app.py

import gradio as gr
import numpy as np
import random
import os
import base64
import requests
import time
import io
from PIL import Image, ImageOps
import pillow_heif  # For HEIF/AVIF support

# --- Constants ---
MAX_SEED = np.iinfo(np.int32).max
API_URL = "https://router.huggingface.co/fal-ai/fal-ai/flux-kontext/dev?_subdomain=queue"

def get_headers():
    """Get headers for API requests"""
    hf_token = os.getenv("HF_TOKEN")
    if not hf_token:
        raise gr.Error("HF_TOKEN environment variable not found. Please add your Hugging Face token to the Space settings.")
    
    return {
        "Authorization": f"Bearer {hf_token}",
        "X-HF-Bill-To": "huggingface"
    }

def query_api(payload, progress_callback=None):
    """Send request to the API and return response"""
    headers = get_headers()
    
    # Submit the job
    response = requests.post(API_URL, headers=headers, json=payload)
    
    if response.status_code != 200:
        raise gr.Error(f"API request failed with status {response.status_code}: {response.text}")
    
    # Parse the initial response
    try:
        json_response = response.json()
        print(f"Initial response: {json_response}")
    except:
        raise gr.Error("Failed to parse initial API response as JSON")
    
    # Check if job was queued
    if json_response.get("status") == "IN_QUEUE":
        status_url = json_response.get("status_url")
        if not status_url:
            raise gr.Error("No status URL provided in queue response")
        
        # Poll for completion
        max_attempts = 60  # Wait up to 5 minutes (60 * 5 seconds)
        attempt = 0
        
        while attempt < max_attempts:
            if progress_callback:
                progress_callback(0.1 + (attempt / max_attempts) * 0.8, f"Processing... (attempt {attempt + 1}/60)")
            
            time.sleep(5)  # Wait 5 seconds between polls
            
            # Check status
            status_response = requests.get(status_url, headers=headers)
            
            if status_response.status_code != 200:
                raise gr.Error(f"Status check failed: {status_response.status_code}")
            
            try:
                status_data = status_response.json()
                print(f"Status check {attempt + 1}: {status_data}")
                
                if status_data.get("status") == "COMPLETED":
                    # Job completed, get the result
                    response_url = json_response.get("response_url")
                    if not response_url:
                        raise gr.Error("No response URL provided")
                    
                    result_response = requests.get(response_url, headers=headers)
                    if result_response.status_code != 200:
                        raise gr.Error(f"Failed to get result: {result_response.status_code}")
                    
                    # Check if result is JSON with image data
                    try:
                        result_data = result_response.json()
                        print(f"Result data: {result_data}")
                        
                        # Look for image in various possible fields
                        if 'images' in result_data and len(result_data['images']) > 0:
                            # Images array with URLs or base64
                            image_data = result_data['images'][0]
                            if isinstance(image_data, dict) and 'url' in image_data:
                                # Image URL - fetch it
                                img_response = requests.get(image_data['url'])
                                return img_response.content
                            elif isinstance(image_data, str):
                                # Assume base64
                                return base64.b64decode(image_data)
                        elif 'image' in result_data:
                            # Single image field
                            if isinstance(result_data['image'], str):
                                return base64.b64decode(result_data['image'])
                        elif 'url' in result_data:
                            # Direct URL
                            img_response = requests.get(result_data['url'])
                            return img_response.content
                        else:
                            raise gr.Error(f"No image found in result: {result_data}")
                            
                    except requests.exceptions.JSONDecodeError:
                        # Result might be direct image bytes
                        return result_response.content
                        
                elif status_data.get("status") == "FAILED":
                    error_msg = status_data.get("error", "Unknown error")
                    raise gr.Error(f"Job failed: {error_msg}")
                
                # Still processing, continue polling
                attempt += 1
                
            except requests.exceptions.JSONDecodeError:
                raise gr.Error("Failed to parse status response")
    
        raise gr.Error("Job timed out after 5 minutes")
    
    elif json_response.get("status") == "COMPLETED":
        # Job completed immediately
        if 'images' in json_response and len(json_response['images']) > 0:
            image_data = json_response['images'][0]
            if isinstance(image_data, str):
                return base64.b64decode(image_data)
        elif 'image' in json_response:
            return base64.b64decode(json_response['image'])
        else:
            raise gr.Error(f"No image found in immediate response: {json_response}")
    
    else:
        raise gr.Error(f"Unexpected response status: {json_response.get('status', 'unknown')}")

# --- 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.
    """
    # Register HEIF opener with PIL for AVIF/HEIF support
    pillow_heif.register_heif_opener()
    
    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)

    # Prepare the payload
    payload = {
        "parameters": {
            "prompt": prompt,
            "seed": seed,
            "guidance_scale": guidance_scale,
            "num_inference_steps": steps
        }
    }

    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 base64 for the API
            img_byte_arr = io.BytesIO()
            input_image.save(img_byte_arr, format='PNG')
            img_byte_arr.seek(0)
            image_base64 = base64.b64encode(img_byte_arr.getvalue()).decode('utf-8')
            
            # Add image to payload for image-to-image
            payload["inputs"] = image_base64
            
        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).")
            
        progress(0.1, desc="Processing image...")
    else:
        print(f"Received prompt for text-to-image: {prompt}")
        # For text-to-image, we don't need the inputs field
        progress(0.1, desc="Generating image...")

    try:
        # Make API request
        image_bytes = query_api(payload)
        
        # Try to convert response bytes to PIL Image with better error handling
        try:
            image = Image.open(io.BytesIO(image_bytes))
        except Exception as img_error:
            print(f"Failed to open image directly: {img_error}")
            # Maybe it's a different format, try to save and examine
            with open('/tmp/debug_response.bin', 'wb') as f:
                f.write(image_bytes)
            print(f"Saved response to /tmp/debug_response.bin for debugging")
            
            # Try to decode as base64 if direct opening failed
            try:
                decoded_bytes = base64.b64decode(image_bytes)
                image = Image.open(io.BytesIO(decoded_bytes))
            except:
                raise gr.Error(f"Could not process API response as image. Response type: {type(image_bytes)}, Length: {len(image_bytes) if isinstance(image_bytes, (bytes, str)) else 'unknown'}")
        
        progress(1.0, desc="Complete!")
        return gr.Image(value=image)
        
    except gr.Error:
        # Re-raise gradio errors as-is
        raise
    except Exception as e:
        raise gr.Error(f"Failed to generate image: {str(e)}")

# --- 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)

demo = gr.ChatInterface(
    fn=chat_fn,
    title="FLUX.1 Kontext [dev] - Direct API",
    description="""<p style='text-align: center;'>
    A simple chat UI for the <b>FLUX.1 Kontext</b> model using direct API calls with requests.
    <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()