#!/usr/bin/env python3
"""
Compose Generated Scene Script

This script takes a layout JSON (with model_uids) and composes a GLB scene.
It handles flattening of functional zones/groups and applies transforms.
Also generates room geometry (floor, walls, ceiling) from boundary_polygon.

Supports both:
- Original asset library (with per-asset-type rotation handling)
- Normalized asset library (pre-processed, no rotation needed)
"""

import os
import json
import trimesh
import numpy as np
import argparse
import sys
from pathlib import Path
from shapely.geometry import Polygon as ShapelyPolygon
from trimesh.visual import ColorVisuals

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

# Add InternScenes_Real2Sim to path to import compose_scenes
sys.path.insert(0, os.path.join(REPO_ROOT, "InternScenes", "InternScenes_Real2Sim"))

# Import loaders
from compose_scenes import AssetMeshLoader

# Try to import normalized asset loader
try:
    from tools.asset_description.normalized_asset_loader import NormalizedAssetMeshLoader
    NORMALIZED_LOADER_AVAILABLE = True
except ImportError:
    NORMALIZED_LOADER_AVAILABLE = False

def normalize_rotation(rot):
    """
    Normalize rotation to radians.
    Heuristic: if any value is outside [-2pi, 2pi], assume degrees.
    """
    rot = np.array(rot, dtype=np.float64)
    if np.any(np.abs(rot) > 2 * np.pi + 1e-3):
        return np.radians(rot)
    return rot

def get_scale_transform(mesh_size, target_size, category):
    """
    Calculate scale matrix based on target size and mesh size.
    Includes special handling for carpets/clothes similar to compose_scenes.py
    """
    scale_matrix = np.eye(4)
    
    # Avoid division by zero
    mesh_size = np.maximum(mesh_size, 1e-6)
    
    if category == "carpet":
        scale_factors = target_size / mesh_size
        # Check for orientation issues (carpet standing up)
        # Heuristic from compose_scenes.py
        if target_size[2]/target_size[0] > 150 or target_size[2]/target_size[1] > 150:
             if target_size[2]/target_size[0] > target_size[2]/target_size[1]:
                 # Rotate 90 around Y
                 rot_mat = trimesh.transformations.rotation_matrix(0.5 * np.pi, [0, 1, 0])
                 new_target = np.array([target_size[2], target_size[0], target_size[1]])
                 scale_factors = new_target / mesh_size
                 scale_matrix = np.diag([scale_factors[0], scale_factors[1], scale_factors[2]/100.0, 1])
                 return scale_matrix @ rot_mat
             else:
                 # Rotate 90 around X
                 rot_mat = trimesh.transformations.rotation_matrix(0.5 * np.pi, [1, 0, 0])
                 new_target = np.array([target_size[0], target_size[2], target_size[1]])
                 scale_factors = new_target / mesh_size
                 scale_matrix = np.diag([scale_factors[0], scale_factors[1], scale_factors[2]/100.0, 1])
                 return scale_matrix @ rot_mat
        else:
             scale_matrix = np.diag([scale_factors[0], scale_factors[1], scale_factors[2]/100.0, 1])
             return scale_matrix
             
    elif category == "clothes":
        scale = target_size / mesh_size
        min_scale = min(scale)
        scale_matrix = np.diag([min_scale, min_scale, min_scale, 1])
        return scale_matrix
        
    else:
        scale = target_size / mesh_size
        scale_matrix = np.diag([scale[0], scale[1], scale[2], 1])
        return scale_matrix


# ============================================
# Room Geometry Generation from Boundary
# ============================================

# Default colors for room structure
FLOOR_COLOR = np.array([200, 200, 200, 255], dtype=np.uint8)  # Light gray
WALL_COLOR = np.array([240, 240, 240, 180], dtype=np.uint8)   # White with some transparency
CEILING_COLOR = np.array([250, 250, 250, 128], dtype=np.uint8)  # Very light, more transparent


def triangulate_polygon(vertices_2d: np.ndarray) -> tuple:
    """
    Triangulate a 2D polygon (supports concave polygons like L-shape, H-shape).
    
    Uses trimesh's triangulate_polygon which handles concave polygons correctly
    via earcut algorithm.
    
