"""
Depth Estimation Comparison Demo (Depth Anything v1/v2 + Pixel-Perfect Depth)

Compare Depth Anything models (v1 and v2) and Pixel-Perfect Depth side-by-side or with a slider using Gradio.
Inspired by the Stereo Matching Methods Comparison Demo.
"""

from __future__ import annotations

import os
import sys
import logging
import tempfile
import shutil
import inspect
from pathlib import Path
from typing import Optional, Tuple, Dict, List
import numpy as np
import cv2
import gradio as gr
from huggingface_hub import hf_hub_download
import open3d as o3d
import trimesh
from PIL import Image

# Import v1 and v2 model code
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "Depth-Anything"))
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "Depth-Anything-V2"))
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "Depth-Anything-3-anysize", "src"))

# v1 imports
from depth_anything.dpt import DepthAnything as DepthAnythingV1
from depth_anything.util.transform import Resize, NormalizeImage, PrepareForNet
import torch
import torch.nn.functional as F
from torchvision.transforms import Compose

# v2 imports
from depth_anything_v2.dpt import DepthAnythingV2

import matplotlib

# Depth Anything v3 imports
from depth_anything_3.api import DepthAnything3
from depth_anything_3.utils.visualize import visualize_depth

# Pixel-Perfect Depth imports
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "Pixel-Perfect-Depth"))
from ppd.utils.set_seed import set_seed
from ppd.utils.align_depth_func import recover_metric_depth_ransac
from ppd.utils.depth2pcd import depth2pcd
from moge.model.v2 import MoGeModel
from ppd.models.ppd import PixelPerfectDepth

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

# Device selection
DEVICE = 'cuda' if torch.cuda.is_available() else 'cpu'
TORCH_DEVICE = torch.device(DEVICE)

# Model configs
V1_MODEL_CONFIGS = {
    "vits14": {
        "model_name": "LiheYoung/depth_anything_vits14",
        "display_name": "Depth Anything v1 ViT-S (Small, Fastest)"
    },
    "vitb14": {
        "model_name": "LiheYoung/depth_anything_vitb14",
        "display_name": "Depth Anything v1 ViT-B (Base, Balanced)"
    },
    "vitl14": {
        "model_name": "LiheYoung/depth_anything_vitl14",
        "display_name": "Depth Anything v1 ViT-L (Large, Best Quality)"
    }
}

V2_MODEL_CONFIGS = {
    'vits': {
        'display_name': 'Depth Anything v2 ViT-Small',
        'checkpoint': 'Depth-Anything-V2/checkpoints/depth_anything_v2_vits.pth',
        'features': 64, 'out_channels': [48, 96, 192, 384]
    },
    'vitb': {
        'display_name': 'Depth Anything v2 ViT-Base',
        'checkpoint': 'Depth-Anything-V2/checkpoints/depth_anything_v2_vitb.pth',
        'features': 128, 'out_channels': [96, 192, 384, 768]
    },
    'vitl': {
        'display_name': 'Depth Anything v2 ViT-Large',
        'checkpoint': 'Depth-Anything-V2/checkpoints/depth_anything_v2_vitl.pth',
        'features': 256, 'out_channels': [256, 512, 1024, 1024]
    }
}

DA3_MODEL_SOURCES = {
    "nested_giant_large": {
        "display_name": "Depth Anything v3 Nested Giant Large",
        "repo_id": "depth-anything/DA3NESTED-GIANT-LARGE",
    },
    "giant": {
        "display_name": "Depth Anything v3 Giant",
        "repo_id": "depth-anything/DA3-GIANT",
    },
    "large": {
        "display_name": "Depth Anything v3 Large",
        "repo_id": "depth-anything/DA3-LARGE",
    },
    "base": {
        "display_name": "Depth Anything v3 Base",
        "repo_id": "depth-anything/DA3-BASE",
    },
    "small": {
        "display_name": "Depth Anything v3 Small",
        "repo_id": "depth-anything/DA3-SMALL",
    },
    "metric_large": {
        "display_name": "Depth Anything v3 Metric Large",
        "repo_id": "depth-anything/DA3METRIC-LARGE",
    },
    "mono_large": {
        "display_name": "Depth Anything v3 Mono Large",
        "repo_id": "depth-anything/DA3MONO-LARGE",
    },
}

