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)

        # 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() and len(st.session_state.get("input_text", "").strip()) >= 10 else [("Hindi", 1.0, "हिन्दी")]
            source_lang = detected_options[0][0] if detected_options else "Hindi"
            source_lang_code = next((k for k, v in LANGUAGES.items() if v[1] == source_lang), "hi")
            st.selectbox("Source", options=[LANGUAGES[source_lang_code][0]] + [v[0] for v in LANGUAGES.values()], index=0, key="source_lang")
            input_type = st.radio("Input", ["Text", "File"], horizontal=True, key="input_type", label_visibility="hidden")
            if input_type == "Text":
                input_text = st.text_area("Input", height=200, key="input_text", on_change=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")
            else:
                input_text = st.file_uploader("Input", type=["txt", "docx", "pdf"], key="file_input", on_change=trigger_translation, args=(translation, lang_detect, audio_processor,), label_visibility="hidden")
                if input_text:
                    st.session_state.input_text = input_text.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("Output", value=st.session_state.translated_text, height=200, key="output_text", disabled=True, label_visibility="hidden")
            if st.button("🔊", key="audio_btn", on_click=play_audio, args=(audio_processor,), help="Play audio"):
                pass  # Handled by play_audio

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

def trigger_translation(translation, lang_detect, audio_processor):
    text = st.session_state.input_text.strip()
    if text:
        source_lang = next((k for k, v in LANGUAGES.items() if v[0] == st.session_state.source_lang), "hi")
        target_lang = next((k for k, v in LANGUAGES.items() if v[0] == st.session_state.target_lang), "en")
        if source_lang != "en" and target_lang != "en":
            temp = translation.translate(text, source_lang, "en")
            if temp and len(temp.split()) >= 2:
                st.session_state.translated_text = translation.translate(temp, "en", target_lang)
            else:
                st.session_state.translated_text = text
        else:
            st.session_state.translated_text = translation.translate(text, source_lang, 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")
        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")

if __name__ == "__main__":
    main()