extends Node3D

## Rig lab — the room where a character's rig is adjusted by eye, in 3D, live.
##
##   godot --path . res://debug/rig_lab.tscn
##
## Everything about a rig that CAN be derived from the skeleton is derived: the
## bone roles, the mount rotation, the wrist roll, the weapon size, which
## surfaces are hair. What is left over is not a missing derivation, it is
## judgement — how high a stock rides, how far an elbow flares, how far down the
## palm a grip sits on THIS character's hand. Judgement wants an eye and a
## slider, not another constant tuned against one rig and wrong on the next.
##
## This is the environment for that. Three things can be adjusted here:
##
##   HOLD      how this character holds this weapon. Per character AND weapon,
##             because a rifle and a pistol are not held alike.
##             -> assets/characters/weapon_holds.json
##   ANCHORS   where the grip sits in the palm and how the gun rolls in the
##             fingers. Per character only — that is a fact about the hand.
##             -> assets/characters/rig_anchors.json
##   SURFACES  what the importer decided each surface of the model IS. Read-only
##             here, but isolating a class is how you check the decision: click
##             `hair` and only the hair should remain.
##
## Both tuning files are layered (defaults -> this character -> this weapon) and
## an absent file means "use what the code derives", so nothing here is required
## for the game to run correctly.
##
## CONTROLS
##   drag a MARKER  move that anchor    left drag    orbit
##   middle drag    pan                 wheel        zoom
##   F              frame the hands
##   R              reset knobs         S  save      C  copy JSON to clipboard
##
## The three coloured markers ARE the anchors — red is the trigger grip, green
## the support hand on the handguard, blue the buttstock — and they can be
## dragged. The marker under the mouse swells; drag it and the hand follows.
##
## Dragging an anchor is not the same as any slider above it. The sliders move
## the GUN: `grip_offset` slides the weapon around inside the fist, and
## `gun_fore` / `gun_stock` slide the hands along the weapon's own axis. Neither
## can take a hand OFF that axis, which is what a handguard below the bore, an
## angled foregrip or a pistol grip all need. A drag writes `grip_shift` or
## `fore_shift`, in the gun's own across/up/along frame, so a nudge sideways
## stays sideways as the weapon pitches; the buttstock marker writes the shoulder
## pocket for whichever pose is showing.
##
## If a hand is not ON its marker, the IK could not reach — a different problem
## from the marker being in the wrong place, and dragging the marker further will
## not fix it.

const POSES := [
	["Low ready", "ground", 0.0, 0.0],
	["Aiming", "ground", 0.0, 1.0],
	["Running", "ground", 9.0, 0.0],
	["Crouched", "ground", 0.0, 0.0],
]

## The two editable knob groups, and everything the UI needs to build, resolve
## and save each one. Adding a third group is adding a row here.
##
## `subject` is what the group is keyed on inside its file: a weapon id for the
## hold, a fixed word for anchors, because an anchor is per character and
## re-tuning it per gun would be re-answering the same question.
const GROUPS := {
	"hold": {
		"title": "HOLD  ·  this character, this weapon",
		"per_weapon": true,
	},
	"anchors": {
		"title": "ANCHORS  ·  this character",
		"per_weapon": false,
	},
}

var _model: SkinnedPlayerModel
var _skins: Array = []
var _weapons: Array = []
var _skin := 0
var _weapon := 0
var _pose := 0
## group -> resolved knob table, and group -> the whole file it came from.
var _knobs: Dictionary = {"hold": {}, "anchors": {}}
var _all: Dictionary = {"hold": {}, "anchors": {}}
## group -> key -> {spec, label, x, y, z}
var _sliders: Dictionary = {"hold": {}, "anchors": {}}
## "" means the pose buttons drive the model; anything else is a canonical clip
## being played on its own so a single animation can be watched end to end.
var _clip := ""
var _clip_picker: OptionButton
var _surface_box: VBoxContainer
var _isolated := ""
## MeshInstance3D -> surface index -> the override material displaced by
## isolation, so it can be put back without rebuilding the character.
var _hidden_surfaces: Dictionary = {}
var _status: Label
var _cam: Camera3D
var _yaw := 0.6
var _pitch := -0.1
var _dist := 2.2
var _pivot := Vector3(0, 1.25, 0)
var _markers: Array = []
var _pickers: Dictionary = {}


