signup_username and signup_password:
+                    signup_user(signup_username, signup_password)
+                else:
+                    st.error("Please enter both username and password.")
+
+def dashboard_ui():
+    # Header buttons (Dark Mode, Profile) - Placeholder functionality
+    header_cols = st.columns([0.8, 0.1, 0.1])
+    with header_cols[1]:
+        st.button("🌙", key="dark_mode_btn", help="Toggle Dark Mode")
+    with header_cols[2]:
+        if st.button("👤", key="profile_btn", help="User Profile"):
+            st.session_state.current_page = 'settings' # Go to settings on profile click
+            st.rerun()
+
+    st.title("Coding Instructor AI")
+    st.markdown("---")
+
+    # --- Popular Topics ---
+    st.markdown("""
+    <div class="popular-topics-card">
+        <h3><span style="color: #F8B400; font-size: 1.2rem;">💡</span> Popular Topics</h3>
+        <ul>
+            <li>JavaScript Closures</li>
+            <li>Python Decorators</li>
+            <li>React Hooks</li>
+            <li>Recursion Patterns</li>
+            <li>Async/Await</li>
+        </ul>
+    </div>
+    """, unsafe_allow_html=True)
+    
+    st.markdown("<br>", unsafe_allow_html=True)
+
+    # --- Stats Cards ---
+    col1, col2 = st.columns(2)
+    with col1:
+        st.markdown('<div class="stat-card"><h3>Questions Solved</h3><p>1,248</p></div>', unsafe_allow_html=True)
+    with col2:
+        st.markdown('<div class="stat-card"><h3>Languages</h3><p>24</p></div>', unsafe_allow_html=True)
+    
+    st.markdown("<br>", unsafe_allow_html=True)
+
+    # --- Ask a Coding Question Section ---
+    st.subheader("💬 Ask a Coding Question")
+
+    # How to use info box
+    st.markdown("""
+    <div class="info-box">
+        <strong>ⓘ How to use:</strong> Ask any coding-related question in any programming language. The AI is specialized to help with coding problems and concepts.
+        <br>For non-coding questions, responses may be unpredictable.
+    </div>
+    """, unsafe_allow_html=True)
+
+    # Initial load of messages for the current chat ID
+    if st.session_state.current_chat_id and not st.session_state.messages:
+        with st.spinner("Loading chat..."):
+            st.session_state.messages = load_chat_messages(st.session_state.current_chat_id)
+            time.sleep(0.5)
+
+    # Display messages
+    chat_container = st.container(height=400, border=False)
+    with chat_container:
+        if not st.session_state.messages and not st.session_state.is_loading:
+            st.session_state.messages.append({"role": "assistant", "content": "How can I help you with your coding questions today?", "timestamp": datetime.now()})
+            # No rerun here, let the main loop handle it to avoid infinite reruns on first load
+        
+        for msg in st.session_state.messages:
+            message_class = "st-chat-message-user" if msg['role'] == 'user' else "st-chat-message-assistant"
+            st.markdown(f'<div class="stChatMessage {message_class}">', unsafe_allow_html=True)
+            st.markdown(msg['content'])
+            if 'timestamp' in msg and msg['timestamp']:
+                st.caption(f"Sent: {msg['timestamp'].strftime('%Y-%m-%d %H:%M:%S')}")
+            st.markdown('</div>', unsafe_allow_html=True)
+
+    if st.session_state.ollama_api_error:
+        st.error(st.session_state.ollama_api_error)
+
+    with st.form("chat_form", clear_on_submit=True):
+        user_input = st.text_input(
+            "Your Coding Question",
+            key="chat_input_text",
+            placeholder="e.g., Explain closures in JavaScript. How to implement binary search in Python. What is recursion?",
+            disabled=st.session_state.is_loading or not st.session_state.user_id,
+            label_visibility="visible"
+        )
+        
+        col_send_new = st.columns([1, 1])
+        with col_send_new[0]:
+            send_button = st.form_submit_button(
+                "Ask Coding Instructor",
+                disabled=st.session_state.is_loading or not user_input.strip() or not st.session_state.user_id,
+                help="Send your coding question to the AI.",
+                use_container_width=True
+            )
+        with col_send_new[1]:
+            new_chat_button = st.form_submit_button(
+                "Start New Chat",
+                disabled=st.session_state.is_loading or not st.session_state.user_id,
+                help="Clear current chat and start a new conversation.",
+                use_container_width=True
+            )
+
+        if send_button:
+            st.session_state.input_message = user_input
+            send_message()
+        elif new_chat_button:
+            start_new_chat_session()
+
+
+def history_ui():
+    st.title("📜 Chat History")
+    st.markdown("---")
+    if not st.session_state.firebase_initialized or not st.session_state.user_id:
+        st.warning("Database not ready or user not logged in. Cannot load history.")