# Model cache
_v1_models = {}
_v2_models = {}
_da3_models: Dict[str, DepthAnything3] = {}

# v1 transform
v1_transform = Compose([
    Resize(width=518, height=518, resize_target=False, keep_aspect_ratio=True, ensure_multiple_of=14, resize_method='lower_bound', image_interpolation_method=cv2.INTER_CUBIC),
    NormalizeImage(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]),
    PrepareForNet(),
])

def load_v1_model(key: str):
    if key in _v1_models:
        return _v1_models[key]
    model = DepthAnythingV1.from_pretrained(V1_MODEL_CONFIGS[key]["model_name"]).to(DEVICE).eval()
    _v1_models[key] = model
    return model

def load_v2_model(key: str):
    if key in _v2_models:
        return _v2_models[key]
    config = V2_MODEL_CONFIGS[key]
    model = DepthAnythingV2(encoder=key, features=config['features'], out_channels=config['out_channels'])
    
    # Try to download from HF Hub first, fallback to local checkpoint
    try:
        # Map variant to model names used in HF Hub
        model_name_mapping = {
            'vits': 'Small',
            'vitb': 'Base', 
            'vitl': 'Large'
        }
        
        model_name = model_name_mapping.get(key, 'Large')  # Default to Large
        filename = f"depth_anything_v2_{key}.pth"
        
        # Try to download from HF Hub first
        try:
            filepath = hf_hub_download(
                repo_id=f"depth-anything/Depth-Anything-V2-{model_name}", 
                filename=filename, 
                repo_type="model"
            )
            logging.info(f"Downloaded V2 model from HF Hub: {filepath}")
            checkpoint_path = filepath
        except Exception as e:
            logging.warning(f"Failed to download V2 model from HF Hub: {e}")
            # Fallback to local checkpoint
            checkpoint_path = config['checkpoint']
            if not os.path.exists(checkpoint_path):
                raise FileNotFoundError(f"Neither HF Hub download nor local checkpoint available: {checkpoint_path}")
            logging.info(f"Using local V2 checkpoint: {checkpoint_path}")
        
        state_dict = torch.load(checkpoint_path, map_location=DEVICE)
    except Exception as e:
        logging.error(f"Failed to load V2 model {key}: {e}")
        raise
    
    model.load_state_dict(state_dict)
    model = model.to(DEVICE).eval()
    _v2_models[key] = model
    return model


def load_da3_model(key: str) -> DepthAnything3:
    if key in _da3_models:
        return _da3_models[key]
    repo_id = DA3_MODEL_SOURCES[key]["repo_id"]
    model = DepthAnything3.from_pretrained(repo_id)
    model = model.to(device=TORCH_DEVICE)
    model.eval()
    _da3_models[key] = model
    return model


def _prep_da3_image(image: np.ndarray) -> np.ndarray:
    if image.ndim == 2:
        image = np.stack([image] * 3, axis=-1)
    if image.dtype != np.uint8:
        image = np.clip(image, 0, 255).astype(np.uint8)
    return image