## Frames to wait before the self-shot below. The model loads asynchronously and
## the cloth solver needs a moment to settle, so an immediate capture shows a
## half-built character.
const SHOT_WARMUP := 40
var _shot_path := ""
var _frames := 0


func _ready() -> void:
	_build_world()
	_collect_sources()
	# `-- shot <path> [skin] [weapon]` renders one frame and quits, so the lab
	# can be checked without a human at the controls.
	var args := OS.get_cmdline_user_args()
	if args.size() >= 2 and String(args[0]) == "shot":
		_shot_path = String(args[1])
		if args.size() > 2:
			_skin = maxi(0, _index_of(_skins, String(args[2])))
		if args.size() > 3:
			_weapon = maxi(0, _index_of(_weapons, String(args[3])))
	_build_ui()
	_reload_model()


func _index_of(list: Array, id: String) -> int:
	for i in list.size():
		if String(list[i].id) == id:
			return i
	return -1


# ── scene ─────────────────────────────────────────────────────────────────────

func _build_world() -> void:
	var env := WorldEnvironment.new()
	var e := Environment.new()
	e.background_mode = Environment.BG_COLOR
	e.background_color = Color(0.17, 0.18, 0.22)
	e.ambient_light_source = Environment.AMBIENT_SOURCE_COLOR
	e.ambient_light_color = Color(0.55, 0.57, 0.65)
	e.ambient_light_energy = 1.0
	env.environment = e
	add_child(env)

	var key := DirectionalLight3D.new()
	key.rotation_degrees = Vector3(-42, 132, 0)
	key.light_energy = 1.5
	add_child(key)
	var fill := DirectionalLight3D.new()
	fill.rotation_degrees = Vector3(-18, -40, 0)
	fill.light_energy = 0.5
	add_child(fill)

	_cam = Camera3D.new()
	_cam.fov = 45.0
	add_child(_cam)
	_update_camera()

	# Grip / support / stock, so the points under the sliders are visible.
	for c in [Color(1, 0.3, 0.3), Color(0.3, 1, 0.4), Color(0.4, 0.6, 1)]:
		var m := MeshInstance3D.new()
		var sphere := SphereMesh.new()
		sphere.radius = 0.012
		sphere.height = 0.024
		m.mesh = sphere
		var mat := StandardMaterial3D.new()
		mat.albedo_color = c
		mat.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
		# Depth-tested on purpose. Drawn through the body they look like they are
		# floating in front of the chest when they are in fact behind an arm,
		# which is exactly the wrong impression for judging whether a hand is on
		# its target. `_process` lifts this for the marker under the mouse, so
		# the one you are about to grab is the one you can see.
		mat.no_depth_test = false
		m.material_override = mat
		add_child(m)
		_markers.append(m)


func _collect_sources() -> void:
	for id in SkinManager.skins:
		var s = SkinManager.skins[id]
		# GLB-backed skins only; the colour tints have no skeleton to pose.
		if "model_path" in s and String(s.model_path) != "":
			_skins.append({"id": id, "name": s.skin_name, "path": s.model_path})
	_skins.sort_custom(func(a, b): return a.id < b.id)
	for id in LoadoutManager.weapon_db:
		var w: Dictionary = LoadoutManager.weapon_db[id]
		if String(w.get("script", "")) != "":
			_weapons.append({"id": id, "name": w.get("name", id),
				"script": w["script"]})
	_weapons.sort_custom(func(a, b): return a.id < b.id)
	_all["hold"] = WeaponHoldTuning.load_all()
	_all["anchors"] = RigAnchors.load_all()