+        return
+
+    st.write(f"Logged in as: **{st.session_state.user_name}** (User ID: `{st.session_state.user_id}`)")
+
+    try:
+        chats_ref = get_chats_collection_ref(st.session_state.db, st.session_state.user_id)
+        chat_docs = chats_ref.order_by('createdAt', direction=firestore.Query.DESCENDING).get()
+
+        if not chat_docs:
+            st.info("No chat sessions found. Start a new chat from the Dashboard!")
+            return
+
+        for chat_doc in chat_docs:
+            chat_data = chat_doc.to_dict()
+            chat_id = chat_doc.id
+            created_at = chat_data.get('createdAt')
+            if created_at and hasattr(created_at, 'strftime'):
+                 created_at_str = created_at.strftime('%Y-%m-%d %H:%M')
+            else:
+                 created_at_str = "Unknown Date"
+
+            title = chat_data.get('title', f"Chat ({created_at_str})")
+
+            col_chat, col_delete = st.columns([5, 1])
+            with col_chat:
+                if st.button(f"**{title}**", key=f"chat_{chat_id}_select", use_container_width=True):
+                    st.session_state.current_chat_id = chat_id
+                    st.session_state.messages = load_chat_messages(chat_id)
+                    st.session_state.current_page = 'dashboard'
+                    st.rerun()
+            with col_delete:
+                if st.button("Delete", key=f"chat_{chat_id}_delete", use_container_width=True):
+                    # Confirmation for deletion
+                    if st.checkbox(f"Confirm delete '{title}'?", key=f"confirm_del_{chat_id}"):
+                        delete_chat_and_messages(chat_id, chats_ref)
+                        st.success(f"Chat '{title}' deleted.")
+                        st.rerun()
+    except Exception as e:
+        st.error(f"Error fetching chat history: {e}")
+
+def delete_chat_and_messages(chat_id, chats_ref):
+    messages_ref = chats_ref.document(chat_id).collection("messages")
+    for msg_doc in messages_ref.get():
+        msg_doc.reference.delete()
+    chats_ref.document(chat_id).delete()
+    if st.session_state.current_chat_id == chat_id:
+        st.session_state.current_chat_id = None
+        st.session_state.messages = []
+
+
+def tutorials_ui():
+    st.title("📚 Tutorials")
+    st.markdown("---")
+    st.info("This section is under construction. Future updates will include interactive coding tutorials!")
+
+def playground_ui():
+    st.title("▶️ Playground")
+    st.markdown("---")
+    st.info("This section is under construction. Future updates will include a coding playground to test your code.")
+
+def settings_ui():
+    st.title("⚙️ Settings")
+    st.markdown("---")
+    if not st.session_state.firebase_initialized or not st.session_state.user_id:
+        st.warning("Database not ready or user not logged in. Cannot load/save settings.")
+        return
+
+    settings_doc_ref = get_settings_doc_ref(st.session_state.db, st.session_state.user_id)
+
+    if not st.session_state.loaded_user_name:
+        try:
+            settings_snap = settings_doc_ref.get()
+            if settings_snap.exists:
+                st.session_state.user_name = settings_snap.to_dict().get('userName', '')
+            st.session_state.loaded_user_name = True
+        except Exception as e:
+            st.error(f"Error loading user settings: {e}")
+            st.session_state.loaded_user_name = True
+
+    new_user_name = st.text_input("Your Name:", value=st.session_state.user_name, key="settings_user_name_input")
+    if st.button("Save Settings"):
+        if new_user_name.strip():
+            try:
+                settings_doc_ref.set({'userName': new_user_name.strip()}, merge=True)
+                st.session_state.user_name = new_user_name.strip()
+                st.success("Settings saved successfully!")
+            except Exception as e:
+                st.error(f"Failed to save settings: {e}")
+        else:
+            st.warning("User name cannot be empty.")
+
+    st.info(f"Your current User ID: `{st.session_state.user_id}`")
+    if st.session_state.user_email:
+        st.info(f"Your associated email: `{st.session_state.user_email}`")
+    st.markdown("---")
+    st.write("### Authentication Status")
+    st.write("For persistent data across sessions, ensure your Hugging Face Space is configured with persistent authentication or link your account.")
+    st.write("Currently, the app uses a session-based ID or the `__initial_auth_token` provided by the Canvas environment.")
+    
+    st.button("Logout", on_click=logout_user)
+
+    st.markdown("---")
+    st.write("### Raw Ollama Response (Debug)")
+    if st.session_state.raw_ollama_response:
+        st.code(st.session_state.raw_ollama_response, language="json")
+    else:
+        st.info("No raw Ollama response available yet. Send a message in the chat to see it here.")
