app.py

"""
CREStereo Gradio Demo with ZeroGPU Integration

This demo showcases the CREStereo model for stereo depth estimation.
Optimized for Hugging Face Spaces with ZeroGPU support.

Key ZeroGPU optimizations:
- @spaces.GPU decorators for GPU-intensive functions
- CUDA operations only within GPU context
- Memory-efficient inference with cleanup
- Safe CUDA initialization patterns
"""

import os
import sys
import logging
import tempfile
import gc
from pathlib import Path
from typing import Optional, Tuple, Union
import numpy as np
import cv2
import gradio as gr
import imageio

# Import spaces BEFORE torch to ensure proper ZeroGPU initialization
import spaces

# Import torch after spaces - avoid any CUDA calls during import
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.cuda.amp import autocast

# Completely avoid CUDA operations during import phase
# Do not set default tensor type or modify CUDA settings outside GPU context
# torch.set_default_tensor_type('torch.FloatTensor')  # Commented out - causes CUDA init

# Do not modify CUDA settings during import - this can trigger CUDA initialization
# torch.backends.cudnn.enabled = False  # Commented out
# torch.backends.cudnn.benchmark = False  # Commented out

# Use current directory as base
current_dir = os.path.dirname(os.path.abspath(__file__))
base_dir = current_dir

# Add current directory to path for local imports
sys.path.insert(0, current_dir)

# Import local modules
from nets import Model

# Import Open3D with error handling
OPEN3D_AVAILABLE = False
try:
    # Set Open3D to CPU mode to avoid CUDA initialization
    os.environ['OPEN3D_CPU_RENDERING'] = '1'
    # Don't import open3d here - do it inside functions
    # import open3d as o3d
    OPEN3D_AVAILABLE = True  # Assume available, will check later
except Exception as e:
    logging.warning(f"Open3D setup failed: {e}")
    OPEN3D_AVAILABLE = False

# Configure logging
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')

# Model configuration
MODEL_VARIANTS = {
    "crestereo_eth3d": {
        "display_name": "CREStereo ETH3D (Pre-trained model)",
        "model_file": "models/crestereo_eth3d.pth",
        "max_disp": 256
    }
}

# Global variables for model caching
_cached_model = None
_cached_device = None
_cached_model_selection = None


class InputPadder:
    """ Pads images such that dimensions are divisible by divis_by """
    def __init__(self, dims, divis_by=8, force_square=False):
        self.ht, self.wd = dims[-2:]
        pad_ht = (((self.ht // divis_by) + 1) * divis_by - self.ht) % divis_by
        pad_wd = (((self.wd // divis_by) + 1) * divis_by - self.wd) % divis_by
        
        if force_square:
            # Make the padded dimensions square
            max_dim = max(self.ht + pad_ht, self.wd + pad_wd)
            pad_ht = max_dim - self.ht
            pad_wd = max_dim - self.wd
        
        self._pad = [pad_wd//2, pad_wd - pad_wd//2, pad_ht//2, pad_ht - pad_ht//2]

    def pad(self, *inputs):
        return [F.pad(x, self._pad, mode='replicate') for x in inputs]

    def unpad(self, x):
        ht, wd = x.shape[-2:]
        c = [self._pad[2], ht-self._pad[3], self._pad[0], wd-self._pad[1]]
        return x[..., c[0]:c[1], c[2]:c[3]]


def aggressive_cleanup():
    """Perform basic cleanup - no CUDA operations outside GPU context"""
    import gc
    gc.collect()
    logging.info("Performed basic memory cleanup")


@spaces.GPU
def initialize_gpu_context():
    """Initialize GPU context safely for ZeroGPU"""
    try:
        # Set CUDA settings safely within GPU context
        torch.set_default_tensor_type('torch.cuda.FloatTensor')
        torch.backends.cudnn.enabled = True
        torch.backends.cudnn.benchmark = True
        
        # Check GPU availability and log info
        if torch.cuda.is_available():
            device_name = torch.cuda.get_device_name(0)
            memory_total = torch.cuda.get_device_properties(0).total_memory / 1024**3
            logging.info(f"GPU initialized: {device_name}, Total memory: {memory_total:.2f}GB")
            return True
        else:
            logging.error("CUDA not available after GPU context initialization")
            return False
    except Exception as e:
        logging.error(f"GPU context initialization failed: {e}")
        return False