func _reload_model() -> void:
	if _model:
		_model.queue_free()
	_model = SkinnedPlayerModel.new()
	_model.model_path = _skins[_skin].path
	_model.skin_id = _skins[_skin].id
	add_child(_model)
	await get_tree().process_frame
	_load_knobs()
	_model.set_weapon(_weapons[_weapon].script)
	_push("hold")
	_push("anchors")
	_clip = ""
	_refresh_clip_picker()
	_rebuild_surface_list()
	_apply_pose()


## Fill the clip list from what this character actually HAS.
##
## Canonical names, from the model's own resolution table, rather than the raw
## clip names in the GLB — those differ per character (one rig's "CrouchIdle" is
## another's "Crouch_Idle_Loop") and the canonical name is the one the game asks
## for, so it is the one worth being able to audition.
func _refresh_clip_picker() -> void:
	if _clip_picker == null:
		return
	_clip_picker.clear()
	_clip_picker.add_item("(pose driven)")
	if _model:
		var names: Array = _model.clip_names_debug()
		names.sort()
		for n in names:
			_clip_picker.add_item(n)
	_clip_picker.select(0)


func _select_clip(index: int) -> void:
	_clip = "" if index <= 0 else _clip_picker.get_item_text(index)
	if _clip != "" and _model:
		_model.play_clip_debug(_clip)
	_status.text = "Pose buttons driving" if _clip == "" \
		else "Playing '%s' on its own" % _clip


func _apply_pose() -> void:
	if not _model or not _model.loaded:
		return
	# A clip chosen in the scrubber owns playback: driving update_state as well
	# would blend straight back to whatever the pose implies, and the clip would
	# never be seen.
	if _clip != "":
		return
	var p: Array = POSES[_pose]
	_model.update_state(p[1], p[2], _pose == 3)
	_model.set_locomotion(0.0, 1.0 if p[2] > 0.1 else 0.0, p[3])


func _process(_delta: float) -> void:
	_apply_pose()
	if _shot_path != "":
		_frames += 1
		if _frames == SHOT_WARMUP:
			# Frame the hands, which is the only part anyone is judging.
			if _model and _model._pose_mod:
				_pivot = _model.skeleton.global_transform * _model._pose_mod.dbg_grip
				_dist = 0.7
				_yaw = 1.15
				_pitch = -0.15
				_update_camera()
		elif _frames > SHOT_WARMUP + 2:
			var img := get_viewport().get_texture().get_image()
			img.save_png(_shot_path)
			print("rig_lab: saved ", _shot_path)
			get_tree().quit()
			return
	if _model and _model._pose_mod and _model.skeleton:
		var to_world: Transform3D = _model.skeleton.global_transform
		var pm = _model._pose_mod
		var pts := [pm.dbg_grip, pm.dbg_fore, pm.dbg_stock]
		for i in _markers.size():
			_markers[i].global_position = to_world * pts[i]
			_markers[i].visible = pts[i] != Vector3.ZERO
			# The one being dragged, or the one the mouse is over, swells AND
			# draws through the body.
			#
			# Depth testing is right for the other two: drawn through the mesh
			# they look like they are floating in front of the chest when they
			# are in fact behind an arm, which is the wrong impression for
			# judging whether a hand reached its target. But it is wrong for the
			# one being grabbed — at any useful framing the hands occlude all
			# three markers, and a handle you cannot see is a handle you cannot
			# find. `_marker_under` never cared about occlusion; this makes that
			# visible rather than a secret.
			var hot: bool = (i == _drag_marker) or (_drag_marker < 0 and i == _hover_marker)
			_markers[i].scale = Vector3.ONE * (1.9 if hot else 1.0)
			var mat := _markers[i].material_override as StandardMaterial3D
			if mat:
				mat.no_depth_test = hot


