# Headless GLB fixup: rotate a model to face +Z and scale to a target height,
# baking the transform into vertices via the root node transform on export.
# Env: ROT_IN (glb path), ROT_OUT (glb path), ROT_YAW_DEG, ROT_HEIGHT_M
extends SceneTree

func _init() -> void:
	var in_path := OS.get_environment("ROT_IN")
	var out_path := OS.get_environment("ROT_OUT")
	var yaw_deg := float(OS.get_environment("ROT_YAW_DEG"))
	var target_h := float(OS.get_environment("ROT_HEIGHT_M"))

	var doc := GLTFDocument.new()
	var state := GLTFState.new()
	if doc.append_from_file(in_path, state) != OK:
		push_error("load failed: " + in_path)
		quit(1)
		return
	var scene := doc.generate_scene(state)

	# measure current height from merged mesh AABB
	var merged := AABB()
	var first := true
	var stack: Array = [scene]
	while not stack.is_empty():
		var n: Node = stack.pop_back()
		if n is MeshInstance3D:
			var box: AABB = (n as MeshInstance3D).get_aabb()
			if first:
				merged = box
				first = false
			else:
				merged = merged.merge(box)
		for c in n.get_children():
			stack.push_back(c)
	var h := merged.size.y
	var s := target_h / h if h > 0.001 else 1.0
	print("height=", h, " scale=", s)

	var wrapper := Node3D.new()
	wrapper.name = "Root"
	wrapper.rotate_y(deg_to_rad(yaw_deg))
	wrapper.scale = Vector3(s, s, s)
	# move model so feet sit at y=0 after scaling
	scene.position.y = -merged.position.y
	var parent := scene.get_parent()
	if parent != null:
		parent.remove_child(scene)
	wrapper.add_child(scene)
	_own_recursive(scene, wrapper)

	var out_doc := GLTFDocument.new()
	var out_state := GLTFState.new()
	if out_doc.append_from_scene(wrapper, out_state) != OK:
		push_error("export append failed")
		quit(1)
		return
	if out_doc.write_to_filesystem(out_state, out_path) != OK:
		push_error("write failed: " + out_path)
		quit(1)
		return
	print("WROTE ", out_path)
	quit(0)

func _own_recursive(n: Node, owner: Node) -> void:
	n.owner = owner
	for c in n.get_children():
		_own_recursive(c, owner)