import streamlit as st
import importlib
from io import BytesIO

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

# Import LANGUAGES from translation.py
try:
    from translation import LANGUAGES
except ImportError as e:
    st.error(f"Failed to import translation module: {e}")
    st.stop()

def main():
    try:
        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 and Input/Output Layout
        col1, col2 = st.columns(2)
        with col1:
            detected_options = lang_detect.detect_language(st.session_state.get("input_text", "")) if st.session_state.get("input_text", "").strip() else [("Auto-detect", 1.0, "Auto-detect")]
            source_lang = detected_options[0][0] if detected_options[0][0] != "Auto-detect" else "Auto-detect"
            source_lang_code = next((k for k, v in LANGUAGES.items() if v[0] == source_lang), "hi") if source_lang != "Auto-detect" else "auto"
            source_options = ["Auto-detect"] + [v[0] for v in LANGUAGES.values()]
            st.selectbox("Source", options=source_options, index=0 if source_lang == "Auto-detect" else source_options.index(source_lang), key="source_lang")
            input_type = st.radio("", ["Text", "File"], horizontal=True, label_visibility="hidden")
            if input_type == "Text":
                st.text_area("", height=200, key="input_text", on_change=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")
            else:
                uploaded_file = st.file_uploader("", type=["txt", "docx", "pdf"], key="file_input", on_change=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")
                if uploaded_file:
                    st.session_state.input_text = uploaded_file.read().decode("utf-8").strip()
            st.button("Translate", key="translate_btn", on_click=trigger_translation, args=(translation, lang_detect, audio_processor,))
        with col2:
            st.selectbox("Target", options=[v[0] for v in LANGUAGES.values()], index=list(LANGUAGES.values()).index(LANGUAGES["en"]), key="target_lang")
            if "translated_text" in st.session_state:
                st.text_area("", value=st.session_state.translated_text, height=200, key="output_text", disabled=True, label_visibility="hidden")
                st.button("🔊", key="audio_btn", on_click=play_audio, args=(audio_processor,), help="Play audio", use_container_width=False)

    except Exception as e:
        st.error(f"App error: {e}")
        st.stop()

def trigger_translation(translation, lang_detect, audio_processor):
    text = st.session_state.get("input_text", "").strip()
    if text:
        source_lang = st.session_state.source_lang
        target_lang = next((k for k, v in LANGUAGES.items() if v[0] == st.session_state.target_lang), "en")
        if source_lang == "Auto-detect":
            detected_options = lang_detect.detect_language(text)
            source_lang_code = next((k for k, v in LANGUAGES.items() if v[1] == detected_options[0][0]), "hi")
        else:
            source_lang_code = next((k for k, v in LANGUAGES.items() if v[0] == source_lang), "hi")
        st.session_state.translated_text = translation.translate(text, source_lang_code, target_lang) or text

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), "en")
        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")

if __name__ == "__main__":
    main()