# ── dragging the anchors ──────────────────────────────────────────────────────
#
# The markers are the anchor POINTS the hands are solved onto. Until now they
# could only be moved through the sliders, and two of the three could only move
# along the barrel — `gun_stock` and `gun_fore` are distances along the gun's own
# axis, so the trigger and support hands slid up and down the weapon and nowhere
# else. What the sliders DID move freely was the gun itself, under anchors that
# stayed put.
#
# So: grab a marker and drag it. Each one writes to the knob that expresses that
# motion, in the frame that knob is written in — which is why the pose layer now
# publishes the gun's basis. A drag left has to mean "left across the weapon"
# whether the muzzle is down at low ready or level at ADS.

## marker index -> [knob key, frame]. "gun" is the weapon's own across/up/along
## basis; "skeleton" is the model's, which is where the shoulder pocket lives.
const MARKER_KNOB := [
	["grip_shift", "gun"],
	["fore_shift", "gun"],
	["pocket", "skeleton"],   # resolved to pocket_hip / pocket_ads by pose
]
## How close, in pixels, the mouse has to be to a marker to take hold of it.
const GRAB_RADIUS := 26.0

var _drag_marker := -1
var _hover_marker := -1
## The plane a drag is measured on: fixed at grab time so it does not drift
## toward the camera as the marker follows the mouse.
var _drag_plane_at := Vector3.ZERO
var _drag_last := Vector3.ZERO


## The stock anchor is a blend of two knobs; a drag edits whichever one this
## pose is actually showing. Dragging at low ready must not silently rewrite the
## aiming pocket.
func _stock_knob() -> String:
	return "pocket_ads" if POSES[_pose][3] > 0.5 else "pocket_hip"


func _knob_for(marker: int) -> String:
	var key: String = MARKER_KNOB[marker][0]
	return _stock_knob() if key == "pocket" else key


func _marker_under(mouse: Vector2) -> int:
	var best := -1
	var best_d := GRAB_RADIUS
	for i in _markers.size():
		if not _markers[i].visible:
			continue
		var p: Vector3 = _markers[i].global_position
		# Behind the camera projects to a nonsense point that can still land
		# within the grab radius.
		if _cam.is_position_behind(p):
			continue
		var d := _cam.unproject_position(p).distance_to(mouse)
		if d < best_d:
			best_d = d
			best = i
	return best


## Where the mouse ray meets the drag plane — through the grab point, facing the
## camera.
func _plane_hit(mouse: Vector2) -> Vector3:
	var origin := _cam.project_ray_origin(mouse)
	var dir := _cam.project_ray_normal(mouse)
	var n := -_cam.global_transform.basis.z
	var denom := dir.dot(n)
	if absf(denom) < 1e-5:
		return _drag_last
	return origin + dir * (((_drag_plane_at - origin).dot(n)) / denom)


func _begin_drag(marker: int, mouse: Vector2) -> void:
	_drag_marker = marker
	_drag_plane_at = _markers[marker].global_position
	_drag_last = _plane_hit(mouse)
	_status.text = "Dragging the %s anchor (%s)" % [
		["trigger hand", "support hand", "buttstock"][marker], _knob_for(marker)]


func _drag_to(mouse: Vector2) -> void:
	if _model == null or _model._pose_mod == null or _model.skeleton == null:
		return
	var now := _plane_hit(mouse)
	var world_delta := now - _drag_last
	_drag_last = now