@spaces.GPU
def check_gpu_memory():
    """Check and log current GPU memory usage - only call within GPU context"""
    try:
        allocated = torch.cuda.memory_allocated(0) / 1024**3
        reserved = torch.cuda.memory_reserved(0) / 1024**3
        max_allocated = torch.cuda.max_memory_allocated(0) / 1024**3
        total = torch.cuda.get_device_properties(0).total_memory / 1024**3
        
        logging.info(f"GPU Memory - Allocated: {allocated:.2f}GB, Reserved: {reserved:.2f}GB, Max: {max_allocated:.2f}GB, Total: {total:.2f}GB")
        return allocated, reserved, max_allocated, total
    except RuntimeError as e:
        logging.warning(f"Failed to get GPU memory info: {e}")
        return None, None, None, None


def get_available_models() -> dict:
    """Get all available models with their display names"""
    models = {}
    
    # Check for local models
    for variant, info in MODEL_VARIANTS.items():
        model_path = os.path.join(current_dir, info["model_file"])
        
        if os.path.exists(model_path):
            display_name = info["display_name"]
            models[display_name] = {
                "model_path": model_path,
                "variant": variant,
                "max_disp": info["max_disp"],
                "source": "local"
            }
    
    return models


def get_model_paths_from_selection(model_selection: str) -> Tuple[Optional[str], Optional[dict]]:
    """Get model path and config from the selected model"""
    models = get_available_models()
    
    # Check if it's in our models dict
    if model_selection in models:
        model_info = models[model_selection]
        logging.info(f"📁 Using local model: {model_selection}")
        return model_info["model_path"], model_info
    
    return None, None


@spaces.GPU
def load_model_for_inference(model_path: str, model_info: dict):
    """Load CREStereo model for inference temporarily (demo-style)"""
    # Set CUDA settings safely within GPU context
    torch.set_default_tensor_type('torch.cuda.FloatTensor')  # Now safe to use CUDA tensors
    torch.backends.cudnn.enabled = True
    torch.backends.cudnn.benchmark = True
    
    # Check if CUDA is available after ZeroGPU initialization
    if not torch.cuda.is_available():
        raise RuntimeError("CUDA is not available. ZeroGPU initialization may have failed.")
    
    # Use the first available CUDA device
    device = torch.device("cuda")
    
    # Set CUDA seed safely within GPU context
    try:
        random_seed = 0
        torch.cuda.manual_seed_all(random_seed)
        torch.backends.cudnn.deterministic = True
        torch.backends.cudnn.benchmark = False
    except Exception as e:
        logging.warning(f"Could not set CUDA seed: {e}")
    
    try:
        # Create model
        max_disp = model_info.get("max_disp", 256)
        model = Model(max_disp=max_disp, mixed_precision=False, test_mode=True)
        
        # Load checkpoint
        ckpt = torch.load(model_path, map_location=device)
        model.load_state_dict(ckpt, strict=True)
        model.to(device)
        model.eval()
        
        logging.info("Loaded CREStereo model weights")
        
        # Memory optimizations
        torch.set_grad_enabled(False)
        logging.info("Applied memory optimizations")
        
        return model, device
        
    except Exception as e:
        logging.error(f"Model loading failed: {e}")
        raise RuntimeError(f"Failed to load model: {e}")


def get_cached_model(model_selection: str):
    """Get cached model or load new one if selection changed"""
    global _cached_model, _cached_device, _cached_model_selection
    
    # Get model paths from selection
    model_path, model_info = get_model_paths_from_selection(model_selection)
    
    if model_path is None or model_info is None:
        raise ValueError(f"Selected model not found: {model_selection}")
    
    # Check if we need to reload the model
    if (_cached_model is None or 
        _cached_model_selection != model_selection):
        
        # Clear previous model if exists
        if _cached_model is not None:
            del _cached_model
            torch.cuda.empty_cache()
            gc.collect()
        
        logging.info(f"🚀 Loading model: {model_selection}")
        _cached_model, _cached_device = load_model_for_inference(model_path, model_info)
        _cached_model_selection = model_selection
        
        logging.info(f"✅ Model loaded successfully: {model_selection}")
    else:
        logging.info(f"✅ Using cached model: {model_selection}")
    
    return _cached_model, _cached_device


def clear_model_cache():
    """Clear the cached model to free memory"""
    global _cached_model, _cached_device, _cached_model_selection
    
    if _cached_model is not None:
        logging.info("Clearing model cache...")
        del _cached_model
        _cached_model = None
        _cached_device = None
        _cached_model_selection = None
        