def run_da3_inference(model_key: str, image: np.ndarray) -> Tuple[np.ndarray, np.ndarray, str, str]:
    model = load_da3_model(model_key)
    if image.ndim == 2:
        rgb = cv2.cvtColor(image, cv2.COLOR_GRAY2RGB)
    else:
        rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
    rgb = _prep_da3_image(rgb)
    prediction = model.inference(
        image=[Image.fromarray(rgb)],
        process_res=None,
        process_res_method="keep",
    )
    depth_map = prediction.depth[0]
    depth_vis = visualize_depth(depth_map, cmap="Spectral")
    processed_rgb = (
        prediction.processed_images[0]
        if getattr(prediction, "processed_images", None) is not None
        else rgb
    )
    processed_rgb = np.clip(processed_rgb, 0, 255).astype(np.uint8)
    target_h, target_w = image.shape[:2]
    if depth_vis.shape[:2] != (target_h, target_w):
        depth_vis = cv2.resize(depth_vis, (target_w, target_h), interpolation=cv2.INTER_LINEAR)
    if processed_rgb.shape[:2] != (target_h, target_w):
        processed_rgb = cv2.resize(processed_rgb, (target_w, target_h), interpolation=cv2.INTER_LINEAR)
    label = DA3_MODEL_SOURCES[model_key]["display_name"]
    info_lines = [
        f"**Model:** `{label}`",
        f"**Repo:** `{DA3_MODEL_SOURCES[model_key]['repo_id']}`",
        f"**Device:** `{str(TORCH_DEVICE)}`",
        f"**Depth shape:** `{tuple(prediction.depth.shape)}`",
    ]
    if getattr(prediction, "extrinsics", None) is not None:
        info_lines.append(f"**Extrinsics shape:** `{prediction.extrinsics.shape}`")
    if getattr(prediction, "intrinsics", None) is not None:
        info_lines.append(f"**Intrinsics shape:** `{prediction.intrinsics.shape}`")
    info_text = "\n".join(info_lines)
    return depth_vis, processed_rgb, info_text, label


def da3_single_inference(image, model: str, progress=gr.Progress()):
    if image is None:
        return None, "❌ Please upload an image."

    if isinstance(image, str):
        np_image = cv2.imread(image)
    elif hasattr(image, "save"):
        np_image = np.array(image)
        if len(np_image.shape) == 3 and np_image.shape[2] == 3:
            np_image = cv2.cvtColor(np_image, cv2.COLOR_RGB2BGR)
    else:
        np_image = np.array(image)
        if len(np_image.shape) == 3 and np_image.shape[2] == 3:
            np_image = cv2.cvtColor(np_image, cv2.COLOR_RGB2BGR)

    if np_image is None:
        raise gr.Error("Invalid image input.")

    key = model[4:] if model.startswith("da3_") else model

    progress(0.1, desc=f"Running {model}")
    depth_vis, processed_rgb, info_text, label = run_da3_inference(key, np_image)
    progress(1.0, desc="Done")
    return (processed_rgb, depth_vis), info_text

def predict_v1(model, image: np.ndarray) -> np.ndarray:
    h, w = image.shape[:2]
    image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB) / 255.0
    image = v1_transform({'image': image})['image']
    image = torch.from_numpy(image).unsqueeze(0).to(DEVICE)
    with torch.no_grad():
        depth = model(image)
        depth = F.interpolate(depth[None], (h, w), mode='bilinear', align_corners=False)[0, 0]
    return depth.cpu().numpy()

def predict_v2(model, image: np.ndarray) -> np.ndarray:
    with torch.no_grad():
        depth = model.infer_image(image[:, :, ::-1])  # BGR to RGB
    return depth

def colorize_depth(depth: np.ndarray) -> np.ndarray:
    depth_norm = (depth - depth.min()) / (depth.max() - depth.min() + 1e-8)
    depth_uint8 = (depth_norm * 255).astype(np.uint8)
    cmap = matplotlib.colormaps.get_cmap('Spectral_r')
    colored = (cmap(depth_uint8)[:, :, :3] * 255).astype(np.uint8)
    return colored


# Pixel-Perfect Depth setup -------------------------------------------------
set_seed(666)
PPD_DEFAULT_STEPS = 20
PPD_TEMP_ROOT = Path(tempfile.gettempdir()) / "ppd"

_ppd_model: Optional[PixelPerfectDepth] = None
_moge_model: Optional[MoGeModel] = None
_ppd_cmap = matplotlib.colormaps.get_cmap('Spectral')


def load_ppd_model() -> PixelPerfectDepth:
    global _ppd_model
    if _ppd_model is None:
        model = PixelPerfectDepth(sampling_steps=PPD_DEFAULT_STEPS)
        ckpt_path = hf_hub_download(
            repo_id="gangweix/Pixel-Perfect-Depth",
            filename="ppd.pth",
            repo_type="model"
        )
        state_dict = torch.load(ckpt_path, map_location="cpu")
        model.load_state_dict(state_dict, strict=False)
        model = model.to(TORCH_DEVICE).eval()
        _ppd_model = model
    return _ppd_model