	# World -> skeleton, because that is the space the pose layer works in.
	var delta: Vector3 = _model.skeleton.global_transform.basis.inverse() * world_delta
	if MARKER_KNOB[_drag_marker][1] == "gun":
		# ...and on into the gun's frame for the two hand anchors. Orthonormal,
		# so the inverse is the transpose, but say what is meant.
		delta = _model._pose_mod.dbg_gun_basis.inverse() * delta

	var key := _knob_for(_drag_marker)
	var spec := _spec_for("hold", key)
	var cur: Vector3 = _knobs["hold"].get(key, WeaponHoldTuning.default_for(key))
	if not (cur is Vector3):
		cur = Vector3.ZERO
	var lo: float = spec[2]
	var hi: float = spec[3]
	_set_knob("hold", key, Vector3(
		clampf(cur.x + delta.x, lo, hi),
		clampf(cur.y + delta.y, lo, hi),
		clampf(cur.z + delta.z, lo, hi)))


func _spec_for(group: String, key: String) -> Array:
	for spec in _specs(group):
		if spec[0] == key:
			return spec
	return ["", "", -1.0, 1.0, true, Vector3.ZERO]


## Write a knob from somewhere other than its own slider, and keep the slider in
## step. Without the write-back the sliders would silently disagree with the
## model the moment anything was dragged, and Save would store the sliders.
func _set_knob(group: String, key: String, value) -> void:
	_knobs[group][key] = value
	var entry = _sliders[group].get(key)
	if entry != null:
		if entry.spec[4]:
			entry.x.set_value_no_signal(value.x)
			entry.y.set_value_no_signal(value.y)
			entry.z.set_value_no_signal(value.z)
		else:
			entry.x.set_value_no_signal(float(value))
		_refresh_label(group, key)
	_push(group)


# ── knobs ─────────────────────────────────────────────────────────────────────
#
# The two groups differ only in which spec table describes them, which file they
# live in and what they are keyed on. Everything below is written once against
# those three facts rather than twice against the two groups, so the anchors got
# a full editor — sliders, live preview, reset, save, clipboard — for the cost of
# a spec table.

func _specs(group: String) -> Array:
	return RigAnchors.KNOBS if group == "anchors" else WeaponHoldTuning.KNOBS


func _default_for(group: String, key: String):
	return RigAnchors.default_for(key) if group == "anchors" \
		else WeaponHoldTuning.default_for(key)


func _load_knobs() -> void:
	for group in GROUPS:
		if group == "anchors":
			_knobs[group] = RigAnchors.resolve(_all[group], _skins[_skin].id)
		else:
			_knobs[group] = WeaponHoldTuning.resolve(_all[group],
				_skins[_skin].id, _weapons[_weapon].id)
		for k in _sliders[group]:
			var entry = _sliders[group][k]
			var spec: Array = entry.spec
			if spec[4]:
				var v: Vector3 = _knobs[group].get(k, _default_for(group, k))
				entry.x.set_value_no_signal(v.x)
				entry.y.set_value_no_signal(v.y)
				entry.z.set_value_no_signal(v.z)
			else:
				entry.x.set_value_no_signal(float(_knobs[group].get(k,
					_default_for(group, k))))
			_refresh_label(group, k)


func _knob_changed(group: String, key: String) -> void:
	var entry = _sliders[group][key]
	var spec: Array = entry.spec
	if spec[4]:
		_knobs[group][key] = Vector3(entry.x.value, entry.y.value, entry.z.value)
	else:
		_knobs[group][key] = entry.x.value
	_refresh_label(group, key)
	_push(group)


func _push(group: String) -> void:
	if _model == null:
		return
	if group == "anchors":
		_model.set_anchors(_knobs[group])
	else:
		_model.set_hold_tuning(_knobs[group])


func _refresh_label(group: String, key: String) -> void:
	var entry = _sliders[group][key]
	var spec: Array = entry.spec
	if spec[4]:
		entry.label.text = "%s   %.3f, %.3f, %.3f" % [spec[1], entry.x.value,
			entry.y.value, entry.z.value]
	else:
		var v: float = entry.x.value
		entry.label.text = "%s   %s" % [spec[1],
			"auto" if (key == "weapon_scale" and v < 0.01) else "%.3f" % v]


# ── ui ────────────────────────────────────────────────────────────────────────

func _build_ui() -> void:
	var layer := CanvasLayer.new()
	add_child(layer)