    Args:
        vertices_2d: Nx2 array of (x, y) coordinates in order (CCW or CW)
    
    Returns:
        tuple: (vertices_2d, faces) where vertices may have additional points added
               and faces is Mx3 array of face indices
    """
    from shapely.geometry import Polygon as ShapelyPolygon
    
    # Create a proper shapely polygon
    polygon = ShapelyPolygon(vertices_2d)
    
    # Fix invalid polygons
    if not polygon.is_valid:
        polygon = polygon.buffer(0)
    
    # Use trimesh's triangulation which uses mapbox_earcut for concave polygons
    try:
        # trimesh.creation.triangulate_polygon returns (vertices, faces)
        result_vertices, result_faces = trimesh.creation.triangulate_polygon(
            polygon, 
            triangle_args=None,  # Use default earcut
            engine='earcut'  # Explicitly use earcut for concave support
        )
        
        # Return both vertices and faces - trimesh may add/reorder vertices
        return np.array(result_vertices), result_faces
        
    except Exception as e:
        print(f"Warning: trimesh triangulation failed: {e}, trying earcut directly")
        
    # Fallback: use mapbox_earcut directly if available
    try:
        import mapbox_earcut as earcut
        
        # earcut expects flattened coordinates and ring indices
        rings = np.array([len(vertices_2d)])  # Single ring (no holes)
        flat_coords = vertices_2d.flatten()
        
        # Triangulate - returns flat array of triangle vertex indices
        triangle_indices = earcut.triangulate_float64(flat_coords, rings)
        
        # Reshape to Nx3
        faces = np.array(triangle_indices).reshape(-1, 3)
        return vertices_2d, faces
        
    except ImportError:
        print("Warning: mapbox_earcut not available, using fan triangulation")
    except Exception as e:
        print(f"Warning: earcut failed: {e}")
    
    # Last resort: simple fan triangulation (only works for convex polygons)
    n = len(vertices_2d)
    faces = np.array([[0, i, i+1] for i in range(1, n-1)])
    return vertices_2d, faces


def create_floor_mesh(floor_vertices_2d: np.ndarray, z_height: float = 0.0) -> trimesh.Trimesh:
    """
    Create a floor mesh from 2D polygon vertices.
    Supports concave polygons (L-shape, H-shape, etc.)
    
    Args:
        floor_vertices_2d: Nx2 array of (x, y) coordinates in order
        z_height: Z coordinate for the floor (default 0)
    
    Returns:
        trimesh.Trimesh: Floor mesh
    """
    try:
        # Triangulate using earcut (supports concave polygons)
        # triangulate_polygon returns (vertices_2d, faces) - vertices may be different from input
        result_vertices_2d, faces = triangulate_polygon(floor_vertices_2d)
        
        # Create 3D vertices from the triangulation result
        vertices_3d = np.column_stack([result_vertices_2d, np.full(len(result_vertices_2d), z_height)])
        
        floor_mesh = trimesh.Trimesh(vertices=vertices_3d, faces=faces)
        floor_mesh.visual = ColorVisuals(mesh=floor_mesh, vertex_colors=np.tile(FLOOR_COLOR, (len(vertices_3d), 1)))
        
        return floor_mesh
    except Exception as e:
        print(f"Warning: Failed to create floor mesh: {e}")
        import traceback
        traceback.print_exc()
        return None


def create_ceiling_mesh(floor_vertices_2d: np.ndarray, z_height: float) -> trimesh.Trimesh:
    """
    Create a ceiling mesh from 2D polygon vertices.
    Supports concave polygons (L-shape, H-shape, etc.)
    