        # Simple cleanup
        import gc
        gc.collect()
        torch.cuda.empty_cache()
        logging.info("Model cache cleared")
    else:
        logging.info("No model in cache to clear")


def inference(left, right, model, device, n_iter=20):
    """Run CREStereo inference on stereo pair"""
    print("Model Forwarding...")
    imgL = left.transpose(2, 0, 1)
    imgR = right.transpose(2, 0, 1)
    imgL = np.ascontiguousarray(imgL[None, :, :, :])
    imgR = np.ascontiguousarray(imgR[None, :, :, :])

    imgL = torch.tensor(imgL.astype("float32")).to(device)
    imgR = torch.tensor(imgR.astype("float32")).to(device)

    # Use InputPadder to handle any image size
    padder = InputPadder(imgL.shape, divis_by=8)
    imgL_padded, imgR_padded = padder.pad(imgL, imgR)

    # Downsample for coarse prediction
    imgL_dw2 = F.interpolate(
        imgL_padded,
        size=(imgL_padded.shape[2] // 2, imgL_padded.shape[3] // 2),
        mode="bilinear",
        align_corners=True,
    )
    imgR_dw2 = F.interpolate(
        imgR_padded,
        size=(imgL_padded.shape[2] // 2, imgL_padded.shape[3] // 2),
        mode="bilinear",
        align_corners=True,
    )

    with torch.inference_mode():
        pred_flow_dw2 = model(imgL_dw2, imgR_dw2, iters=n_iter, flow_init=None)
        pred_flow = model(imgL_padded, imgR_padded, iters=n_iter, flow_init=pred_flow_dw2)
    
    # Unpad the result to original dimensions
    pred_flow = padder.unpad(pred_flow)
    pred_disp = torch.squeeze(pred_flow[:, 0, :, :]).cpu().detach().numpy()

    return pred_disp


def vis_disparity(disparity_map, max_val=None):
    """Visualize disparity map"""
    if max_val is None:
        disp_vis = (disparity_map - disparity_map.min()) / (disparity_map.max() - disparity_map.min()) * 255.0
    else:
        disp_vis = np.clip(disparity_map / max_val * 255.0, 0, 255)
    
    disp_vis = disp_vis.astype("uint8")
    disp_vis = cv2.applyColorMap(disp_vis, cv2.COLORMAP_INFERNO)
    disp_vis = cv2.cvtColor(disp_vis, cv2.COLOR_BGR2RGB)
    return disp_vis


# Fixed with static duration
@spaces.GPU(duration=60)  # Static 60 seconds for basic processing
def process_stereo_pair(model_selection: str, left_image: str, right_image: str, 
                       progress: gr.Progress = gr.Progress()) -> Tuple[Optional[np.ndarray], str]:
    """
    Main processing function for stereo pair (with model caching)
    """
    logging.info("Starting stereo pair processing...")
    
    if left_image is None or right_image is None:
        return None, "❌ Please upload both left and right images."
    
    # Convert image paths to numpy arrays
    logging.info(f"Loading images: left={left_image}, right={right_image}")
    
    try:
        # Load left image
        if not os.path.exists(left_image):
            logging.error(f"Left image file does not exist: {left_image}")
            return None, f"❌ Left image file not found: {left_image}"
        
        logging.info(f"Loading left image from: {left_image}")
        left_img = cv2.imread(left_image)
        if left_img is not None:
            left_img = cv2.cvtColor(left_img, cv2.COLOR_BGR2RGB)
        else:
            # Try with imageio as fallback
            left_img = imageio.imread(left_image)
            if len(left_img.shape) == 3 and left_img.shape[2] == 4:
                left_img = left_img[:, :, :3]
        
