extends Node3D
class_name SkinnedPlayerModel

const MECHA_KIT_SCRIPT := preload("res://characters/anime_mecha_kit.gd")

## A player model loaded from a game-ready GLB (produced by tools/pipeline.py)
## with a Mixamo-compatible skeleton and the canonical animation set.
##
## Drop-in replacement for the procedural HumanoidModel:
##   - update_state(state, speed, is_crouching)  — drives animation selection
##   - set_weapon(script_path)                   — third-person weapon in hand
##   - shadows_only                              — legacy local-player mode
##
## View modes (for the LOCAL player only):
##   - first_person_mode = true  → model renders shadows-only for the owner, so
##     the camera (which sits inside the head) never shows the inside of the
##     mesh. Still fully animated; still visible to other players and in shadows.
##   - Press the third-person toggle → set_owner_visible(true) makes the full
##     animated model visible to the owner too (over-the-shoulder camera).
##   - first_person_mode = false → full third-person model for other players.

@export var model_path: String = ""
@export var mecha_theme: String = ""
@export var first_person_mode: bool = false
@export var shadows_only: bool = false
@export var facing_flip: bool = true  # glTF forward is +Z; players face -Z

## Ground speed (m/s) encoded by each root-motion source at 1x playback.
## Measured with tools/audit_animation_speeds.py, not eyeballed. The shipped
## clips are in-place, but these reference velocities let the BlendSpace and
## TimeScale reproduce the source stride length without foot sliding.
@export var walk_anim_reference_speed: float = 0.975
@export var run_anim_reference_speed: float = 5.26148
@export var sprint_anim_reference_speed: float = 8.25
## Low-speed authored combat steps and the high-speed anime run are separate
## clips. The old setup put a 1.8 m/s side-step in the high-speed RunLeft/Right
## slots, then time-scaled it more than 6x at the game's 11 m/s ground speed.
@export var strafe_walk_anim_reference_speed: float = 3.0
@export var strafe_run_anim_reference_speed: float = 8.25
@export var wall_run_anim_reference_speed: float = 8.25
@export var crouch_anim_reference_speed: float = 0.75

## Canonical clip names -> fallback chain. First clip that exists wins, so a
## model with only Idle/Walk/Run still animates in every movement state.
const CLIP_FALLBACKS := {
	"Idle": ["Idle"],
	"Walk": ["Walk", "Run", "Idle"],
	"Run": ["Run", "Walk", "Idle"],
	"Sprint": ["Sprint", "Run", "Walk", "Idle"],
	"Jump": ["Jump", "Fall", "Idle"],
	"Fall": ["Fall", "Jump", "Idle"],
	"Land": ["Land", "Idle"],
	"Crouch": ["CrouchIdle", "Crouch", "Idle"],
	"CrouchWalk": ["CrouchWalk", "Crouch", "CrouchIdle", "Walk"],
	"SlideStart": ["SlideStart", "Slide"],
	"Slide": ["Slide", "CrouchIdle", "Crouch", "Idle"],
	"SlideExit": ["SlideExit", "Slide"],
	"WallRunStart": ["WallRunStart", "WallRunLeft", "Fall"],
	"WallRunLeft": ["WallRunLeft", "Fall"],
	"WallRunRight": ["WallRunRight", "Fall"],
	"WallRunExit": ["WallRunExit", "WallRunLeft", "Fall"],
	"WallCling": ["WallCling", "CrouchIdle", "Idle"],
	"WallClimb": ["WallClimb", "WallCling", "Jump"],
	"Grapple": ["Grapple", "Fall", "Jump", "Idle"],
	"Dash": ["Dash", "Sprint", "Run", "Idle"],
	"StrafeWalkForward": ["StrafeWalkForward", "Walk", "Run", "Idle"],
	"StrafeWalkBackward": ["StrafeWalkBackward", "RunBackward", "Walk", "Idle"],
	"StrafeWalkLeft": ["StrafeWalkLeft", "RunLeft", "Walk", "Idle"],
	"StrafeWalkRight": ["StrafeWalkRight", "RunRight", "Walk", "Idle"],
	"RunForward": ["RunForward", "Run", "Walk"],
	"RunBackward": ["RunBackward", "Run", "Walk"],
	"RunLeft": ["RunLeft", "Run", "Walk"],
	"RunRight": ["RunRight", "Run", "Walk"],
	"Roll": ["Roll", "Dash"],
	"Death": ["Death", "Fall"],
	"Hit": ["Hit", "Idle"],
	"Dance": ["Dance", "Idle"],
	"EmoteStretch": ["EmoteStretch", "Dance", "Idle"],
	"EmoteCall": ["EmoteCall", "Dance", "Idle"],
	"EmoteYes": ["EmoteYes", "Dance", "Idle"],
	"EmoteNo": ["EmoteNo", "Dance", "Idle"],
	"PistolIdle": ["PistolIdle", "Idle"],
	"PistolShoot": ["PistolShoot"],
	"PistolReload": ["PistolReload"],
	"Throw": ["Throw", "Hit"],
}

const LOOPING_CLIPS := ["Idle", "Walk", "Run", "Sprint", "Fall", "Crouch",
	"CrouchIdle", "CrouchWalk", "Slide", "WallRunLeft", "WallRunRight",
	"WallCling", "Grapple",
	"StrafeWalkForward", "StrafeWalkBackward", "StrafeWalkLeft", "StrafeWalkRight",
	"RunForward", "RunBackward", "RunLeft", "RunRight", "Dance",
	"EmoteStretch", "EmoteCall", "EmoteYes", "EmoteNo", "PistolIdle"]

const BLEND_TIME := 0.36
## Per-clip blend overrides. Reaction moves still need to read as instant, but
## nothing cuts hard any more — every clip cross-fades. Locomotion gets the
## longest fades because Idle<->Walk<->Run<->Sprint switch constantly as speed
## drifts across their thresholds, and that is where hard cuts were most
## visible.
const BLEND_TIMES := {
	"Dash": 0.20, "Jump": 0.24, "Hit": 0.14, "Land": 0.28,
	# SlideStart has a distinct authored crouch pose; blending into it from
	# airborne/standing can send the lower body through a ground-plane flip.
	"SlideStart": 0.0, "Slide": 0.30, "Death": 0.34,
	"Throw": 0.20, "PistolReload": 0.30,
	"Idle": 0.42, "PistolIdle": 0.42, "Walk": 0.40, "Run": 0.40, "Sprint": 0.40,
	"CrouchIdle": 0.40, "CrouchWalk": 0.40, "Fall": 0.32,
	# The two authored wall performances start in distinct side poses. A full
	# body crossfade from Fall/ground interpolates the hips and thighs through
	# an upside-down midpoint, so hand off directly to the authored first pose.
	"WallRunLeft": 0.0, "WallRunRight": 0.0,
	"WallCling": 0.32, "Grapple": 0.32,
}
const GROUND_STATE_BLEND := 0.30

## Named gameplay actions -> (clip, lock seconds). Networked via the
## controller's synced action counter.
const ACTIONS := {
	"reload": ["PistolReload", 1.15],
	"throw": ["Throw", 0.55],
	"shoot": ["PistolShoot", 0.2],
	"melee": ["Throw", 0.45],  # overhand arm swing doubles as the knife slash
}

var skeleton: Skeleton3D
var animation_player: AnimationPlayer
var loaded: bool = false
## Coordinate frame for authored traversal clips. It only aligns the imported
## performance's forward axis with gameplay travel; it never rotates bones or
## manufactures poses.
var _motion_root: Node3D
var _wall_glide_velocity_world := Vector3.ZERO
var _wall_surface_normal_world := Vector3.ZERO
var _wall_surface_point_world := Vector3.ZERO
var _motion_yaw := 0.0
var _motion_was_wall_run := false

var _resolved_clips: Dictionary = {}   # canonical name -> actual clip name
var _current_clip: String = ""
## True only for the ignored local evaluation builds made from the copyrighted
## pilot reference. Shipping characters retain the original jet-glide fallback.
var _has_titanfall_motion_reference := false
var _weapon_attachment: BoneAttachment3D
var _grapple_attachment: BoneAttachment3D
var _grapple_shoulder_attachment: BoneAttachment3D
## [child_bone, helper_bone] pairs driven every frame by the pose modifier.
var _joint_helpers: Array = []
## Contents of <model>.rig.json — resolved bone roles, cloth chains, twist pairs
## and leg colliders, written by tools/retarget.py. Empty for a model that was
## rebound onto the library skeleton instead of keeping its own rig.
var _rig_info: Dictionary = {}
## What each surface of this model IS — body, cloth, hair, accessory. Read from
## the same sidecar; drives the per-class cel look and answers `surfaces_of()`.
var _surfaces: SkinSurfaces = null
var _spring_mod: SpringBones
var _mecha_kit: AnimeMechaKit
var is_holding_weapon: bool = false
## Which hold archetype the equipped weapon uses — see WeaponHoldProfiles. Read
## by `_process` (a blade releases the off arm) and by the checks.
var hold_style: String = WeaponHoldProfiles.RIFLE
## Which skin this is, so per-character hold tuning can be looked up. Set by
## whoever spawns the model; falls back to the GLB's basename.
var skin_id: String = ""
## Live hold overrides. Written by debug/rig_lab.gd while tuning and by
## set_weapon() from the saved table otherwise.
var hold_tune: Dictionary = {}
## Live anchor overrides — where the grip sits in the palm, and how the gun
## rolls in the fingers. Same two sources as hold_tune. See RigAnchors.
var anchors: Dictionary = {}
## The weapon's local transform in the hand as `_measure_weapon` left it, before
## the wrist counter-rotation. See `ShooterPoseModifier.wrist_comp_r`.
var _weapon_seat: Transform3D = Transform3D.IDENTITY

# Animation blending: authored locomotion cycles play through synchronized
# speed/direction blend spaces, while traversal states use their own clips;
# gameplay one-shots (reload/throw/shoot/hit) play through an
# AnimationNodeOneShot FILTERED to upper-body bones, so the legs keep
# sliding/running underneath instead of popping to the one-shot's standing legs.
var _anim_tree: AnimationTree
var _state_trans: AnimationNodeTransition
var _loco_blend: AnimationNodeBlendSpace2D
var _crouch_blend: AnimationNodeBlendSpace1D
var _upper_anim: AnimationNodeAnimation
var _current_state_node: String = ""
var _upper_lock: float = 0.0           # seconds the one-shot owns the ARMS
var _upper_total: float = 0.0          # its full duration, for progress 0..1
var _upper_action: String = ""         # which ACTIONS entry is playing
## Bone-name fragments that belong to the upper-body one-shot layer.
##
## NECK AND HEAD ARE DELIBERATELY EXCLUDED. The shared library's action clips
## were authored for a character looking at their own hands: PistolReload alone
## dives the head 33° and bends the whole neck chain 67° (measured). At that
## depth Taila's head/hair weights pinch and the skull visibly changes shape —
## which is what "reloading squishes the headshape" was. Nothing is actually
## scaled; no bone in any clip deviates from the rest pose by more than a
## millimetre. Leaving neck+head on the locomotion layer keeps the character
## looking downrange through a reload, which is also what a shooter wants.
const UPPER_BONE_HINTS := ["shoulder", "upper_arm", "forearm", "hand", "thumb",
	"f_index", "f_middle", "f_ring", "f_pinky", "spine.002", "spine.003"]

