# models_terminal.py
# 目标：读取 ./terminal.glb → 以 OBB 对齐 target pose，位置在 OBB +Z 面中心；
#      然后沿“target pose 的局部 -Z”偏移，再“绕其局部 Z 轴”旋转（可正可负）；
#      最后“在此基础上”沿“target pose 的局部 +Y 轴”再平移一点；
#      输出 ./model_data.json，并在预览中画出加长坐标轴与小球。

import trimesh
import json
import numpy as np

PI = np.pi

# === 可调参数 ===
MODEL_SCALE   = 1.0      # 几何整体缩放倍数
MARKER_FRAC   = 0.02     # 标注物相对物体对角线比例（越小→球/坐标轴更小）
OFFSET_FRAC_Z = 0.746    # 沿局部 -Z 平移 extents[2] * 此比例
ROT_Z_DEG     = -90.0    # 随后绕局部 Z 轴旋转（度）
OFFSET_FRAC_Y = 0.5     # 【新增】在此基础上，沿“局部 +Y”再平移 extents[1] * 此比例

def _to_fused_mesh(obj):
    if isinstance(obj, trimesh.Trimesh):
        return obj
    if isinstance(obj, trimesh.Scene):
        try:
            return obj.to_mesh()
        except Exception:
            geoms = list(obj.dump().geometry.values())
            return trimesh.util.concatenate(geoms)
    raise TypeError(f"Unsupported type: {type(obj)}")

def create_model_data(id="terminal"):
    file_path = f"./{id}.glb"
    save_path = f"./model_data.json"

    # 1) 读模型并融合为单一 Trimesh
    with open(file_path, "rb") as f:
        loaded = trimesh.load(f, file_type="glb")
    mesh = _to_fused_mesh(loaded)

    # 2) 全局缩放
    mesh.apply_scale(MODEL_SCALE)
    scene = trimesh.Scene(mesh)

    # 3) OBB 与自适应标注尺寸
    obb = mesh.bounding_box_oriented
    center = obb.centroid                # 世界系下 OBB 质心
    ext = obb.extents                    # [ex, ey, ez]
    diag = float(np.linalg.norm(ext)) + 1e-12

    axis_len  = diag * MARKER_FRAC * 12.0   # 加长坐标轴
    origin_sz = diag * MARKER_FRAC * 0.6
    r_target  = diag * MARKER_FRAC * 1.2

    red   = [1.0, 0.0, 0.0, 0.5]
    green = [0.0, 1.0, 0.0, 0.5]
    blue  = [0.0, 0.0, 1.0, 0.5]

    # 4) 以 OBB 对齐的“初始 target pose”（在 OBB 的 +Z 面中心）
    T_obb = obb.primitive.transform      # 4x4
    R_obb = T_obb[:3, :3]
    top_center = center + R_obb[:, 2] * (ext[2] / 2.0)

    T_target = np.eye(4, dtype=float)
    T_target[:3, :3] = R_obb
    T_target[:3, 3]  = top_center

    # 5) 局部链：先沿 -Z 偏移，再绕 Z 旋转，再沿 +Y 偏移（均在“局部系”）
    offset_dist_z = ext[2] * OFFSET_FRAC_Z
    T_offset_z = trimesh.transformations.translation_matrix([0.0, 0.0, -offset_dist_z])
    Rz_local   = trimesh.transformations.rotation_matrix(np.deg2rad(ROT_Z_DEG), [0.0, 0.0, 1.0])
    offset_dist_y = ext[1] * OFFSET_FRAC_Y            # 【新增】沿局部 +Y 的距离
    T_offset_y = trimesh.transformations.translation_matrix([0.0, offset_dist_y, 0.0])

    # 组合顺序采用右乘：表示“在当前局部坐标系下”依次执行
    T_final = T_target @ T_offset_z @ Rz_local @ T_offset_y

    # 6) 可视化：目标点小球 + 加长坐标轴（都放在 T_final 处）
    target_sphere = trimesh.creation.icosphere(subdivisions=2, radius=r_target)
    target_sphere.apply_transform(T_final)
    target_sphere.visual.vertex_colors = np.array([red] * len(target_sphere.vertices))
    scene.add_geometry(target_sphere)

    axis = trimesh.creation.axis(
        origin_size=origin_sz,
        axis_length=axis_len,
        axis_radius=origin_sz * 0.3,
    )
    axis.apply_transform(T_final)
    scene.add_geometry(axis)

    print("extents =", ext)
    print("center  =", center)
    print("target pose (before offset/rot) =\n", T_target)
    print("final target pose (after z-offset, z-rot, y-offset) =\n", T_final)

    # 7) 写 JSON（只保留 target 相关字段，其它保持 schema）
    transform_matrix = trimesh.transformations.euler_matrix(0, 0, 0).tolist()
    data = {
        "center": center.tolist(),
        "extents": ext.tolist(),
        "scale": [MODEL_SCALE, MODEL_SCALE, MODEL_SCALE],
        "target_pose": [T_final.tolist()],
        "contact_points_pose": [],
        "transform_matrix": transform_matrix,
        "functional_matrix": [],
        "orientation_point": T_final.tolist(),
        "contact_points_group": [],
        "contact_points_mask": [],
        "contact_points_discription": [],
        "target_point_discription": [
            "OBB +Z face center → local -Z offset → local Z rot → local +Y offset."
        ],
        "functional_point_discription": [""],
        "orientation_point_discription": ["Same as target for schema compatibility."]
    }
    with open(save_path, "w", encoding="utf-8") as f:
        json.dump(data, f, indent=4, ensure_ascii=False, separators=(",", ": "))

    scene.show()

if __name__ == "__main__":
    create_model_data("terminal")