        # Load right image
        if not os.path.exists(right_image):
            logging.error(f"Right image file does not exist: {right_image}")
            return None, f"❌ Right image file not found: {right_image}"
        
        logging.info(f"Loading right image from: {right_image}")
        right_img = cv2.imread(right_image)
        if right_img is not None:
            right_img = cv2.cvtColor(right_img, cv2.COLOR_BGR2RGB)
        else:
            # Try with imageio as fallback
            right_img = imageio.imread(right_image)
            if len(right_img.shape) == 3 and right_img.shape[2] == 4:
                right_img = right_img[:, :, :3]
        
        logging.info(f"Images loaded successfully - Left: {left_img.shape}, Right: {right_img.shape}")
        
    except Exception as e:
        logging.error(f"Failed to load images: {e}")
        return None, f"❌ Failed to load images: {str(e)}"
    
    try:
        # Get cached model
        variant_name = model_selection.split('(')[0].strip() if '(' in model_selection else model_selection
        progress(0.1, desc=f"Loading cached model ({variant_name})...")
        logging.info("🚀 Getting cached model...")
        model, device = get_cached_model(model_selection)
        logging.info("✅ Cached model loaded successfully")
        
        progress(0.2, desc="Preprocessing images...")
        
        # Validate input images
        if left_img.shape != right_img.shape:
            return None, "❌ Left and right images must have the same dimensions."
        
        H, W = left_img.shape[:2]
        
        progress(0.5, desc="Running inference...")
        
        # Process stereo pair
        torch.cuda.empty_cache()  # Clear any cached memory before inference
        
        disp_cpu = inference(left_img, right_img, model, device, n_iter=20)
        
        progress(0.8, desc="Creating visualization...")
        
        # Create visualization
        disparity_vis = vis_disparity(disp_cpu)
        result_image = disparity_vis
        
        progress(1.0, desc="Complete!")
        
        # Create status message
        valid_mask = ~np.isinf(disp_cpu)
        min_disp = disp_cpu[valid_mask].min() if valid_mask.any() else 0
        max_disp = disp_cpu[valid_mask].max() if valid_mask.any() else 0
        mean_disp = disp_cpu[valid_mask].mean() if valid_mask.any() else 0
        
        # Get model variant for status
        variant = variant_name
        
        # Check current memory usage
        try:
            current_memory = torch.cuda.memory_allocated(0) / 1024**3
            max_memory = torch.cuda.max_memory_allocated(0) / 1024**3
            memory_info = f" | GPU: {current_memory:.2f}GB/{max_memory:.2f}GB peak"
        except:
            memory_info = ""
        
        status = f"""✅ Processing successful!
🔧 Model: {variant}{memory_info}
📊 Disparity Statistics:
   • Range: {min_disp:.2f} - {max_disp:.2f}
   • Mean: {mean_disp:.2f}
   • Input size: {W}×{H}
   • Valid pixels: {valid_mask.sum()}/{valid_mask.size}"""
        
        return result_image, status
        
    except Exception as e:
        logging.error(f"Processing failed: {e}")
        # Clean up GPU memory
        torch.cuda.empty_cache()
        gc.collect()
        return None, f"❌ Error: {str(e)}"


# Fixed with static duration
@spaces.GPU(duration=120)  # Static 120 seconds for depth processing
def process_with_depth(model_selection: str, left_image: str, right_image: str, 
                      camera_matrix: str, baseline: float,
                      progress: gr.Progress = gr.Progress()) -> Tuple[Optional[np.ndarray], Optional[str], Optional[str], str]:
    """
    Process stereo pair and generate depth map and point cloud (with model caching)
    """
    # Import Open3D
    global OPEN3D_AVAILABLE
    try:
        import open3d as o3d
        OPEN3D_AVAILABLE = True
    except ImportError as e:
        logging.warning(f"Open3D not available: {e}")
        OPEN3D_AVAILABLE = False
        return None, None, None, "❌ Open3D not available. Point cloud generation disabled."
    
    if left_image is None or right_image is None:
        return None, None, None, "❌ Please upload both left and right images."
    
    try:
        progress(0.1, desc="Parsing camera parameters...")
        
        # Parse camera matrix
        try:
            K_values = list(map(float, camera_matrix.strip().split()))
            if len(K_values) != 9:
                return None, None, None, "❌ Camera matrix must contain exactly 9 values."
            K = np.array(K_values).reshape(3, 3)
        except ValueError:
            return None, None, None, "❌ Invalid camera matrix format. Use space-separated numbers."
        
        if baseline <= 0:
            return None, None, None, "❌ Baseline must be positive."
        
