services/tts_service.py

import uuid
from pathlib import Path
from config import GROQ_TTS_API_KEY, GROQ_TTS_MODEL
from gtts import gTTS

def text_to_speech(
    text: str,
    voice: str = "en",
    fmt: str = "mp3",
) -> str:
    """
    Convert text to speech using gTTS (Google Translate, free).
    Only MP3 is supported.
    """
    if not GROQ_TTS_API_KEY:
        raise RuntimeError("GROQ_TTS_API_KEY is not set in config")
    
    if not text or not text.strip():
        raise ValueError("Text cannot be empty")
    
    url = "https://api.groq.com/openai/v1/audio/speech"
    
    headers = {
        "Authorization": f"Bearer {GROQ_TTS_API_KEY}",
        "Content-Type": "application/json"
    }
    
    payload = {
        "model": GROQ_TTS_MODEL,
        "input": text.strip(),
        "voice": voice,
        "response_format": fmt
    }
    
    if not text or not text.strip():
        raise ValueError("Text cannot be empty")

    if fmt != "mp3":
        raise ValueError("Only MP3 format is supported by the free TTS backend")

    try:
        temp_dir = Path("temp_audio")
        temp_dir.mkdir(exist_ok=True)

        output_filename = f"tts_{uuid.uuid4().hex[:8]}.{fmt}"
        output_path = temp_dir / output_filename

        # gTTS uses language codes; voice kept for compatibility.
        tts = gTTS(text=text.strip(), lang=voice or "en")
        tts.save(str(output_path))

        return str(output_path)

    except Exception as e:
        raise Exception(f"Unexpected error in text_to_speech: {str(e)}")