extends Node3D
## Keep the sun disc inside the cockpit far plane. Aim SunLight.
## Never leave the disc sitting on the Moon.

@export var sun_disc_path: NodePath = ^"SunDisc"
@export var sun_light_path: NodePath = ^"../SunLight"
@export var sun_direction: Vector3 = Vector3(-0.82, 0.45, 0.35)
@export var visual_distance: float = 220000.0
@export var visual_radius: float = 9000.0

var _mesh: MeshInstance3D
var _light: DirectionalLight3D
var _base_radius: float = 0.5


func _ready() -> void:
	_mesh = get_node_or_null(sun_disc_path) as MeshInstance3D
	if _mesh == null:
		_mesh = find_child("SunDisc", true, false) as MeshInstance3D
	if _mesh and _mesh.mesh is SphereMesh:
		_base_radius = maxf((_mesh.mesh as SphereMesh).radius, 0.5)
	_light = get_node_or_null(sun_light_path) as DirectionalLight3D
	if _light == null:
		_light = get_node_or_null("../SunLight") as DirectionalLight3D
	sun_direction = sun_direction.normalized()
	_aim_light()
	set_process(true)


func _aim_light() -> void:
	if _light == null:
		return
	var target: Vector3 = _light.global_position - sun_direction
	if target.is_equal_approx(_light.global_position):
		return
	_light.look_at(target, Vector3.UP)


func _process(_delta: float) -> void:
	if _mesh == null:
		return
	var viewer: Node3D = FloatingOrigin.focus
	var origin: Vector3 = viewer.global_position if viewer and is_instance_valid(viewer) else global_position
	_mesh.global_position = origin + sun_direction * visual_distance
	_mesh.scale = Vector3.ONE * (visual_radius / _base_radius)
	_mesh.visible = true
	_aim_light()