def load_moge_model() -> MoGeModel:
    global _moge_model
    if _moge_model is None:
        model = MoGeModel.from_pretrained("Ruicheng/moge-2-vitl-normal").eval()
        model = model.to(TORCH_DEVICE)
        _moge_model = model
    return _moge_model


def _ensure_ppd_temp_dir(session_hash: str) -> Path:
    PPD_TEMP_ROOT.mkdir(exist_ok=True)
    output_path = PPD_TEMP_ROOT / session_hash
    shutil.rmtree(output_path, ignore_errors=True)
    output_path.mkdir(exist_ok=True, parents=True)
    return output_path


def _normalize_depth_to_rgb(depth: np.ndarray) -> np.ndarray:
    depth_vis = (depth - depth.min()) / (depth.max() - depth.min() + 1e-5) * 255.0
    depth_vis = depth_vis.astype(np.uint8)
    colored = (_ppd_cmap(depth_vis)[:, :, :3] * 255).astype(np.uint8)
    return colored


def pixel_perfect_depth_inference(
    image_bgr: np.ndarray,
    denoise_steps: int,
    apply_filter: bool,
    request: Optional[gr.Request] = None,
    generate_assets: bool = True
):
    if image_bgr is None:
        return None, None, []

    ppd_model = load_ppd_model()
    moge_model = load_moge_model()

    H, W = image_bgr.shape[:2]
    image_rgb = cv2.cvtColor(image_bgr, cv2.COLOR_BGR2RGB)

    # PixelPerfectDepth expects BGR input similar to original demo
    with torch.no_grad():
        depth_rel, resize_image = ppd_model.infer_image(image_bgr, sampling_steps=denoise_steps)
    resize_H, resize_W = resize_image.shape[:2]

    # MoGe expects RGB tensor
    rgb_tensor = torch.tensor(cv2.cvtColor(resize_image, cv2.COLOR_BGR2RGB) / 255, dtype=torch.float32, device=TORCH_DEVICE).permute(2, 0, 1)
    with torch.no_grad():
        metric_depth, mask, intrinsics = moge_model.infer(rgb_tensor)
    metric_depth[~mask] = metric_depth[mask].max()

    # Align relative depth to metric using RANSAC
    metric_depth_aligned = recover_metric_depth_ransac(depth_rel, metric_depth, mask)
    intrinsics[0, 0] *= resize_W
    intrinsics[1, 1] *= resize_H
    intrinsics[0, 2] *= resize_W
    intrinsics[1, 2] *= resize_H

    depth_full = cv2.resize(metric_depth_aligned, (W, H), interpolation=cv2.INTER_LINEAR)
    colored_depth = _normalize_depth_to_rgb(depth_full)

    if not generate_assets:
        return (image_rgb, colored_depth), None, []

    pcd = depth2pcd(
        metric_depth_aligned,
        intrinsics,
        color=cv2.cvtColor(resize_image, cv2.COLOR_BGR2RGB),
        input_mask=mask,
        ret_pcd=True
    )
    if apply_filter:
        _, ind = pcd.remove_statistical_outlier(nb_neighbors=20, std_ratio=2.0)
        pcd = pcd.select_by_index(ind)

    session_hash = getattr(request, "session_hash", "default")
    output_dir = _ensure_ppd_temp_dir(session_hash)

    # Save artifacts
    ply_path = output_dir / "pointcloud.ply"
    pcd.points = o3d.utility.Vector3dVector(np.asarray(pcd.points) * np.array([1, -1, -1], dtype=np.float32))
    o3d.io.write_point_cloud(ply_path.as_posix(), pcd)
    vertices = np.asarray(pcd.points)
    vertex_colors = (np.asarray(pcd.colors) * 255).astype(np.uint8)
    mesh = trimesh.PointCloud(vertices=vertices, colors=vertex_colors)
    glb_path = output_dir / "pointcloud.glb"
    mesh.export(glb_path.as_posix())

    raw_depth_path = output_dir / "raw_depth.npy"
    np.save(raw_depth_path.as_posix(), depth_full)

