app.py

import logging
import random
import warnings
import os
import gradio as gr
import numpy as np
import spaces
import torch
from diffusers import FluxImg2ImgPipeline
from transformers import AutoProcessor, AutoModelForCausalLM
from gradio_imageslider import ImageSlider
from PIL import Image
from huggingface_hub import snapshot_download
import requests

css = """
#col-container {
    margin: 0 auto;
    max-width: 800px;
}
.main-header {
    text-align: center;
    margin-bottom: 2rem;
}
"""

# Device setup
if torch.cuda.is_available():
    power_device = "GPU"
    device = "cuda"
else:
    power_device = "CPU"
    device = "cpu"

# Get HuggingFace token
huggingface_token = os.getenv("HF_TOKEN")

# Download FLUX model
print("📥 Downloading FLUX model...")
model_path = snapshot_download(
    repo_id="black-forest-labs/FLUX.1-dev", 
    repo_type="model", 
    ignore_patterns=["*.md", "*.gitattributes"],
    local_dir="FLUX.1-dev",
    token=huggingface_token,
)

# Load Florence-2 model for image captioning
print("📥 Loading Florence-2 model...")
florence_model = AutoModelForCausalLM.from_pretrained(
    "microsoft/Florence-2-large", 
    torch_dtype=torch.float16,
    trust_remote_code=True,
    attn_implementation="eager"  # Fix for SDPA compatibility issue
).to(device)
florence_processor = AutoProcessor.from_pretrained(
    "microsoft/Florence-2-large", 
    trust_remote_code=True
)

# Load FLUX Img2Img pipeline
print("📥 Loading FLUX Img2Img...")
pipe = FluxImg2ImgPipeline.from_pretrained(
    model_path, 
    torch_dtype=torch.bfloat16
)
pipe.to(device)
pipe.enable_vae_tiling()
pipe.enable_vae_slicing()

print("✅ All models loaded successfully!")

MAX_SEED = 1000000
MAX_PIXEL_BUDGET = 4096 * 4096


def generate_caption(image):
    """Generate detailed caption using Florence-2"""
    try:
        task_prompt = "<MORE_DETAILED_CAPTION>"
        prompt = task_prompt

        inputs = florence_processor(text=prompt, images=image, return_tensors="pt").to(device)
        
        generated_ids = florence_model.generate(
            input_ids=inputs["input_ids"],
            pixel_values=inputs["pixel_values"],
            max_new_tokens=1024,
            num_beams=3,
            do_sample=True,
        )
        
        generated_text = florence_processor.batch_decode(generated_ids, skip_special_tokens=False)[0]
        parsed_answer = florence_processor.post_process_generation(generated_text, task=task_prompt, image_size=(image.width, image.height))
        
        caption = parsed_answer[task_prompt]
        return caption
    except Exception as e:
        print(f"Caption generation failed: {e}")
        return "a high quality detailed image"


def process_input(input_image, upscale_factor):
    """Process input image and handle size constraints"""
    w, h = input_image.size
    w_original, h_original = w, h
    aspect_ratio = w / h

    was_resized = False

    if w * h * upscale_factor**2 > MAX_PIXEL_BUDGET:
        warnings.warn(
            f"Requested output image is too large ({w * upscale_factor}x{h * upscale_factor}). Resizing to fit budget."
        )
        gr.Info(
            f"Requested output image is too large. Resizing input to fit within pixel budget."
        )
        input_image = input_image.resize(
            (
                int(aspect_ratio * MAX_PIXEL_BUDGET**0.5 // upscale_factor),
                int(MAX_PIXEL_BUDGET**0.5 // aspect_ratio // upscale_factor),
            ),
            resample=Image.LANCZOS
        )
        was_resized = True

    # Resize to multiple of 8
    w, h = input_image.size
    w = w - w % 8
    h = h - h % 8

    return input_image.resize((w, h), resample=Image.LANCZOS), w_original, h_original, was_resized


def load_image_from_url(url):
    """Load image from URL"""
    try:
        response = requests.get(url)
        response.raise_for_status()
        return Image.open(requests.get(url, stream=True).raw)
    except Exception as e:
        raise gr.Error(f"Failed to load image from URL: {e}")


@spaces.GPU(duration=120)
def enhance_image(
    image_input,
    image_url,
    seed,
    randomize_seed,
    num_inference_steps,
    upscale_factor,
    guidance_scale,
    denoising_strength,
    use_generated_caption,
    custom_prompt,
    progress=gr.Progress(track_tqdm=True),
):
    """Main enhancement function"""
    # Handle image input
    if image_input is not None:
        input_image = image_input
    elif image_url:
        input_image = load_image_from_url(image_url)
    else:
        raise gr.Error("Please provide an image (upload or URL)")

    if randomize_seed:
        seed = random.randint(0, MAX_SEED)

    true_input_image = input_image
    
    # Process input image
    input_image, w_original, h_original, was_resized = process_input(
        input_image, upscale_factor
    )

    # Generate caption if requested
    if use_generated_caption:
        gr.Info("🔍 Generating image caption...")
        generated_caption = generate_caption(input_image)
        prompt = generated_caption
    else:
        prompt = custom_prompt if custom_prompt.strip() else ""

    # Rescale with upscale factor using LANCZOS
    w, h = input_image.size
    control_image = input_image.resize((w * upscale_factor, h * upscale_factor), resample=Image.LANCZOS)

    generator = torch.Generator().manual_seed(seed)

    gr.Info("🚀 Upscaling image...")
    
