app.py

import streamlit as st
from transformers import pipeline
from gtts import gTTS
import uuid
import os

# Language options and model map (simplified to just one pair)
MODEL_MAP = {
    ("en", "fr"): "Helsinki-NLP/opus-mt-en-fr",
    ("fr", "en"): "Helsinki-NLP/opus-mt-fr-en"
}

TRANSLATORS = {}

# UI
st.title("🌍 Multilingual Translator with Text-to-Speech")

src_lang_name = st.selectbox("Select source language", ["English", "French"], index=0)
tgt_lang_name = st.selectbox("Select target language", ["English", "French"], index=1)

src_lang = "en" if src_lang_name == "English" else "fr"
tgt_lang = "en" if tgt_lang_name == "English" else "fr"

text_input = st.text_area("Enter text to translate:")

if st.button("Translate & Speak"):
    if not text_input.strip():
        st.warning("Please enter some text.")
    elif src_lang == tgt_lang:
        st.warning("Source and target languages must be different.")
    else:
        # Load model lazily
        if (src_lang, tgt_lang) not in TRANSLATORS:
            with st.spinner(f"Loading model: {MODEL_MAP[(src_lang, tgt_lang)]}"):
                TRANSLATORS[(src_lang, tgt_lang)] = pipeline("translation", model=MODEL_MAP[(src_lang, tgt_lang)])

        translator = TRANSLATORS[(src_lang, tgt_lang)]
        with st.spinner("Translating..."):
            translated_text = translator(text_input)[0]["translation_text"]
            st.success("Translation complete!")

        st.text_area("Translated Text:", translated_text)

        try:
            audio_filename = f"{uuid.uuid4().hex}.mp3"
            tts = gTTS(text=translated_text, lang=tgt_lang)
            tts.save(audio_filename)
            audio_file = open(audio_filename, "rb")
            st.audio(audio_file.read(), format="audio/mp3")
            audio_file.close()
            os.remove(audio_filename)
        except Exception as e:
            st.warning(f"Translation OK, but TTS failed: {e}")