# Mechanical shooter pose layer (aim, recoil, and weapon IK), applied after the
# authored animation by a SkeletonModifier3D.
var _pose_mod: ShooterPoseModifier
var _target_strafe: float = 0.0
var _target_fwd: float = 0.0
var _target_ads: float = 0.0
var _target_wall: float = 0.0
var _loco_blend_target := Vector2.ZERO
var _loco_blend_visual := Vector2.ZERO
var _loco_scale_target := 1.0
var _loco_scale_visual := 1.0
var _crouch_blend_target := 0.0
var _crouch_blend_visual := 0.0
var _cur_ads: float = 0.0
var _cur_wall: float = 0.0
var _owner_visible: bool = false
const POSE_SMOOTH := 10.0


func _ready() -> void:
	if model_path != "":
		load_model(model_path)


func load_model(path: String) -> void:
	for child in get_children():
		child.queue_free()
	skeleton = null
	animation_player = null
	_motion_root = null
	_wall_glide_velocity_world = Vector3.ZERO
	_wall_surface_normal_world = Vector3.ZERO
	_wall_surface_point_world = Vector3.ZERO
	_motion_yaw = 0.0
	_motion_was_wall_run = false
	_loco_blend_target = Vector2.ZERO
	_loco_blend_visual = Vector2.ZERO
	_loco_scale_target = 1.0
	_loco_scale_visual = 1.0
	_crouch_blend_target = 0.0
	_crouch_blend_visual = 0.0
	loaded = false
	_resolved_clips.clear()
	_current_clip = ""
	_has_titanfall_motion_reference = false
	_current_state_node = ""
	_slide_start_remaining = 0.0
	_weapon_attachment = null
	_grapple_attachment = null
	_grapple_shoulder_attachment = null
	_mecha_kit = null
	# Cleared, not left standing: a model with no skeleton never reaches the
	# branch that reloads these, and would otherwise be described by the LAST
	# character's sidecar.
	_rig_info = {}
	_surfaces = null

	var scene := GLBLoader.load(path)
	if not scene:
		push_warning("SkinnedPlayerModel: failed to load '%s'" % path)
		return
	_motion_root = Node3D.new()
	_motion_root.name = "MotionOrientation"
	add_child(_motion_root)
	_motion_root.add_child(scene)
	if facing_flip:
		scene.rotation_degrees.y = 180.0

	skeleton = _find_node_of_type(scene, "Skeleton3D") as Skeleton3D
	animation_player = _find_node_of_type(scene, "AnimationPlayer") as AnimationPlayer

	if not skeleton:
		push_warning("SkinnedPlayerModel: no skeleton in '%s'" % path)
	else:
		_ensure_meshes_bound(scene)
		_rig_info = _load_rig_info(path)
		_apply_rig_animation_speeds()
		# `weights_authored` is MEASURED at build time, not inferred from which
		# pipeline branch ran: a model that arrives unrigged still gets a
		# sidecar, and its nearest-bone weights still need the repair below.
		if not _rig_info.get("weights_authored", false):
			# Weights were solved, not painted — every vertex went to its
			# nearest four bones with no idea which limb it belongs to.
			# SkinLegRepair exists solely to undo that, and it is destructive
			# (it snaps weights and deletes triangles), so a model that kept its
			# ARTIST weights must never be put through it.
			var fixed := SkinLegRepair.repair(scene, skeleton)
			if fixed[0] > 0 or fixed[1] > 0:
				print("SkinnedPlayerModel: '%s' — snapped %d cross-leg vertices, dropped %d bridging triangles"
					% [path.get_file(), fixed[0], fixed[1]])
		# Joint subdivision runs for EVERY model, however it was rigged. It is
		# not a weight repair: linear-blend skinning collapses any joint by
		# cos(angle/2) no matter how good the weights are, and dropping it from
		# the authored-weight path measured 0.77 at the knee against 0.99 with
		# it. See SkinJointHelper.
		_joint_helpers = SkinJointHelper.install(scene, skeleton)
		_pose_mod = ShooterPoseModifier.new()
		_pose_mod.joint_helpers = _joint_helpers
		_pose_mod.roles = _rig_info.get("roles", {})
		_pose_mod.fingers = _rig_info.get("fingers", {})
		_pose_mod.name = "ShooterPose"
		skeleton.add_child(_pose_mod)
		var grapple_hand := _role_bone(
			"hand.L", ["hand.L", "Left wrist", "Left hand"])
		var grapple_shoulder := _role_bone(
			"upper_arm.L", ["upper_arm.L", "Left upper arm"])
		if grapple_hand >= 0:
			_grapple_attachment = BoneAttachment3D.new()
			_grapple_attachment.name = "GrappleHandSocket"
			_grapple_attachment.bone_idx = grapple_hand
			skeleton.add_child(_grapple_attachment)
		if grapple_shoulder >= 0:
			_grapple_shoulder_attachment = BoneAttachment3D.new()
			_grapple_shoulder_attachment.name = "GrappleShoulderSocket"
			_grapple_shoulder_attachment.bone_idx = grapple_shoulder
			skeleton.add_child(_grapple_shoulder_attachment)
		# Cloth and hair last, so the springs react to the FINAL body pose —
		# authored animation plus the weapon-mechanics layer.
		if not _rig_info.is_empty():
			_spring_mod = SpringBones.new()
			_spring_mod.name = "SpringBones"
			skeleton.add_child(_spring_mod)
			var driven := _spring_mod.setup(skeleton, _rig_info,
					_cloth_hulls(scene))
			if driven == 0:
				_spring_mod.queue_free()
				_spring_mod = null
			else:
				print("SkinnedPlayerModel: '%s' — %d cloth/hair bones on springs"
					% [path.get_file(), driven])
	# Cel-shaded look: toon shading over the imported textures...
	LevelMaterials.apply_toon_recursive(scene)
	# ...then the character-only pass, which is where the surface table earns
	# its keep: it says which surfaces are hair, cloth, body or an accessory, so
	# each can take its own outline weight and banding instead of all of them
	# taking numbers calibrated on skin. It also identifies the model's own
	# line-work by name and weight rather than by "is it nearly black", which is
	# what used to render a flat-coloured model as a black silhouette.
	_surfaces = SkinSurfaces.from_rig_info(_rig_info)
	LevelMaterials.apply_character_look(scene, _surfaces)
	if skeleton and mecha_theme != "":
		_apply_mecha_base_suit(scene)
		_mecha_kit = MECHA_KIT_SCRIPT.new()
		_mecha_kit.name = "AnimeMechaKit"
		add_child(_mecha_kit)
		_mecha_kit.setup(skeleton, _rig_info.get("roles", {}), mecha_theme)
	if animation_player:
		_index_animations()
		_setup_anim_tree(scene)
	else:
		push_warning("SkinnedPlayerModel: no animations in '%s' — model will T-pose" % path)

	# The local owner renders shadows-only (the camera is inside the head, so
	# showing the mesh would show the inside of it). Other players see it fully.
	# The third-person toggle calls set_owner_visible(true) to reveal it.
	if shadows_only or first_person_mode:
		_set_shadows_recursive(self)

	loaded = true
	_play_ground_locomotion(0.0, false)


## The imported garment is the actual zero-clearance synthetic skin. Recoloring
## that authored, skinned surface is what makes the robotics follow every curve
## and deformation; the procedural kit then only has to add seams and tools.
func _apply_mecha_base_suit(scene: Node) -> void:
	if mecha_theme != "sakura" or _surfaces == null:
		return
	for mesh_node in scene.find_children("*", "MeshInstance3D", true, false):
		var mesh_instance := mesh_node as MeshInstance3D
		if mesh_instance == null or mesh_instance.mesh == null:
			continue
		for surface_index in mesh_instance.mesh.get_surface_count():
			var source := mesh_instance.mesh.surface_get_material(surface_index) as BaseMaterial3D
			if source == null:
				continue
			var resolved: Array = _surfaces.resolve(
				mesh_instance.name, surface_index, source)
			var surface_class := str(resolved[0])
			var is_garment := surface_class == SkinSurfaces.CLOTH
			# Sakura's import keeps the face on material "Head" and the remaining
			# anatomy on material "Body". Turning only that second surface into the
			# membrane closes the waist, thigh, arm and hand gaps without tinting her
			# face or eyes.
			var is_body_membrane := surface_class == SkinSurfaces.BODY \
				and source.resource_name.to_lower() == "body"
			if not is_garment and not is_body_membrane:
				continue
			var current := mesh_instance.get_surface_override_material(surface_index)
			if current is ShaderMaterial:
				var membrane := (current as ShaderMaterial).duplicate(true) as ShaderMaterial
				membrane.set_shader_parameter("albedo_color",
					Color("303852") if is_garment else Color("3b4563"))
				membrane.set_shader_parameter("shadow_color", Color("171b31"))
				membrane.set_shader_parameter("mid_tone", 0.86)
				membrane.set_shader_parameter("rim_strength", 0.13)
				mesh_instance.set_surface_override_material(surface_index, membrane)

## Collision hulls for the cloth solver, taken from the MESH rather than from
## the sidecar: bone name -> the points that bone drives, in its own rest space.
##
## The sidecar carries ten farthest-point samples per cloth bone, which is a good
## description of a panel's OUTLINE and a poor one of a panel. Farthest-point
## sampling lands on corners, edges and the hem; a thigh comes up through the
## MIDDLE of a panel, between every sample, and the solver reported each frame's
## contacts fully resolved while 158 vertices sat 95 mm inside a leg.
##
## The runtime has the actual mesh, so it does not have to guess. Every vertex a
## cloth bone dominates is binned into a ~16 mm grid and one representative per
## cell is kept, which covers a panel evenly for a bounded number of points —
## unlike keeping every vertex, which would be thousands of collision tests per
## frame for no extra accuracy at the scale a limb is shaped.
const HULL_CELL := 0.020
const HULL_MAX := 14

func _cloth_hulls(scene: Node) -> Dictionary:
	var cloth := {}
	for c in _rig_info.get("chains", []):
		for n in c.get("bones", []):
			var bi := skeleton.find_bone(String(n))
			if bi >= 0:
				cloth[bi] = true
	if cloth.is_empty():
		return {}

