"""
Visualize collision between 3D assets in a scene layout.
Finds a pair of colliding assets and renders them with a red transparent bounding box
highlighting the collision region.
"""

import os
import json
import argparse
import subprocess
import sys
import tempfile
import shutil
import numpy as np
import trimesh
from pathlib import Path
from typing import List, Dict, Any, Optional, Tuple
from copy import deepcopy

# Add project root
SCRIPT_DIR = Path(__file__).parent
REPO_ROOT = SCRIPT_DIR.parent.parent
sys.path.insert(0, str(REPO_ROOT))

from trimesh.visual.material import PBRMaterial


def get_asset_position_size(asset: Dict) -> Tuple[Optional[List[float]], Optional[List[float]]]:
    """
    Extract position and size from asset, handling different data formats.
    """
    pos = None
    size = None
    
    # Try transform format first
    if 'transform' in asset:
        transform = asset['transform']
        pos = transform.get('pos') or transform.get('position')
        size = transform.get('size')
    
    # Fallback to direct fields
    if pos is None:
        pos = asset.get('pos') or asset.get('position')
    if size is None:
        size = asset.get('size')
    
    return pos, size


def get_asset_rotation(asset: Dict) -> Optional[List[float]]:
    """Extract rotation from asset."""
    rot = None
    if 'transform' in asset:
        rot = asset['transform'].get('rot')
    if rot is None:
        rot = asset.get('rot')
    return rot


def compute_bbox_intersection(pos1: List, size1: List, pos2: List, size2: List) -> Optional[Dict]:
    """
    Compute the intersection bounding box between two objects.
    Returns None if no intersection, otherwise returns the intersection bbox.
    """
    # Object 1 bounds
    min1 = [pos1[i] - size1[i]/2 for i in range(3)]
    max1 = [pos1[i] + size1[i]/2 for i in range(3)]
    
    # Object 2 bounds
    min2 = [pos2[i] - size2[i]/2 for i in range(3)]
    max2 = [pos2[i] + size2[i]/2 for i in range(3)]
    
    # Calculate intersection bounds
    inter_min = [max(min1[i], min2[i]) for i in range(3)]
    inter_max = [min(max1[i], max2[i]) for i in range(3)]
    
    # Check if there's actually an intersection
    for i in range(3):
        if inter_min[i] >= inter_max[i]:
            return None
    
    # Calculate intersection volume
    volume = (inter_max[0] - inter_min[0]) * (inter_max[1] - inter_min[1]) * (inter_max[2] - inter_min[2])
    
    return {
        'min': inter_min,
        'max': inter_max,
        'center': [(inter_min[i] + inter_max[i]) / 2 for i in range(3)],
        'size': [inter_max[i] - inter_min[i] for i in range(3)],
        'volume': volume
    }


def compute_object_volume(size: List) -> float:
    """Compute volume of an object given its size."""
    return size[0] * size[1] * size[2]


def size_similarity(size1: List, size2: List) -> float:
    """
    Compute similarity between two sizes (0-1, higher is more similar).
    Uses ratio of smaller to larger volume.
    """
    vol1 = compute_object_volume(size1)
    vol2 = compute_object_volume(size2)
    if vol1 == 0 or vol2 == 0:
        return 0.0
    return min(vol1, vol2) / max(vol1, vol2)


def find_collision_pairs(layout: Dict, min_collision_volume: float = 0.001) -> List[Dict]:
    """
    Find all pairs of colliding assets in the layout.
    
    Returns list of collision info dicts sorted by:
    1. Size similarity (more similar sizes preferred)
    2. Collision volume (larger collisions preferred)
    """
    # Flatten all assets
    assets = []
    
    if "assets" in layout:
        for asset in layout["assets"]:
            assets.append(asset)
    
    if "functional_zones" in layout:
        for zone in layout["functional_zones"]:
            for asset in zone.get("assets", []):
                assets.append(asset)
    
    if "groups" in layout:
        for group in layout["groups"]:
            for obj in group.get("objects", []):
                assets.append(obj)
    
    # Find all collision pairs
    collision_pairs = []
    
    for i, asset1 in enumerate(assets):
        pos1, size1 = get_asset_position_size(asset1)
        if pos1 is None or size1 is None:
            continue
        if all(s == 0 for s in size1):
            continue
            
        for j, asset2 in enumerate(assets):
            if j <= i:  # Avoid duplicates and self-collision
                continue
                
            pos2, size2 = get_asset_position_size(asset2)
            if pos2 is None or size2 is None:
                continue
            if all(s == 0 for s in size2):
                continue
            
