"""诊断：导入 FBX 检查几何是否损坏（NaN 顶点/退化面/validate 修复量）。
用法：blender -b --factory-startup --python tests/bl_diag_mesh.py -- <model.fbx> [apply]
"""
import math
import os
import sys

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))


def main():
    import bpy
    from bl_decimate import join_meshes
    argv = sys.argv[sys.argv.index("--") + 1:]
    path = argv[0]
    do_apply = len(argv) > 1 and argv[1] == "apply"

    bpy.ops.wm.read_factory_settings(use_empty=True)
    before = set(bpy.data.objects)
    bpy.ops.import_scene.fbx(filepath=path)
    new = [o for o in bpy.data.objects if o not in before]
    meshes = [o for o in new if o.type == 'MESH']
    print("DIAG objects=%d meshes=%d" % (len(new), len(meshes)))
    for o in new:
        print("DIAG   obj=%r type=%s scale=%s" % (o.name, o.type, tuple(round(s, 4) for s in o.scale)))
    obj = join_meshes(meshes)
    if do_apply:
        bpy.ops.object.select_all(action='DESELECT')
        obj.select_set(True)
        bpy.context.view_layer.objects.active = obj
        bpy.ops.object.transform_apply(location=True, rotation=True, scale=True)
        print("DIAG transform applied")

    me = obj.data
    print("DIAG verts=%d polys=%d dims=%s" % (
        len(me.vertices), len(me.polygons),
        tuple(round(d, 4) for d in obj.dimensions)))

    nan_verts = 0
    huge_verts = 0
    for v in me.vertices:
        x, y, z = v.co
        if any(math.isnan(c) or math.isinf(c) for c in (x, y, z)):
            nan_verts += 1
        elif max(abs(x), abs(y), abs(z)) > 1e6:
            huge_verts += 1
    print("DIAG nan_verts=%d huge_verts=%d" % (nan_verts, huge_verts))

    zero_area = sum(1 for p in me.polygons if p.area < 1e-12)
    print("DIAG zero_area_polys=%d" % zero_area)

    # validate(verbose) 会打印它修的每个问题；返回 True 表示有改动
    changed = me.validate(verbose=True)
    print("DIAG validate_changed=%s" % changed)
    print("DIAG after_validate verts=%d polys=%d" % (len(me.vertices), len(me.polygons)))
    print("DIAG DONE")


if __name__ == "__main__" and "--" in sys.argv:
    main()