app.py

import torch
import gradio as gr
import spaces  # Import spaces for ZeroGPU support
from functools import lru_cache
from diffusers import StableDiffusionXLPipeline  # ✅ Correct pipeline for text-to-image

# LoRA model path on Hugging Face Hub
color_book_lora_path = "artificialguybr/ColoringBookRedmond-V2"
color_book_trigger = ", ColoringBookAF, Coloring Book"

# Load model on CPU initially
@lru_cache(maxsize=1)
def load_pipeline(use_lora: bool):
    """Load Stable Diffusion XL pipeline and LoRA weights (if selected)."""
    
    # ✅ Use StableDiffusionXLPipeline for text-to-image generation
    pipe = StableDiffusionXLPipeline.from_pretrained(
        "stabilityai/stable-diffusion-xl-base-1.0",
        torch_dtype=torch.float16 if torch.cuda.is_available() else torch.float32,
        use_safetensors=True
    )

    # Keep the model on CPU until GPU is requested
    pipe.to("cpu")

    # Load LoRA if selected
    if use_lora:
        pipe.load_lora_weights(color_book_lora_path)

    return pipe

# Define styles
styles = {
    "Neonpunk": {
        "prompt": "neonpunk style, cyberpunk, vaporwave, neon, vibrant, stunningly beautiful, crisp, "
                  "detailed, sleek, ultramodern, magenta highlights, dark purple shadows, high contrast, cinematic",
        "negative_prompt": "painting, drawing, illustration, glitch, deformed, mutated, cross-eyed, ugly, disfigured"
    },
    "Retro Cyberpunk": {
        "prompt": "retro cyberpunk, 80's inspired, synthwave, neon, vibrant, detailed, retro futurism",
        "negative_prompt": "modern, desaturated, black and white, realism, low contrast"
    },
    "Dark Fantasy": {
        "prompt": "Dark Fantasy Art, dark, moody, dark fantasy style",
        "negative_prompt": "ugly, deformed, noisy, blurry, low contrast, bright, sunny"
    },
    "Double Exposure": {
        "prompt": "Double Exposure Style, double image ghost effect, image combination, double exposure style",
        "negative_prompt": "ugly, deformed, noisy, blurry, low contrast"
    },
    "None": {
        "prompt": "8K",
        "negative_prompt": "painting, drawing, illustration, glitch, deformed, mutated, cross-eyed, ugly, disfigured"
    }
}

@spaces.GPU  # ZeroGPU: Allocate GPU only when generating images
def generate_image(prompt: str, style_name: str, use_lora: bool):
    """Generate an image using Stable Diffusion XL with optional LoRA fine-tuning."""
    
    # Load the pipeline (cached)
    pipeline = load_pipeline(use_lora)

    # Move model to GPU only when needed
    pipeline.to("cuda")

    # Get the selected style details
    style_prompt = styles.get(style_name, {}).get("prompt", "")
    negative_prompt = styles.get(style_name, {}).get("negative_prompt", "")

    # Apply LoRA trigger phrase if enabled
    if use_lora:
        prompt += color_book_trigger

    # ✅ Ensure text-to-image pipeline is used correctly
    image = pipeline(
        prompt=prompt + " " + style_prompt,
        negative_prompt="blurred, ugly, watermark, low resolution, " + negative_prompt,
        num_inference_steps=20,
        guidance_scale=9.0
    ).images[0]

    # Move model back to CPU to free GPU resources
    pipeline.to("cpu")

    return image

# Gradio Interface for Hugging Face Spaces (ZeroGPU-compatible)
interface = gr.Interface(
    fn=generate_image,
    inputs=[
        gr.Textbox(label="Enter Your Prompt", placeholder="A cute lion"),
        gr.Dropdown(label="Select a Style", choices=list(styles.keys()), value="None"),
        gr.Checkbox(label="Use Coloring Book LoRA", value=False)
    ],
    outputs=gr.Image(label="Generated Image"),
    title="🎨 AI Coloring Book & Style Generator",
    description="Generate AI-powered art using Stable Diffusion XL on Hugging Face Spaces. "
                "Choose a style or enable a LoRA fine-tuned coloring book effect."
)

# Run Gradio app for Hugging Face Spaces
if __name__ == "__main__":
    interface.launch()