        # First get disparity using the same process as basic function
        disparity_result, status = process_stereo_pair(model_selection, left_image, right_image, progress)
        
        if disparity_result is None:
            return None, None, None, status
        
        # Load images again for depth processing
        left_img = cv2.imread(left_image)
        left_img = cv2.cvtColor(left_img, cv2.COLOR_BGR2RGB)
        
        # Get disparity from model again (we need the raw values, not the visualization)
        model, device = get_cached_model(model_selection)
        disp_cpu = inference(left_img, cv2.cvtColor(cv2.imread(right_image), cv2.COLOR_BGR2RGB), model, device, n_iter=20)
        
        progress(0.6, desc="Converting to depth...")
        
        # Remove invisible points
        H, W = disp_cpu.shape
        yy, xx = np.meshgrid(np.arange(H), np.arange(W), indexing='ij')
        us_right = xx - disp_cpu
        invalid = us_right < 0
        disp_cpu[invalid] = np.inf
        
        # Convert to depth using the formula: depth = focal_length * baseline / disparity
        depth = K[0, 0] * baseline / disp_cpu
        
        # Visualize depth
        depth_vis = vis_disparity(depth, max_val=10.0)
        
        progress(0.8, desc="Generating point cloud...")
        
        # Generate point cloud
        fx, fy = K[0, 0], K[1, 1]
        cx, cy = K[0, 2], K[1, 2]
        
        # Create coordinate meshgrids
        u, v = np.meshgrid(np.arange(W), np.arange(H))
        
        # Convert to 3D coordinates
        valid_depth = ~np.isinf(depth)
        z = depth[valid_depth]  # Z coordinate (depth)
        x = (u[valid_depth] - cx) * z / fx  # X coordinate  
        y = (v[valid_depth] - cy) * z / fy  # Y coordinate
        
        # Stack coordinates (X, Y, Z)
        points = np.stack([x, y, z], axis=-1)
        
        # Get corresponding colors
        colors = left_img[valid_depth]
        
        # Filter points by depth range
        depth_mask = (z > 0) & (z <= 10.0)
        valid_points = points[depth_mask]
        valid_colors = colors[depth_mask]
        
        if len(valid_points) == 0:
            return depth_vis, None, None, "⚠️ No valid points generated for point cloud."
        
        # Subsample points for better performance
        if len(valid_points) > 100000:
            indices = np.random.choice(len(valid_points), 100000, replace=False)
            valid_points = valid_points[indices]
            valid_colors = valid_colors[indices]
        
        # Transform coordinates for proper visualization
        transformed_points = valid_points.copy()
        transformed_points[:, 1] = -transformed_points[:, 1]  # Flip Y axis
        transformed_points[:, 2] = -transformed_points[:, 2]  # Flip Z axis
        
        # Generate point cloud
        pcd = o3d.geometry.PointCloud()
        pcd.points = o3d.utility.Vector3dVector(transformed_points)
        pcd.colors = o3d.utility.Vector3dVector(valid_colors / 255.0)
        
        progress(1.0, desc="Complete!")
        
        # Check current memory usage
        try:
            current_memory = torch.cuda.memory_allocated(0) / 1024**3
            max_memory = torch.cuda.max_memory_allocated(0) / 1024**3
            memory_info = f" | GPU: {current_memory:.2f}GB/{max_memory:.2f}GB peak"
        except:
            memory_info = ""
        
        variant = model_selection.split('(')[0].strip() if '(' in model_selection else model_selection
        
        status = f"""✅ Depth processing successful!
🔧 Model: {variant}{memory_info}
📊 Statistics:
   • Valid points: {len(valid_points):,}
   • Depth range: {z.min():.2f} - {z.max():.2f} m
   • Baseline: {baseline} m
   • Point cloud generated with {len(valid_points)} points
   • 3D visualization available"""
        
        return depth_vis, None, None, status
        
    except Exception as e:
        logging.error(f"Depth processing failed: {e}")
        torch.cuda.empty_cache()
        gc.collect()
        return None, None, None, f"❌ Error: {str(e)}"


def create_app() -> gr.Blocks:
    """Create the Gradio application"""
    
    # Get available models
    try:
        available_models = get_available_models()
        logging.info(f"Successfully got available models: {len(available_models)} found")
    except Exception as e:
        logging.error(f"Failed to get available models: {e}")
        available_models = {}
    
    with gr.Blocks(
        title="CREStereo - Stereo Depth Estimation",
        theme=gr.themes.Soft(),
        css="footer {visibility: hidden}",
        delete_cache=(60, 60)
    ) as app:
        
        gr.Markdown("""
        # 🔍 CREStereo: Practical Stereo Matching
        
        Upload a pair of **rectified** stereo images to get disparity estimation using CREStereo.
        
