import streamlit as st
from transformers import MarianMTModel, MarianTokenizer

# Function to load a translation model
@st.cache_resource
def load_model(src_lang, tgt_lang):
    model_name = f"Helsinki-NLP/opus-mt-{src_lang}-{tgt_lang}"
    tokenizer = MarianTokenizer.from_pretrained(model_name)
    model = MarianMTModel.from_pretrained(model_name)
    return model, tokenizer

def translate_text(text, model, tokenizer):
    inputs = tokenizer.encode(text, return_tensors="pt", truncation=True)
    outputs = model.generate(inputs, max_length=512, num_beams=5, early_stopping=True)
    translated_text = tokenizer.decode(outputs[0], skip_special_tokens=True)
    return translated_text

# Streamlit UI
st.title("Multi-Language Translator")

st.sidebar.header("Translation Settings")

# Dropdown menus for source and target languages
language_options = {
    "English": "en",
    "Urdu": "ur",
    "German": "de",
    "French": "fr",
    "Spanish": "es",
    "Italian": "it",
}

src_lang = st.sidebar.selectbox("Select Source Language", list(language_options.keys()))
tgt_lang = st.sidebar.selectbox("Select Target Language", list(language_options.keys()))

# Get language codes
src_lang_code = language_options[src_lang]
tgt_lang_code = language_options[tgt_lang]

# Input text
text_to_translate = st.text_area("Enter text to translate:")

# Translate button
if st.button("Translate"):
    if not text_to_translate.strip():
        st.error("Please enter some text to translate.")
    elif src_lang_code == tgt_lang_code:
        st.error("Source and target languages must be different.")
    else:
        try:
            with st.spinner("Translating..."):
                # Load the model
                model, tokenizer = load_model(src_lang_code, tgt_lang_code)
                # Translate the text
                translated_text = translate_text(text_to_translate, model, tokenizer)
            st.markdown(f"### Translated Text:\n{translated_text}")
        except Exception as e:
            st.error(f"Error during translation: {str(e)}")