    Args:
        floor_vertices_2d: Nx2 array of (x, y) coordinates
        z_height: Z coordinate for the ceiling
    
    Returns:
        trimesh.Trimesh: Ceiling mesh
    """
    try:
        # Triangulate using earcut (supports concave polygons)
        # triangulate_polygon returns (vertices_2d, faces) - vertices may be different from input
        result_vertices_2d, faces = triangulate_polygon(floor_vertices_2d)
        
        # Create 3D vertices from the triangulation result
        vertices_3d = np.column_stack([result_vertices_2d, np.full(len(result_vertices_2d), z_height)])
        
        # Reverse face winding for ceiling (faces down)
        faces = faces[:, ::-1]
        
        ceiling_mesh = trimesh.Trimesh(vertices=vertices_3d, faces=faces)
        ceiling_mesh.visual = ColorVisuals(mesh=ceiling_mesh, vertex_colors=np.tile(CEILING_COLOR, (len(vertices_3d), 1)))
        
        return ceiling_mesh
    except Exception as e:
        print(f"Warning: Failed to create ceiling mesh: {e}")
        import traceback
        traceback.print_exc()
        return None


def create_wall_mesh(v1_bottom: np.ndarray, v2_bottom: np.ndarray, height: float) -> trimesh.Trimesh:
    """
    Create a single wall segment mesh.
    
    Args:
        v1_bottom: First bottom vertex (x, y, z)
        v2_bottom: Second bottom vertex (x, y, z)
        height: Wall height
    
    Returns:
        trimesh.Trimesh: Wall mesh
    """
    v1_top = v1_bottom.copy()
    v1_top[2] = v1_bottom[2] + height
    v2_top = v2_bottom.copy()
    v2_top[2] = v2_bottom[2] + height
    
    # Create quad as two triangles
    vertices = np.array([v1_bottom, v2_bottom, v2_top, v1_top])
    faces = np.array([[0, 1, 2], [0, 2, 3]])
    
    wall_mesh = trimesh.Trimesh(vertices=vertices, faces=faces)
    wall_mesh.visual = ColorVisuals(mesh=wall_mesh, vertex_colors=np.tile(WALL_COLOR, (4, 1)))
    
    return wall_mesh


def create_walls_mesh(floor_vertices_2d: np.ndarray, floor_z: float, height: float) -> trimesh.Trimesh:
    """
    Create all wall meshes from floor polygon.
    
    Args:
        floor_vertices_2d: Nx2 array of (x, y) floor coordinates
        floor_z: Z coordinate of the floor
        height: Wall height
    
    Returns:
        trimesh.Trimesh: Combined walls mesh
    """
    wall_meshes = []
    n = len(floor_vertices_2d)
    
    for i in range(n):
        v1_2d = floor_vertices_2d[i]
        v2_2d = floor_vertices_2d[(i + 1) % n]
        
        v1_bottom = np.array([v1_2d[0], v1_2d[1], floor_z])
        v2_bottom = np.array([v2_2d[0], v2_2d[1], floor_z])
        
        wall = create_wall_mesh(v1_bottom, v2_bottom, height)
        if wall is not None:
            wall_meshes.append(wall)
    
    if wall_meshes:
        return trimesh.util.concatenate(wall_meshes)
    return None


def generate_room_geometry(layout: dict, add_floor: bool = True, add_walls: bool = True, add_ceiling: bool = True) -> list:
    """
    Generate room geometry (floor, walls, ceiling) from layout's architecture data.
    
    Args:
        layout: Layout dictionary containing 'architecture' with 'boundary_polygon' and 'height'
        add_floor: Whether to add floor mesh
        add_walls: Whether to add wall meshes
        add_ceiling: Whether to add ceiling mesh
    
    Returns:
        List of (name, mesh) tuples
    """
    geometries = []
    
    architecture = layout.get("architecture", {})
    boundary_polygon = architecture.get("boundary_polygon", [])
    height = architecture.get("height", 2.6)  # Default 2.6m height
    
    if not boundary_polygon:
        print("Warning: No boundary_polygon found in architecture, skipping room geometry")
        return geometries
    
    # Parse boundary polygon
    # Format: [[x, y, z], ...] - first half are floor vertices, second half are ceiling vertices
    # Or it could be just floor vertices with separate height
    boundary_polygon = np.array(boundary_polygon)
    
    if len(boundary_polygon) == 0:
        return geometries
    
    # Determine floor and ceiling vertices
    # Usually boundary_polygon contains floor vertices (z=0) and ceiling vertices (z=height)
    # Split by z coordinate
    if boundary_polygon.shape[1] >= 3:
        z_values = boundary_polygon[:, 2]
        z_min = np.min(z_values)
        z_max = np.max(z_values)
        