            # Check for intersection
            intersection = compute_bbox_intersection(pos1, size1, pos2, size2)
            
            if intersection and intersection['volume'] >= min_collision_volume:
                similarity = size_similarity(size1, size2)
                
                collision_pairs.append({
                    'asset1': asset1,
                    'asset2': asset2,
                    'asset1_idx': i,
                    'asset2_idx': j,
                    'pos1': pos1,
                    'size1': size1,
                    'pos2': pos2,
                    'size2': size2,
                    'intersection': intersection,
                    'size_similarity': similarity,
                    'collision_volume': intersection['volume'],
                })
    
    # Sort by collision volume (descending) - largest collision first
    collision_pairs.sort(key=lambda x: x['collision_volume'], reverse=True)
    
    return collision_pairs


def create_collision_bbox_glb(intersection: Dict, output_path: str):
    """
    Create a GLB file with a semi-transparent red bounding box for the collision region.
    """
    min_pt = np.array(intersection['min'])
    max_pt = np.array(intersection['max'])
    
    # Global rotation matrix (same as compose_generated.py)
    global_rot = trimesh.transformations.rotation_matrix(-np.pi / 2, [1, 0, 0])
    
    # Create a solid box for the collision region
    center = (min_pt + max_pt) / 2
    size = max_pt - min_pt
    
    # Create box mesh
    box = trimesh.creation.box(extents=size)
    box.apply_translation(center)
    box.apply_transform(global_rot)
    
    # Apply semi-transparent red material
    # Red with ~70% opacity for better visibility
    red_material = PBRMaterial(
        baseColorFactor=[255, 30, 30, 200],  # RGBA: bright red with alpha=200 (~78% opacity)
        metallicFactor=0.0,
        roughnessFactor=0.5,
        alphaMode='BLEND',
    )
    box.visual = trimesh.visual.TextureVisuals(material=red_material)
    
    # Export
    scene = trimesh.Scene()
    scene.add_geometry(box, node_name="collision_region")
    scene.export(output_path)
    print(f"  Created collision bbox GLB: {output_path}")


def create_object_bbox_glb(pos: List, size: List, color: Tuple, output_path: str, label: str = "object"):
    """
    Create a GLB file with a wireframe bounding box for an object.
    """
    min_pt = np.array([pos[i] - size[i]/2 for i in range(3)])
    max_pt = np.array([pos[i] + size[i]/2 for i in range(3)])
    
    # Global rotation matrix
    global_rot = trimesh.transformations.rotation_matrix(-np.pi / 2, [1, 0, 0])
    
    scene = trimesh.Scene()
    
    # Create wireframe edges
    vertices = np.array([
        [min_pt[0], min_pt[1], min_pt[2]],
        [max_pt[0], min_pt[1], min_pt[2]],
        [max_pt[0], max_pt[1], min_pt[2]],
        [min_pt[0], max_pt[1], min_pt[2]],
        [min_pt[0], min_pt[1], max_pt[2]],
        [max_pt[0], min_pt[1], max_pt[2]],
        [max_pt[0], max_pt[1], max_pt[2]],
        [min_pt[0], max_pt[1], max_pt[2]],
    ])
    
    edges = [
        [0, 1], [1, 2], [2, 3], [3, 0],
        [4, 5], [5, 6], [6, 7], [7, 4],
        [0, 4], [1, 5], [2, 6], [3, 7],
    ]
    
    rgba = [int(c * 255) for c in color] + [255]
    material = PBRMaterial(
        baseColorFactor=rgba,
        metallicFactor=0.0,
        roughnessFactor=0.5,
    )
    
    edge_radius = 0.015
    
    for i, edge in enumerate(edges):
        start = vertices[edge[0]]
        end = vertices[edge[1]]
        segment = end - start
        length = np.linalg.norm(segment)
        
        if length < 0.001:
            continue
        
        cylinder = trimesh.creation.cylinder(radius=edge_radius, height=length, sections=8)
        
        direction = segment / length
        z_axis = np.array([0, 0, 1])
        
