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

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

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: #2E86C1;'>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
    col_lang, col_target = st.columns([1, 1])
    with col_lang:
        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"
        native_lang_map = {
            "English": "English", "French": "Français", "Spanish": "Español",
            "German": "Deutsch", "Hindi": "हिन्दी", "Chinese": "中文",
            "Arabic": "العربية", "Russian": "Русский", "Japanese": "日本語"
        }
        source_lang_display = st.selectbox("Source Language (Auto-Detected)", [native_lang_map.get(source_lang, source_lang)] + list(native_lang_map.values()), index=0, key="source_lang", label_visibility="collapsed", help="Auto-detected language, override if needed")
    with col_target:
        target_options = list(native_lang_map.values())
        target_lang_display = st.selectbox("Target Language", target_options, index=target_options.index("हिन्दी") if "हिन्दी" in target_options else 0, key="target_lang", label_visibility="collapsed")
        target_lang = next((k for k, v in native_lang_map.items() if v == target_lang_display), "Hindi")

    # Input Section
    col_input, col_output = st.columns([1, 1])
    with col_input:
        st.markdown("<div style='margin-bottom: 10px;'></div>", unsafe_allow_html=True)
        input_type = st.radio("Input", ["Text", "File Upload"], horizontal=True, label_visibility="collapsed", key="input_type")
        user_text = st.text_area("Enter or paste text", height=200, key="user_text").strip() if input_type == "Text" else ""
        if input_type == "File Upload":
            doc_file = st.file_uploader("Upload File", type=["txt", "docx", "pdf"], key="doc_input", accept_multiple_files=False, label_visibility="collapsed", help="Drag and drop or browse files")
            user_text = doc_file.read().decode("utf-8").strip() if doc_file else st.session_state.get("user_text", "")
        char_count = len(user_text)
        st.markdown(f"<small style='color: grey;'>Characters: {char_count}/1000</small>", unsafe_allow_html=True)

        if user_text and (st.session_state.get("last_text", "") != user_text or st.button("Translate", key="translate_btn")):
            st.session_state.last_text = user_text
            spinner = st.empty()
            spinner.info("Translating...")
            start_time = time.time()
            try:
                # Use English as buffer for translation with validation
                if source_lang != "English" and target_lang != "English":
                    temp_translation = translation.translate(user_text, source_lang, "English")
                    if not temp_translation or len(temp_translation.split()) < 2:  # Validate intermediate result
                        raise ValueError("Intermediate translation failed")
                    translated_text = translation.translate(temp_translation, "English", target_lang)
                else:
                    translated_text = translation.translate(user_text, source_lang, target_lang)
                if not translated_text or len(translated_text.split()) < 2:  # Validate final result
                    raise ValueError("Final translation failed")
                st.session_state.translated_text = translated_text
                st.session_state.translation_time = time.time() - start_time
            except Exception as e:
                st.session_state.translated_text = user_text
                st.session_state.translation_time = time.time() - start_time
                st.warning(f"Translation issue: {str(e)}. Using input as fallback.")
            finally:
                spinner.empty()

    # Output Section
    with col_output:
        st.markdown("<div style='margin-bottom: 10px;'></div>", unsafe_allow_html=True)
        if "translated_text" in st.session_state and st.session_state.translated_text:
            line_count = max(len(st.session_state.translated_text.splitlines()), len(user_text.splitlines()))
            output_height = max(200, line_count * 20 + 50)
            st.text_area("Translation:", value=st.session_state.translated_text, height=output_height, key="output_area")
            st.write(f"Translation time: {st.session_state.translation_time:.2f} seconds")
            col_copy, col_audio = st.columns([0.5, 0.5])
            with col_copy:
                if st.button("📋", key="copy_btn", help="Copy to clipboard"):
                    st.clipboard(st.session_state.translated_text)
                    st.success("Copied to clipboard!")
            with col_audio:
                output_option = st.radio("Output", ["Text", "Audio"], horizontal=True, label_visibility="collapsed", key="output_option")
                if output_option == "Audio" and "translated_text" in st.session_state:
                    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, "English")
                        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.")

    # Footer
    st.markdown("""
        <p style='font-size: small; color: grey; text-align: center; margin-top: 20px;'>
            Developed by: Krishna Prakash <a href='https://www.linkedin.com/in/krishnaprakash-profile/' target='_blank'>
                <img src='https://img.icons8.com/ios-filled/30/0077b5/linkedin.png' alt='LinkedIn' style='vertical-align: middle; margin: 0 5px;'/>
            </a>
        </p>
    """, unsafe_allow_html=True)

if __name__ == "__main__":
    main()