app.py

import random

import gradio as gr
import numpy as np
import torch

from src.chatterbox.mtl_tts import SUPPORTED_LANGUAGES, ChatterboxMultilingualTTS

DEVICE = "cuda" if torch.cuda.is_available() else "cpu"
print(f"🚀 Running on device: {DEVICE}")

# --- Global Model Initialization ---
MODEL = None

LANGUAGE_CONFIG = {
    "da": {
        "audio_options": {
            "mic": "voices/mic.wav",
            "nic": "voices/nic.wav"
        },
        "default_audio": "voices/mic.wav",  # Default to mic
        "text": "København er Danmarks hovedstad og ligger på øerne Sjælland og Amager, hvor mange turister besøger de smukke kanaler og historiske bygninger."
    },
    "en": {
        "audio": "voices/en_f1.flac",
        "text": "Last month, we reached a new milestone with two billion views on our YouTube channel."
    },
}

# --- UI Helpers ---
def default_audio_for_ui(lang: str, danish_voice: str = "mic") -> str | None:
    config = LANGUAGE_CONFIG.get(lang, {})
    if lang == "da" and "audio_options" in config:
        return config["audio_options"].get(danish_voice, config.get("default_audio"))
    return config.get("audio")


def default_text_for_ui(lang: str) -> str:
    return LANGUAGE_CONFIG.get(lang, {}).get("text", "")


def get_danish_voice_options() -> list[tuple[str, str]]:
    """Get the available Danish voice options for the dropdown."""
    return [("Mic", "mic"), ("Nic", "nic")]


def get_supported_languages_display() -> str:
    """Generate a formatted display of all supported languages."""
    language_items = []
    for code, name in sorted(SUPPORTED_LANGUAGES.items()):
        language_items.append(f"**{name}** (`{code}`)")
    
    # Split into 2 lines
    mid = len(language_items) // 2
    line1 = " • ".join(language_items[:mid])
    line2 = " • ".join(language_items[mid:])
    
    return f"""
### Supported Languages)
{line1}

{line2}
"""


def get_or_load_model():
    """Loads the ChatterboxMultilingualTTS model if it hasn't been loaded already,
    and ensures it's on the correct device."""
    global MODEL
    if MODEL is None:
        print("Model not loaded, initializing...")
        try:
            MODEL = ChatterboxMultilingualTTS.from_pretrained(DEVICE)
            if hasattr(MODEL, 'to') and str(MODEL.device) != DEVICE:
                MODEL.to(DEVICE)
            print(f"Model loaded successfully. Internal device: {getattr(MODEL, 'device', 'N/A')}")
        except Exception as e:
            print(f"Error loading model: {e}")
            raise
    return MODEL

# Attempt to load the model at startup.
try:
    get_or_load_model()
except Exception as e:
    print(f"CRITICAL: Failed to load model on startup. Application may not function. Error: {e}")

def set_seed(seed: int):
    """Sets the random seed for reproducibility across torch, numpy, and random."""
    torch.manual_seed(seed)
    if DEVICE == "cuda":
        torch.cuda.manual_seed(seed)
        torch.cuda.manual_seed_all(seed)
    random.seed(seed)
    np.random.seed(seed)
    
def resolve_audio_prompt(language_id: str, provided_path: str | None, danish_voice: str = "mic") -> str | None:
    """
    Decide which audio prompt to use:
    - If user provided a path (upload/mic/url), use it.
    - Else, fall back to language-specific default (if any).
    - For Danish, use the selected voice option.
    """
    if provided_path and str(provided_path).strip():
        return provided_path
    return default_audio_for_ui(language_id, danish_voice)


def generate_tts_audio(
    text_input: str,
    language_id: str,
    audio_prompt_path_input: str = None,
    danish_voice_input: str = "mic",
    temperature_input: float = 0.8,
    seed_num_input: int = 0,
    cfgw_input: float = 0.5
) -> tuple[int, np.ndarray]:
    """
    Generate high-quality speech audio from text using Chatterbox Multilingual model with optional reference audio styling.
    Supported languages: English, French, German, Spanish, Italian, Portuguese, and Hindi.
    
    This tool synthesizes natural-sounding speech from input text. When a reference audio file 
    is provided, it captures the speaker's voice characteristics and speaking style. The generated audio 
    maintains the prosody, tone, and vocal qualities of the reference speaker, or uses default voice if no reference is provided.

    Args:
        text_input (str): The text to synthesize into speech (maximum 300 characters)
        language_id (str): The language code for synthesis (eg. en, fr, de, es, it, pt, hi)
        audio_prompt_path_input (str, optional): File path or URL to the reference audio file that defines the target voice style. Defaults to None.
        temperature_input (float, optional): Controls randomness in generation (0.05-5.0, higher=more varied). Defaults to 0.8.
        seed_num_input (int, optional): Random seed for reproducible results (0 for random generation). Defaults to 0.
        cfgw_input (float, optional): CFG/Pace weight controlling generation guidance (0.2-1.0). Defaults to 0.5, 0 for language transfer. 