	# The lab is a dev tool, but it is still a screen in this game, and the
	# theme is meant to be the ONE theme. It also has to be applied to this
	# Control rather than only to the Window: a CanvasLayer is not a Control, so
	# theme inheritance stops at it.
	UITheme.apply_global(get_tree())
	var panel := PanelContainer.new()
	panel.theme = UITheme.build()
	panel.set_anchors_preset(Control.PRESET_LEFT_WIDE)
	panel.custom_minimum_size = Vector2(440, 0)
	layer.add_child(panel)

	var scroll := ScrollContainer.new()
	panel.add_child(scroll)
	var box := VBoxContainer.new()
	box.custom_minimum_size = Vector2(410, 0)
	box.add_theme_constant_override("separation", 2)
	scroll.add_child(box)

	box.add_child(UITheme.title("RIG LAB", 34, 0.0))
	box.add_child(UITheme.divider(0.3))

	box.add_child(_picker("Character", _skins, func(i):
		_skin = i
		_reload_model()))
	box.add_child(_picker("Weapon", _weapons, func(i):
		_weapon = i
		_load_knobs()
		if _model:
			_model.set_weapon(_weapons[_weapon].script)
			_push("hold")
			_push("anchors")))
	var poses: Array = []
	for p in POSES:
		poses.append({"name": p[0]})
	box.add_child(_picker("Pose", poses, func(i): _pose = i))
	# Clip scrubber. The four poses above are the states the game drives; this
	# plays one clip on its own, which is the only way to watch a whole
	# animation end to end and see where a retarget went wrong.
	var clip_row := _picker("Clip", [{"name": "(pose driven)"}],
		func(i): _select_clip(i))
	_clip_picker = clip_row.get_child(1)
	box.add_child(clip_row)

	for group in GROUPS:
		box.add_child(UITheme.divider(0.5))
		box.add_child(UITheme.heading(GROUPS[group]["title"], 18))
		for spec in _specs(group):
			box.add_child(_knob_row(group, spec))
		box.add_child(_group_buttons(group))

	box.add_child(UITheme.divider(0.7))
	box.add_child(UITheme.heading("SURFACES  ·  click to isolate", 18))
	_surface_box = VBoxContainer.new()
	_surface_box.add_theme_constant_override("separation", 1)
	box.add_child(_surface_box)

	_status = Label.new()
	_status.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
	_status.custom_minimum_size = Vector2(400, 40)
	_status.text = "DRAG A MARKER to move that anchor  ·  left drag orbit  ·  wheel zoom  ·  middle drag pan  ·  F frame hands"
	box.add_child(_status)
	# Reflect whatever the shot arguments or the defaults selected, or the
	# dropdown says one thing while the scene shows another.
	_pickers["Character"].select(_skin)
	_pickers["Weapon"].select(_weapon)
	_pickers["Pose"].select(_pose)


func _picker(label: String, items: Array, on_pick: Callable) -> Control:
	var row := HBoxContainer.new()
	var l := Label.new()
	l.text = label
	l.custom_minimum_size = Vector2(90, 0)
	row.add_child(l)
	var opt := OptionButton.new()
	opt.size_flags_horizontal = Control.SIZE_EXPAND_FILL
	for it in items:
		opt.add_item(String(it.name))
	opt.item_selected.connect(on_pick)
	row.add_child(opt)
	_pickers[label] = opt
	return row


func _knob_row(group: String, spec: Array) -> Control:
	var key: String = spec[0]
	var box := VBoxContainer.new()
	box.add_theme_constant_override("separation", 0)
	var label := Label.new()
	label.add_theme_font_size_override("font_size", 16)
	box.add_child(label)
	var entry := {"spec": spec, "label": label}
	var axes := ["x", "y", "z"] if spec[4] else ["x"]
	for a in axes:
		var sl := HSlider.new()
		sl.min_value = spec[2]
		sl.max_value = spec[3]
		sl.step = 0.001
		sl.custom_minimum_size = Vector2(400, 14)
		sl.value_changed.connect(func(_v): _knob_changed(group, key))
		box.add_child(sl)
		entry[a] = sl
	_sliders[group][key] = entry
	return box