	# bone -> cell key -> the vertex nearest that cell's centre.
	var cells := {}
	for mi in scene.find_children("*", "MeshInstance3D", true, false):
		if mi.mesh == null or mi.skin == null:
			continue
		var skin: Skin = mi.skin
		var bone_of := {}
		for b in skin.get_bind_count():
			var bi := skin.get_bind_bone(b)
			if bi < 0:
				bi = skeleton.find_bone(skin.get_bind_name(b))
			bone_of[b] = bi
		for s in mi.mesh.get_surface_count():
			var arrays: Array = mi.mesh.surface_get_arrays(s)
			var verts: PackedVector3Array = arrays[Mesh.ARRAY_VERTEX]
			var bones: PackedInt32Array = arrays[Mesh.ARRAY_BONES]
			var weights: PackedFloat32Array = arrays[Mesh.ARRAY_WEIGHTS]
			if bones.is_empty() or verts.is_empty():
				continue
			var per: int = bones.size() / verts.size()
			for v in verts.size():
				# A vertex belongs to whichever bone holds the largest share of
				# it — that is the bone whose motion actually decides where it
				# ends up, and so the bone that has to keep it out of a leg.
				var best := 0.0
				var bind := -1
				for k in per:
					var w: float = weights[v * per + k]
					if w > best:
						best = w
						bind = bones[v * per + k]
				if bind < 0 or best < 0.5:
					continue
				var bi: int = bone_of.get(bind, -1)
				if not cloth.has(bi):
					continue
				# The bind pose maps a vertex straight into its bone's rest
				# space, which is exactly the frame the solver poses hulls in.
				var local: Vector3 = skin.get_bind_pose(bind) * verts[v]
				var key := "%d_%d_%d" % [
					int(round(local.x / HULL_CELL)),
					int(round(local.y / HULL_CELL)),
					int(round(local.z / HULL_CELL))]
				if not cells.has(bi):
					cells[bi] = {}
				if not cells[bi].has(key):
					cells[bi][key] = local

	var out := {}
	var total := 0
	for bi in cells:
		var pts: Array = cells[bi].values()
		if pts.size() > HULL_MAX:
			# Keep the OUTERMOST cells. What clips is the part of a panel
			# furthest from the bone it hangs on, and the grid has already made
			# sure those are spread over the whole sheet rather than clustered.
			pts.sort_custom(func(a, b): return a.length_squared() > b.length_squared())
			pts = pts.slice(0, HULL_MAX)
		var packed := PackedVector3Array()
		for p in pts:
			packed.append(p)
		out[skeleton.get_bone_name(bi)] = packed
		total += packed.size()
	print("SkinnedPlayerModel: cloth hulls from mesh — %d bones, %d points"
		% [out.size(), total])
	return out


## Character-specific authored gait speeds, measured from source root motion
## before it is stripped for gameplay. This keeps native clips at their
## original cadence instead of imposing the generic library's timing.
func _apply_rig_animation_speeds() -> void:
	var speeds: Dictionary = _rig_info.get("animation_speeds", {})
	if speeds.is_empty():
		return
	walk_anim_reference_speed = maxf(
		float(speeds.get("walk", walk_anim_reference_speed)), 0.01)
	run_anim_reference_speed = maxf(
		float(speeds.get("run", run_anim_reference_speed)), 0.01)
	sprint_anim_reference_speed = maxf(
		float(speeds.get("sprint", sprint_anim_reference_speed)), 0.01)
	strafe_walk_anim_reference_speed = maxf(
		float(speeds.get("strafe_walk", strafe_walk_anim_reference_speed)), 0.01)
	strafe_run_anim_reference_speed = maxf(
		float(speeds.get("strafe_run", strafe_run_anim_reference_speed)), 0.01)
	print("SkinnedPlayerModel: native gait speeds walk=%.2f run=%.2f sprint=%.2f strafe=%.2f/%.2f m/s" % [
		walk_anim_reference_speed, run_anim_reference_speed,
		sprint_anim_reference_speed, strafe_walk_anim_reference_speed,
		strafe_run_anim_reference_speed,
	])


## Read the rig sidecar that tools/retarget.py writes next to the GLB.
##
## Its presence is also the signal that this model kept its OWN skeleton and
## authored weights, which is what decides whether the load-time weight repair
## below is needed at all.
func _load_rig_info(model_path: String) -> Dictionary:
	var side := model_path.get_basename() + ".rig.json"
	if not FileAccess.file_exists(side):
		return {}
	var text := FileAccess.get_file_as_string(side)
	var parsed = JSON.parse_string(text)
	if typeof(parsed) != TYPE_DICTIONARY:
		push_warning("SkinnedPlayerModel: could not parse '%s'" % side)
		return {}
	return parsed


## Every [mesh, surface index] of this model belonging to one surface class —
## SkinSurfaces.BODY, CLOTH, HAIR or ACCESSORY.
##
## The point of separating a character into a body, garments and hair is that
## the game can then treat them differently, and it can only do that if it can
## ask which is which. This is that question. It is used by the rig lab to let
## an artist isolate a class, and it is what a damage flash on skin only, or a
## hidden hat, or a per-class LOD would be built on.
func surfaces_of(surface_class: String) -> Array:
	var out: Array = []
	if _surfaces == null:
		return out
	for mi in find_children("*", "MeshInstance3D", true, false):
		if mi.mesh == null:
			continue
		for s in mi.mesh.get_surface_count():
			var src: BaseMaterial3D = mi.mesh.surface_get_material(s) as BaseMaterial3D
			if _surfaces.resolve(mi.name, s, src)[0] == surface_class:
				out.append([mi, s])
	return out


## The surface table, for tools that want to show or edit it. May be null.
func surface_table() -> SkinSurfaces:
	return _surfaces


## Make sure every skinned MeshInstance3D is actually driven by the skeleton.
## A correctly-exported GLB binds automatically, but if one imports with a skin
## resource whose `skeleton` NodePath doesn't resolve, the mesh renders its bind
## pose (a permanent T-pose) while the skeleton animates invisibly. This repairs
## that at load time so a bad export degrades gracefully instead of T-posing.
func _ensure_meshes_bound(scene: Node) -> void:
	for mi in scene.find_children("*", "MeshInstance3D", true, false):
		if mi.skin == null:
			continue  # not a skinned mesh
		if mi.skeleton.is_empty() or mi.get_node_or_null(mi.skeleton) != skeleton:
			mi.skeleton = mi.get_path_to(skeleton)


## Map canonical clip names to whatever actually shipped in the GLB and set
## loop modes (glTF has no loop flag, so we set it here).
func _index_animations() -> void:
	var available := animation_player.get_animation_list()
	# ReviewWallHangFront is unique to the ignored local Titanfall motion lab.
	# A canonical WallRunLeft/Right pair also exists in shipping animation packs
	# and must not opt those rigs into the Titanfall-specific side convention.
	_has_titanfall_motion_reference = \
		_find_clip(available, "ReviewWallHangFront") != ""
	_normalize_rotation_track_signs()
	for canonical in CLIP_FALLBACKS:
		for candidate in CLIP_FALLBACKS[canonical]:
			var match_name := _find_clip(available, candidate)
			if match_name != "":
				_resolved_clips[canonical] = match_name
				break
	for canonical in LOOPING_CLIPS:
		if _resolved_clips.has(canonical):
			var anim := animation_player.get_animation(_resolved_clips[canonical])
			if anim:
				anim.loop_mode = Animation.LOOP_LINEAR


## Quaternions q and -q encode the same pose, but interpolation does not know
## that unless adjacent keys use a consistent sign. A few imported traversal
## tracks contain those sign changes, so Godot interpolates the long arc and
## briefly turns the waist/legs upside down on wall-run entry. Normalize every
## rotation track once after GLB import so the authored pose is preserved while
## interpolation always takes the shortest arc between keys.
func _normalize_rotation_track_signs() -> void:
	for animation_name in animation_player.get_animation_list():
		var animation := animation_player.get_animation(animation_name)
		if animation == null:
			continue
		for track_index in animation.get_track_count():
			if animation.track_get_type(track_index) != Animation.TYPE_ROTATION_3D:
				continue
			var previous := Quaternion.IDENTITY
			var has_previous := false
			for key_index in animation.track_get_key_count(track_index):
				var value = animation.track_get_key_value(track_index, key_index)
				if not value is Quaternion:
					continue
				var current: Quaternion = value.normalized()
				if has_previous and previous.dot(current) < 0.0:
					current = -current
					animation.track_set_key_value(track_index, key_index, current)
				previous = current
				has_previous = true


## Runtime blend tree:
##
##   authored cycles -> direction/speed BlendSpaces \
##   authored traversal/action clips ----------------> state Transition
##                                                     -> TimeScale
##                                                     -> upper OneShot -> output
##
## The ground blend position is the measured horizontal velocity, so a speed
## change affects the legs on this frame. Cyclic sync keeps every active gait on
## the same foot phase while Idle/Walk/Run/Sprint and cardinal strafes blend.
## There is no delayed tier ladder and no procedural leg pose.
func _setup_anim_tree(scene: Node) -> void:
	var bt := AnimationNodeBlendTree.new()
	_state_trans = AnimationNodeTransition.new()
	_state_trans.xfade_time = BLEND_TIME
	_state_trans.allow_transition_to_self = true  # lets Land restart itself
	bt.add_node("state", _state_trans, Vector2(-120, 0))

	_loco_blend = AnimationNodeBlendSpace2D.new()
	_loco_blend.min_space = Vector2(-sprint_anim_reference_speed,
		-sprint_anim_reference_speed)
	_loco_blend.max_space = Vector2(sprint_anim_reference_speed,
		sprint_anim_reference_speed)
	_loco_blend.snap = Vector2(0.1, 0.1)
	_loco_blend.sync_mode = AnimationNodeBlendSpace2D.SYNC_MODE_CYCLIC_MUTABLE
	var ground_points := [
		["Idle", Vector2.ZERO],
		["Walk", Vector2(0.0, walk_anim_reference_speed)],
		["StrafeWalkForward", Vector2(0.0, strafe_walk_anim_reference_speed)],
		["RunForward", Vector2(0.0, run_anim_reference_speed)],
		["Sprint", Vector2(0.0, sprint_anim_reference_speed)],
		["StrafeWalkBackward", Vector2(0.0, -strafe_walk_anim_reference_speed)],
		["RunBackward", Vector2(0.0, -strafe_run_anim_reference_speed)],
		["StrafeWalkLeft", Vector2(-strafe_walk_anim_reference_speed, 0.0)],
		["RunLeft", Vector2(-strafe_run_anim_reference_speed, 0.0)],
		["StrafeWalkRight", Vector2(strafe_walk_anim_reference_speed, 0.0)],
		["RunRight", Vector2(strafe_run_anim_reference_speed, 0.0)],
	]
	for point in ground_points:
		var canonical: String = point[0]
		if not _resolved_clips.has(canonical):
			continue
		var anim_node := AnimationNodeAnimation.new()
		anim_node.animation = _resolved_clips[canonical]
		_loco_blend.add_blend_point(anim_node, point[1], -1, canonical)
	bt.add_node("loco_blend", _loco_blend, Vector2(-520, -100))
	_state_trans.add_input("Locomotion")
	bt.connect_node("state", 0, "loco_blend")