    Returns:
        tuple[int, np.ndarray]: A tuple containing the sample rate (int) and the generated audio waveform (numpy.ndarray)
    """
    current_model = get_or_load_model()
    exaggeration = 0.5


    if current_model is None:
        raise RuntimeError("TTS model is not loaded.")

    if seed_num_input != 0:
        set_seed(int(seed_num_input))

    print(f"Generating audio for text: '{text_input[:50]}...'")
    
    # Handle optional audio prompt
    chosen_prompt = resolve_audio_prompt(language_id, audio_prompt_path_input, danish_voice_input)

    generate_kwargs = {
        "exaggeration": exaggeration,
        "temperature": temperature_input,
        "cfg_weight": cfgw_input,
    }
    if chosen_prompt:
        generate_kwargs["audio_prompt_path"] = chosen_prompt
        print(f"Using audio prompt: {chosen_prompt}")
    else:
        print("No audio prompt provided; using default voice.")
        
    wav = current_model.generate(
        text_input[:300],  # Truncate text to max chars
        language_id=language_id,
        **generate_kwargs
    )
    print("Audio generation complete.")
    return (current_model.sr, wav.squeeze(0).numpy())

with gr.Blocks() as demo:
    gr.Markdown(
        """
        # Danish TTS Demo 🇩🇰
        Generate high-quality danish speech from text with reference audio styling.
        This is a preview of a model that was developed as part of the CoRal project, and is a finetuned version of the Chatterbox Multilingual.
        """
    )
    
    # Display supported languages
    gr.Markdown(get_supported_languages_display())
    with gr.Row():
        with gr.Column():
            initial_lang = "da"
            text = gr.Textbox(
                value=default_text_for_ui(initial_lang),
                label="Text to synthesize (max chars 300)",
                max_lines=5
            )
            
            language_id = gr.Dropdown(
                choices=list(ChatterboxMultilingualTTS.get_supported_languages().keys()),
                value=initial_lang,
                label="Language",
                info="Select the language for text-to-speech synthesis"
            )
            
            danish_voice = gr.Dropdown(
                choices=get_danish_voice_options(),
                value="mic",
                label="Danish Voice Selection",
                info="Choose between different Danish voice options",
                visible=(initial_lang == "da")
            )
            
            ref_wav = gr.Audio(
                sources=["upload", "microphone"],
                type="filepath",
                label="Reference Audio File (Optional)",
                value=default_audio_for_ui(initial_lang)
            )
            
            gr.Markdown(
                "💡 **Note**: Ensure that the reference clip matches the specified language tag. Otherwise, language transfer outputs may inherit the accent of the reference clip's language. To mitigate this, set the CFG weight to 0.",
                elem_classes=["audio-note"]
            )
            
            cfg_weight = gr.Slider(
                0.2, 1, step=.05, label="CFG/Pace", value=0.5
            )

            with gr.Accordion("More options", open=False):
                seed_num = gr.Number(value=0, label="Random seed (0 for random)")
                temp = gr.Slider(0.05, 2.5, step=.05, label="Temperature", value=.8)

            run_btn = gr.Button("Generate", variant="primary")

        with gr.Column():
            audio_output = gr.Audio(label="Output Audio")

        def on_language_change(lang, current_ref, current_text):
            is_danish = (lang == "da")
            danish_voice_val = "mic" if is_danish else "mic"  # Default to mic
            return (
                default_audio_for_ui(lang, danish_voice_val), 
                default_text_for_ui(lang), 
                gr.update(visible=is_danish),  # Update Danish voice dropdown visibility
                danish_voice_val
            )

        def on_danish_voice_change(lang, danish_voice_val):
            if lang == "da":
                return default_audio_for_ui(lang, danish_voice_val)
            return gr.update()  # No change if not Danish

        language_id.change(
            fn=on_language_change,
            inputs=[language_id, ref_wav, text],
            outputs=[ref_wav, text, danish_voice, danish_voice],
            show_progress=False
        )

        danish_voice.change(
            fn=on_danish_voice_change,
            inputs=[language_id, danish_voice],
            outputs=[ref_wav],
            show_progress=False
        )

    run_btn.click(
        fn=generate_tts_audio,
        inputs=[
            text,
            language_id,
            ref_wav,
            danish_voice,
            temp,
            seed_num,
            cfg_weight,
        ],
        outputs=[audio_output],
    )

demo.launch() #mcp_server=True