extends Node3D
## The tutorial's hut outline (docs/TUTORIAL_DESIGN.md §2, step 17): a pale,
## see-through 4 x 4 m hut on a good spot near your fire, the same 20 pieces
## the game's own snapping makes (floors, walls and a door, roofs, gables).
## Each piece of the outline fades out once a real piece of that kind stands
## in its place. It's a suggestion: you can build anywhere.

## [item, offset from the first floor, yaw] (from build_system.gd
## debug_build_hut at yaw 0: the pieces snap to a fixed grid).
const LAYOUT := [
	["wood_floor", Vector3(0, 0, 0), 0.0], ["wood_floor", Vector3(2, 0, 0), 0.0],
	["wood_floor", Vector3(0, 0, 2), 0.0], ["wood_floor", Vector3(2, 0, 2), 0.0],
	["wood_wall", Vector3(0, 0, -1), 0.0], ["wood_wall", Vector3(0, 0, 3), 0.0],
	["wood_wall", Vector3(2, 0, -1), 0.0], ["wood_door", Vector3(2, 0, 3), 0.0],
	["wood_wall", Vector3(3, 0, 0), PI * 0.5], ["wood_wall", Vector3(-1, 0, 0), PI * 0.5],
	["wood_wall", Vector3(3, 0, 2), PI * 0.5], ["wood_wall", Vector3(-1, 0, 2), PI * 0.5],
	["wood_roof", Vector3(0, 2, 3), 0.0], ["wood_roof", Vector3(0, 2, -1), PI],
	["wood_roof", Vector3(2, 2, 3), 0.0], ["wood_roof", Vector3(2, 2, -1), PI],
	["wood_gable", Vector3(-1, 2, 2), PI * 0.5], ["wood_gable", Vector3(-1, 2, 0), -PI * 0.5],
	["wood_gable", Vector3(3, 2, 2), PI * 0.5], ["wood_gable", Vector3(3, 2, 0), -PI * 0.5],
]
const MATCH := 0.35              ## a real piece this close to a slot fills it

var world: Node3D
var origin := Transform3D()      ## the first floor's place
var slots: Array = []            ## [item, Transform3D, MeshInstance3D]
var _check := 0.0

## Lays the outline out with its first floor at `xf` (from build_system's
## free placement, so it sits level on the ground).
func setup(w: Node3D, xf: Transform3D) -> void:
	world = w
	origin = xf
	var m := StandardMaterial3D.new()
	m.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	m.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
	m.albedo_color = Color(0.6, 0.88, 1.0, 0.22)
	m.cull_mode = BaseMaterial3D.CULL_DISABLED
	m.no_depth_test = false
	for e in LAYOUT:
		var t := Transform3D(xf.basis * Basis(Vector3.UP, float(e[2])), xf * (e[1] as Vector3))
		var mi := MeshInstance3D.new()
		mi.mesh = ItemDB.mesh_for(String(e[0]))
		mi.material_override = m
		mi.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_OFF
		add_child(mi)
		mi.global_transform = t
		slots.append([String(e[0]), t, mi])

## The middle of the hut (the guide's marker points here).
func center() -> Vector3:
	return origin * Vector3(1, 0, 1)

func _process(delta: float) -> void:
	_check -= delta
	if _check <= 0.0:
		_check = 0.5
		refresh()

## Hides each slot a real piece of its kind now fills. Returns how many are
## left to build.
func refresh() -> int:
	var left := 0
	var built: Array = world.build.build_pieces() if world != null else []
	for s in slots:
		var filled := false
		for p in built:
			if p.item_id == s[0] and (p as Node3D).global_position.distance_to((s[1] as Transform3D).origin) < MATCH:
				filled = true
				break
		(s[2] as MeshInstance3D).visible = not filled
		if not filled:
			left += 1
	return left