	_crouch_blend = AnimationNodeBlendSpace1D.new()
	_crouch_blend.min_space = 0.0
	_crouch_blend.max_space = crouch_anim_reference_speed
	_crouch_blend.snap = 0.1
	_crouch_blend.sync_mode = AnimationNodeBlendSpace1D.SYNC_MODE_CYCLIC_MUTABLE
	for point in [["Crouch", 0.0], ["CrouchWalk", crouch_anim_reference_speed]]:
		var canonical: String = point[0]
		if not _resolved_clips.has(canonical):
			continue
		var anim_node := AnimationNodeAnimation.new()
		anim_node.animation = _resolved_clips[canonical]
		_crouch_blend.add_blend_point(anim_node, point[1], -1, canonical)
	bt.add_node("crouch_blend", _crouch_blend, Vector2(-520, 80))
	_state_trans.add_input("CrouchLocomotion")
	bt.connect_node("state", 1, "crouch_blend")

	# Direct inputs preserve authored traversal and debug clip playback.
	var seen := {}
	var idx := 2
	for canonical in _resolved_clips:
		var clip_name: String = _resolved_clips[canonical]
		if seen.has(clip_name):
			continue
		seen[clip_name] = true
		var an := AnimationNodeAnimation.new()
		an.animation = clip_name
		var node_id := "clip_%d" % idx
		bt.add_node(node_id, an, Vector2(-500, idx * 60))
		_state_trans.add_input(clip_name)
		bt.connect_node("state", idx, node_id)
		idx += 1

	var ts := AnimationNodeTimeScale.new()
	bt.add_node("loco_scale", ts, Vector2(0, 0))
	bt.connect_node("loco_scale", 0, "state")

	var upper := AnimationNodeOneShot.new()
	# The upper-body one-shot pops in and out over the locomotion clip, so its
	# own fades matter as much as the locomotion cross-fade.
	upper.fadein_time = 0.20
	upper.fadeout_time = 0.30
	upper.filter_enabled = true
	_upper_anim = AnimationNodeAnimation.new()
	bt.add_node("upper_clip", _upper_anim, Vector2(0, 240))
	bt.add_node("upper", upper, Vector2(220, 0))
	bt.connect_node("upper", 0, "loco_scale")
	bt.connect_node("upper", 1, "upper_clip")
	bt.connect_node("output", 0, "upper")

	# Filter = every track whose bone is upper-body. Track paths are identical
	# across the library's clips, so sample any one of them.
	var sample: Animation = animation_player.get_animation(_resolved_clips.values()[0])
	for t in sample.get_track_count():
		var p := sample.track_get_path(t)
		var bone := String(p.get_concatenated_subnames())
		for hint in UPPER_BONE_HINTS:
			if bone.findn(hint) != -1:
				upper.set_filter_path(p, true)
				break

	_anim_tree = AnimationTree.new()
	_anim_tree.name = "AnimTree"
	_anim_tree.tree_root = bt
	scene.add_child(_anim_tree)
	_anim_tree.anim_player = _anim_tree.get_path_to(animation_player)
	_anim_tree.active = true


func _find_clip(available: PackedStringArray, wanted: String) -> String:
	for name in available:
		if name == wanted:
			return name
	# Tolerate library prefixes ("mixamo/Run") and case differences.
	var wanted_lower := wanted.to_lower()
	for name in available:
		var base := name.get_slice("/", name.get_slice_count("/") - 1).to_lower()
		if base == wanted_lower:
			return name
	return ""


# ── View modes ────────────────────────────────────────────────────────────────

## Show or hide the model to its OWNER. In first person we render shadows-only
## (on=false) so the camera doesn't see the inside of the mesh; the third-person
## toggle calls this with on=true to reveal the full animated model. Either way
## the model keeps casting shadows and stays visible to other players.
func set_owner_visible(on: bool) -> void:
	_owner_visible = on
	var mode := GeometryInstance3D.SHADOW_CASTING_SETTING_ON if on \
		else GeometryInstance3D.SHADOW_CASTING_SETTING_SHADOWS_ONLY
	_set_shadow_mode_recursive(self, mode)


func _set_shadow_mode_recursive(node: Node, mode: int) -> void:
	if node is GeometryInstance3D:
		node.cast_shadow = mode
	for child in node.get_children():
		_set_shadow_mode_recursive(child, mode)


# ── Animation state ───────────────────────────────────────────────────────────

var _prev_state: String = ""
var _oneshot_lock: float = 0.0  # seconds left where a one-shot owns playback
var _slide_start_remaining: float = 0.0
var _dancing: bool = false
## Which authored entry in DanceRoutines.ROUTINES is playing.
var _dance_index: int = 0


## Play a one-shot clip over locomotion for `lock_time` seconds.
## Whole-body moments (Land) briefly own the full skeleton; everything else
## (reload/throw/shoot/hit) plays on the UPPER BODY ONLY through the filtered
## OneShot node, so the legs keep doing whatever the movement state says —
## you can reload mid-slide and stay sliding.
const FULL_BODY_ONESHOTS := ["Land"]

func play_oneshot(canonical: String, lock_time: float = 0.35) -> void:
	if not loaded or not _resolved_clips.has(canonical):
		return
	if canonical in FULL_BODY_ONESHOTS or not _anim_tree:
		_oneshot_lock = lock_time
		_play_clip(canonical, true)
		return
	_upper_lock = lock_time
	_upper_total = lock_time
	_upper_anim.animation = _resolved_clips[canonical]
	_anim_tree.set("parameters/upper/request", AnimationNodeOneShot.ONE_SHOT_REQUEST_FIRE)


## Emote toggle (Dance). Shown while grounded and near-idle; any real
## movement breaks it (the controller clears the flag too).
##
## `which` selects one of five separately authored library clips. No runtime
## bone oscillation or procedural emote modifier is involved.
func set_dancing(on: bool, which: int = -1) -> void:
	_dancing = on
	if which >= 0:
		_dance_index = which
	# The authored emotes own the full body. Leaving the live weapon attached
	# makes otherwise-correct gestures drive a rifle through the face and chest.
	# Hide only the third-person prop; the gameplay loadout remains unchanged
	# and comes back immediately when the emote ends.
	if _weapon_attachment and _weapon_attachment.get_child_count() > 0:
		var held_weapon := _weapon_attachment.get_child(0) as Node3D
		if held_weapon:
			held_weapon.visible = not on


## Play a named gameplay action (reload / throw / shoot) as a one-shot.
func play_action(action: String) -> void:
	if ACTIONS.has(action):
		_upper_action = action
		play_oneshot(ACTIONS[action][0], ACTIONS[action][1])


## Aim pitch in radians (up positive) — the upper body follows the camera.
func set_aim_pitch(pitch: float) -> void:
	if _pose_mod:
		_pose_mod.aim_pitch = clampf(pitch, -1.2, 1.2)


## Kick the pose recoil (fires on every shot, local echo or remote replay).
func add_gun_recoil(strength: float = 1.0) -> void:
	if _pose_mod:
		_pose_mod.recoil = minf(_pose_mod.recoil + strength, 1.5)


## Same contract as HumanoidModel.update_state(). Called by the movement
## controller each frame with either local or network-synced state.
func update_state(state: String, speed: float, is_crouching: bool = false) -> void:
	if not loaded or not animation_player:
		return
	var previous_state := _prev_state
	var exiting_wall_run := previous_state == "wall_run" and state != "wall_run"

	# One-shots (Land, Hit) own playback briefly.
	if _oneshot_lock > 0.0:
		_oneshot_lock -= get_process_delta_time()
		if _oneshot_lock > 0.0:
			_prev_state = state
			return
	# A heavy landing plays the Land one-shot before locomotion resumes.
	if state in ["ground", "idle"] and _prev_state == "air" \
			and _vertical_speed() < -12.0 and _resolved_clips.has("Land"):
		_oneshot_lock = 0.25
		_play_clip("Land")
		_prev_state = state
		return
	_prev_state = state
	if state != "slide":
		_slide_start_remaining = 0.0

	var clip := "Idle"
	match state:
		"ground", "idle":
			if _dancing and speed < 0.5 and not is_crouching:
				clip = DanceRoutines.clip_of(_dance_index)
			else:
				_play_ground_locomotion(speed, is_crouching)
				clip = ""
		"air":
			# Rising = jump, falling = the fall loop.
			clip = "Jump" if _vertical_speed() > 0.5 else "Fall"
		"slide":
			if previous_state != "slide":
				_slide_start_remaining = _animation_length_if_distinct(
					"SlideStart", "Slide") / _slide_playback_scale(speed)
			if _slide_start_remaining > 0.0:
				clip = "SlideStart"
			else:
				clip = "Slide"
		"wall_run":
			# The jets still own propulsion, but the authored pilot pack supplies a
			# distinct compact wall-performance for each side.  This is body motion,
			# not gameplay root motion or procedural feet planted against the wall.
			if _has_titanfall_motion_reference:
				# The imported pair is mirrored relative to gameplay's wall-side
				# convention: the clip named Right is the left-wall performance and
				# vice versa. Keep that conversion here rather than swapping physics
				# wall_side values, which would break camera tilt and networking.
				clip = "WallRunRight" if _target_wall < 0.0 else "WallRunLeft"
			else:
				clip = "Grapple"
		"wall_cling":
			clip = "WallCling"
		"wall_climb":
			clip = "WallClimb"
		"grapple":
			clip = "Grapple"
		"dash":
			clip = "Dash"
		"death":
			clip = "Death"

	if clip != "":
		# A wall jump hands the full body from a side performance to Jump/Fall.
		# Interpolating those two poses can put the thighs through the horizontal
		# midpoint, which reads as a delayed leg flip on the jump frame.
		_play_clip(clip, false, 0.0 if exiting_wall_run else -1.0)

	if _pose_mod:
		_pose_mod.state = state
		if state != "grapple":
			_pose_mod.grapple_active = false

	# Traversal clips are authored loops too. Above their reference velocity,
	# time-scale the whole cycle so their planted foot/hand cadence still tracks
	# gameplay speed; never synthesize a different pose.
	if _anim_tree and clip != "":
		var scale := 1.0
		if clip in ["SlideStart", "Slide"]:
			scale = _slide_playback_scale(speed)
		elif clip == "Grapple" or clip in ["WallRunLeft", "WallRunRight"]:
			# Grapple is held, and the wall clips are compact propulsion loops.
			# Neither should become a frantic treadmill at high traversal speed.
			scale = 1.0
		elif clip == "Dash":
			scale = clampf(speed / 13.0, 0.75, 1.8)
		_anim_tree.set("parameters/loco_scale/scale", scale)


## Drives the authored direction BlendSpace and live ADS mechanic.
##   strafe: -1 (moving left) .. +1 (moving right), relative to facing
##   fwd:    -1 (moving back) .. +1 (moving forward), relative to facing
##   ads:     0 (hip) .. 1 (aiming down sights)
func set_locomotion(strafe: float, fwd: float, ads: float) -> void:
	_target_strafe = clampf(strafe, -1.0, 1.0)
	_target_fwd = clampf(fwd, -1.0, 1.0)
	_target_ads = clampf(ads, 0.0, 1.0)


## Wall side during a wall glide: -1 wall on left, +1 wall on right, 0 none.
func set_wall_side(side: float) -> void:
	_target_wall = clampf(side, -1.0, 1.0)


