app.py

import gradio as gr
import numpy as np
import random
import os
import tempfile
from PIL import Image, ImageOps
import pillow_heif  # For HEIF/AVIF support
from huggingface_hub import InferenceClient
import io

# --- Constants ---
MAX_SEED = np.iinfo(np.int32).max

# --- Global client variable ---
client = None

def load_client():
    """Initialize the Inference Client"""
    global client
    if client is None:
        # Register HEIF opener with PIL for AVIF/HEIF support
        pillow_heif.register_heif_opener()
        
        # Get token from environment variable
        hf_token = os.getenv("HF_TOKEN")
        if hf_token:
            client = InferenceClient(
                provider="fal-ai",
                api_key=hf_token,
                bill_to="huggingface",
            )
        else:
            raise gr.Error("HF_TOKEN environment variable not found. Please add your Hugging Face token to the Space settings.")
    return client

# --- Core Inference Function for ChatInterface ---
def chat_fn(message, chat_history, seed, randomize_seed, guidance_scale, steps, progress=gr.Progress()):
    """
    Performs image generation or editing based on user input from the chat interface.
    """
    # Load client
    client = load_client()
    
    prompt = message["text"]
    files = message["files"]

    if not prompt and not files:
        raise gr.Error("Please provide a prompt and/or upload an image.")

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

    input_image = None
    if files:
        print(f"Received image: {files[0]}")
        try:
            # Try to open and convert the image
            input_image = Image.open(files[0])
            # Convert to RGB if needed (handles RGBA, P, etc.)
            if input_image.mode != "RGB":
                input_image = input_image.convert("RGB")
            # Auto-orient the image based on EXIF data
            input_image = ImageOps.exif_transpose(input_image)
            
            # Convert PIL image to bytes for the API
            img_byte_arr = io.BytesIO()
            input_image.save(img_byte_arr, format='PNG')
            input_image_bytes = img_byte_arr.getvalue()
            
        except Exception as e:
            raise gr.Error(f"Could not process the uploaded image: {str(e)}. Please try uploading a different image format (JPEG, PNG, WebP).")
            
        # Use image_to_image for editing
        progress(0.1, desc="Processing image...")
        image = client.image_to_image(
            input_image_bytes,
            prompt=prompt,
            model="black-forest-labs/FLUX.1-Kontext-dev",
            # Note: guidance_scale and steps might not be supported by the API
            # Check the API documentation for available parameters
        )
        progress(1.0, desc="Complete!")
    else:
        print(f"Received prompt for text-to-image: {prompt}")
        # Use text_to_image for generation
        progress(0.1, desc="Generating image...")
        image = client.text_to_image(
            prompt=prompt,
            model="black-forest-labs/FLUX.1-Kontext-dev",
            # Note: guidance_scale and steps might not be supported by the API
            # Check the API documentation for available parameters
        )
        progress(1.0, desc="Complete!")
    
    # The client returns a PIL Image object
    return gr.Image(value=image)

# --- UI Definition using gr.ChatInterface ---

seed_slider = gr.Slider(label="Seed", minimum=0, maximum=MAX_SEED, step=1, value=42)
randomize_checkbox = gr.Checkbox(label="Randomize seed", value=False)
guidance_slider = gr.Slider(label="Guidance Scale", minimum=1.0, maximum=10.0, step=0.1, value=2.5)
steps_slider = gr.Slider(label="Steps", minimum=1, maximum=30, value=28, step=1)

# Note: The Inference Client API may not support all parameters like guidance_scale and steps
# Check the API documentation for supported parameters

demo = gr.ChatInterface(
    fn=chat_fn,
    title="FLUX.1 Kontext [dev] - Inference Client",
    description="""<p style='text-align: center;'>
    A simple chat UI for the <b>FLUX.1 Kontext</b> model using Hugging Face Inference Client with fal-ai provider.
    <br>
    To edit an image, upload it and type your instructions (e.g., "Add a hat").
    <br>
    To generate an image, just type a prompt (e.g., "A photo of an astronaut on a horse").
    <br>
    Find the model on <a href='https://huggingface.co/black-forest-labs/FLUX.1-Kontext-dev' target='_blank'>Hugging Face</a>.
    </p>""",
    multimodal=True,
    textbox=gr.MultimodalTextbox(
        file_types=["image"],
        placeholder="Type a prompt and/or upload an image...",
        render=False
    ),
    additional_inputs=[
        seed_slider,
        randomize_checkbox,
        guidance_slider,
        steps_slider
    ],
    theme="soft"
)

if __name__ == "__main__":
    demo.launch()