"""Blender 内运行：校验低模 FBX 的 UV 质量门；无 UV 或不达标就地 seam 重展并覆盖导出。
调用：blender -b --factory-startup --python bl_uvgate.py -- <low.fbx> [mode_label]
mode_label 仅用于日志/回退警告中标注上游展开方式（默认 rizom）。"""
import os
import sys

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


def main():
    import bpy
    import json
    from bl_decimate import (join_meshes, uv_gate_ok, _collect_uv_metrics,
                             _do_unwrap)
    argv = sys.argv[sys.argv.index("--") + 1:]
    fbx = argv[0]
    mode_label = argv[1] if len(argv) > 1 else "rizom"
    warnings = []

    bpy.ops.wm.read_factory_settings(use_empty=True)
    bpy.ops.import_scene.fbx(filepath=fbx)
    meshes = [o for o in bpy.data.objects if o.type == 'MESH']
    if not meshes:
        print("MT_SUMMARY " + json.dumps({"error": "FBX 中没有 mesh"},
                                         ensure_ascii=False))
        return
    obj = join_meshes(meshes)

    if obj.data.uv_layers:
        m = _collect_uv_metrics(obj)
        if uv_gate_ok(m["flipped"], m["overlap"]):
            m["mode"] = mode_label
            print("MT_SUMMARY " + json.dumps(
                {"uv": m, "reexported": False, "warnings": warnings},
                ensure_ascii=False))
            return
        warnings.append("%s UV 质量不达标（翻转 %.1f%% 重叠 %s），回退 seam"
                        % (mode_label, m["flipped"] * 100,
                           "%.1f%%" % (m["overlap"] * 100)
                           if m["overlap"] is not None else "未知"))
    else:
        warnings.append("%s 输出无 UV，回退 seam" % mode_label)

    m = _do_unwrap(obj, "seam", warnings)   # 内部自带 smart 回退
    if m["mode"] == "seam":
        m["mode"] = "seam_fallback"
    bpy.ops.object.select_all(action='DESELECT')
    obj.select_set(True)
    bpy.ops.export_scene.fbx(filepath=os.path.abspath(fbx), use_selection=True,
                             path_mode='STRIP', embed_textures=False)
    print("MT_SUMMARY " + json.dumps(
        {"uv": m, "reexported": True, "warnings": warnings},
        ensure_ascii=False))


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