        if np.allclose(direction, z_axis):
            rotation = np.eye(4)
        elif np.allclose(direction, -z_axis):
            rotation = trimesh.transformations.rotation_matrix(np.pi, [1, 0, 0])
        else:
            axis = np.cross(z_axis, direction)
            axis = axis / np.linalg.norm(axis)
            angle = np.arccos(np.clip(np.dot(z_axis, direction), -1, 1))
            rotation = trimesh.transformations.rotation_matrix(angle, axis)
        
        midpoint = (start + end) / 2
        translation = trimesh.transformations.translation_matrix(midpoint)
        
        cylinder.apply_transform(rotation)
        cylinder.apply_transform(translation)
        cylinder.apply_transform(global_rot)
        cylinder.visual = trimesh.visual.TextureVisuals(material=material)
        
        scene.add_geometry(cylinder, node_name=f"{label}_edge_{i}")
    
    scene.export(output_path)
    print(f"  Created object bbox GLB: {output_path}")


def compose_collision_scene(asset1: Dict, asset2: Dict, output_path: str):
    """
    Compose a scene with only the two colliding assets.
    """
    from tools.data_gen.compose_generated import compose_scene
    
    # Create a minimal layout with just these two assets
    layout = {
        "meta": {"scene_type": "collision_vis"},
        "architecture": {"boundary_polygon": []},  # No boundary needed
        "assets": [asset1, asset2]
    }
    
    compose_scene(
        layout=layout,
        output_path=output_path,
        add_floor=False,
        add_walls=False,
        add_ceiling=False,
    )
    print(f"  Composed collision scene: {output_path}")


def merge_glb_files(base_path: str, overlay_path: str, output_path: str):
    """Merge two GLB files."""
    base_mesh = trimesh.load(base_path)
    overlay_mesh = trimesh.load(overlay_path)
    
    if isinstance(base_mesh, trimesh.Scene):
        scene = base_mesh
    else:
        scene = trimesh.Scene()
        scene.add_geometry(base_mesh, node_name="base")
    
    if isinstance(overlay_mesh, trimesh.Scene):
        for name, geom in overlay_mesh.geometry.items():
            scene.add_geometry(geom, node_name=f"overlay_{name}")
    else:
        scene.add_geometry(overlay_mesh, node_name="overlay")
    
    scene.export(output_path)


def run_command(cmd, env=None, quiet=False):
    """Run a shell command."""
    print(f"  Running: {cmd[:100]}...")
    try:
        if quiet:
            subprocess.check_call(cmd, shell=True, env=env,
                                  stdout=subprocess.DEVNULL,
                                  stderr=subprocess.DEVNULL)
        else:
            subprocess.check_call(cmd, shell=True, env=env)
        return True
    except subprocess.CalledProcessError as e:
        print(f"  Command failed: {e}")
        return False


def render_scene(glb_path: str, output_path: str, view_mode: str = "diagonal",
                 width: int = 1200, height: int = 900):
    """Render a GLB scene using Blender."""
    current_env = os.environ.copy()
    
    cmd = (
        f"conda run -n blender python InternScenes/InternScenes_Real2Sim/blender_renderer.py "
        f"--input '{glb_path}' "
        f"--output '{output_path}' "
        f"--width {width} --height {height} "
        f"--engine BLENDER_EEVEE --samples 64 "
        f"--view-mode {view_mode} --auto-crop "
        f"--floor-material solid "
        f"--diagonal-distance 2.0 "  # Farther view for better overview
        f"--camera-factor 1.5 "  # Wider angle
    )
    
    run_command(cmd, env=current_env, quiet=True)


def visualize_collision(
    layout_path: str,
    output_dir: str,
    collision_idx: int = 0,
    render_views: List[str] = None,
):
    """
    Main function to visualize collision between assets.
    
    Args:
        layout_path: Path to layout.json file
        output_dir: Directory to save outputs
        collision_idx: Index of collision pair to visualize (0 = best match)
        render_views: List of view modes to render
    """
    if render_views is None:
        render_views = ["diagonal", "diagonal2"]
    
    print(f"\n{'='*60}")
    print(f"Collision Visualization")
    print(f"{'='*60}")
    print(f"Input: {layout_path}")
    print(f"Output: {output_dir}")
    print(f"{'='*60}\n")
    
    # Load layout
    with open(layout_path, 'r') as f:
        layout = json.load(f)
    
    # Create output directory
    os.makedirs(output_dir, exist_ok=True)
    
    # Find collision pairs
    print("Finding collision pairs...")
    collision_pairs = find_collision_pairs(layout)
    
    if not collision_pairs:
        print("No collisions found in this layout!")
        return
    
    print(f"Found {len(collision_pairs)} collision pairs")
    