        ⚠️ **Important**: Images should be rectified (epipolar lines are horizontal) and undistorted.
        ⚡ **GPU Powered**: Runs on CUDA-enabled GPUs for fast inference.
        """)
        
        # Instructions section
        with gr.Accordion("📋 Instructions", open=False):
            gr.Markdown("""
            ## 🚀 How to Use This Demo
            
            ### 🖼️ Input Requirements
            1. **Image Format**: Upload images in JPEG or PNG format.
            2. **Image Size**: Images should be of the same size and resolution.
            3. **Rectification**: Ensure images are rectified (epipolar lines are horizontal) and undistorted.
            4. **Camera Parameters**: For depth processing, provide camera matrix and baseline distance.
                        
            ### 📊 Using the Demo
            1. **Select Model**: Choose the CREStereo model variant
            2. **Upload Images**: Provide rectified stereo image pairs
            3. **Basic Processing**: Get disparity visualization
            4. **Advanced Processing**: Generate depth maps and 3D point clouds (requires camera parameters)
            
            ### 📖 Original Work
            This demo is based on CREStereo: Practical Stereo Matching via Cascaded Recurrent Network.
            - **Paper**: [CREStereo: Practical Stereo Matching via Cascaded Recurrent Network](https://arxiv.org/abs/2203.11483)
            - **Official Repository**: [https://github.com/megvii-research/CREStereo](https://github.com/megvii-research/CREStereo)
            """)
        
        # Model selection
        with gr.Row():
            all_choices = list(available_models.keys())
            
            if not all_choices:
                all_choices = ["No models found - Please ensure crestereo_eth3d.pth is in models/ directory"]
            
            default_model = all_choices[0] if all_choices else None
            
            model_selector = gr.Dropdown(
                choices=all_choices,
                value=default_model,
                label="🎯 Select Model",
                info="Choose the CREStereo model variant.",
                interactive=True
            )

        with gr.Tabs():
            # Basic stereo processing tab
            with gr.TabItem("🖼️ Basic Stereo Processing"):
                with gr.Row():
                    with gr.Column():
                        left_input = gr.Image(
                            label="📷 Left Image",
                            type="filepath",
                            height=300
                        )
                        right_input = gr.Image(
                            label="📷 Right Image", 
                            type="filepath",
                            height=300
                        )
                        
                        process_btn = gr.Button(
                            "🚀 Process Stereo Pair",
                            variant="primary",
                            size="lg"
                        )
                    
                    with gr.Column():
                        output_image = gr.Image(
                            label="📊 Disparity Visualization",
                            height=400
                        )
                        status_text = gr.Textbox(
                            label="Status",
                            interactive=False,
                            lines=8
                        )
                
                # Example images
                examples_list = []
                
                # Example 1
                if os.path.exists(os.path.join(current_dir, "assets", "example1", "left.png")):
                    examples_list.append([
                        os.path.join(current_dir, "assets", "example1", "left.png"),
                        os.path.join(current_dir, "assets", "example1", "right.png")
                    ])
                
                # Example 2
                if os.path.exists(os.path.join(current_dir, "assets", "example2", "left.png")):
                    examples_list.append([
                        os.path.join(current_dir, "assets", "example2", "left.png"),
                        os.path.join(current_dir, "assets", "example2", "right.png")
                    ])
                
                if examples_list:
                    gr.Examples(
                        examples=examples_list,
                        inputs=[left_input, right_input],
                        label="📋 Example Images"
                    )
            
            # Advanced processing with depth
            with gr.TabItem("📐 Advanced Processing (Depth & Point Cloud)"):
                with gr.Row():
                    with gr.Column():
                        left_input_adv = gr.Image(
                            label="📷 Left Image",
                            type="filepath",
                            height=250
                        )
                        right_input_adv = gr.Image(
                            label="📷 Right Image",
                            type="filepath", 
                            height=250
                        )
                        