## Retain the live wall plane as traversal telemetry. The authored animation
## remains untouched; this is available to presentation/debug consumers only.
## `normal_world` points from the wall toward the player.
func set_wall_surface(normal_world: Vector3,
		contact_point_world: Vector3 = Vector3.ZERO) -> void:
	_wall_surface_normal_world = normal_world.normalized() \
		if normal_world.length_squared() > 0.0001 else Vector3.ZERO
	_wall_surface_point_world = contact_point_world


## Gameplay velocity aligns the held glide silhouette with the live wall
## tangent. The mechanic still reports `wall_run` internally for save/network
## compatibility, but the character presentation is entirely propulsion-based.
func set_wall_glide_motion(velocity_world: Vector3) -> void:
	_wall_glide_velocity_world = velocity_world


## Compatibility entry point for older controller scenes and debug tools.
func set_wall_run_motion(velocity_world: Vector3) -> void:
	set_wall_glide_motion(velocity_world)


## Regression telemetry: the authored model's forward direction in world space.
func wall_glide_forward_debug() -> Vector3:
	if not is_instance_valid(_motion_root):
		return Vector3.ZERO
	var source_forward := Vector3.FORWARD if facing_flip else Vector3.BACK
	return (
		global_transform.basis * _motion_root.transform.basis * source_forward
	).normalized()


func wall_run_forward_debug() -> Vector3:
	return wall_glide_forward_debug()


func set_helmet_closed(closed: bool, immediate: bool = false) -> void:
	if is_instance_valid(_mecha_kit) and _mecha_kit.has_method("set_helmet_closed"):
		_mecha_kit.set_helmet_closed(closed, immediate)


func toggle_helmet() -> void:
	if is_instance_valid(_mecha_kit) and _mecha_kit.has_method("toggle_helmet"):
		_mecha_kit.toggle_helmet()


func helmet_closed_debug() -> bool:
	return _mecha_kit.helmet_closed() \
		if is_instance_valid(_mecha_kit) and _mecha_kit.has_method("helmet_closed") \
		else false


func helmet_progress_debug() -> float:
	return _mecha_kit.helmet_progress_debug() \
		if is_instance_valid(_mecha_kit) and _mecha_kit.has_method("helmet_progress_debug") \
		else 0.0


## Live grapple mechanics layered over the authored airborne performance.
## The clip supplies weight and secondary motion; gameplay supplies the one
## constraint an authored fixed pose cannot know: the actual cable direction.
func set_grapple_target(point_world: Vector3,
		velocity_world: Vector3 = Vector3.ZERO) -> void:
	if not _pose_mod:
		return
	_pose_mod.grapple_target_world = point_world
	_pose_mod.grapple_velocity_world = velocity_world
	_pose_mod.grapple_active = true


## Cable socket after animation + grapple IK. BoneAttachment3D observes the
## final modified skeleton pose (unlike a raw pose query made after the
## modifier pass, which has already been restored for the next animation tick).
func get_grapple_hand_world_position() -> Vector3:
	if is_instance_valid(_grapple_attachment):
		return _grapple_attachment.global_position
	if not skeleton:
		return global_position
	var hand := _role_bone("hand.L", ["hand.L", "Left wrist", "Left hand"])
	if hand < 0:
		return global_position
	return (skeleton.global_transform * skeleton.get_bone_global_pose(hand)).origin


## Test/lab telemetry: hand-to-line error in metres and the physical body
## alignment factor (0 hanging under gravity, 1 aligned into the rope).
func grapple_debug() -> Dictionary:
	if not _pose_mod or not skeleton:
		return {}
	var shoulder_world := _grapple_shoulder_attachment.global_position \
		if is_instance_valid(_grapple_shoulder_attachment) \
		else global_position
	var hand_world := get_grapple_hand_world_position()
	var line := _pose_mod.grapple_target_world - shoulder_world
	var reach := hand_world - shoulder_world
	var error := 0.0
	if line.length_squared() > 0.000001:
		error = reach.cross(line.normalized()).length()
	return {
		"line_error": error,
		"alignment": _pose_mod.grapple_alignment,
		"active": _pose_mod.grapple_active,
		"body_angle": _pose_mod._grapple_body.angle_to(Quaternion.IDENTITY),
		"body_rotation": _pose_mod._grapple_body,
		"shoulder": shoulder_world,
		"hand": hand_world,
		"target": _pose_mod.grapple_target_world,
	}


## How far away each cloth detail level starts, in metres. See SpringBones.lod —
## the solver is expensive enough that only the character being looked at can
## afford the full thing.
const CLOTH_LOD_RANGES := [6.0, 14.0, 28.0]
var _lod_timer: float = 0.0


func _process(delta: float) -> void:
	_update_cloth_lod(delta)
	_update_motion_orientation(delta)
	if _slide_start_remaining > 0.0:
		_slide_start_remaining = maxf(_slide_start_remaining - delta, 0.0)
	_update_mecha_nozzles()
	_update_animation_smoothing(delta)
	if not _pose_mod:
		return
	_hold_weapon_still()
	var t := 1.0 - exp(-POSE_SMOOTH * delta)
	_cur_ads = lerpf(_cur_ads, _target_ads, t)
	var wall_target := _target_wall if _pose_mod.state == "wall_run" else 0.0
	_cur_wall = lerpf(_cur_wall, wall_target, t)
	_pose_mod.ads = _cur_ads

	if _upper_lock > 0.0:
		_upper_lock -= delta
		if _upper_lock <= 0.0:
			# Explicitly retire the one-shot. Its `active` parameter does NOT
			# reliably clear on its own, and anything still treating the shot
			# as live permanently disables the rifle hold — after one reload
			# the character would hold the gun with clip arms forever.
			_upper_action = ""
			if _anim_tree:
				_anim_tree.set("parameters/upper/request",
					AnimationNodeOneShot.ONE_SHOT_REQUEST_FADE_OUT)
	# Two-hand rifle hold: owns the arms whenever a weapon is held, EXCEPT when
	# a one-shot clip (reload/throw/hit) or a full-body moment (Land lock,
	# dance, death) needs the authored animation to read through. The upper
	# one-shot's own `active` flag is the truth for how long it owns the arms.
	var st: String = _pose_mod.state
	# `_upper_lock` (a timer we own) is the authority on how long the one-shot
	# owns the arms — NOT the OneShot node's `active` flag, which can stay
	# true indefinitely and would strand the arms on the clip forever.
	var reloading := _upper_action == "reload" and _upper_lock > 0.0
	# A RELOAD must never hand the right arm to the clip: the gun is parented
	# to that hand, and the library's pistol-reload rotates the wrist — which
	# flipped the rifle upside-down (mag pointing at the sky) while the hand
	# reached "down" for it. During a reload the hold keeps the gun steady and
	# the support hand does the magazine work at the real mag well instead.
	var clip_owns_arms := (_oneshot_lock > 0.0 or _upper_lock > 0.0 \
		or _dancing or st == "death") and not reloading
	var hold_r := 0.0
	var hold_l := 0.0
	if is_holding_weapon and not clip_owns_arms:
		hold_r = 1.0
		# A one-handed weapon RELEASES the off arm back to the animation, so it
		# swings with the run cycle instead of gripping a handguard that is not
		# there. That released arm is most of what makes a knife read as a knife
		# from across a map.
		hold_l = 0.0 if _pose_mod.support_mode == WeaponHoldProfiles.SUPPORT_FREE \
			else 1.0
		match st:
			"slide":
				hold_l = 0.0      # trailing arm braces the ground
			"wall_run":
				# A glide is stabilized by the suit; neither hand needs to touch
				# the wall, so weapon posture can remain coherent.
				pass
			"grapple":
				hold_l = 0.0      # left hand rides the grapple line
	_pose_mod.hold_r_target = hold_r
	_pose_mod.hold_l_target = hold_l

	# Reload progress drives the support hand's trip to the mag well.
	var rl_target := 0.0
	if reloading and _upper_total > 0.0:
		rl_target = clampf(1.0 - (_upper_lock / _upper_total), 0.0, 1.0)
	_pose_mod.reload_phase = rl_target


func _update_motion_orientation(delta: float) -> void:
	if not is_instance_valid(_motion_root):
		return
	var wall_run_active := _pose_mod != null and _pose_mod.state == "wall_run"
	if not wall_run_active:
		# This root is only a presentation frame for lateral wall-run clips.
		# Blending it back to zero makes the whole character visibly spin on the
		# floor when a wall run ends into a slide/ground state.
		if _motion_was_wall_run:
			_motion_yaw = 0.0
			_motion_root.rotation.y = 0.0
		_motion_was_wall_run = false
		return
	_motion_was_wall_run = true
	var wanted_yaw := 0.0
	if _pose_mod and _pose_mod.state == "wall_run":
		var local_velocity := global_transform.basis.inverse() \
			* _wall_glide_velocity_world
		local_velocity.y = 0.0
		if local_velocity.length_squared() > 0.01:
			var source_forward := Vector3.FORWARD \
				if facing_flip else Vector3.BACK
			wanted_yaw = source_forward.signed_angle_to(
				local_velocity.normalized(), Vector3.UP)
	var blend := 1.0 - exp(-8.5 * delta)
	_motion_yaw = lerp_angle(_motion_yaw, wanted_yaw, blend)
	_motion_root.rotation.y = _motion_yaw


func _animation_length_if_distinct(start: String, loop: String) -> float:
	if not _resolved_clips.has(start) or not _resolved_clips.has(loop):
		return 0.0
	var start_name: String = _resolved_clips[start]
	var loop_name: String = _resolved_clips[loop]
	if start_name == loop_name:
		return 0.0
	var clip := animation_player.get_animation(start_name)
	return clip.length if clip else 0.0


func _slide_playback_scale(speed: float) -> float:
	# SlideStart is part of the same momentum gesture as Slide. It must advance
	# with the entry velocity too, otherwise a fast slide spends a full authored
	# second in a slow crouch pose before the loop catches up.
	return clampf(speed / maxf(run_anim_reference_speed, 0.01), 0.75, 1.8)


## Pick the cloth solver's detail level from how far the camera is.
##
## Re-checked a few times a second rather than every frame: the answer changes
## slowly, and the distance query is not free either.
func _update_cloth_lod(delta: float) -> void:
	if _spring_mod == null:
		return
	_lod_timer -= delta
	if _lod_timer > 0.0:
		return
	_lod_timer = 0.25
	var cam := get_viewport().get_camera_3d() if is_inside_tree() else null
	if cam == null:
		return
	var d := cam.global_position.distance_to(global_position)
	var want := CLOTH_LOD_RANGES.size()
	for i in CLOTH_LOD_RANGES.size():
		if d < CLOTH_LOD_RANGES[i]:
			want = i
			break
	_spring_mod.lod = want


