app.py

import gradio as gr
import torch
from transformers import AutoTokenizer, AutoModelForSequenceClassification
import re

# Load Bengali sentiment model (multi-label)
model_name = "Subha95/bengali-sentiment-model"
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForSequenceClassification.from_pretrained(model_name)

# Map labels to human-readable text + emoji
label_map = {
    "LABEL_0": "Assertive 💬",
    "LABEL_1": "Negative 🙁",
    "LABEL_2": "Doubtful 🤔",
    "LABEL_3": "Happiness 🙂",
    "LABEL_4": "Sadness 😢",
}

# Detect if text has any Bengali characters
def is_bengali(text):
    return re.search(r"[\u0980-\u09FF]", text) is not None

def predict_labels(text, threshold=0.5):
    inputs = tokenizer(text, return_tensors="pt")
    with torch.no_grad():
        outputs = model(**inputs)
        probs = torch.sigmoid(outputs.logits).cpu().numpy()[0]

    results = []
    for i, p in enumerate(probs):
        if p >= threshold:  # multi-label condition
            label = model.config.id2label[i]
            results.append(f"{label_map.get(label, label)} ({p:.2f})")

    if not results:  # if nothing crosses threshold
        best_idx = probs.argmax()
        label = model.config.id2label[best_idx]
        results = [f"{label_map.get(label, label)} ({probs[best_idx]:.2f})"]

    return results

def chatbot(message, history):
    try:
        # Check language
        if not is_bengali(message):
            response = "⚠️ This chatbot only works for Bengali text. Please write in বাংলা."
        else:
            results = predict_labels(message, threshold=0.5)
            response = " / ".join(results)
    except Exception as e:
        response = f"⚠️ Error: {str(e)}"

    history = history or []
    history.append((message, response))
    return history, history, ""  # clear textbox after sending

with gr.Blocks(theme=gr.themes.Soft()) as demo:
    gr.Markdown("Bengali Sentiment Chatbot (Multi-Label)")

    chatbot_ui = gr.Chatbot(height=400)
    with gr.Row():
        msg = gr.Textbox(placeholder="বাংলায় কিছু লিখুন...", scale=9)
        send = gr.Button("Send", scale=1)
    clear = gr.Button("🗑️ Clear Chat")

    send.click(chatbot, [msg, chatbot_ui], [chatbot_ui, chatbot_ui, msg])
    msg.submit(chatbot, [msg, chatbot_ui], [chatbot_ui, chatbot_ui, msg])
    clear.click(lambda: None, None, chatbot_ui, queue=False)

demo.launch()