func _group_buttons(group: String) -> Control:
	var row := HBoxContainer.new()
	for b in [["Save", func(): _save(group)], ["Reset", func(): _reset(group)],
			["Copy", func(): _copy(group)]]:
		var btn := Button.new()
		btn.text = b[0]
		btn.pressed.connect(b[1])
		row.add_child(btn)
	return row


func _save(group: String) -> void:
	var where := ""
	if group == "anchors":
		where = RigAnchors.save(_all[group], _skins[_skin].id, _knobs[group])
		_status.text = "Saved %s anchors to %s" % [_skins[_skin].id, where]
	else:
		where = WeaponHoldTuning.save(_all[group], _skins[_skin].id,
			_weapons[_weapon].id, _knobs[group])
		_status.text = "Saved %s + %s hold to %s" % [_skins[_skin].id,
			_weapons[_weapon].id, where]


func _reset(group: String) -> void:
	_knobs[group] = {}
	for k in _sliders[group]:
		var e = _sliders[group][k]
		for a in ["x", "y", "z"]:
			if e.has(a):
				# Back to the DEFAULT, not to zero. Those are the same thing for
				# every anchor and for most of the hold, but not for all of it —
				# a slider parked at 0 next to a code default of 1.0 means reset
				# quietly switched that behaviour off rather than restoring it.
				var d = _default_for(group, k)
				var v: float = (d[a] if d is Vector3 else float(d)) \
					if e.spec[4] else float(d)
				e[a].set_value_no_signal(v)
		_refresh_label(group, k)
	_push(group)
	_status.text = "Reset %s to what the code derives" % group


func _copy(group: String) -> void:
	DisplayServer.clipboard_set(JSON.stringify(
		TuningStore.flatten(_knobs[group]), "  "))
	_status.text = "Copied %s to the clipboard" % group


# ── surfaces ──────────────────────────────────────────────────────────────────
#
# What the importer decided each surface of this model IS. Read-only, because
# the decision belongs in the sidecar where the whole game reads it — but
# ISOLATING a class is how the decision gets checked. Click `hair` and only the
# hair should be left standing. Anything else still visible was misclassified.

func _rebuild_surface_list() -> void:
	for c in _surface_box.get_children():
		c.queue_free()
	_isolated = ""
	_hidden_surfaces.clear()
	if _model == null:
		return
	var counts := {}
	for cls in [SkinSurfaces.BODY, SkinSurfaces.CLOTH, SkinSurfaces.HAIR,
			SkinSurfaces.ACCESSORY, SkinSurfaces.LINEWORK]:
		var n: int = _model.surfaces_of(cls).size()
		if n > 0:
			counts[cls] = n
	for cls in counts:
		var btn := Button.new()
		btn.text = "%s  ×%d" % [cls, counts[cls]]
		btn.toggle_mode = true
		btn.pressed.connect(func(): _isolate(cls if _isolated != cls else ""))
		_surface_box.add_child(btn)
	if counts.is_empty():
		_surface_box.add_child(UITheme.heading("no surface table", 16))


## Show only one surface class, or "" for all of them.
##
## Hidden by swapping in a fully transparent material rather than by hiding the
## MeshInstance, because a mesh is not one class: Miku's body, face and hair are
## three surfaces of a single mesh, and hiding the node would take all three.
## The displaced materials are kept so this is reversible without rebuilding the
## character — which would also throw away whatever is being tuned.
func _isolate(cls: String) -> void:
	for mi in _hidden_surfaces:
		if is_instance_valid(mi):
			for s in _hidden_surfaces[mi]:
				mi.set_surface_override_material(s, _hidden_surfaces[mi][s])
	_hidden_surfaces.clear()
	_isolated = cls
	for b in _surface_box.get_children():
		if b is Button:
			b.set_pressed_no_signal(b.text.begins_with(cls) and cls != "")
	if cls == "" or _model == null:
		_status.text = "Showing every surface"
		return

