app.py

import os
import numpy as np
import tempfile
import soundfile as sf
import wave

from flask import Flask, request, jsonify, send_file, send_from_directory
from flask_cors import CORS
from werkzeug.utils import secure_filename

from kokoro import KPipeline
from gtts import gTTS, lang

from google import generativeai as genai
from google.genai import types

# Flask app setup
app = Flask(__name__, static_folder='static')
CORS(app)

# Gemini API configuration
GEMINI_API_KEY = os.getenv("GEMINI_API_KEY")
if not GEMINI_API_KEY:
    raise ValueError("GEMINI_API_KEY environment variable not set")
genai.configure(api_key=GEMINI_API_KEY)
client = genai.Client(api_key=GEMINI_API_KEY)

# Language support
KOKORO_LANGUAGES = {
    "American English": "a", "British English": "b", "Mandarin Chinese": "z",
    "Spanish": "e", "French": "f", "Hindi": "h", "Italian": "i", "Brazilian Portuguese": "p"
}
GTTS_LANGUAGES = lang.tts_langs()
GTTS_LANGUAGES['ja'] = 'Japanese'
SUPPORTED_LANGUAGES = sorted(list(set(list(KOKORO_LANGUAGES.keys()) + list(GTTS_LANGUAGES.values()))))

GEMINI_VOICES = {
    "ar-EG": "Kore", "de-DE": "Kore", "en-US": "Kore", "es-US": "Kore", "fr-FR": "Kore",
    "hi-IN": "Kore", "id-ID": "Kore", "it-IT": "Kore", "ja-JP": "Kore", "ko-KR": "Kore",
    "pt-BR": "Kore", "ru-RU": "Kore", "nl-NL": "Kore", "pl-PL": "Kore", "th-TH": "Kore",
    "tr-TR": "Kore", "vi-VN": "Kore", "ro-RO": "Kore", "uk-UA": "Kore", "bn-BD": "Kore",
    "en-IN": "Kore", "mr-IN": "Kore", "ta-IN": "Kore", "te-IN": "Kore"
}


def wave_file(filename, pcm, channels=1, rate=24000, sample_width=2):
    with wave.open(filename, "wb") as wf:
        wf.setnchannels(channels)
        wf.setsampwidth(sample_width)
        wf.setframerate(rate)
        wf.writeframes(pcm)


@app.route('/')
def serve_index():
    return send_from_directory(app.static_folder, 'index.html')


@app.route('/languages')
def get_languages():
    return jsonify(SUPPORTED_LANGUAGES)


@app.route('/translate', methods=['POST'])
def translate_audio():
    try:
        if 'audio' not in request.files:
            return jsonify({'error': 'No audio file uploaded'}), 400

        audio_file = request.files['audio']
        target_language = request.form.get('language', 'English')

        if not audio_file or audio_file.filename == '':
            return jsonify({'error': 'Invalid audio file'}), 400

        allowed_mime_types = ['audio/wav', 'audio/mpeg', 'audio/mp4', 'audio/webm']
        if audio_file.mimetype not in allowed_mime_types:
            return jsonify({'error': f'Unsupported file type: {audio_file.mimetype}'}), 400

        model = genai.GenerativeModel("gemini-2.0-flash")
        audio_blob = {'mime_type': audio_file.mimetype, 'data': audio_file.read()}

        convo = model.start_chat()
        convo.send_message("You are a professional transcriber. Transcribe this audio accurately and verbatim in the original language. Respond only with the transcription.")
        response = convo.send_message(audio_blob)
        transcription = response.text.strip()

        prompt = f"Translate the following text to {target_language} preserving meaning and cultural nuances. Respond only with the translation:\n\n{transcription}"
        response = model.generate_content(prompt)
        translated_text = response.text.strip()

        voice_name = GEMINI_VOICES.get(get_bcp47_code(target_language), None)

        if voice_name:
            response = client.models.generate_content(
                model="gemini-2.5-flash-preview-tts",
                contents=translated_text,
                config=types.GenerateContentConfig(
                    response_modalities=["AUDIO"],
                    speech_config=types.SpeechConfig(
                        voice_config=types.VoiceConfig(
                            prebuilt_voice_config=types.PrebuiltVoiceConfig(voice_name=voice_name)
                        )
                    )
                )
            )
            data = response.candidates[0].content.parts[0].inline_data.data
            temp_path = os.path.join(tempfile.gettempdir(), f'tts_{secure_filename(audio_file.filename)}.wav')
            wave_file(temp_path, data)
        elif target_language in KOKORO_LANGUAGES:
            lang_code = KOKORO_LANGUAGES[target_language]
            pipeline = KPipeline(lang_code=lang_code)
            generator = pipeline(translated_text, voice="af_heart", speed=1)

            audio_segments = []
            for _, _, audio in generator:
                if audio is not None:
                    audio_segments.append(audio)

            if audio_segments:
                audio_data = np.concatenate(audio_segments)
                temp_path = os.path.join(tempfile.gettempdir(), f'kokoro_{secure_filename(audio_file.filename)}.wav')
                sf.write(temp_path, audio_data, 24000)
            else:
                raise ValueError("No audio generated by Kokoro")
        else:
            lang_code = next((k for k, v in GTTS_LANGUAGES.items() if v == target_language), 'en')
            tts = gTTS(translated_text, lang=lang_code)
            temp_path = os.path.join(tempfile.gettempdir(), f'gtts_{secure_filename(audio_file.filename)}.mp3')
            tts.save(temp_path)

        return jsonify({
            'transcription': transcription,
            'translation': translated_text,
            'audio_url': f'/download/{os.path.basename(temp_path)}'
        })

    except Exception as e:
        app.logger.error(f"Error processing request: {str(e)}")
        return jsonify({'error': str(e)}), 500


@app.route('/download/<filename>')
def download_file(filename):
    try:
        return send_file(
            os.path.join(tempfile.gettempdir(), filename),
            mimetype="audio/mpeg",
            as_attachment=True,
            download_name=f"translated_{filename}"
        )
    except FileNotFoundError:
        return jsonify({'error': 'File not found'}), 404


def get_bcp47_code(language):
    bcp_map = {
        "Arabic": "ar-EG", "German": "de-DE", "English": "en-US", "Spanish": "es-US", "French": "fr-FR",
        "Hindi": "hi-IN", "Indonesian": "id-ID", "Italian": "it-IT", "Japanese": "ja-JP", "Korean": "ko-KR",
        "Portuguese": "pt-BR", "Russian": "ru-RU", "Dutch": "nl-NL", "Polish": "pl-PL", "Thai": "th-TH",
        "Turkish": "tr-TR", "Vietnamese": "vi-VN", "Romanian": "ro-RO", "Ukrainian": "uk-UA", "Bengali": "bn-BD",
        "Indian English": "en-IN", "Marathi": "mr-IN", "Tamil": "ta-IN", "Telugu": "te-IN"
    }
    return bcp_map.get(language)


if __name__ == '__main__':
    app.run(host="0.0.0.0", port=7860)