+
+
+# --- Main App Navigation and Page Rendering ---
+# Sidebar navigation
+with st.sidebar:
+    st.markdown("## 🤖 Code Mentor AI")
+    
+    if st.session_state.user_id: # Show user name if logged in
+        st.markdown(f"<p style='text-align: center; color: #69BFF8; font-weight: bold;'>Welcome, {st.session_state.user_name}!</p>", unsafe_allow_html=True)
+    
+    st.markdown("<br>", unsafe_allow_html=True)
+
+    def set_page_and_rerun(page_name):
+        st.session_state.current_page = page_name
+        st.rerun()
+
+    # Dashboard button
+    dashboard_button_class = "sidebar-button-active" if st.session_state.current_page == "dashboard" else ""
+    st.markdown(f'<button class="stButton secondary-button {dashboard_button_class}" onclick="window.parent.document.querySelector(\'[data-testid=stSidebar] button[key=sidebar_dashboard]\').click()" key="sidebar_dashboard">💬 Dashboard</button>', unsafe_allow_html=True)
+    st.button("Dashboard", on_click=set_page_and_rerun, args=("dashboard",), key="sidebar_dashboard",
+              type="secondary", use_container_width=True,
+              help="Go to the main dashboard")
+    
+    # History button
+    history_button_class = "sidebar-button-active" if st.session_state.current_page == "history" else ""
+    st.markdown(f'<button class="stButton secondary-button {history_button_class}" onclick="window.parent.document.querySelector(\'[data-testid=stSidebar] button[key=sidebar_history]\').click()" key="sidebar_history">📚 History</button>', unsafe_allow_html=True)
+    st.button("History", on_click=set_page_and_rerun, args=("history",), key="sidebar_history",
+              type="secondary", use_container_width=True,
+              help="View your past conversations")
+    
+    # Tutorials button
+    tutorials_button_class = "sidebar-button-active" if st.session_state.current_page == "tutorials" else ""
+    st.markdown(f'<button class="stButton secondary-button {tutorials_button_class}" onclick="window.parent.document.querySelector(\'[data-testid=stSidebar] button[key=sidebar_tutorials]\').click()" key="sidebar_tutorials">📖 Tutorials</button>', unsafe_allow_html=True)
+    st.button("Tutorials", on_click=set_page_and_rerun, args=("tutorials",), key="sidebar_tutorials",
+              type="secondary", use_container_width=True,
+              help="Access coding tutorials")
+              
+    # Playground button
+    playground_button_class = "sidebar-button-active" if st.session_state.current_page == "playground" else ""
+    st.markdown(f'<button class="stButton secondary-button {playground_button_class}" onclick="window.parent.document.querySelector(\'[data-testid=stSidebar] button[key=sidebar_playground]\').click()" key="sidebar_playground">▶️ Playground</button>', unsafe_allow_html=True)
+    st.button("Playground", on_click=set_page_and_rerun, args=("playground",), key="sidebar_playground",
+              type="secondary", use_container_width=True,
+              help="Experiment with code snippets")
+              
+    # Settings button
+    settings_button_class = "sidebar-button-active" if st.session_state.current_page == "settings" else ""
+    st.markdown(f'<button class="stButton secondary-button {settings_button_class}" onclick="window.parent.document.querySelector(\'[data-testid=stSidebar] button[key=sidebar_settings]\').click()" key="sidebar_settings">⚙️ Settings</button>', unsafe_allow_html=True)
+    st.button("Settings", on_click=set_page_and_rerun, args=("settings",), key="sidebar_settings",
+              type="secondary", use_container_width=True,
+              help="Adjust application settings")
+
+    st.markdown("""
+        ---
+        <div style="text-align:center; color: #94A3B8; font-size: 0.8rem;">
+            Code Mentor AI v2.0<br>
+            Powered by Streamlit & Ollama
+        </div>
+    """, unsafe_allow_html=True)
+
+
+# Render Current Page based on st.session_state.current_page
+if not st.session_state.user_id:
+    auth_ui()
+elif st.session_state.current_page == 'dashboard':
+    dashboard_ui()
+elif st.session_state.current_page == 'history':
+    history_ui()
+elif st.session_state.current_page == 'tutorials':
+    tutorials_ui()
+elif st.session_state.current_page == 'playground':
+    playground_ui()
+elif st.session_state.current_page == 'settings':
+    settings_ui()
+
+# Initial chat session creation on first run if no chat is selected and user is logged in
+if (st.session_state.firebase_initialized and st.session_state.user_id and
+    st.session_state.current_page == 'dashboard' and
+    not st.session_state.current_chat_id and
+    not st.session_state.messages):
+    start_new_chat_session()