utils/tts.py

import os
import logging
import time
import soundfile as sf

logger = logging.getLogger(__name__)

# Flag to track TTS engine availability
KOKORO_AVAILABLE = False
DIA_AVAILABLE = False

# Try to import Kokoro first
try:
    from kokoro import KPipeline
    KOKORO_AVAILABLE = True
    logger.info("Kokoro TTS engine is available")
except AttributeError as e:
    # Specifically catch the EspeakWrapper.set_data_path error
    if "EspeakWrapper" in str(e) and "set_data_path" in str(e):
        logger.warning("Kokoro import failed due to EspeakWrapper.set_data_path issue")
    else:
        # Re-raise if it's a different error
        logger.error(f"Kokoro import failed with unexpected error: {str(e)}")
        raise
except ImportError:
    logger.warning("Kokoro TTS engine is not available")

# Try to import Dia as fallback
if not KOKORO_AVAILABLE:
    try:
        from utils.tts_dia import _get_model as get_dia_model
        DIA_AVAILABLE = True
        logger.info("Dia TTS engine is available as fallback")
    except ImportError as e:
        logger.warning(f"Dia TTS engine is not available: {str(e)}")
        logger.warning("Will use dummy TTS implementation as fallback")

class TTSEngine:
    def __init__(self, lang_code='z'):
        """Initialize TTS Engine with Kokoro or Dia as fallback
        
        Args:
            lang_code (str): Language code ('a' for US English, 'b' for British English,
                           'j' for Japanese, 'z' for Mandarin Chinese)
                           Note: lang_code is only used for Kokoro, not for Dia
        """
        logger.info("Initializing TTS Engine")
        self.engine_type = None
        
        if KOKORO_AVAILABLE:
            self.pipeline = KPipeline(lang_code=lang_code)
            self.engine_type = "kokoro"
            logger.info("TTS engine initialized with Kokoro")
        elif DIA_AVAILABLE:
            # For Dia, we don't need to initialize anything here
            # The model will be lazy-loaded when needed
            self.pipeline = None
            self.engine_type = "dia"
            logger.info("TTS engine initialized with Dia (lazy loading)")
        else:
            logger.warning("Using dummy TTS implementation as no TTS engines are available")
            self.pipeline = None
            self.engine_type = "dummy"

    def generate_speech(self, text: str, voice: str = 'af_heart', speed: float = 1.0) -> str:
        """Generate speech from text using available TTS engine
        
        Args:
            text (str): Input text to synthesize
            voice (str): Voice ID to use (e.g., 'af_heart', 'af_bella', etc.)
                         Note: voice parameter is only used for Kokoro, not for Dia
            speed (float): Speech speed multiplier (0.5 to 2.0)
                           Note: speed parameter is only used for Kokoro, not for Dia
            
        Returns:
            str: Path to the generated audio file
        """
        logger.info(f"Generating speech for text length: {len(text)}")
        
        try:
            # Create output directory if it doesn't exist
            os.makedirs("temp/outputs", exist_ok=True)
            
            # Generate unique output path
            output_path = f"temp/outputs/output_{int(time.time())}.wav"
            
            # Use the appropriate TTS engine based on availability
            if self.engine_type == "kokoro":
                # Use Kokoro for TTS generation
                generator = self.pipeline(text, voice=voice, speed=speed)
                for _, _, audio in generator:
                    logger.info(f"Saving Kokoro audio to {output_path}")
                    sf.write(output_path, audio, 24000)
                    break
            elif self.engine_type == "dia":
                # Use Dia for TTS generation
                try:
                    # Import here to avoid circular imports
                    from utils.tts_dia import generate_speech as dia_generate_speech
                    # Call Dia's generate_speech function
                    output_path = dia_generate_speech(text)
                    logger.info(f"Generated audio with Dia: {output_path}")
                except Exception as dia_error:
                    logger.error(f"Dia TTS generation failed: {str(dia_error)}", exc_info=True)
                    # Fall back to dummy audio if Dia fails
                    return self._generate_dummy_audio(output_path)
            else:
                # Generate dummy audio as fallback
                return self._generate_dummy_audio(output_path)
            
            logger.info(f"Audio generation complete: {output_path}")
            return output_path

        except Exception as e:
            logger.error(f"TTS generation failed: {str(e)}", exc_info=True)
            raise
            
    def _generate_dummy_audio(self, output_path):
        """Generate a dummy audio file with a simple sine wave
        
