app.py

import os
import time
import tempfile
import google.generativeai as genai
import requests
from flask import Flask, request, render_template, send_from_directory, url_for, flash
from moviepy.editor import VideoFileClip, AudioFileClip
from werkzeug.utils import secure_filename

# --- 1. INITIALIZE FLASK APP AND LOAD SECRETS ---
app = Flask(__name__)

# Load secrets from environment variables for security
GEMINI_API_KEY = os.getenv("GEMINI_API_KEY")
TTS_API_URL = os.getenv("TTS_API_URL")

# Application needs a secret key for flashing messages
app.config['SECRET_KEY'] = os.urandom(24)

# Check if the secrets were loaded correctly
if not GEMINI_API_KEY:
    raise ValueError("GEMINI_API_KEY secret not found! Please set it as an environment variable.")
if not TTS_API_URL:
    raise ValueError("TTS_API_URL secret not found! Please set it as an environment variable.")

# Configure the Gemini API with the loaded key
genai.configure(api_key=GEMINI_API_KEY)

# Configure directories for file uploads and processed downloads
UPLOAD_FOLDER = 'uploads'
DOWNLOAD_FOLDER = 'downloads'
os.makedirs(UPLOAD_FOLDER, exist_ok=True)
os.makedirs(DOWNLOAD_FOLDER, exist_ok=True)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
app.config['DOWNLOAD_FOLDER'] = DOWNLOAD_FOLDER

# --- 2. DEFINE VOICE CHOICES AND GEMINI PROMPT ---
VOICE_CHOICES = {
    "Male (Charon)": "Charon",
    "Female (Zephyr)": "Zephyr"
}

GEMINI_PROMPT = """
You are an AI scriptwriter. Your task is to watch the provided video and transcribe ALL spoken dialogue into a SINGLE, CONTINUOUS block of modern, colloquial Tamil.

**CRITICAL INSTRUCTIONS:**
1.  **Single Script:** Combine all dialogue from all speakers into one continuous script.
2.  **NO Timestamps or Speaker Labels:** Do NOT include any timestamps or speaker identifiers.
3.  **Incorporate Performance:** Add English style prompts (e.g., `Say happily:`, `Whisper mysteriously:`) and performance tags (e.g., `[laugh]`, `[sigh]`) directly into the text.

**EXAMPLE OUTPUT:**
Say happily: வணக்கம்! [laugh] எப்படி இருக்கீங்க? Whisper mysteriously: அந்த ரகசியம் எனக்கு மட்டும் தான் தெரியும்.
"""

# --- 3. HELPER FUNCTIONS (CORE LOGIC) ---

def generate_tamil_script(video_file_path):
    """Generates a single, continuous Tamil script from the video."""
    print("Uploading file to Gemini for transcription...")
    video_file = genai.upload_file(video_file_path, mime_type="video/mp4")
    
    print("Waiting for file processing...")
    while video_file.state.name == "PROCESSING":
        time.sleep(5)
        video_file = genai.get_file(video_file.name)
    if video_file.state.name != "ACTIVE":
        raise Exception(f"File {video_file.name} failed to process on Gemini's side.")

    print("Generating single narrator script...")
    model = genai.GenerativeModel(model_name="models/gemini-1.5-pro-latest")
    response = model.generate_content([GEMINI_PROMPT, video_file])
    
    genai.delete_file(video_file.name)
    print("Deleted file from Gemini.")

    if response.text:
        return " ".join(response.text.strip().splitlines())
    raise Exception("No valid script was generated by Gemini. The video might be silent or have unrecognized speech.")

def generate_single_audio_track(dialogue_text, voice_name, is_cheerful, output_path):
    """Generates one continuous audio track for the entire script."""
    print(f"Generating audio with voice '{voice_name}' | Cheerful: {is_cheerful}")
    payload = {"text": dialogue_text, "voice_name": voice_name, "cheerful": is_cheerful}
    response = requests.post(TTS_API_URL, json=payload, timeout=300) # Added timeout
    if response.status_code == 200:
        with open(output_path, "wb") as f:
            f.write(response.content)
        print(f"Audio track saved successfully to {output_path}")
        return True
    raise Exception(f"Error from TTS API: {response.status_code} - {response.text}")

def replace_video_audio(video_path, new_audio_path, output_path):
    """Replaces the audio of a video with a new audio file."""
    print("Replacing video audio...")
    try:
        video_clip = VideoFileClip(video_path)
        audio_clip = AudioFileClip(new_audio_path)
        final_clip = video_clip.set_audio(audio_clip)
        final_clip.write_videofile(output_path, codec="libx264", audio_codec="aac", logger='bar')
    finally:
        # Ensure clips are closed to release file handles
        if 'video_clip' in locals():
            video_clip.close()
        if 'audio_clip' in locals():
            audio_clip.close()
        if 'final_clip' in locals():
            final_clip.close()
    print(f"Final video saved to {output_path}")

# --- 4. FLASK ROUTES ---

@app.route('/', methods=['GET'])
def index():
    """Renders the main upload page."""
    return render_template('index.html')

@app.route('/process', methods=['POST'])
def process_video():
    """Handles the video upload and dubbing process."""
    if 'video' not in request.files:
        flash("No video file part in the request.", "error")
        return render_template('index.html')
    
    file = request.files['video']
    if file.filename == '':
        flash("No file was selected. Please choose a video to upload.", "error")
        return render_template('index.html')

    if file:
        filename = secure_filename(file.filename)
        upload_path = os.path.join(app.config['UPLOAD_FOLDER'], filename)
        temp_audio_path = None
        
        try:
            file.save(upload_path)

            voice_choice = request.form['voice_choice']
            is_cheerful = 'cheerful' in request.form
            voice_name = VOICE_CHOICES[voice_choice]
            
            # Generate the script
            script = generate_tamil_script(upload_path)
            
            # Generate the audio track in a temporary file
            temp_audio_fd, temp_audio_path = tempfile.mkstemp(suffix=".wav")
            os.close(temp_audio_fd) # Close file descriptor
            generate_single_audio_track(script, voice_name, is_cheerful, temp_audio_path)
            
            # Create the final video
            final_video_name = f"dubbed_{filename}"
            final_video_path = os.path.join(app.config['DOWNLOAD_FOLDER'], final_video_name)
            replace_video_audio(upload_path, temp_audio_path, final_video_path)
            
            # Render the page again with the results
            return render_template('index.html', 
                                   result_video=url_for('serve_video', filename=final_video_name), 
                                   script=script)

        except Exception as e:
            print(f"An error occurred: {e}")
            flash(f"An error occurred during processing: {e}", "error")
            return render_template('index.html')
        finally:
            # Clean up temporary audio file if it exists
            if temp_audio_path and os.path.exists(temp_audio_path):
                os.remove(temp_audio_path)

@app.route('/downloads/<filename>')
def serve_video(filename):
    """Serves the final dubbed video from the downloads directory."""
    return send_from_directory(app.config['DOWNLOAD_FOLDER'], filename)

if __name__ == '__main__':
    # Use host='0.0.0.0' to make it accessible on your local network
    app.run(host="0.0.0.0", port=7860)