app.py

import streamlit as st
from transformers import BertForSequenceClassification, BertTokenizer
import torch
import time
import streamlit.components.v1 as components

# Custom CSS for chat interface
def local_css():
    st.markdown("""
        <style>
        .chat-container {
            padding: 10px;
            border-radius: 5px;
            margin-bottom: 10px;
            display: flex;
            flex-direction: column;
        }
        
        .user-message {
            background-color: #e3f2fd;
            padding: 10px;
            border-radius: 15px;
            margin: 5px;
            margin-left: 20%;
            margin-right: 5px;
            align-self: flex-end;
            max-width: 70%;
        }
        
        .bot-message {
            background-color: #f5f5f5;
            padding: 10px;
            border-radius: 15px;
            margin: 5px;
            margin-right: 20%;
            margin-left: 5px;
            align-self: flex-start;
            max-width: 70%;
        }
        
        .chat-input {
            position: fixed;
            bottom: 0;
            width: 100%;
            padding: 20px;
            background-color: white;
        }
        
        .thinking-animation {
            display: flex;
            align-items: center;
            margin-left: 10px;
        }
        
        .dot {
            width: 8px;
            height: 8px;
            margin: 0 3px;
            background: #888;
            border-radius: 50%;
            animation: bounce 0.8s infinite;
        }
        
        .dot:nth-child(2) { animation-delay: 0.2s; }
        .dot:nth-child(3) { animation-delay: 0.4s; }
        
        @keyframes bounce {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-5px); }
        }
        </style>
    """, unsafe_allow_html=True)

# Load model and tokenizer
@st.cache_resource
def load_model():
    model = BertForSequenceClassification.from_pretrained("trituenhantaoio/bert-base-vietnamese-uncased")
    tokenizer = BertTokenizer.from_pretrained("trituenhantaoio/bert-base-vietnamese-uncased")
    return model, tokenizer

def predict(text, model, tokenizer):
    inputs = tokenizer(text, return_tensors="pt", padding=True, truncation=True, max_length=512)
    
    with torch.no_grad():
        outputs = model(**inputs)
        predictions = torch.nn.functional.softmax(outputs.logits, dim=-1)
        predicted_class = torch.argmax(predictions, dim=1).item()
    
    return predicted_class, predictions[0]

def get_bot_response(predicted_class, confidence):
    # Customize these responses based on your model's classes
    responses = {
        0: "I understand this is about [Class 0]. Let me help you with that.",
        1: "This seems to be related to [Class 1]. Here's what I can tell you.",
        # Add more responses for your classes
    }
    
    default_response = "I'm not quite sure about that. Could you please rephrase?"
    return responses.get(predicted_class, default_response)

def init_session_state():
    if 'messages' not in st.session_state:
        st.session_state.messages = []
    if 'thinking' not in st.session_state:
        st.session_state.thinking = False

def display_chat_history():
    for message in st.session_state.messages:
        if message['role'] == 'user':
            st.markdown(f'<div class="user-message">{message["content"]}</div>', unsafe_allow_html=True)
        else:
            st.markdown(f'<div class="bot-message">{message["content"]}</div>', unsafe_allow_html=True)

def main():
    st.set_page_config(page_title="AI Chatbot", page_icon="🤖", layout="wide")
    local_css()
    init_session_state()
    
    # Load model
    model, tokenizer = load_model()
    
    # Chat interface
    st.title("AI Chatbot 🤖")
    st.markdown("Welcome! I'm here to help answer your questions in Vietnamese.")
    
    # Chat history container
    chat_container = st.container()
    
    # Input container at the bottom
    with st.container():
        col1, col2 = st.columns([6, 1])
        with col1:
            user_input = st.text_input("Type your message...", key="user_input", label_visibility="hidden")
        with col2:
            send_button = st.button("Send")
    
    if user_input and send_button:
        # Add user message to chat
        st.session_state.messages.append({"role": "user", "content": user_input})
        
        # Show thinking animation
        st.session_state.thinking = True
        
        # Get model prediction
        predicted_class, probabilities = predict(user_input, model, tokenizer)
        
        # Get bot response
        bot_response = get_bot_response(predicted_class, probabilities)
        
        # Add bot response to chat
        time.sleep(1)  # Simulate processing time
        st.session_state.messages.append({"role": "assistant", "content": bot_response})
        st.session_state.thinking = False
        
        # Clear input
        st.rerun()
    
    # Display chat history
    with chat_container:
        display_chat_history()
        
        # Show thinking animation
        if st.session_state.thinking:
            st.markdown("""
                <div class="thinking-animation">
                    <div class="dot"></div>
                    <div class="dot"></div>
                    <div class="dot"></div>
                </div>
            """, unsafe_allow_html=True)

if __name__ == "__main__":
    main()