        Args:
            output_path (str): Path to save the dummy audio file
            
        Returns:
            str: Path to the generated dummy audio file
        """
        import numpy as np
        sample_rate = 24000
        duration = 3.0  # seconds
        t = np.linspace(0, duration, int(sample_rate * duration), False)
        tone = np.sin(2 * np.pi * 440 * t) * 0.3
        
        logger.info(f"Saving dummy audio to {output_path}")
        sf.write(output_path, tone, sample_rate)
        logger.info(f"Dummy audio generation complete: {output_path}")
        return output_path

    def generate_speech_stream(self, text: str, voice: str = 'af_heart', speed: float = 1.0):
        """Generate speech from text and yield each segment
        
        Args:
            text (str): Input text to synthesize
            voice (str): Voice ID to use (e.g., 'af_heart', 'af_bella', etc.)
            speed (float): Speech speed multiplier (0.5 to 2.0)
            
        Yields:
            tuple: (sample_rate, audio_data) pairs for each segment
        """
        try:
            # Use the appropriate TTS engine based on availability
            if self.engine_type == "kokoro":
                # Use Kokoro for streaming TTS
                generator = self.pipeline(text, voice=voice, speed=speed)
                for _, _, audio in generator:
                    yield 24000, audio
            elif self.engine_type == "dia":
                # Dia doesn't support streaming natively, so we generate the full audio
                # and then yield it as a single chunk
                try:
                    # Import here to avoid circular imports
                    import torch
                    from utils.tts_dia import _get_model, DEFAULT_SAMPLE_RATE
                    
                    # Get the Dia model
                    model = _get_model()
                    
                    # Generate audio
                    with torch.inference_mode():
                        output_audio_np = model.generate(
                            text,
                            max_tokens=None,
                            cfg_scale=3.0,
                            temperature=1.3,
                            top_p=0.95,
                            cfg_filter_top_k=35,
                            use_torch_compile=False,
                            verbose=False
                        )
                    
                    if output_audio_np is not None:
                        yield DEFAULT_SAMPLE_RATE, output_audio_np
                    else:
                        # Fall back to dummy audio if Dia fails
                        yield from self._generate_dummy_audio_stream()
                except Exception as dia_error:
                    logger.error(f"Dia TTS streaming failed: {str(dia_error)}", exc_info=True)
                    # Fall back to dummy audio if Dia fails
                    yield from self._generate_dummy_audio_stream()
            else:
                # Generate dummy audio chunks as fallback
                yield from self._generate_dummy_audio_stream()
                
        except Exception as e:
            logger.error(f"TTS streaming failed: {str(e)}", exc_info=True)
            raise
            
    def _generate_dummy_audio_stream(self):
        """Generate dummy audio chunks with simple sine waves
        
        Yields:
            tuple: (sample_rate, audio_data) pairs for each dummy segment
        """
        import numpy as np
        sample_rate = 24000
        duration = 1.0  # seconds per chunk
        
        # Create 3 chunks of dummy audio
        for i in range(3):
            t = np.linspace(0, duration, int(sample_rate * duration), False)
            freq = 440 + (i * 220)  # Different frequency for each chunk
            tone = np.sin(2 * np.pi * freq * t) * 0.3
            yield sample_rate, tone

# Initialize TTS engine with cache decorator if using Streamlit
def get_tts_engine(lang_code='a'):
    """Get or create TTS engine instance
    
    Args:
        lang_code (str): Language code for the pipeline
        
    Returns:
        TTSEngine: Initialized TTS engine instance
    """
    try:
        import streamlit as st
        @st.cache_resource
        def _get_engine():
            return TTSEngine(lang_code)
        return _get_engine()
    except ImportError:
        return TTSEngine(lang_code)

def generate_speech(text: str, voice: str = 'af_heart', speed: float = 1.0) -> str:
    """Public interface for TTS generation
    
    Args:
        text (str): Input text to synthesize
        voice (str): Voice ID to use
        speed (float): Speech speed multiplier
        
    Returns:
        str: Path to generated audio file
    """
    engine = get_tts_engine()
    return engine.generate_speech(text, voice, speed)