class_name StairFlight
extends RefCounted

# A single static assembly: continuous walking ramp and attached smooth guards.
static func build(parent: Node3D, origin: Vector3, direction: float, rise: float, exterior: bool, batch: UrbanMeshBatch) -> void:
 var body := StaticBody3D.new()
 body.name = "UnifiedStairFlight"
 body.collision_layer = 1
 body.collision_mask = 0
 parent.add_child(body)
 var points := PackedVector3Array()
 for end in [0.0, 1.0]:
  var z: float = origin.z + direction * (-0.6 + end * 8.0)
  var y: float = origin.y + end * rise
  for x in [-1.06, 1.06]:
   for h in [-0.24, 0.0]: points.append(Vector3(origin.x+x, y+h, z))
 add_shape(body, points)
 if exterior:
  for side in [-1, 1]:
   # The guard shares the ramp boundary; no gap or individual tread faces.
   StairGuard.build(body, origin.x + side, origin.z, direction, origin.y, rise, batch)

static func add_shape(body: StaticBody3D, points: PackedVector3Array) -> void:
 var shape := ConvexPolygonShape3D.new()
 shape.points = points
 var collider := CollisionShape3D.new()
 collider.shape = shape
 body.add_child(collider)