extends Node3D
class_name Targetable

@export var attached_to: Node3D = owner

static func is_targetable(node: Node3D) -> Targetable:
	return node.get_node_or_null("is_targetable")

func make_target():
	walk_meshes_post_order(self.get_parent(), change_all_materials)

func unmake_target():
	walk_meshes_post_order(self.get_parent(), unchange_all_materials)

func walk_meshes_post_order(parent: Node3D, f: Callable):
	for child in parent.get_children():
		walk_meshes_post_order(child, f)
	if parent is MeshInstance3D:
		f.call(parent)

func change_all_materials(mesh: MeshInstance3D):
	for i in range(mesh.get_surface_override_material_count()):
		var original_mat: BaseMaterial3D = mesh.get_active_material(i)
		var layer0 = original_mat.duplicate()
		var layer1 = preload("control_target_overlay.material").duplicate()
		# Non-occlused
		var layer2 = original_mat.duplicate()
		layer0.next_pass = layer1
		layer1.next_pass = layer2
		
		layer0.render_priority = 0
		layer1.render_priority = 1
		layer2.render_priority = 2
		
		
		
		layer0.no_depth_test = true
		layer0.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA_DEPTH_PRE_PASS
		layer0.grow = true
		layer0.grow_amount = -0.001
		layer0.albedo_color = layer0.albedo_color.darkened(0.5)
		
		layer2.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA_DEPTH_PRE_PASS
		layer2.depth_draw_mode = BaseMaterial3D.DEPTH_DRAW_ALWAYS
		
		mesh.set_surface_override_material(i, layer0)
		#mesh.set_surface_override_material(i, mat)
		#mat.next_pass = preload("control_target_overlay.material")
		

func unchange_all_materials(mesh: MeshInstance3D):
	for i in range(mesh.get_surface_override_material_count()):
		var mat := mesh.get_active_material(i)
		unchange_material(mat)
		while mat.next_pass != null:
			unchange_material(mat.next_pass)
			mat = mat.next_pass
		mat.next_pass = null

func change_material(mat: BaseMaterial3D) -> BaseMaterial3D:
	mat = mat.duplicate()
	mat.render_priority = 100
	mat.no_depth_test = true
	return mat

func unchange_material(mat: BaseMaterial3D) -> BaseMaterial3D:
	mat.render_priority = 0
	mat.no_depth_test = false
	return mat