import streamlit as st
from transformers import pipeline

# Language pair to model mapping
model_mapping = {
    ("English", "Hindi"):"zoya23/en-hi-translation     # "Helsinki-NLP/opus-mt-en-hi",
    ("Hindi", "English"): "TestZee/Finetuned-hindi-to-english-V5",   # "TestZee/Finetuned-hindi-to-english-V5"
}

# Streamlit page config
st.set_page_config(page_title="Translator", layout="wide")

# Only allowed languages
languages = ["English", "Hindi"]

# UI
st.markdown("""
    <style>
    .big-font { font-size:25px !important; font-weight: bold; }
    .output-box { background-color: #f9f9f9; padding: 20px; border-radius: 10px; min-height: 300px; font-size: 22px; }
    </style>
""", unsafe_allow_html=True)

# Two columns
col1, col2 = st.columns(2)

with col1:
    source_lang = st.selectbox("Detected Language", languages, index=0)
    st.markdown('<div class="big-font">Enter your text:</div>', unsafe_allow_html=True)
    user_input = st.text_area("", "hi how are you", height=250)
    translate_button = st.button("Translate", use_container_width=True)

with col2:
    target_lang = st.selectbox("Translate To", languages, index=1)
    
    if translate_button and user_input:
        if (source_lang, target_lang) in model_mapping:
            model_name = model_mapping[(source_lang, target_lang)]
            translator = pipeline("translation", model=model_name)
            translated_text = translator(user_input, max_length=400)[0]['translation_text']
        else:
            translated_text = "❌ Translation not available for selected language pair."
    else:
        translated_text = ""

    st.markdown('<div class="output-box">' + (translated_text if translated_text else "") + '</div>', unsafe_allow_html=True)

    if translated_text and "❌" not in translated_text:
        st.button("Copy", use_container_width=True)
        st.button("Paraphrase", use_container_width=True)