extends SceneTree

const OUTPUT_PATH := "res://world/jajce/JajceNavigationMesh.tres"
const WORLD_SCENE_PATH := "res://world/jajce/JajceWorld.tscn"
const TERRAIN_PATH := "TerrainRoot/Terrain3D"


func _initialize() -> void:
	call_deferred("_run")


func _run() -> void:
	var world_scene := load(WORLD_SCENE_PATH) as PackedScene
	if world_scene == null:
		push_error("Could not load %s" % WORLD_SCENE_PATH)
		quit(1)
		return

	var world := world_scene.instantiate() as Node3D
	root.add_child(world)
	await process_frame
	for _frame in 10:
		await physics_frame

	var terrain := world.get_node(TERRAIN_PATH) as Terrain3D
	if terrain == null or terrain.data == null:
		push_error("Jajce Terrain3D data is not available")
		quit(1)
		return

	var nav_mesh := _create_navigation_mesh_template()
	var bake_aabb: AABB = nav_mesh.filter_baking_aabb
	bake_aabb.position += nav_mesh.filter_baking_aabb_offset

	var terrain_faces: PackedVector3Array = terrain.generate_nav_mesh_source_geometry(bake_aabb, false)
	if terrain_faces.is_empty():
		push_error("Terrain3D produced no navigation source faces")
		quit(1)
		return

	var source_geometry := NavigationMeshSourceGeometryData3D.new()
	source_geometry.add_faces(terrain_faces, Transform3D.IDENTITY)
	NavigationServer3D.bake_from_source_geometry_data(nav_mesh, source_geometry)

	if nav_mesh.get_polygon_count() == 0:
		push_error("Baked Jajce navigation mesh contains no polygons")
		quit(1)
		return

	var error := ResourceSaver.save(nav_mesh, OUTPUT_PATH)
	if error != OK:
		push_error("Could not save %s: %s" % [OUTPUT_PATH, error_string(error)])
		quit(1)
		return

	print(
		"[TOOL] Saved %s with %d vertices and %d polygons"
		% [OUTPUT_PATH, nav_mesh.get_vertices().size(), nav_mesh.get_polygon_count()]
	)
	quit(0)


func _create_navigation_mesh_template() -> NavigationMesh:
	var nav_mesh := NavigationMesh.new()
	nav_mesh.agent_height = 1.7
	nav_mesh.agent_radius = 0.4
	nav_mesh.agent_max_climb = 0.55
	nav_mesh.agent_max_slope = 35.0
	nav_mesh.cell_size = 0.25
	nav_mesh.cell_height = 0.1
	nav_mesh.filter_baking_aabb = AABB(
		Vector3(-36.0, -8.0, -36.0), Vector3(72.0, 32.0, 72.0)
	)
	return nav_mesh