                        # Camera parameters
                        with gr.Group():
                            gr.Markdown("### 📹 Camera Parameters")
                            camera_matrix_input = gr.Textbox(
                                label="Camera Matrix (9 values: fx 0 cx 0 fy cy 0 0 1)",
                                value="",
                            )
                            baseline_input = gr.Number(
                                label="Baseline (meters)",
                                value=None,
                                minimum=0.001,
                                maximum=10.0,
                                step=0.001
                            )
                        
                        process_depth_btn = gr.Button(
                            "🔬 Process with Depth",
                            variant="primary",
                            size="lg"
                        )
                    
                    with gr.Column():
                        depth_output = gr.Image(
                            label="📏 Depth Visualization",
                            height=300
                        )
                        pointcloud_output = gr.File(
                            label="☁️ Point Cloud Download (.ply)",
                            file_types=[".ply"]
                        )
                        status_depth = gr.Textbox(
                            label="Status",
                            interactive=False,
                            lines=6
                        )
                
                # 3D Point Cloud Visualization
                with gr.Row():
                    pointcloud_3d = gr.Model3D(
                        label="🌐 3D Point Cloud Viewer",
                        clear_color=[0.0, 0.0, 0.0, 0.0],
                        height=400
                    )
                
                # Example images for advanced processing
                examples_advanced_list = []
                
                # Try to read camera parameters from K.txt files
                # Example 1
                if os.path.exists(os.path.join(current_dir, "assets", "example1", "left.png")):
                    k_file = os.path.join(current_dir, "assets", "example1", "K.txt")
                    camera_matrix_str = ""
                    baseline_val = 0.063  # default
                    
                    if os.path.exists(k_file):
                        try:
                            with open(k_file, 'r') as f:
                                lines = f.readlines()
                                if len(lines) >= 1:
                                    camera_matrix_str = lines[0].strip()
                                if len(lines) >= 2:
                                    baseline_val = float(lines[1].strip())
                        except:
                            camera_matrix_str = "754.6680908203125 0.0 489.3794860839844 0.0 754.6680908203125 265.16162109375 0.0 0.0 1.0"
                    
                    examples_advanced_list.append([
                        os.path.join(current_dir, "assets", "example1", "left.png"),
                        os.path.join(current_dir, "assets", "example1", "right.png"),
                        camera_matrix_str,
                        baseline_val
                    ])
                
                # Example 2
                if os.path.exists(os.path.join(current_dir, "assets", "example2", "left.png")):
                    k_file = os.path.join(current_dir, "assets", "example2", "K.txt")
                    camera_matrix_str = ""
                    baseline_val = 0.537  # default
                    
                    if os.path.exists(k_file):
                        try:
                            with open(k_file, 'r') as f:
                                lines = f.readlines()
                                if len(lines) >= 1:
                                    camera_matrix_str = lines[0].strip()
                                if len(lines) >= 2:
                                    baseline_val = float(lines[1].strip())
                        except:
                            camera_matrix_str = "1733.74 0.0 792.27 0.0 1733.74 541.89 0.0 0.0 1.0"
                    
                    examples_advanced_list.append([
                        os.path.join(current_dir, "assets", "example2", "left.png"),
                        os.path.join(current_dir, "assets", "example2", "right.png"),
                        camera_matrix_str,
                        baseline_val
                    ])
                
                if examples_advanced_list:
                    gr.Examples(
                        examples=examples_advanced_list,
                        inputs=[left_input_adv, right_input_adv, camera_matrix_input, baseline_input],
                        label="📋 Example Images with Camera Parameters"
                    )
        