    # Generate upscaled image
    image = pipe(
        prompt=prompt,
        image=control_image,
        strength=denoising_strength,
        num_inference_steps=num_inference_steps,
        guidance_scale=guidance_scale,
        height=control_image.size[1],
        width=control_image.size[0],
        generator=generator,
    ).images[0]

    if was_resized:
        gr.Info(f"📏 Resizing output to target size: {w_original * upscale_factor}x{h_original * upscale_factor}")

    # Resize to target desired size
    final_image = image.resize((w_original * upscale_factor, h_original * upscale_factor), resample=Image.LANCZOS)
    
    return [true_input_image, final_image], seed, generated_caption if use_generated_caption else ""


# Create Gradio interface
with gr.Blocks(css=css, title="🎨 AI Image Enhancer - Florence-2 + FLUX") as demo:
    gr.HTML("""
    <div class="main-header">
        <h1>🎨 AI Image Enhancer</h1>
        <p>Upload an image or provide a URL to enhance it using Florence-2 captioning and FLUX upscaling</p>
        <p>Currently running on <strong>{}</strong></p>
    </div>
    """.format(power_device))

    with gr.Row():
        with gr.Column(scale=1):
            gr.HTML("<h3>📤 Input</h3>")
            
            with gr.Tabs():
                with gr.TabItem("📁 Upload Image"):
                    input_image = gr.Image(
                        label="Upload Image",
                        type="pil",
                        height=300
                    )
                
                with gr.TabItem("🔗 Image URL"):
                    image_url = gr.Textbox(
                        label="Image URL",
                        placeholder="https://example.com/image.jpg",
                        value="https://upload.wikimedia.org/wikipedia/commons/thumb/a/a7/Example.jpg/800px-Example.jpg"
                    )
            
            gr.HTML("<h3>🎛️ Caption Settings</h3>")
            
            use_generated_caption = gr.Checkbox(
                label="Use AI-generated caption (Florence-2)",
                value=True,
                info="Generate detailed caption automatically"
            )
            
            custom_prompt = gr.Textbox(
                label="Custom Prompt (optional)",
                placeholder="Enter custom prompt or leave empty for generated caption",
                lines=2
            )
            
            gr.HTML("<h3>⚙️ Enhancement Settings</h3>")
            
            upscale_factor = gr.Slider(
                label="Upscale Factor",
                minimum=1,
                maximum=4,
                step=1,
                value=2,
                info="How much to upscale the image"
            )
            
            num_inference_steps = gr.Slider(
                label="Number of Inference Steps",
                minimum=8,
                maximum=50,
                step=1,
                value=25,
                info="More steps = better quality but slower"
            )
            
            guidance_scale = gr.Slider(
                label="Guidance Scale",
                minimum=1.0,
                maximum=10.0,
                step=0.5,
                value=3.5,
                info="How closely to follow the prompt"
            )
            
            denoising_strength = gr.Slider(
                label="Denoising Strength",
                minimum=0.0,
                maximum=1.0,
                step=0.05,
                value=0.3,
                info="Controls how much the image is transformed"
            )
            
            with gr.Row():
                randomize_seed = gr.Checkbox(
                    label="Randomize seed",
                    value=True
                )
                seed = gr.Slider(
                    label="Seed",
                    minimum=0,
                    maximum=MAX_SEED,
                    step=1,
                    value=42,
                    interactive=True
                )
            
            enhance_btn = gr.Button(
                "🚀 Enhance Image",
                variant="primary",
                size="lg"
            )

        with gr.Column(scale=1):
            gr.HTML("<h3>📊 Results</h3>")
            
            result_slider = ImageSlider(
                label="Input / Enhanced",
                type="pil",
                interactive=True,
                height=400
            )
            
            with gr.Row():
                output_seed = gr.Number(
                    label="Used Seed",
                    precision=0,
                    interactive=False
                )
            
            generated_caption_output = gr.Textbox(
                label="Generated Caption",
                placeholder="AI-generated caption will appear here...",
                lines=3,
                interactive=False
            )

    # Examples
    gr.Examples(
        examples=[
            [None, "https://upload.wikimedia.org/wikipedia/commons/thumb/a/a7/Example.jpg/800px-Example.jpg", 42, False, 25, 2, 3.5, 0.3, True, ""],
            [None, "https://picsum.photos/512/512", 123, False, 25, 3, 4.0, 0.3, True, ""],
        ],
        inputs=[
            input_image,
            image_url,
            seed,
            randomize_seed,
            num_inference_steps,
            upscale_factor,
            guidance_scale,
            denoising_strength,
            use_generated_caption,
            custom_prompt,
        ]
    )

    # Event handler
    enhance_btn.click(
        fn=enhance_image,
        inputs=[
            input_image,
            image_url,
            seed,
            randomize_seed,
            num_inference_steps,
            upscale_factor,
            guidance_scale,
            denoising_strength,
            use_generated_caption,
            custom_prompt,
        ],
        outputs=[result_slider, output_seed, generated_caption_output]
    )

    gr.HTML("""
    <div style="margin-top: 2rem; padding: 1rem; background: #f0f0f0; border-radius: 8px;">
        <h4>💡 How it works:</h4>
        <ol>
            <li><strong>Florence-2</strong> analyzes your image and generates a detailed caption</li>
            <li>Initial upscale with LANCZOS interpolation</li>
            <li><strong>FLUX Img2Img</strong> enhances the upscaled image with AI diffusion guided by the caption</li>
        </ol>
        <p><strong>Note:</strong> Output limited to 4096x4096 pixels total budget to prevent memory issues.</p>
    </div>
    """)

if __name__ == "__main__":
    demo.queue().launch(share=True, server_name="0.0.0.0", server_port=7860)