class_name WmoRenderBuildStepPlanner
extends RefCounted

## Selects one value-only WMO render-group build operation without engine objects.

const OPERATION_MESH: StringName = &"mesh"
const OPERATION_MULTIMESH: StringName = &"multimesh"
const OPERATION_COMPLETE: StringName = &"complete"


## Selects the next mesh-first build operation and returns its selected index
## plus the cursor values to adopt after that one operation. Counts and cursors
## are intentionally not clamped so the loader's historical comparisons remain
## exact for every integer input.
func plan_step(
		mesh_count: int,
		mesh_index: int,
		multimesh_count: int,
		multimesh_index: int
) -> Dictionary:
	if mesh_index < mesh_count:
		return {
			"operation": OPERATION_MESH,
			"selected_index": mesh_index,
			"next_mesh_index": mesh_index + 1,
			"next_multimesh_index": multimesh_index,
		}
	if multimesh_index < multimesh_count:
		return {
			"operation": OPERATION_MULTIMESH,
			"selected_index": multimesh_index,
			"next_mesh_index": mesh_index,
			"next_multimesh_index": multimesh_index + 1,
		}
	return {
		"operation": OPERATION_COMPLETE,
		"selected_index": -1,
		"next_mesh_index": mesh_index,
		"next_multimesh_index": multimesh_index,
	}