Godot repack fbx file to res (or scn) - godot

Question

hi I'm trying to repack fbx file to a readable file for the Godot engine and I gat so far:
func fbx_to_scn(node):
var spi = Spatial.new()
add_child(spi)
spi.name = node
node = get_node(node+"/RootNode")
var ps
var mesh
for i in node.get_child_count():
if node.get_child(i).get_class() == "Skeleton":
ps = node.get_child(i)
elif node.get_child(i).get_class() == "MeshInstance":
mesh = node.get_child(i)
if not ps == null:
var new_sklet : Skeleton = Skeleton.new()
for i in ps.get_bone_count():
new_sklet.add_bone(ps.get_bone_name(i))
new_sklet.set_bone_rest(i,ps.get_bone_rest(i))
if ps.get_bone_parent(i) == -1:
continue
new_sklet.set_bone_parent(i,ps.get_bone_parent(i))
spi.add_child(new_sklet)
new_sklet.owner = spi
new_sklet.name = "Skeleton"
var mi = MeshInstance.new()
mi.name = "MeshInstance"
mi.mesh = mesh.mesh
spi.add_child(mi)
mi.owner = spi
if not ps == null:
mi.skeleton = "../Skeleton"
var pack = PackedScene.new()
pack.pack(spi)
if ResourceSaver.save("res://save_file/" +spi.name+ ".scn",pack) == OK:
print("file saved")
else:
print("some thing went wrong")
everything goes well and the file is created like this
but the rig is so bad
the left shape is the fbx file and the right is scn file
the rig is completely reverse and it's not even the same (had some changes)