app.py

import streamlit as st
import importlib
from io import BytesIO
import time

st.set_page_config(page_title="Multilingual Translator", layout="centered")

# Import LANGUAGES from translation.py
from translation import LANGUAGES

def main():
    translation = importlib.import_module("translation")
    lang_detect = importlib.import_module("lang_detect")
    audio_processor = importlib.import_module("audio_processor")

    # Header
    st.markdown("<h1 style='text-align: center; color: #4285F4;'>Multilingual Translator</h1>", unsafe_allow_html=True)
    st.markdown("<p style='text-align: center; color: #666;'>Translate text like Google Translate</p>", unsafe_allow_html=True)

    # Language Controls
    col1, col2 = st.columns([1, 1])
    with col1:
        detected_options = lang_detect.detect_language(st.session_state.get("user_text", "")) if st.session_state.get("user_text", "").strip() and len(st.session_state.get("user_text", "").strip()) >= 10 else [("English", 1.0, "English")]
        source_lang = detected_options[0][0] if detected_options else "English"
        source_lang_code = next((k for k, v in LANGUAGES.items() if v[1] == source_lang), "en")
        source_lang_display = st.selectbox("Source Language", options=[LANGUAGES[source_lang_code][0]] + [v[0] for v in LANGUAGES.values()], index=0, key="source_lang", help="Auto-detected, override if needed", label_visibility="hidden")
    with col2:
        target_lang_display = st.selectbox("Target Language", options=[v[0] for v in LANGUAGES.values()], index=list(LANGUAGES.values()).index(LANGUAGES["hi"]), key="target_lang", label_visibility="hidden")
        target_lang = next((k for k, v in LANGUAGES.items() if v[0] == target_lang_display), "hi")

    # Input Section
    if "user_text" not in st.session_state:
        st.session_state.user_text = ""
    col_input = st.container()
    with col_input:
        input_type = st.radio("Input Method", ["Text", "File Upload"], horizontal=True, key="input_type", label_visibility="hidden")
        if input_type == "Text":
            user_text = st.text_area("Enter or paste text", height=200, key="user_text", on_change=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")
        else:
            user_text = st.file_uploader("Upload File", type=["txt", "docx", "pdf"], key="doc_input", on_change=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")
            if user_text:
                st.session_state.user_text = user_text.read().decode("utf-8").strip()
        st.markdown(f"<small style='color: grey;'>Characters: {len(st.session_state.user_text)}/1000</small>", unsafe_allow_html=True)
        st.button("Translate", key="translate_btn", on_click=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")

    # Output Section
    col_output = st.container()
    with col_output:
        if "translated_text" in st.session_state and st.session_state.translated_text:
            st.text_area("Translation", value=st.session_state.translated_text, height=200, key="output_area", disabled=True, label_visibility="hidden")
            col_a = st.columns([1])[0]  # Single column for speaker icon
            if st.button("🔊", key="audio_btn", on_click=play_audio, args=(audio_processor,), help="Listen to translation", label_visibility="hidden"):
                pass  # Handled by play_audio function

def trigger_translation(translation, lang_detect, audio_processor):
    user_text = st.session_state.user_text.strip()
    if user_text:
        spinner = st.empty()
        spinner.info("Translating...")
        start_time = time.time()
        try:
            source_lang = next((k for k, v in LANGUAGES.items() if v[0] == st.session_state.source_lang), "en")
            target_lang = next((k for k, v in LANGUAGES.items() if v[0] == st.session_state.target_lang), "hi")
            if source_lang != "en" and target_lang != "en":
                temp_translation = translation.translate(user_text, source_lang, "en")
                if not temp_translation or len(temp_translation.split()) < 2:
                    raise ValueError("Intermediate translation invalid")
                translated_text = translation.translate(temp_translation, "en", target_lang)
            else:
                translated_text = translation.translate(user_text, source_lang, target_lang)
            if not translated_text or len(translated_text.split()) < 2:
                raise ValueError("Final translation invalid")
            st.session_state.translated_text = translated_text
        except Exception as e:
            st.session_state.translated_text = user_text
            st.warning(f"Translation issue: {str(e)}. Using input as fallback.")
        finally:
            spinner.empty()

def play_audio(audio_processor):
    if "translated_text" in st.session_state and st.session_state.translated_text:
        target_lang = next((k for k, v in LANGUAGES.items() if v[0] == st.session_state.target_lang), "hi")
        audio = audio_processor.text_to_speech(st.session_state.translated_text, target_lang)
        if audio and audio.getbuffer().nbytes > 0:
            st.audio(audio, format="audio/mp3", start_time=0)
            st.success("Audio playing.")
        else:
            audio_fallback = audio_processor.text_to_speech(st.session_state.translated_text, "en")
            if audio_fallback and audio_fallback.getbuffer().nbytes > 0:
                st.audio(audio_fallback, format="audio/mp3", start_time=0)
                st.success("Fallback audio in English playing.")
            else:
                st.error("Audio generation failed. Try again later.")

if __name__ == "__main__":
    main()