    split_region = np.ones((image_bgr.shape[0], 50, 3), dtype=np.uint8) * 255
    combined_result = cv2.hconcat([image_bgr, split_region, colored_depth[:, :, ::-1]])
    vis_path = output_dir / "image_depth_vis.png"
    cv2.imwrite(vis_path.as_posix(), combined_result)

    available_files = [
        path.as_posix()
        for path in [vis_path, raw_depth_path, ply_path]
        if path.exists()
    ]

    return (image_rgb, colored_depth), glb_path.as_posix(), available_files


def get_model_choices() -> List[Tuple[str, str]]:
    choices = []
    for k, v in V1_MODEL_CONFIGS.items():
        choices.append((v['display_name'], f'v1_{k}'))
    for k, v in V2_MODEL_CONFIGS.items():
        choices.append((v['display_name'], f'v2_{k}'))
    for k, v in DA3_MODEL_SOURCES.items():
        choices.append((v['display_name'], f'da3_{k}'))
    choices.append(("Pixel-Perfect Depth", "ppd"))
    return choices

def run_model(model_key: str, image: np.ndarray) -> Tuple[np.ndarray, str]:
    if model_key.startswith('v1_'):
        key = model_key[3:]
        model = load_v1_model(key)
        depth = predict_v1(model, image)
        label = V1_MODEL_CONFIGS[key]['display_name']
    elif model_key.startswith('v2_'):
        key = model_key[3:]
        model = load_v2_model(key)
        depth = predict_v2(model, image)
        label = V2_MODEL_CONFIGS[key]['display_name']
    elif model_key.startswith('da3_'):
        key = model_key[4:]
        depth_vis, _, _, label = run_da3_inference(key, image)
        return depth_vis, label
    elif model_key == 'ppd':
        slider_data, _, _ = pixel_perfect_depth_inference(
            image,
            denoise_steps=PPD_DEFAULT_STEPS,
            apply_filter=False,
            request=None,
            generate_assets=False
        )
        depth = slider_data[1]
        label = "Pixel-Perfect Depth"
        return depth, label
    else:
        raise ValueError(f"Unknown model key: {model_key}")
    colored = colorize_depth(depth)
    return colored, label

def compare_models(image, model1: str, model2: str, progress=gr.Progress()) -> Tuple[np.ndarray, str]:
    if image is None:
        return None, "❌ Please upload an image."

    # Convert image to numpy array if needed
    if isinstance(image, str):
        # If it's a file path
        image = cv2.imread(image)
    elif hasattr(image, 'save'):
        # If it's a PIL Image
        image = np.array(image)
        if len(image.shape) == 3 and image.shape[2] == 3:
            image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)

    progress(0.1, desc=f"Running {model1}")
    out1, label1 = run_model(model1, image)
    progress(0.5, desc=f"Running {model2}")
    out2, label2 = run_model(model2, image)
    h, w = out1.shape[:2]
    canvas = np.ones((h + 40, w * 2 + 20, 3), dtype=np.uint8) * 255
    canvas[40:40+h, 10:10+w] = out1
    canvas[40:40+h, w+20:w*2+20] = out2
    font = cv2.FONT_HERSHEY_SIMPLEX
    font_scale = 0.7
    thickness = 2
    size1 = cv2.getTextSize(label1, font, font_scale, thickness)[0]
    size2 = cv2.getTextSize(label2, font, font_scale, thickness)[0]
    cv2.putText(canvas, label1, (10 + (w - size1[0]) // 2, 28), font, font_scale, (0,0,0), thickness)
    cv2.putText(canvas, label2, (w+20 + (w - size2[0]) // 2, 28), font, font_scale, (0,0,0), thickness)
    progress(1.0, desc="Done")
    return canvas, f"**{label1}** vs **{label2}**"

def slider_compare(image, model1: str, model2: str, progress=gr.Progress()):
    if image is None:
        return None, "❌ Please upload an image."