        # Event handlers
        if available_models:
            process_btn.click(
                fn=process_stereo_pair,
                inputs=[model_selector, left_input, right_input],
                outputs=[output_image, status_text],
                show_progress=True
            )
            
            if OPEN3D_AVAILABLE:
                process_depth_btn.click(
                    fn=process_with_depth,
                    inputs=[model_selector, left_input_adv, right_input_adv, camera_matrix_input, baseline_input],
                    outputs=[depth_output, pointcloud_output, pointcloud_3d, status_depth],
                    show_progress=True
                )
            else:
                process_depth_btn.click(
                    fn=lambda *args: (None, None, None, "❌ Open3D not available. Install with: pip install open3d"),
                    inputs=[model_selector, left_input_adv, right_input_adv, camera_matrix_input, baseline_input],
                    outputs=[depth_output, pointcloud_output, pointcloud_3d, status_depth]
                )
        else:
            # No models available
            process_btn.click(
                fn=lambda *args: (None, "❌ No models available. Please ensure crestereo_eth3d.pth is in models/ directory."),
                inputs=[model_selector, left_input, right_input],
                outputs=[output_image, status_text]
            )
            
            process_depth_btn.click(
                fn=lambda *args: (None, None, None, "❌ No models available. Please ensure crestereo_eth3d.pth is in models/ directory."),
                inputs=[model_selector, left_input_adv, right_input_adv, camera_matrix_input, baseline_input],
                outputs=[depth_output, pointcloud_output, pointcloud_3d, status_depth]
            )
        
        # Citation section at the bottom
        with gr.Accordion("📖 Citation", open=False):
            gr.Markdown("""
            ### 📄 Please Cite the Original Paper
            
            If you use this work in your research, please cite:
            
            ```bibtex
            @article{li2022practical,
              title={Practical Stereo Matching via Cascaded Recurrent Network with Adaptive Correlation},
              author={Li, Jiankun and Wang, Peisen and Xiong, Pengfei and Cai, Tao and Yan, Ziwei and Yang, Lei and Liu, Jiangyu and Fan, Haoqiang and Liu, Shuaicheng},
              journal={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
              pages={16263--16272},
              year={2022}
            }
            ```
            """)
        
        # Footer
        gr.Markdown("""
        ---
        ### 📝 Notes:
        - **Input images must be rectified stereo pairs** (epipolar lines are horizontal)
        - **⚡ GPU Acceleration**: Requires CUDA-compatible GPU
        - **📦 Model Caching**: Models are cached for efficient repeated usage
        - For best results, use high-quality rectified stereo pairs
        - Model works on RGB images and supports various resolutions
        
        ### 🔗 References:
        - [CREStereo Paper](https://arxiv.org/abs/2203.11483)
        - [Original GitHub Repository](https://github.com/megvii-research/CREStereo)
        - [This PyTorch Implementation](https://github.com/ibaiGorordo/CREStereo-Pytorch)
        """)
    
    return app


def main():
    """Main function to launch the app"""
    
    # Ensure no CUDA operations during startup
    if torch.cuda.is_available():
        logging.warning("CUDA detected during startup - this should not happen in ZeroGPU")
    
    logging.info("🚀 Starting CREStereo Gradio App...")
    
    # Parse command line arguments
    import argparse
    parser = argparse.ArgumentParser(description="CREStereo Gradio App")
    parser.add_argument("--host", type=str, default="0.0.0.0", help="Host to bind to")
    parser.add_argument("--port", type=int, default=7860, help="Port to bind to")
    parser.add_argument("--share", action="store_true", help="Create shareable link")
    parser.add_argument("--debug", action="store_true", help="Enable debug mode")
    
    args = parser.parse_args()
    
    if args.debug:
        logging.getLogger().setLevel(logging.DEBUG)
    
    try:
        # Create and launch app
        logging.info("Creating Gradio app...")
        app = create_app()
        logging.info("✅ Gradio app created successfully")
        
        logging.info(f"Launching app on {args.host}:{args.port}")
        if args.share:
            logging.info("Share link will be created")
        
        # For ZeroGPU compatibility, launch with appropriate settings
        app.launch(
            server_name=args.host,
            server_port=args.port,
            share=args.share,
            show_error=True,
            favicon_path=None,
            ssr_mode=False,  # Disable SSR for ZeroGPU compatibility
            allowed_paths=["./"]  # Allow access to local files
        )
    except Exception as e:
        logging.error(f"Failed to launch app: {e}")
        raise


if __name__ == "__main__":
    # Additional safety check for ZeroGPU environment
    if 'SPACE_ID' in os.environ:
        logging.info("Running in Hugging Face Spaces environment")
    
    # Do not check CUDA status during startup - this can trigger CUDA initialization
    # The CUDA status will be checked inside the @spaces.GPU decorated functions
    logging.info("✅ CUDA status will be checked within GPU-decorated functions")
    
    main()