import os
import tempfile
import streamlit as st
from gtts import gTTS
from pydub import AudioSegment
from moviepy.editor import ImageClip, concatenate_videoclips, AudioFileClip
from pydub.exceptions import CouldntDecodeError

# Hugging Face Spaces configuration
tempfile.tempdir = "/tmp"

# ==================================================================
# Core Functions (Updated with working gender voices)
# ==================================================================
def text_to_speech(slide_texts, lang='en', gender='female', transition_delay=0):
    """Convert text to speech with verified gender selection"""
    audio_clips = []
    durations = []
    
    # Verified voice configuration matrix
    tld_map = {
        'female': {
            'en': 'us',    # American English
            'es': 'es',    # European Spanish
            'fr': 'fr',    # French (France)
            'de': 'de',    # German (Germany)
            'ja': 'jp'     # Japanese
        },
        'male': {
            'en': 'co.uk',  # British English
            'es': 'com.mx', # Mexican Spanish
            'fr': 'ca',     # Canadian French
            'de': 'at',     # Austrian German
            'ja': 'jp'      # Japanese (fallback)
        }
    }

    for i, text in enumerate(slide_texts):
        with tempfile.NamedTemporaryFile(suffix=".mp3", delete=False) as fp:
            try:
                # Get valid TLD for selected gender and language
                tld = tld_map[gender].get(lang, tld_map['female'][lang])
                
                tts = gTTS(
                    text=text,
                    lang=lang,
                    tld=tld,
                    slow=False
                )
                tts.save(fp.name)
                clip = AudioSegment.from_mp3(fp.name)
                
                # Add transition delay as silence
                silence = AudioSegment.silent(duration=transition_delay*1000)
                clip_with_delay = clip + silence
                
                audio_clips.append(clip_with_delay)
                durations.append(len(clip_with_delay))
            finally:
                os.unlink(fp.name)
    
    combined_audio = sum(audio_clips)
    with tempfile.NamedTemporaryFile(suffix=".mp3", delete=False) as fp:
        combined_audio.export(fp.name, format="mp3")
        return durations, fp.name

def add_background_music(voice_path, music_path, volume_reduction=25):
    """Mix voice-over with background music"""
    voice = AudioSegment.from_mp3(voice_path)
    
    if music_path:
        try:
            music = AudioSegment.from_file(music_path)
            music = music[:len(voice)].fade_out(2000)
            music = music - volume_reduction
            final_audio = voice.overlay(music)
        except CouldntDecodeError:
            raise ValueError("Invalid music file format")
    else:
        final_audio = voice
    
    with tempfile.NamedTemporaryFile(suffix=".mp3", delete=False) as fp:
        final_audio.export(fp.name, format="mp3")
        return len(final_audio) / 1000, fp.name

def create_video(img_paths, durations, audio_path):
    """Generate video synchronized with audio"""
    clips = []
    
    for img_path, duration in zip(img_paths, durations):
        clip = ImageClip(img_path).set_duration(duration / 1000)
        clips.append(clip)
    
    video = concatenate_videoclips(clips, method="compose")
    video = video.set_audio(AudioFileClip(audio_path))
    
    with tempfile.NamedTemporaryFile(suffix=".mp4", delete=False) as fp:
        video.write_videofile(fp.name, fps=24, threads=4)
        return fp.name

# ==================================================================
# Streamlit UI (Updated with language support warnings)
# ==================================================================
st.title("PNG Slides to Video Maker 🖼️➡️🎥")
st.markdown("Upload PNG slides, add scripts, and generate a video!")