    # Convert image to numpy array if needed
    if isinstance(image, str):
        # If it's a file path
        image = cv2.imread(image)
    elif hasattr(image, 'save'):
        # If it's a PIL Image
        image = np.array(image)
        if len(image.shape) == 3 and image.shape[2] == 3:
            image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)

    progress(0.1, desc=f"Running {model1}")
    out1, label1 = run_model(model1, image)
    progress(0.5, desc=f"Running {model2}")
    out2, label2 = run_model(model2, image)
    def add_label(img, label):
        h, w = img.shape[:2]
        canvas = np.ones((h+40, w, 3), dtype=np.uint8) * 255
        canvas[40:, :] = img
        font = cv2.FONT_HERSHEY_SIMPLEX
        font_scale = 0.7
        thickness = 2
        size = cv2.getTextSize(label, font, font_scale, thickness)[0]
        cv2.putText(canvas, label, ((w-size[0])//2, 28), font, font_scale, (0,0,0), thickness)
        return canvas
    return (add_label(out1, label1), add_label(out2, label2)), f"Slider: **{label1}** vs **{label2}**"

def single_inference(image, model: str, progress=gr.Progress()):
    if image is None:
        return None, "❌ Please upload an image."

    # Store original image for slider comparison
    original_image = None
    
    # Convert image to numpy array if needed
    if isinstance(image, str):
        # If it's a file path
        original_image = cv2.imread(image)
        original_image = cv2.cvtColor(original_image, cv2.COLOR_BGR2RGB)  # Convert to RGB for display
        image = cv2.imread(image)
    elif hasattr(image, 'save'):
        # If it's a PIL Image
        original_image = np.array(image)  # PIL images are already in RGB
        image = np.array(image)
        if len(image.shape) == 3 and image.shape[2] == 3:
            image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)
    else:
        # If it's already a numpy array (from Gradio)
        original_image = np.array(image)  # Keep original in RGB
        image = np.array(image)
        if len(image.shape) == 3 and image.shape[2] == 3:
            image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)

    progress(0.1, desc=f"Running {model}")
    depth_result, label = run_model(model, image)
    
    # Convert depth result back to RGB for slider (depth_result is already in RGB from colorize_depth)
    depth_result_rgb = depth_result  # colorize_depth already returns RGB
    
    progress(1.0, desc="Done")
    return (original_image, depth_result_rgb), f"**Original** vs **{label}**"

def get_example_images() -> List[str]:
    import re

    def natural_sort_key(filename):
        """Sort filenames with numbers naturally (demo1, demo2, ..., demo10, demo11)"""
        # Split by numbers and convert numeric parts to integers for proper sorting
        return [int(part) if part.isdigit() else part for part in re.split(r'(\d+)', filename)]

    # Try both v1 and v2 examples
    examples = []
    for ex_dir in [
        "assets/examples",
        "Depth-Anything/assets/examples",
        "Depth-Anything-V2/assets/examples",
        "Depth-Anything-3-anysize/assets/examples",
        "Pixel-Perfect-Depth/assets/examples",
    ]:
        ex_path = os.path.join(os.path.dirname(__file__), ex_dir)
        if os.path.exists(ex_path):
            # Get all image files and sort them naturally
            all_files = [f for f in os.listdir(ex_path) if f.lower().endswith(('.png', '.jpg', '.jpeg'))]
            sorted_files = sorted(all_files, key=natural_sort_key)
            files = [os.path.join(ex_path, f) for f in sorted_files]
            examples.extend(files)
    return examples

def get_paginated_examples(examples: List[str], page: int = 0, per_page: int = 6) -> Tuple[List[str], int, bool, bool]:
    """Get paginated examples with navigation info"""
    total_pages = (len(examples) - 1) // per_page + 1 if examples else 0
    start_idx = page * per_page
    end_idx = min(start_idx + per_page, len(examples))
    
    current_examples = examples[start_idx:end_idx]
    has_prev = page > 0
    has_next = page < total_pages - 1
    