        # If all z values are the same, use height parameter
        if abs(z_max - z_min) < 0.01:
            floor_vertices = boundary_polygon
            floor_z = z_min
            ceiling_z = z_min + height
        else:
            # Split into floor and ceiling based on z
            z_mid = (z_min + z_max) / 2
            floor_mask = z_values < z_mid
            
            floor_vertices = boundary_polygon[floor_mask]
            ceiling_vertices = boundary_polygon[~floor_mask]
            
            if len(floor_vertices) == 0:
                floor_vertices = ceiling_vertices
                floor_z = z_min
            else:
                floor_z = floor_vertices[0, 2] if len(floor_vertices) > 0 else z_min
            
            ceiling_z = z_max
            height = ceiling_z - floor_z
    else:
        # 2D polygon, assume z=0 for floor
        floor_vertices = np.column_stack([boundary_polygon, np.zeros(len(boundary_polygon))])
        floor_z = 0
        ceiling_z = height
    
    # Extract 2D coordinates (x, y) for triangulation
    floor_vertices_2d = floor_vertices[:, :2]
    
    # Create floor
    if add_floor:
        floor_mesh = create_floor_mesh(floor_vertices_2d, floor_z)
        if floor_mesh is not None:
            geometries.append(("floor", floor_mesh))
    
    # Create walls
    if add_walls:
        walls_mesh = create_walls_mesh(floor_vertices_2d, floor_z, height)
        if walls_mesh is not None:
            geometries.append(("walls", walls_mesh))
    
    # Create ceiling
    if add_ceiling:
        ceiling_mesh = create_ceiling_mesh(floor_vertices_2d, ceiling_z)
        if ceiling_mesh is not None:
            geometries.append(("ceiling", ceiling_mesh))
    
    return geometries


def compose_scene(layout, output_path, add_floor=True, add_walls=True, add_ceiling=True, 
                  input_coord_system="z-up", use_normalized_assets=True, normalized_asset_dir=None):
    """
    Compose a scene from layout JSON.
    
    Args:
        layout: layout JSON
        output_path: Path to output GLB file
        add_floor: Whether to add floor mesh
        add_walls: Whether to add wall meshes
        add_ceiling: Whether to add ceiling mesh
        input_coord_system: Coordinate system of input data. "z-up" (default) or "y-up"
        use_normalized_assets: If True, use pre-normalized assets (no per-type rotation)
        normalized_asset_dir: Path to normalized asset library (only if use_normalized_assets=True)
    """
    # 如果没有指定路径，从环境变量读取
    if normalized_asset_dir is None:
        normalized_asset_dir = os.environ.get('PTH_ASSET_NORMALIZED_LIBRARY')
        if not normalized_asset_dir:
            # 优先使用 ~/backup (本地环境)，如果不存在则使用 /backup (集群环境)
            home_path = os.path.expanduser("~/backup/datas/InternScenes/asset_library_normalized")
            if os.path.exists(home_path):
                normalized_asset_dir = home_path
            else:
                normalized_asset_dir = "/backup/datas/InternScenes/asset_library_normalized"
    
    # with open(layout_path, 'r') as f:
    #     layout = json.load(f)
    
    # Auto-detect coordinate system from meta if available
    meta = layout.get("meta", {})
    if "coordinate_system" in meta:
        detected = meta["coordinate_system"].lower().replace("_", "-")
        if detected in ["z-up", "zup"]:
            input_coord_system = "z-up"
        elif detected in ["y-up", "yup"]:
            input_coord_system = "y-up"
    
    print(f"Using coordinate system: {input_coord_system}")
    
    # Select asset loader
    if use_normalized_assets:
        if not NORMALIZED_LOADER_AVAILABLE:
            raise ImportError("NormalizedAssetMeshLoader not available. Please check installation.")
        loader = NormalizedAssetMeshLoader(normalized_asset_dir)
        print(f"Using normalized asset library: {loader.asset_dir}")
    else:
        loader = AssetMeshLoader()
        print("Using original asset library with per-type rotation")
    
    scene = trimesh.Scene()
    