	var keep := {}
	for pair in _model.surfaces_of(cls):
		keep["%s|%d" % [pair[0].get_instance_id(), pair[1]]] = true
	var blank := StandardMaterial3D.new()
	blank.shading_mode = BaseMaterial3D.SHADING_MODE_UNSHADED
	blank.transparency = BaseMaterial3D.TRANSPARENCY_ALPHA
	blank.albedo_color = Color(0, 0, 0, 0)
	for mi in _model.find_children("*", "MeshInstance3D", true, false):
		if mi.mesh == null:
			continue
		for s in mi.mesh.get_surface_count():
			if keep.has("%s|%d" % [mi.get_instance_id(), s]):
				continue
			if not _hidden_surfaces.has(mi):
				_hidden_surfaces[mi] = {}
			_hidden_surfaces[mi][s] = mi.get_surface_override_material(s)
			mi.set_surface_override_material(s, blank)
	_status.text = "Isolated '%s' — anything else still visible is misclassified" % cls


# ── camera ────────────────────────────────────────────────────────────────────

func _update_camera() -> void:
	var b := Basis.from_euler(Vector3(_pitch, _yaw, 0))
	_cam.global_transform = Transform3D(b, _pivot + b * Vector3(0, 0, _dist))


func _unhandled_input(e: InputEvent) -> void:
	if e is InputEventMouseMotion:
		# An anchor drag OWNS the left button — otherwise grabbing a marker
		# would also orbit the camera, and the anchor would appear to move
		# because the view did.
		if _drag_marker >= 0:
			_drag_to(e.position)
			return
		_hover_marker = _marker_under(e.position) \
			if e.button_mask == 0 else _hover_marker
		if e.button_mask & MOUSE_BUTTON_MASK_LEFT:
			_yaw -= e.relative.x * 0.006
			_pitch = clampf(_pitch - e.relative.y * 0.006, -1.4, 1.4)
			_update_camera()
		elif e.button_mask & MOUSE_BUTTON_MASK_MIDDLE:
			var b := _cam.global_transform.basis
			_pivot += (b.x * -e.relative.x + b.y * e.relative.y) * _dist * 0.0015
			_update_camera()
	elif e is InputEventMouseButton and e.button_index == MOUSE_BUTTON_LEFT:
		if e.pressed:
			var hit := _marker_under(e.position)
			if hit >= 0:
				_begin_drag(hit, e.position)
		elif _drag_marker >= 0:
			_status.text = "%s is now %s — Save to keep it" % [
				_knob_for(_drag_marker),
				_knobs["hold"].get(_knob_for(_drag_marker), Vector3.ZERO)]
			_drag_marker = -1
	elif e is InputEventMouseButton and e.pressed:
		if e.button_index == MOUSE_BUTTON_WHEEL_UP:
			_dist = maxf(_dist * 0.9, 0.15)
			_update_camera()
		elif e.button_index == MOUSE_BUTTON_WHEEL_DOWN:
			_dist = minf(_dist * 1.1, 8.0)
			_update_camera()
	elif e is InputEventKey and e.pressed and not e.echo:
		match e.keycode:
			KEY_F:
				# Frame the hands, which is what is actually being judged.
				if _model and _model._pose_mod:
					_pivot = _model.skeleton.global_transform \
						* _model._pose_mod.dbg_grip
					_dist = 0.55
					_update_camera()
			# The shortcuts act on the HOLD group, which is what they meant
			# when it was the only group. Anchors have their own buttons.
			KEY_S: _save("hold")
			KEY_R: _reset("hold")
			KEY_C: _copy("hold")
			KEY_ESCAPE: get_tree().quit()