    return current_examples, total_pages, has_prev, has_next

def create_app():
    model_choices = get_model_choices()
    default1 = model_choices[0][1]
    default2 = model_choices[1][1]
    da3_choices = [(cfg['display_name'], f"da3_{key}") for key, cfg in DA3_MODEL_SOURCES.items()]
    if not da3_choices:
        raise ValueError("Depth Anything v3 models are not configured.")
    da3_default = da3_choices[2][1] if len(da3_choices) > 2 else da3_choices[0][1]
    example_images = get_example_images()
    blocks_kwargs = {"title": "Depth Anything v1 vs v2 Comparison"}
    try:
        if "theme" in inspect.signature(gr.Blocks.__init__).parameters and hasattr(gr, "themes"):
            # Use theme only when the installed gradio version accepts it.
            blocks_kwargs["theme"] = gr.themes.Soft()
    except (ValueError, TypeError):
        pass
    with gr.Blocks(**blocks_kwargs) as app:
        gr.Markdown("""
        # Depth Estimation Comparison
        Compare Depth Anything v1, Depth Anything v2, and Pixel-Perfect Depth side-by-side or with a slider.
        """)
        with gr.Tabs():  # Select the first tab (Slider Comparison) by default
            with gr.Tab("🎚️ Slider Comparison"):
                with gr.Row():
                    img_input2 = gr.Image(label="Input Image", type="numpy")
                    with gr.Column():
                        m1s = gr.Dropdown(choices=model_choices, label="Model A", value=default1)
                        m2s = gr.Dropdown(choices=model_choices, label="Model B", value=default2)
                        btn2 = gr.Button("Slider Compare", variant="primary")
                slider = gr.ImageSlider(label="Model Comparison Slider")
                slider_status = gr.Markdown()
                btn2.click(slider_compare, inputs=[img_input2, m1s, m2s], outputs=[slider, slider_status], show_progress=True)

                if example_images:
                    def slider_example_fn(image):
                        return slider_compare(image, default1, default2)
                    gr.Examples(examples=example_images, inputs=[img_input2], outputs=[slider, slider_status], fn=slider_example_fn)
            with gr.Tab("🔍 Method Comparison"):
                with gr.Row():
                    img_input = gr.Image(label="Input Image", type="numpy")
                    with gr.Column():
                        m1 = gr.Dropdown(choices=model_choices, label="Model 1", value=default1)
                        m2 = gr.Dropdown(choices=model_choices, label="Model 2", value=default2)
                        btn = gr.Button("Compare", variant="primary")
                out_img = gr.Image(label="Comparison Result")
                out_status = gr.Markdown()
                btn.click(compare_models, inputs=[img_input, m1, m2], outputs=[out_img, out_status], show_progress=True)

                if example_images:
                    def compare_example_fn(image):
                        return compare_models(image, default1, default2)
                    gr.Examples(examples=example_images, inputs=[img_input], outputs=[out_img, out_status], fn=compare_example_fn)
            with gr.Tab("📷 Single Model"):
                with gr.Row():
                    img_input3 = gr.Image(label="Input Image", type="numpy")
                    m_single = gr.Dropdown(choices=model_choices, label="Model", value=default1)
                    btn3 = gr.Button("Run", variant="primary")
                single_slider = gr.ImageSlider(label="Original vs Depth")
                out_single_status = gr.Markdown()
                btn3.click(single_inference, inputs=[img_input3, m_single], outputs=[single_slider, out_single_status], show_progress=True)

                if example_images:
                    def single_example_fn(image):
                        return single_inference(image, default1)
                    gr.Examples(examples=example_images, inputs=[img_input3], outputs=[single_slider, out_single_status], fn=single_example_fn)
        gr.Markdown("""
        ---
        - **v1**: [Depth Anything v1](https://github.com/LiheYoung/Depth-Anything)
        - **v2**: [Depth Anything v2](https://github.com/DepthAnything/Depth-Anything-V2)
        - **v3**: [Depth Anything v3](https://github.com/ByteDance-Seed/Depth-Anything-3) & [Depth-Anything-3-anysize](https://github.com/shriarul5273/Depth-Anything-3-anysize)
        - **PPD**: [Pixel-Perfect Depth](https://github.com/gangweix/pixel-perfect-depth)
        """)
    return app

def main():
    logging.info("🚀 Starting Depth Anything Comparison App...")
    app = create_app()
    app.queue().launch(show_error=True)

if __name__ == "__main__":
    main()