## Drive authored ground cycles directly from the current velocity.
##
## The old tier ladder could spend 0.34 s in Idle and another 0.34 s in Walk
## even though gameplay acceleration reached running speed in one physics frame.
## That is the visible "sliding, then slow walk, then run" failure. Here the
## BlendSpace position is physical metres/second on this call, so the feet react
## immediately but ease over a few rendered frames instead of teleporting from
## one gait/direction pose to another.
func _update_animation_smoothing(delta: float) -> void:
	if not _anim_tree:
		return
	var current_speed := _loco_blend_visual.length()
	var target_speed := _loco_blend_target.length()
	var reversing := current_speed > 0.2 and target_speed > 0.2 \
		and _loco_blend_visual.dot(_loco_blend_target) < 0.0
	var response := 10.0 if target_speed > current_speed else 6.5
	if reversing:
		response = 5.5
	var position_weight := 1.0 - exp(-response * delta)
	_loco_blend_visual = _loco_blend_visual.lerp(
		_loco_blend_target, position_weight)
	_crouch_blend_visual = lerpf(_crouch_blend_visual,
		_crouch_blend_target, 1.0 - exp(-8.0 * delta))
	_loco_scale_visual = lerpf(_loco_scale_visual,
		_loco_scale_target, 1.0 - exp(-7.0 * delta))
	_anim_tree.set("parameters/loco_blend/blend_position", _loco_blend_visual)
	_anim_tree.set("parameters/crouch_blend/blend_position", _crouch_blend_visual)
	if _current_state_node in ["Locomotion", "CrouchLocomotion"]:
		_anim_tree.set("parameters/loco_scale/scale", _loco_scale_visual)


func _play_ground_locomotion(speed: float, crouched: bool) -> void:
	if not _anim_tree:
		return
	var state_node := "CrouchLocomotion" if crouched else "Locomotion"
	if _current_state_node != state_node:
		var exiting_wall_run := _current_state_node in [
			"WallRunLeft", "WallRunRight"]
		_state_trans.xfade_time = 0.0 if exiting_wall_run \
			else GROUND_STATE_BLEND
		_anim_tree.set("parameters/state/transition_request", state_node)
		_current_state_node = state_node

	if crouched:
		var authored_speed := minf(speed, crouch_anim_reference_speed)
		_crouch_blend_target = authored_speed
		_loco_scale_target = maxf(1.0,
			speed / maxf(crouch_anim_reference_speed, 0.01))
		_current_clip = _resolved_clips.get(
			"CrouchWalk" if speed > 0.1 else "Crouch", "")
		return

	var direction := Vector2(_target_strafe, _target_fwd)
	if direction.length_squared() < 0.0001:
		direction = Vector2(0.0, 1.0)
	else:
		direction = direction.normalized()

	# Each axis is positioned at its measured source velocity. The edge of the
	# BlendSpace is therefore a velocity envelope, not an arbitrary circle:
	# solve where this heading intersects the line between its two neighboring
	# authored clips. Above that speed, TimeScale advances the authored cycle
	# proportionally instead of letting the mesh slide over planted feet.
	var forward_limit := sprint_anim_reference_speed \
		if direction.y > 0.0 else strafe_run_anim_reference_speed
	var inverse_limit := (
		absf(direction.x) / maxf(strafe_run_anim_reference_speed, 0.01)
		+ absf(direction.y) / maxf(forward_limit, 0.01)
	)
	var authored_limit := 1.0 / maxf(inverse_limit, 0.01)
	var authored_speed := minf(speed, authored_limit)
	_loco_blend_target = direction * authored_speed
	_loco_scale_target = maxf(1.0,
		speed / maxf(authored_limit, 0.01))

	var canonical := "Idle"
	if speed > 0.1:
		if absf(direction.x) > absf(direction.y):
			canonical = "RunRight" if direction.x > 0.0 else "RunLeft"
		elif direction.y < 0.0:
			canonical = "RunBackward"
		elif speed < (walk_anim_reference_speed + run_anim_reference_speed) * 0.5:
			canonical = "Walk"
		elif speed < (run_anim_reference_speed + sprint_anim_reference_speed) * 0.5:
			canonical = "RunForward"
		else:
			canonical = "Sprint"
	_current_clip = _resolved_clips.get(canonical, "")


func _play_clip(canonical: String, restart: bool = false,
		blend_override: float = -1.0) -> void:
	if not _anim_tree or not _resolved_clips.has(canonical):
		return
	var clip_name: String = _resolved_clips[canonical]
	if not restart and _current_state_node == clip_name:
		return
	_state_trans.xfade_time = blend_override \
		if blend_override >= 0.0 else BLEND_TIMES.get(canonical, BLEND_TIME)
	_anim_tree.set("parameters/state/transition_request", clip_name)
	_current_state_node = clip_name
	_current_clip = clip_name


## Procedural locomotion lean was removed; kept for regression compatibility.
func get_lean_debug() -> float:
	return 0.0


func get_brake_debug() -> float:
	return 0.0


## Smoothed visual velocity currently driving the authored ground BlendSpace.
func locomotion_blend_debug() -> Vector2:
	if not _anim_tree:
		return Vector2.ZERO
	var value = _anim_tree.get("parameters/loco_blend/blend_position")
	return value if value is Vector2 else Vector2.ZERO


func locomotion_blend_target_debug() -> Vector2:
	return _loco_blend_target


## Visual velocity represented by the authored stride after playback-rate calibration.
## The raw BlendSpace position stops at the source clip's measured velocity;
## TimeScale covers faster gameplay without changing the pose or foot phase.
func locomotion_effective_speed_debug() -> float:
	if not _anim_tree:
		return 0.0
	var scale_value = _anim_tree.get("parameters/loco_scale/scale")
	var scale := float(scale_value) if scale_value != null else 1.0
	return locomotion_blend_debug().length() * scale


## Animated world-space anchors for the two shoulder and two foot jets.
## Offsets use the skeleton frame, not each limb's twisting frame, so the
## nozzles stay on the character's back/heels through every authored clip.
func _animated_jet_socket_world_positions() -> Array[Vector3]:
	if not skeleton:
		return []
	var roles_and_fallbacks := [
		["shoulder.L", ["shoulder.L", "upper_arm.L", "Left shoulder"]],
		["shoulder.R", ["shoulder.R", "upper_arm.R", "Right shoulder"]],
		["foot.L", ["foot.L", "Left ankle", "Left foot"]],
		["foot.R", ["foot.R", "Right ankle", "Right foot"]],
	]
	var sockets: Array[Vector3] = []
	for i in roles_and_fallbacks.size():
		var spec: Array = roles_and_fallbacks[i]
		var bone := _role_bone(spec[0], spec[1])
		if bone < 0:
			return []
		var world_pose := skeleton.global_transform * skeleton.get_bone_global_pose(bone)
		# The shoulder pair sits just outside the back silhouette. This extra
		# clearance matters for long-haired skins: mounting at the literal joint
		# leaves both flames completely buried in the hair mesh.
		var side := 0.10 if i == 0 else -0.10
		var offset := skeleton.global_transform.basis \
			* (Vector3(side, -0.03, -0.30) if i < 2 \
				else Vector3(0.0, 0.035, -0.045))
		sockets.append(world_pose.origin + offset)
	return sockets


func _update_mecha_nozzles() -> void:
	if not is_instance_valid(_mecha_kit) or not skeleton:
		return
	var sockets := _animated_jet_socket_world_positions()
	if sockets.size() == 4:
		_mecha_kit.update_nozzles(sockets, skeleton.global_transform.basis)


func get_jet_socket_world_positions() -> Array[Vector3]:
	var sockets := _animated_jet_socket_world_positions()
	if is_instance_valid(_mecha_kit) and sockets.size() == 4:
		_mecha_kit.update_nozzles(sockets, skeleton.global_transform.basis)
		return _mecha_kit.nozzle_world_positions()
	return sockets


func mecha_nozzle_count_debug() -> int:
	return _mecha_kit.nozzle_count() if is_instance_valid(_mecha_kit) else 0


func mecha_detail_part_count_debug() -> int:
	return _mecha_kit.detail_part_count_debug() \
		if is_instance_valid(_mecha_kit) else 0


## Every canonical clip this character resolved to something real.
##
## Canonical rather than raw, because the raw names differ per character — one
## rig's "CrouchIdle" is another's "Crouch_Idle_Loop" — and the canonical name is
## what the game asks for. For debug/rig_lab.gd's clip scrubber.
func clip_names_debug() -> Array:
	return _resolved_clips.keys()


## Play one clip outright, ignoring the locomotion state machine. Lab only.
func play_clip_debug(canonical: String) -> void:
	_play_clip(canonical, true)


## Push a new hold tuning table in and re-seat the weapon with it.
##
## For debug/rig_lab.gd: the knobs that live on the pose layer take effect on
## the next frame, but weapon SIZE and the grip offset are baked into the
## attachment when the weapon is seated, so those need the weapon re-measured.
func set_hold_tuning(t: Dictionary) -> void:
	hold_tune = t
	if _pose_mod:
		_pose_mod.tune = t
	_reseat_weapon()


## Push a new anchor table in and re-seat the weapon on it.
##
## Separate from set_hold_tuning because the two are separate questions with
## separate scopes — a hold is per character AND weapon, an anchor is per
## character — and the lab edits them on different screens.
func set_anchors(a: Dictionary) -> void:
	anchors = a
	_reseat_weapon()


## Keep the weapon where the solver put it while the wrist turns under it.
##
## The two are welded by construction — the gun is a child of a BoneAttachment3D
## on the trigger hand — so a wrist rotation swings the barrel off the aim line
## and takes every control that could correct it along for the ride. The pose
## layer works out the exact counter-rotation in the hand's own local frame;
## this applies it.
##
## Deliberately in `_process` rather than inside the modifier pass. The gun's
## mount is not something the skeleton owns, and the value being compensated
## only changes when a slider moves or the ADS blend travels, so being one frame
## behind is a rotation of a fraction of a degree that nothing can see. Reaching
## into the modifier to touch a scene node would be worse.
func _hold_weapon_still() -> void:
	if _weapon_attachment == null or _weapon_attachment.get_child_count() == 0:
		return
	var w := _weapon_attachment.get_child(0) as Node3D
	if w == null:
		return
	var comp: Quaternion = _pose_mod.wrist_comp_r
	w.transform = Transform3D(Basis(comp), Vector3.ZERO) * _weapon_seat


## Re-apply the grip anchor and re-measure, after either table changed.
##
## `_measure_weapon` reads the weapon's transform to work out where its grip and
## muzzle are, so the anchor has to be back in place BEFORE it runs — measuring
## from identity and then offsetting would move the gun without moving the
## points the hands are being solved onto.
func _reseat_weapon() -> void:
	if _weapon_attachment == null or _weapon_attachment.get_child_count() == 0:
		return
	var w := _weapon_attachment.get_child(0) as Node3D
	if w:
		w.transform = RigAnchors.grip_transform(anchors)
		_measure_weapon(w)


## Compatibility probe: authored direction clips always play forward.
func stride_reversed_debug() -> bool:
	return false


## Clip currently playing. For debug/transition_check.gd.
func current_clip_debug() -> String:
	return _current_clip


## Vertical velocity of the body this model is attached to (0 if detached).
func _vertical_speed() -> float:
	var p := get_parent()
	if p is CharacterBody3D:
		return p.velocity.y
	return 0.0


