app.py

# app_gradio.py
import gradio as gr
import numpy as np
import torch
import os
import yaml
from dotenv import load_dotenv
from threading import Thread
from gradio_webrtc import WebRTC
from twilio.rest import Client

# --- TTS & AI Imports ---
from parler_tts import ParlerTTSForConditionalGeneration
from transformers import AutoTokenizer, AutoFeatureExtractor
from streamer import ParlerTTSStreamer 

# --- Local Project Imports ---
from src.detection.factory import get_detector
from src.alerting.alert_system import get_alerter

# --- Load Configuration and Environment Variables ---
load_dotenv()
config_path = 'config.yaml'
with open(config_path, 'r') as f:
    config = yaml.safe_load(f)
secrets = {"gemini_api_key": os.getenv("GEMINI_API_KEY")}

# --- Initialize Backend Components ---
print("Initializing detector and alerter...")
detector = get_detector(config)
alerter = get_alerter(config, secrets["gemini_api_key"])
print("Initialization complete.")

# --- Twilio TURN Server Setup ---
account_sid = os.environ.get("TURN_USERNAME")
auth_token = os.environ.get("TURN_CREDENTIAL")
rtc_configuration = None
if account_sid and auth_token:
    try:
        client = Client(account_sid, auth_token)
        token = client.tokens.create()
        rtc_configuration = {"iceServers": token.ice_servers}
        print("Twilio TURN server configured successfully.")
    except Exception as e:
        print(f"Warning: Failed to create Twilio token. Using public STUN server. Error: {e}")
# Fallback to a public STUN server if Twilio fails or is not configured
if rtc_configuration is None:
    print("Using public STun server.")
    rtc_configuration = {"iceServers": [{"urls": ["stun:stun.l.google.com:19302"]}]}


# --- Parler-TTS Model Setup ---
print("Loading Parler-TTS model...")
device = "cuda:0" if torch.cuda.is_available() else "cpu"
if device == "cpu":
    print("\nWARNING: Running Parler-TTS on a CPU is slow. A GPU is highly recommended.\n")
torch_dtype = torch.float16 if device != "cpu" else torch.float32

repo_id = "parler-tts/parler_tts_mini_v0.1"
model = ParlerTTSForConditionalGeneration.from_pretrained(repo_id, torch_dtype=torch_dtype).to(device)
tokenizer = AutoTokenizer.from_pretrained(repo_id)
feature_extractor = AutoFeatureExtractor.from_pretrained(repo_id)
print("Parler-TTS model loaded.")

# --- Audio Streaming Generator ---
def stream_alert_audio(text_prompt):
    """A generator that streams audio chunks for a given text prompt."""
    sampling_rate = model.config.sampling_rate
    description = "A female speaker with a clear and urgent voice."
    prompt_ids = tokenizer(text_prompt, return_tensors="pt").input_ids.to(device)
    description_ids = tokenizer(description, return_tensors="pt").input_ids.to(device)
    streamer = ParlerTTSStreamer(model, device, play_steps=int(sampling_rate * 2.0))
    generation_kwargs = dict(input_ids=description_ids, prompt_input_ids=prompt_ids, streamer=streamer, do_sample=True, temperature=1.0, repetition_penalty=1.2)
    thread = Thread(target=model.generate, kwargs=generation_kwargs)
    try:
        thread.start()
        print(f"Audio stream started for: '{text_prompt}'")
        for new_audio_chunk in streamer:
            yield (sampling_rate, new_audio_chunk)
    finally:
        print("Audio stream finished. Resetting alerter state.")
        alerter.reset_alert()

# --- Decoupled Processing Functions ---

def process_video_and_update_state(frame_dict: dict, state: dict):
    """
    HIGH-FREQUENCY LOOP: Processes video, updates shared state, and returns the processed frame.
    This function's speed directly impacts video latency.
    """
    if not frame_dict or "video" not in frame_dict or frame_dict["video"] is None:
        return np.zeros((480, 640, 3), dtype=np.uint8), state

    frame = frame_dict["video"]
    processed_frame, indicators, _ = detector.process_frame(frame)
    state['indicators'] = indicators
    return processed_frame, state

def update_ui_from_state(state: dict):
    """
    LOW-FREQUENCY LOOP: Reads from state to update status text and trigger audio.
    This runs independently of the video loop.
    """
    indicators = state.get('indicators', {})
    drowsiness_level = indicators.get("drowsiness_level", "Awake")
    lighting = indicators.get("lighting", "Good")
    score = indicators.get("details", {}).get("Score", 0)

    status_text = f"Lighting: {lighting}\nStatus: {drowsiness_level}\nScore: {score:.2f}"
    if lighting == "Low":
        status_text = "Lighting: Low\nDetection paused due to low light."

    audio_output = None
    if drowsiness_level != "Awake":
        alert_text = alerter.trigger_alert(level=drowsiness_level)
        if alert_text:
            audio_output = stream_alert_audio(alert_text)
    return status_text, audio_output

# --- Gradio UI Definition ---
with gr.Blocks(theme=gr.themes.Default(primary_hue="blue")) as app:
    gr.Markdown("# 🚗 Drive Paddy - Drowsiness Detection (WebRTC)")
    gr.Markdown("Low-latency video processing via WebRTC, with decoupled UI updates for smooth performance.")
    
    # Shared state object to pass data between the two processing loops
    shared_state = gr.State(value={'indicators': {}})

    with gr.Row():
        with gr.Column(scale=2):
            # This WebRTC component is now correctly used for both input and output of the video stream.
            webcam = WebRTC(label="Live Camera Feed", rtc_configuration=rtc_configuration)
        with gr.Column(scale=1):
            status_output = gr.Textbox(label="Live Status", lines=3, interactive=False)
            audio_alert_output = gr.Audio(label="Alert System", autoplay=True, visible=False, streaming=True)
            
    # LOOP 1: High-Frequency Video Stream (as fast as possible)
    # This takes video from the webcam, processes it, and sends it right back.
    webcam.stream(
        fn=process_video_and_update_state,
        inputs=[webcam, shared_state],
        outputs=[webcam, shared_state],
    )

    # LOOP 2: Low-Frequency UI Updates (4 times per second)
    # This runs on a timer, reads the shared state, and updates the other UI elements.
    app.load(
        fn=update_ui_from_state,
        inputs=[shared_state],
        outputs=[status_output, audio_alert_output],
    )

if __name__ == "__main__":
    print("Starting Drive Paddy WebRTC Application...")
    app.launch(debug=True)