    # Save all collision pairs info
    collision_info_path = os.path.join(output_dir, "collision_pairs.json")
    collision_info = []
    for i, pair in enumerate(collision_pairs):
        info = {
            'index': i,
            'asset1_category': pair['asset1'].get('category', 'unknown'),
            'asset2_category': pair['asset2'].get('category', 'unknown'),
            'asset1_description': pair['asset1'].get('description', '')[:50] + '...',
            'asset2_description': pair['asset2'].get('description', '')[:50] + '...',
            'collision_volume': pair['collision_volume'],
            'size_similarity': pair['size_similarity'],
            'intersection': pair['intersection'],
        }
        collision_info.append(info)
        print(f"  [{i}] {info['asset1_category']} vs {info['asset2_category']}: "
              f"vol={pair['collision_volume']:.4f}, sim={pair['size_similarity']:.2f}")
    
    with open(collision_info_path, 'w') as f:
        json.dump(collision_info, f, indent=2)
    print(f"\nSaved collision info to: {collision_info_path}")
    
    # Select collision pair to visualize
    if collision_idx >= len(collision_pairs):
        print(f"Warning: collision_idx {collision_idx} out of range, using 0")
        collision_idx = 0
    
    pair = collision_pairs[collision_idx]
    print(f"\nVisualizing collision pair [{collision_idx}]:")
    print(f"  Asset 1: {pair['asset1'].get('category', 'unknown')}")
    print(f"  Asset 2: {pair['asset2'].get('category', 'unknown')}")
    print(f"  Collision volume: {pair['collision_volume']:.4f}")
    print(f"  Size similarity: {pair['size_similarity']:.2f}")
    
    # Create temp directory
    temp_dir = os.path.join(output_dir, "_temp")
    os.makedirs(temp_dir, exist_ok=True)
    
    # Step 1: Compose scene with just the two assets
    print("\nComposing collision scene...")
    scene_glb = os.path.join(temp_dir, "collision_scene.glb")
    compose_collision_scene(pair['asset1'], pair['asset2'], scene_glb)
    
    # Step 2: Create collision region bbox (red transparent) - only this, no object bboxes
    print("\nCreating collision region bbox...")
    collision_glb = os.path.join(temp_dir, "collision_region.glb")
    create_collision_bbox_glb(pair['intersection'], collision_glb)
    
    # Step 3: Merge scene with collision bbox only
    print("\nMerging scene components...")
    final_glb = os.path.join(temp_dir, "final.glb")
    merge_glb_files(scene_glb, collision_glb, final_glb)
    
    # Copy final GLB to output
    final_output_glb = os.path.join(output_dir, "collision_scene.glb")
    shutil.copy(final_glb, final_output_glb)
    print(f"  Final GLB saved to: {final_output_glb}")
    
    # Step 5: Render
    print("\nRendering...")
    for view in render_views:
        render_path = os.path.join(output_dir, f"collision_{view}.png")
        print(f"  Rendering {view} view...")
        render_scene(final_glb, render_path, view_mode=view)
    
    # Clean up
    # shutil.rmtree(temp_dir)  # Uncomment to clean up temp files
    
    print(f"\n{'='*60}")
    print(f"Done! Outputs saved to: {output_dir}")
    print(f"{'='*60}")
    
    return pair


def main():
    parser = argparse.ArgumentParser(description="Visualize collision between 3D assets")
    parser.add_argument("--input", 
                        default="test_vis_output6/3rscan_422885ce-192d-25fc-851a-df2d675a6559_fine/layout_retrieved.json",
                        help="Path to layout.json file")
    parser.add_argument("--output", default="collision_vis_output", help="Output directory")
    parser.add_argument("--collision-idx", type=int, default=0,
                        help="Index of collision pair to visualize (0 = best size match)")
    parser.add_argument("--all-views", action="store_true",
                        help="Render all view modes (diagonal, diagonal2, side views)")
    
    args = parser.parse_args()
    
    views = ["diagonal", "diagonal2"]
    if args.all_views:
        views = ["diagonal", "diagonal2", "side_front", "side_back", "side_left", "side_right"]
    
    visualize_collision(
        layout_path=args.input,
        output_dir=args.output,
        collision_idx=args.collision_idx,
        render_views=views,
    )


if __name__ == "__main__":
    main()