app.py

import streamlit as st
from transformers import (
    MarianMTModel, MarianTokenizer, 
    GPT2LMHeadModel, GPT2Tokenizer,
    pipeline
)
st.title("Multi Chatbot")
models = {
    "English to French": {
        "name": "Helsinki-NLP/opus-mt-en-fr",
        "description": "Translate English text to French."
    },
    "Sentiment Analysis": {
        "name": "distilbert-base-uncased-finetuned-sst-2-english",
        "description": "Analyze the sentiment of input text."
    },
    "Story Generator": {
        "name": "distilgpt2",  
        "description": "Generate creative stories based on input."
    }
}

st.sidebar.header("Choose a Model")
selected_model_key = st.sidebar.radio("Select a Model:", list(models.keys()))
model_name = models[selected_model_key]["name"]
model_description = models[selected_model_key]["description"]

st.sidebar.markdown(f"### Model Description\n{model_description}")

@st.cache_resource
def load_english_to_french():
    tokenizer = MarianTokenizer.from_pretrained("Helsinki-NLP/opus-mt-en-fr")
    model = MarianMTModel.from_pretrained("Helsinki-NLP/opus-mt-en-fr")
    return tokenizer, model

@st.cache_resource
def load_sentiment_analysis():
    return pipeline("sentiment-analysis", model="distilbert-base-uncased-finetuned-sst-2-english")

@st.cache_resource
def load_story_generator():
    tokenizer = GPT2Tokenizer.from_pretrained("distilgpt2")
    model = GPT2LMHeadModel.from_pretrained("distilgpt2")
    tokenizer.pad_token = tokenizer.eos_token  # Set pad token to EOS token
    return tokenizer, model


if selected_model_key == "English to French":
    st.write("Loading English to French model...")
    en_fr_tokenizer, en_fr_model = load_english_to_french()
    st.write("English to French model loaded successfully.")

elif selected_model_key == "Sentiment Analysis":
    st.write("Loading Sentiment Analysis model...")
    sentiment_analyzer = load_sentiment_analysis()
    st.write("Sentiment Analysis model loaded successfully.")

elif selected_model_key == "Story Generator":
    st.write("Loading Story Generator model...")
    story_gen_tokenizer, story_gen_model = load_story_generator()
    st.write("Story Generator model loaded successfully.")

user_input = st.text_input("Enter your query:")

if user_input:
    if selected_model_key == "English to French":
        try:
            inputs = en_fr_tokenizer(user_input, return_tensors="pt", truncation=True, padding=True)
            outputs = en_fr_model.generate(inputs["input_ids"], max_length=150, num_return_sequences=1)
            translated_text = en_fr_tokenizer.decode(outputs[0], skip_special_tokens=True)
            st.write(f"Translated Text: {translated_text}")
        except Exception as e:
            st.error(f"Error during translation: {e}")

    elif selected_model_key == "Sentiment Analysis":
        try:
            result = sentiment_analyzer(user_input)[0]
            st.write(f"Sentiment: {result['label']}")
            st.write(f"Confidence: {result['score']:.2f}")
        except Exception as e:
            st.error(f"Error during sentiment analysis: {e}")

    elif selected_model_key == "Story Generator":
        try:
            inputs = story_gen_tokenizer(user_input, return_tensors="pt", truncation=True, padding=True)
            outputs = story_gen_model.generate(
                inputs["input_ids"], 
                attention_mask=inputs["attention_mask"],  # Pass the attention mask
                max_length=200, 
                num_return_sequences=1, 
                temperature=0.7,
                no_repeat_ngram_size=2
            )
            story = story_gen_tokenizer.decode(outputs[0], skip_special_tokens=True)
            st.write(f"Generated Story: {story}")
        except Exception as e:
            st.error(f"Error during story generation: {e}")