# Language support warning
st.warning("""
**Voice Gender Support:**  
✓ English (Male: British, Female: American)  
✓ Spanish (Male: Mexican, Female: European)  
✓ French (Male: Canadian, Female: France)  
✓ German (Male: Austrian, Female: German)  
✗ Japanese/Others: Female only  
""")

# Main file uploader
uploaded_images = st.file_uploader(
    "Step 1: Upload PNG Slides",
    type=["png"],
    accept_multiple_files=True,
    key="main_uploader"
)

if not uploaded_images:
    st.info("ℹ️ Please upload PNG slides to begin")
    st.stop()

# Slide ordering
st.subheader("Step 2: Arrange Slide Order")
filenames = [img.name for img in uploaded_images]
st.session_state.slide_order = st.multiselect(
    "Drag to reorder slides:",
    filenames,
    default=filenames,
    key="sort_slides"
)
uploaded_images = [img for name in st.session_state.slide_order 
                  for img in uploaded_images if img.name == name]

# Video settings
st.subheader("Step 3: Video Settings")
col1, col2 = st.columns(2)
with col1:
    transition_delay = st.slider(
        "Transition Delay (seconds)",
        min_value=0,
        max_value=5,
        value=2,
        help="Silence between slides after voice finishes"
    )
with col2:
    gender = st.selectbox(
        "Voice Gender",
        options=['female', 'male'],
        help="Gender selection for supported languages"
    )

# Language selector with full names
lang = st.selectbox(
    "Voice Language", 
    options=[
        ('English', 'en'),
        ('Spanish', 'es'),
        ('French', 'fr'),
        ('German', 'de'),
        ('Japanese', 'ja'),
        ('Chinese', 'zh-CN'),
        ('Hindi', 'hi')
    ],
    format_func=lambda x: x[0],
    index=0
)[1]  # Get language code

# Script input
st.subheader("Step 4: Add Scripts")
slide_texts = []
with st.expander(f"Scripts for {len(uploaded_images)} Slides", expanded=True):
    for i, img in enumerate(uploaded_images):
        text = st.text_area(
            f"Slide {i+1} Text", 
            key=f"slide_{i}",
            placeholder="Enter text for this slide...",
            height=100
        )
        slide_texts.append(text.strip())

# Music settings
st.subheader("Step 5: Background Music (Optional)")
uploaded_music = st.file_uploader(
    "Upload MP3 file", 
    type=["mp3"],
    key="music_uploader"
)
music_volume = st.slider(
    "Music Volume Reduction (dB)", 
    0, 30, 25,
    help="Higher values make background music quieter"
) if uploaded_music else 0

# Generate button
st.subheader("Step 6: Generate Video")
if st.button("🚀 Generate Video", use_container_width=True, type="primary"):
    # Validation
    if len(slide_texts) != len(uploaded_images):
        st.error("Number of scripts doesn't match number of slides!")
        st.stop()
        
    if any(not text for text in slide_texts):
        st.error("All slides must have non-empty text!")
        st.stop()

    with st.spinner("Creating your video... This may take a minute ⏳"):
        try:
            # 1. Save images to temp files
            img_paths = []
            for img in uploaded_images:
                with tempfile.NamedTemporaryFile(suffix=".png", delete=False) as f:
                    f.write(img.getbuffer())
                    img_paths.append(f.name)

            # 2. Generate voiceover with delays
            durations, voice_path = text_to_speech(
                slide_texts, 
                lang, 
                gender,
                transition_delay
            )

            # 3. Process background music
            music_path = None
            if uploaded_music:
                with tempfile.NamedTemporaryFile(suffix=".mp3", delete=False) as f:
                    f.write(uploaded_music.getbuffer())
                    music_path = f.name
            
            audio_duration, final_audio_path = add_background_music(
                voice_path, 
                music_path, 
                music_volume
            )

            # 4. Create video
            video_path = create_video(img_paths, durations, final_audio_path)

            # 5. Display result
            st.success("✅ Video Ready! Play it below")
            st.video(video_path)

            # 6. Cleanup
            cleanup_files = img_paths + [voice_path, final_audio_path]
            if music_path:
                cleanup_files.append(music_path)
            cleanup_files.append(video_path)
            
            for f in cleanup_files:
                if os.path.exists(f):
                    os.unlink(f)

        except ValueError as e:
            st.error(f"Audio Error: {str(e)}")
        except Exception as e:
            st.error(f"Processing Error: {str(e)}")