    # Flatten assets
    instances = []
    if "assets" in layout:
        instances.extend(layout["assets"])
    if "functional_zones" in layout:
        for zone in layout["functional_zones"]:
            if "assets" in zone:
                instances.extend(zone["assets"])
    if "groups" in layout:
        for group in layout["groups"]:
            if "objects" in group:
                instances.extend(group["objects"])
                
    print(f"Composing scene with {len(instances)} instances...")
    
    for i, instance in enumerate(instances):
        uid = instance.get("model_uid")
        if not uid:
            continue
            
        try:
            # Load canonical mesh (centers and aligns)
            # use_texture=True is important for rendering
            mesh = loader.load_canonical_mesh(uid, use_texture=True)
            if mesh is None:
                print(f"Warning: Mesh not found for {uid}")
                continue
            
            # Extract transform data
            pos = None
            rot = None
            size = None
            
            # Case 1: Nested transform (Unified Layout / 3D-FRONT)
            if "transform" in instance and isinstance(instance["transform"], dict):
                t = instance["transform"]
                pos = t.get("pos")
                rot = t.get("rot")
                size = t.get("size")
            
            # Case 2: Flat structure (Zones Data / Model Output)
            if pos is None:
                pos = instance.get("pos")
            if rot is None:
                rot = instance.get("rot")
            if size is None:
                size = instance.get("size")
                
            # Case 3: Legacy bbox (9 elements)
            if pos is None and "bbox" in instance:
                bbox = instance["bbox"]
                pos = bbox[0:3]
                size = bbox[3:6]
                rot = bbox[6:9]

            # Case 4: Matrix transform (fallback)
            if pos is None and "transform" in instance and isinstance(instance["transform"], list):
                 # This is a raw matrix, we can just use it directly if we trust it
                 # But usually we want to use the decomposed values if available
                 transform_matrix = np.array(instance["transform"]).reshape(4, 4)
                 # Apply directly
                 scene.add_geometry(mesh, transform=transform_matrix)
                 continue

            if pos is None or rot is None or size is None:
                print(f"Warning: Missing transform data for {uid}")
                continue

            # Convert to numpy
            pos = np.array(pos, dtype=np.float64)
            rot = np.array(rot, dtype=np.float64)
            size = np.array(size, dtype=np.float64)
            
            # --- Coordinate System Handling ---
            if input_coord_system == "y-up":
                # Convert Y-up to Z-up: [x, y, z]_Yup -> [x, z, y]_Zup
                pos = np.array([pos[0], pos[2], pos[1]])
                size = np.array([size[0], size[2], size[1]])
                rot = np.array([rot[0], rot[2], rot[1]])
            # else: input is already Z-up, no conversion needed
            
            # Adjust for Floor Alignment
            # In Z-up, Z is height. If pos[2] ≈ 0 (object on floor),
            # we need to lift it by half its height (size[2]) since mesh is centered.
            if abs(pos[2]) < 1e-3:
                pos[2] = size[2] / 2.0
            # ---------------------------------------------------
            
            # Normalize rotation (degrees -> radians if needed)
            rot = normalize_rotation(rot)
            
            # Start with identity
            transform_final = np.eye(4)
            
            # 1. Scale
            mesh_size = mesh.bounding_box.extents
            category = instance.get("category", "")
            scale_mat = get_scale_transform(mesh_size, size, category)
            transform_final = scale_mat @ transform_final
            
            # 2. Rotation
            # Use rzxy order as per compose_scenes.py
            # Note: compose_scenes.py uses euler_matrix(rot[0], rot[1], rot[2], axes='rzxy')
            # where rot is [rx, ry, rz] (or [rx, rz, ry] after our conversion).
            # 'rzxy' means rotate around Z, then X, then Y.
            # The input 'rot' from layout is typically [0, rotation_y, 0] for simple objects.
            # After our conversion to Z-up, it becomes [0, 0, rotation_y].
            # So rot[0]=0, rot[1]=0, rot[2]=rotation_y.
            # euler_matrix(0, 0, rotation_y, 'rzxy') -> rotates around Z by rotation_y. Correct.
            rot_mat = trimesh.transformations.euler_matrix(rot[0], rot[1], rot[2], axes='rzxy')
            transform_final = rot_mat @ transform_final
            