# ── Third-person weapon ───────────────────────────────────────────────────────

## Attach a weapon (by weapon script path) to the right hand bone so other
## players see what this player is holding. Mirrors HumanoidModel.set_weapon().
func set_weapon(script_path: String) -> void:
	if _weapon_attachment:
		_weapon_attachment.queue_free()
		_weapon_attachment = null
	is_holding_weapon = script_path != ""
	if script_path == "" or not skeleton:
		return
	# How this KIND of weapon is held, then the per-character tuning on top.
	#
	# The profile is a defaults layer: it answers "what sort of thing is this"
	# for a weapon nobody has tuned, and every knob an artist saved in the rig lab
	# still wins, because the JSON is merged over it with overwrite. Aria's
	# hand-tuned AK-47 hold is byte-for-byte what it was.
	var sid := skin_id if skin_id != "" else model_path.get_file().get_basename()
	var weapon_id := script_path.get_file().get_basename()
	if hold_tune.is_empty():
		hold_tune = WeaponHoldProfiles.knobs_for(weapon_id)
		hold_tune.merge(WeaponHoldTuning.resolve(WeaponHoldTuning.load_all(),
			sid, weapon_id), true)
	if _pose_mod:
		# Structural, not tunable — see WeaponHoldProfiles. These decide where the
		# off hand goes and how it is turned there, and whether the head comes
		# down to the stock, which no slider on the rifle solve could express.
		var style := WeaponHoldProfiles.style_for(weapon_id)
		_pose_mod.support_mode = WeaponHoldProfiles.support_for(weapon_id)
		_pose_mod.cheek = WeaponHoldProfiles.cheek_for(weapon_id)
		_pose_mod.full_fist = style == WeaponHoldProfiles.BLADE
	hold_style = WeaponHoldProfiles.style_for(weapon_id)
	# Anchors are per character, not per weapon — where a grip sits in a palm is
	# a fact about the hand — so unlike hold_tune they are not re-read per gun
	# unless the lab has pushed a live set in.
	if anchors.is_empty():
		anchors = RigAnchors.resolve(RigAnchors.load_all(), sid)

	var script = load(script_path)
	if not script:
		return
	var w = script.new()
	w.name = "ThirdPersonWeapon"
	w.set_meta("is_third_person_weapon", true)
	w.ready.connect(func():
		w.set_process(false)
		w.set_process_input(false)
		# Owner's first-person view must not see their own held weapon (it
		# sits right in front of the lens as a huge blob) — shadows only,
		# same as the body. Skip when the owner is already in third person
		# (weapon swap while toggled), else the new weapon comes up invisible.
		if (shadows_only or first_person_mode) and not _owner_visible:
			_set_shadows_recursive(w)
		# Seat the weapon in the hand with NO hand-relative rotation.
		#
		# There used to be a fixed `rotation_degrees = (0, 90, -90)` here, which
		# is the offset that happens to be right for the library's own DEF-hand.R
		# and is wrong for every rig whose hand bone has a different roll. A bone
		# attachment is expressed in the BONE's axes, and no two rigs agree on
		# those, so a constant here mounts the gun differently on every character
		# — which is what "the hand mount points are totally wrong on all models"
		# was.
		#
		# It does not need to be right, because the pose layer aims the gun by
		# rotating the WRIST until the weapon's forward axis lies on the aim line
		# (see _apply_rifle_hold). Handing it the identity means "the gun's
		# forward is the hand bone's -Z", which is true by construction on any
		# rig, and the wrist then absorbs whatever that bone's roll happens to be.
		# The grip is placed at the bone's origin below, so the gun sits IN the
		# hand rather than at a fixed offset from a differently-oriented bone.
		#
		# ...with one adjustment on top: the character's own grip ANCHOR. A hand
		# bone's origin is the wrist, not the palm, and how far down the palm a
		# grip should sit is a fact about that character's hand — how big it is,
		# how the fingers were modelled — which cannot be derived. It defaults to
		# identity, so a character nobody has tuned behaves exactly as before.
		w.transform = RigAnchors.grip_transform(anchors)
		if _pose_mod:
			_pose_mod.gun_fwd_hand = Vector3(0, 0, -1)
			_pose_mod.gun_up_hand = Vector3(0, 1, 0)
			_measure_weapon(w)
	)

	var hand_idx := _role_bone("hand.R", ["RightHand", "Hand_R", "hand.R"])
	if hand_idx >= 0:
		_weapon_attachment = BoneAttachment3D.new()
		_weapon_attachment.name = "WeaponAttachment"
		skeleton.add_child(_weapon_attachment)
		_weapon_attachment.bone_idx = hand_idx
		_weapon_attachment.add_child(w)
	else:
		# No hand bone — hold it at chest height like the procedural model did.
		w.ready.connect(func():
			w.position = Vector3(-0.15, 1.0, 0.4)
			w.rotation_degrees = Vector3(0, 180, 0)
		)
		add_child(w)


## The muzzle of the gun actually in this character's hand.
##
## Anything the WORLD sees — tracers, muzzle flash, the shot's audio position —
## has to originate here whenever the character model is what the viewer is
## looking at. The first-person viewmodel is parented to the camera, so ITS
## muzzle sits inside the player's head; using it in third person put the flash
## next to the character's shoulder.
func get_muzzle_node() -> Node3D:
	if not _weapon_attachment or _weapon_attachment.get_child_count() == 0:
		return null
	var w := _weapon_attachment.get_child(0)
	if "muzzle_flash" in w and w.muzzle_flash:
		return w.muzzle_flash
	return w as Node3D


## Seat the weapon in the hand and tell the pose layer where the support hand
## and stock are, using the weapon's OWN authored markers.
##
## This used to derive everything from mesh AABBs, which silently produced
## nonsense: the FBX guns report bind-pose bounds tens of metres across (the M4
## measured 24 m long), so the grip offset threw the gun 7.5 m in front of the
## character. Nothing about a mesh's bounding box is trustworthy here.
##
## The reliable data is already authored: WeaponManager places the first-person
## viewmodel's hands at GRIP_LOCAL and SUPPORT_LOCAL in weapon space, and every
## weapon sets muzzle_flash.position at its barrel tip. Third person simply
## reaches for the same points the viewmodel does.
## How far a weapon may be scaled down before it reads as a toy.
const MIN_WEAPON_SCALE := 0.55
## Forward offset of the stock pocket from the shoulder joint — see POCKET_HIP.
const POCKET_FORWARD := 0.06


## Scale the weapon so this character can actually reach its handguard.
##
## Not against a fixed reference size: against the arm that has to hold it. The
## set is modelled at real-world scale — an M4 is 0.84 m butt to muzzle — and
## these characters are stylised, with arms around 0.47 m against an adult 0.52.
##
## The binding constraint is the SUPPORT arm. Its hand has to reach a point
## (stock + fore) in front of the shoulder pocket, from a shoulder half the
## shoulder-width off the weapon's axis. Solve that triangle for the largest gun
## whose handguard still lands inside the arm's reach, and the support hand stops
## being dragged back down the barrel.
##
## Measured on Taila before this: a support offset authored at 0.35 m collapsed
## to 0.083 m, which puts the support fist on top of the trigger fist — a
## two-handed pistol grip, not a rifle. That is what "the hands are not on the
## rails" was.
func _weapon_scale(span: float) -> float:
	if not _pose_mod or not skeleton or span <= 0.01:
		return 1.0
	var reach: float = _pose_mod._arm_reach(skeleton, "DEF-upper_arm.L",
		"DEF-forearm.L", "DEF-hand.L") * 0.94
	if reach <= 0.01:
		return 1.0
	var ua_l: int = _pose_mod._idx.get("DEF-upper_arm.L", -1)
	var ua_r: int = _pose_mod._idx.get("DEF-upper_arm.R", -1)
	var lateral := 0.14
	if ua_l >= 0 and ua_r >= 0:
		# The weapon rides near the right shoulder, so the support arm crosses
		# about half the shoulder width to get to it.
		lateral = skeleton.get_bone_global_rest(ua_l).origin.distance_to(
			skeleton.get_bone_global_rest(ua_r).origin) * 0.5
	var forward := sqrt(maxf(reach * reach - lateral * lateral, 0.01))
	return clampf((forward - POCKET_FORWARD) / span, MIN_WEAPON_SCALE, 1.0)


func _measure_weapon(w: Node3D) -> void:
	var grip: Vector3 = WeaponGrips.GRIP
	var support: Vector3 = WeaponGrips.SUPPORT
	var fwd := Vector3(0, 0, -1)  # the weapon's own muzzle axis

	# Barrel length, grip to muzzle. Every weapon marks its own barrel tip.
	var muzzle_dist: float = WeaponGrips.DEFAULT_MUZZLE_DIST
	if "muzzle_flash" in w and w.muzzle_flash:
		muzzle_dist = maxf(absf((w.muzzle_flash.position - grip).dot(fwd)), 0.1)

	# Support hand: where the viewmodel's off hand rides — but NEVER past the
	# muzzle. That offset is one constant for all weapons, so on a short gun
	# (the MP7's barrel is only 0.30 m) it used to hang the support hand out in
	# front of the barrel with nothing to hold, which is why some weapons did
	# not look supported by the arms.
	var fore: float = absf((support - grip).dot(fwd))
	var fore_u: float = clampf(minf(fore, muzzle_dist * 0.8), 0.12, 0.45)
	var stock_u: float = clampf(muzzle_dist * 0.5, 0.10, 0.40)

	# Size the gun to the arm that has to hold it, then seat the grip in the fist.
	var k := _weapon_scale(stock_u + fore_u)
	# A tuned size wins over the derived one. The derivation keeps the handguard
	# inside the support arm's reach, which is a floor on believability, not a
	# statement about how big the gun should LOOK.
	if hold_tune.get("weapon_scale", 0.0) > 0.01:
		k = float(hold_tune["weapon_scale"])
	w.scale = Vector3.ONE * k
	w.position -= w.transform.basis * grip

	_pose_mod.gun_fore = fore_u * k
	if hold_tune.get("gun_fore", 0.0) > 0.0001:
		_pose_mod.gun_fore = float(hold_tune["gun_fore"])

	# Stock: not authored anywhere, so derive it from the barrel. Half the
	# grip-to-muzzle distance behind the grip lands the butt in the shoulder
	# pocket for every gun in the set.
	_pose_mod.gun_stock = stock_u * k
	if hold_tune.get("gun_stock", 0.0) > 0.0001:
		_pose_mod.gun_stock = float(hold_tune["gun_stock"])
	_pose_mod.tune = hold_tune
	# Where the weapon sits in the hand once everything derived and tuned has
	# been applied. Kept because `_process` re-derives the mount every frame from
	# it plus the wrist counter-rotation, and recomputing the seat instead would
	# re-run this whole measurement sixty times a second.
	_weapon_seat = w.transform


