import tensorflow as tf
import huggingface_hub as hf_hub
import gradio as gr


num_rows = 3
num_cols = 3
num_images = num_rows * num_cols
image_size = 64
plot_image_size = 64


def load_model():
    model = hf_hub.from_pretrained_keras("beresandras/denoising-diffusion-model")
    return model

def diffusion_schedule(diffusion_times, min_signal_rate, max_signal_rate):
    start_angle = tf.acos(max_signal_rate)
    end_angle = tf.acos(min_signal_rate)

    diffusion_angles = start_angle + diffusion_times * (end_angle - start_angle)

    signal_rates = tf.cos(diffusion_angles)
    noise_rates = tf.sin(diffusion_angles)
    
    return noise_rates, signal_rates

def generate_images(model, num_images, diffusion_steps, stochasticity, min_signal_rate, max_signal_rate):
    step_size = 1.0 / diffusion_steps
    initial_noise = tf.random.normal(shape=(num_images, image_size, image_size, 3))
    
    noisy_images = initial_noise
    for step in range(diffusion_steps):
        diffusion_times = tf.ones((num_images, 1, 1, 1)) - step * step_size
        next_diffusion_times = diffusion_times - step_size
        
        noise_rates, signal_rates = diffusion_schedule(diffusion_times, min_signal_rate, max_signal_rate)
        next_noise_rates, next_signal_rates = diffusion_schedule(next_diffusion_times, min_signal_rate, max_signal_rate)
        
        sample_noises = tf.random.normal(shape=(num_images, image_size, image_size, 3))
        sample_noise_rates = stochasticity * (1.0 - (signal_rates / next_signal_rates)**2)**0.5 * (next_noise_rates / noise_rates)
        
        pred_noises = model([noisy_images, noise_rates])
        pred_images = (noisy_images - noise_rates * pred_noises) / signal_rates
        noisy_images = (
            next_signal_rates * pred_images
            + (next_noise_rates**2 - sample_noise_rates**2)**0.5 * pred_noises
            + sample_noise_rates * sample_noises
        )
        
    generated_images = tf.clip_by_value(0.5 + 0.3 * pred_images, 0.0, 1.0)
    generated_images = tf.image.resize(
            generated_images, (plot_image_size, plot_image_size), method="nearest"
    )
    return generated_images.numpy()


model = load_model()
gr.Interface(
    generate_images,
    inputs=[
        model,
        num_images,
        gr.inputs.Slider(1, 20, default=10, label="Diffusion steps"),
        gr.inputs.Slider(0.0, 1.0, step=0.05, default=0.0, label="Stochasticity"),
        gr.inputs.Slider(0.02, 0.10, step=0.01, default=0.02, label="Minimal signal rate"),
        gr.inputs.Slider(0.80, 0.95, step=0.01, default=0.95, label="Maximal signal rate"),
    ],
    outputs="image",
).launch()