            # 3. Translation
            transform_final[:3, 3] = pos
            
            # 4. Global Rotation (Z-up to Y-up)
            # compose_scenes.py applies -90 deg around X at the end
            global_rot = trimesh.transformations.rotation_matrix(-np.pi / 2, [1, 0, 0])
            transform_final = global_rot @ transform_final
            
            # Add to scene
            # We use a unique node name to avoid conflicts
            node_name = f"{i}_{uid.replace('/', '_')}"
            
            # Create a parent node with the transform (same as compose_scenes.py)
            scene.graph.update(frame_to=node_name, matrix=transform_final)
            
            # Handle both Trimesh and Scene types
            if isinstance(mesh, trimesh.Scene):
                # Add all geometries from the sub-scene as children
                for geom_name, mesh_part in mesh.geometry.items():
                    nodes_for_geom = mesh.graph.geometry_nodes.get(geom_name, [])
                    for j, sub_node in enumerate(nodes_for_geom):
                        internal_transform, _ = mesh.graph.get(sub_node)
                        scene.add_geometry(
                            mesh_part,
                            geom_name=f"{node_name}_{geom_name}_{j}",
                            transform=internal_transform,
                            parent_node_name=node_name
                        )
            else:
                # Simple Trimesh - add as child of parent node (same as compose_scenes.py)
                scene.add_geometry(
                    mesh,
                    geom_name=f"{node_name}_geom",
                    parent_node_name=node_name
                )
            
        except Exception as e:
            print(f"Error processing {uid}: {e}")
            import traceback
            traceback.print_exc()
            continue
    
    # Generate and add room geometry (floor, walls, ceiling)
    print("Generating room geometry from boundary polygon...")
    room_geometries = generate_room_geometry(layout, add_floor=add_floor, add_walls=add_walls, add_ceiling=add_ceiling)
    
    for name, geom in room_geometries:
        # Apply the same global rotation to room geometry
        global_rot = trimesh.transformations.rotation_matrix(-np.pi / 2, [1, 0, 0])
        scene.add_geometry(geom, node_name=name, transform=global_rot)
        print(f"  Added {name} geometry")
    
    if not room_geometries:
        print("  Warning: No room geometry generated (missing boundary_polygon in architecture)")
            
    # Export
    print(f"Exporting scene to {output_path}")
    os.makedirs(os.path.dirname(os.path.abspath(output_path)), exist_ok=True)
    scene.export(output_path)

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--input", required=True, help="Input layout JSON file")
    parser.add_argument("--output", required=True, help="Output GLB file")
    parser.add_argument("--no-floor", action="store_true", help="Don't add floor mesh")
    parser.add_argument("--no-walls", action="store_true", help="Don't add wall meshes")
    parser.add_argument("--no-ceiling", action="store_true", help="Don't add ceiling mesh")
    parser.add_argument("--coord-system", type=str, default="z-up", choices=["z-up", "y-up"],
                        help="Input coordinate system (default: z-up)")
    parser.add_argument("--use-normalized", default=True,
                        help="Use pre-normalized asset library (no per-type rotations needed)")
    # 默认路径逻辑：优先 ~/backup，否则 /backup
    _default_normalized_dir = os.environ.get('PTH_ASSET_NORMALIZED_LIBRARY')
    if not _default_normalized_dir:
        _home_path = os.path.expanduser("~/backup/datas/InternScenes/asset_library_normalized")
        _default_normalized_dir = _home_path if os.path.exists(_home_path) else "/backup/datas/InternScenes/asset_library_normalized"
    parser.add_argument("--normalized-dir", type=str, default=_default_normalized_dir,
                        help="Path to normalized asset directory (required if --use-normalized)")
    args = parser.parse_args()
    
    # Validate normalized asset arguments
    if args.use_normalized and not args.normalized_dir:
        parser.error("--normalized-dir is required when using --use-normalized")
    
    compose_scene(
        args.input, 
        args.output,
        add_floor=not args.no_floor,
        add_walls=not args.no_walls,
        add_ceiling=not args.no_ceiling,
        input_coord_system=args.coord_system,
        use_normalized_assets=args.use_normalized,
        normalized_asset_dir=args.normalized_dir
    )