# ── Helpers ───────────────────────────────────────────────────────────────────

## A bone by its resolved ROLE, falling back to name matching.
##
## tools/rig_map.py resolves every rig to roles and writes them to the sidecar so
## that nothing downstream has to guess a bone name — but a hardcoded lookup here
## meant four characters could not hold a gun. Their hands resolve perfectly as
## "Right wrist" and "J_Bip_R_Hand"; none of them matches a spelling this file
## knew, so set_weapon fell through to parenting the weapon to the model root at
## a fixed chest offset, where it is not attached to the character at all.
##
## The fallback stays for a model with no sidecar. It must never be the first
## thing tried.
func _role_bone(role: String, fallbacks: Array) -> int:
	var roles: Dictionary = _rig_info.get("roles", {})
	var actual := String(roles.get(role, ""))
	if actual != "" and skeleton:
		var b := RigRoles.find_imported_bone(skeleton, actual)
		if b >= 0:
			return b
	return _find_bone(fallbacks)


func _find_bone(name_parts: Array) -> int:
	if not skeleton:
		return -1
	for i in range(skeleton.get_bone_count()):
		var bone_name := skeleton.get_bone_name(i)
		for part in name_parts:
			if bone_name.findn(part) != -1:
				return i
	return -1


func _find_node_of_type(node: Node, type_name: String) -> Node:
	if node.is_class(type_name):
		return node
	for child in node.get_children():
		var found := _find_node_of_type(child, type_name)
		if found:
			return found
	return null


func _set_shadows_recursive(node: Node) -> void:
	if node is GeometryInstance3D:
		node.cast_shadow = GeometryInstance3D.SHADOW_CASTING_SETTING_SHADOWS_ONLY
	for child in node.get_children():
		_set_shadows_recursive(child)


# ── Mechanical shooter pose layer ─────────────────────────────────────────────
#
# Authored clips own body motion. This modifier handles only mechanics that must
# follow live gameplay data: aim pitch, weapon IK, cheek weld, finger grip, and
# recoil.
class ShooterPoseModifier extends SkeletonModifier3D:
	# Inputs, written by the owning SkinnedPlayerModel each frame.
	var ads: float = 0.0         # 0 hip .. 1 aiming
	var aim_pitch: float = 0.0   # radians, up positive — upper body follows aim
	var recoil: float = 0.0      # decaying shot kick
	var state: String = "idle"
	# Grapple target/velocity arrive in world space from the movement state.
	# They are converted to skeleton space at solve time, after the authored
	# animation has placed the shoulders.
	var grapple_active: bool = false
	var grapple_target_world: Vector3 = Vector3.ZERO
	var grapple_velocity_world: Vector3 = Vector3.ZERO
	var grapple_alignment: float = 0.0
	var _grapple_body: Quaternion = Quaternion.IDENTITY
	# Per-arm rifle-hold weights (0 = clip owns the arm, 1 = hold pose owns it).
	var hold_r_target: float = 0.0
	var hold_l_target: float = 0.0
	var _hold_r: float = 0.0
	var _hold_l: float = 0.0
	# The attached gun's forward/up axes in hand-bone space (set on set_weapon).
	var gun_fwd_hand: Vector3 = Vector3.ZERO
	var gun_up_hand: Vector3 = Vector3.UP
	# Measured gun geometry (metres from the grip): how far out the support
	# hand rides, and how far back the stock butt reaches. See _measure_weapon.
	var gun_fore: float = 0.26
	var gun_stock: float = 0.20
	# 0..1 through a reload — drives the support hand to the mag well and back.
	var reload_phase: float = 0.0
	# What KIND of weapon is being held. See WeaponHoldProfiles: these three are
	# the differences a slider cannot express, and they are what make a launcher
	# read as a launcher rather than as a very large rifle.
	var support_mode: String = WeaponHoldProfiles.SUPPORT_BARREL
	## How far the head comes down and across to the stock, 0..1. Negative leans
	## it away, which is what a tube over the shoulder needs.
	var cheek: float = 0.0
	## Whether the trigger finger closes with the rest. True for a blade, which
	## has nothing to keep a finger straight along.
	var full_fist: bool = false
	# [child_bone, helper_bone] pairs; see SkinJointHelper.
	var joint_helpers: Array = []

	const HOLD_SMOOTH := 8.0     # how fast the hold takes/releases the arms

	## The library skeleton's spine, hips first. Shared with the dance layer via
	## RigRoles, which also owns the mapping onto a rig that kept its own names.
	const SPINE := RigRoles.SPINE

	var _idx: Dictionary = {}
	var _resolved := false
	## Role -> actual bone name for THIS rig, from <model>.rig.json. Empty when
	## the model was rebound onto the library skeleton, where the names below
	## already match.
	var roles: Dictionary = {}
	## "index.L" -> its bone names, knuckle to fingertip, from the same sidecar.
	var fingers: Dictionary = {}
	## Per-character hold overrides — see characters/weapon_hold_tuning.gd and
	## debug/rig_lab.gd. A dictionary rather than a field per knob so a new
	## knob needs no plumbing: add it here, read it with _t/_tv, and the lab
	## picks it up from the same table.
	var tune: Dictionary = {}
	## Where the hold put the weapon this frame, in skeleton space. The lab draws
	## these so the points being tuned are visible rather than inferred.
	var dbg_grip: Vector3 = Vector3.ZERO
	var dbg_fore: Vector3 = Vector3.ZERO
	var dbg_stock: Vector3 = Vector3.ZERO
	## The gun's frame this frame — across, up, along the barrel. The lab needs
	## it to turn a mouse drag on an anchor marker back into the axes its knob is
	## expressed in; without it, dragging left would mean something different at
	## every pitch of the weapon.
	var dbg_gun_basis: Basis = Basis.IDENTITY
	## What the weapon mount must be rotated by, in the trigger hand's own local
	## frame, to undo `wrist_r` — so the hand turns and the GUN does not.
	##
	## The weapon is parented to a BoneAttachment3D on that hand, so without this
	## the two are welded: rotating the wrist swings the barrel off the aim line,
	## and there is no second control that could bring it back, because every
	## control that moves the gun is expressed relative to the same hand. The
	## wrist knob was therefore unusable for the one thing it exists for.
	##
	## Identity when `wrist_r` is untuned, so a character nobody has touched
	## mounts its weapon exactly as before.
	var wrist_comp_r: Quaternion = Quaternion.IDENTITY

	func _t(key: String, fallback: float) -> float:
		return float(tune.get(key, fallback))

	func _tv(key: String, fallback: Vector3) -> Vector3:
		var v = tune.get(key)
		# A zero-length vector means "not set" — see WeaponHoldTuning. It is how
		# the elbow poles keep their hip/ADS blend unless overridden.
		return v if (v is Vector3 and v.length() > 0.0001) else fallback

	## A per-pose scalar knob, blended by `ads` the same way the hold itself is.
	##
	## Stored as `<stem>_hip` and `<stem>_ads` — the convention `pocket_hip` and
	## `pocket_ads` already used, now that every knob which ought to differ
	## between the two holds can.
	func _tp(stem: String, d_hip: float, d_ads: float) -> float:
		return lerpf(_t(stem + "_hip", d_hip), _t(stem + "_ads", d_ads), ads)

	func _tvp(stem: String, d_hip: Vector3, d_ads: Vector3) -> Vector3:
		return _tv(stem + "_hip", d_hip).lerp(_tv(stem + "_ads", d_ads), ads)

	## The wrist offset for one hand, as a rotation in the GUN's frame.
	##
	## Pitch about the weapon's across-axis, yaw about its up, roll about the
	## barrel — so the three sliders mean the same thing whether the muzzle is
	## down at low ready or level down the sights. Identity when untuned, which
	## is exactly what the hold did before there was anything but a roll.
	func _wrist(stem: String, side: Vector3, up: Vector3, fwd: Vector3) -> Quaternion:
		var w := _tvp(stem, Vector3.ZERO, Vector3.ZERO)
		if w == Vector3.ZERO:
			return Quaternion.IDENTITY
		return Quaternion(side, w.x) * Quaternion(up, w.y) * Quaternion(fwd, w.z)
	var _fing: Dictionary = {}        # same, resolved to bone indices
	var _curl: Dictionary = {}        # "L"/"R" -> curl axis in the rest frame
	## "L"/"R" -> Basis(along, palm, curl), the hand's anatomy in the rest pose.
	var _hand_frame: Dictionary = {}

	func _resolve() -> void:
		var skel := get_skeleton()
		# The canonical names are the LIBRARY skeleton's, and a model that kept
		# its own rig names things differently — Taila's hips are DEF-spine, her
		# head is DEF-spine.006, and she has no bone with "neck" in its name at
		# all. RigRoles maps weapon IK and aim onto those authored names through
		# the sidecar rather than imposing one skeleton naming convention.
		_idx = RigRoles.resolve(skel, roles)
		_resolve_hands(skel)
		_resolved = true

	## Finger bones, and the axis a finger closes about, per hand.
	##
	## The axis is derived from the hand's OWN ANATOMY in the rest pose, because
	## no two rigs agree on finger bone orientation and a constant would close
	## one character's hand and splay another's:
	##
	##   along  wrist -> middle knuckle, the length of the hand
	##   palm   middle knuckle -> thumb tip, across it. The thumb opposes the
	##          fingers, so it is on the palm side by construction — which is
	##          true of a hand, not of a rig convention.
	##   curl   along x palm, so turning about it swings the fingers into the
	##          palm rather than sideways or backwards.
	func _resolve_hands(skel: Skeleton3D) -> void:
		for key in fingers:
			var list := PackedInt32Array()
			for n in fingers[key]:
				var b := skel.find_bone(String(n))
				if b >= 0:
					list.append(b)
			if not list.is_empty():
				_fing[key] = list
		for side in ["L", "R"]:
			var hand: int = _idx.get("DEF-hand." + side, -1)
			var mid: PackedInt32Array = _fing.get("middle." + side, PackedInt32Array())
			if hand < 0 or mid.is_empty():
				continue
			var wrist := skel.get_bone_global_rest(hand).origin
			var knuckle := skel.get_bone_global_rest(mid[0]).origin
			var along := knuckle - wrist
			if along.length() < 0.0001:
				continue
			along = along.normalized()
			var palm := Vector3.ZERO
			var thumb: PackedInt32Array = _fing.get("thumb." + side, PackedInt32Array())
			if not thumb.is_empty():
				palm = skel.get_bone_global_rest(thumb[thumb.size() - 1]).origin - knuckle
			else:
				# No thumb on this rig: fall back to the knuckle line, which
				# gives a plane but not a side, so the sign may be wrong.
				var ix: PackedInt32Array = _fing.get("index." + side, PackedInt32Array())
				var pk: PackedInt32Array = _fing.get("pinky." + side, PackedInt32Array())
				if ix.is_empty() or pk.is_empty():
					continue
				palm = (skel.get_bone_global_rest(pk[0]).origin
					- skel.get_bone_global_rest(ix[0]).origin).cross(along)
			palm -= along * palm.dot(along)
			if palm.length() < 0.0001:
				continue
			palm = palm.normalized()
			var curl := along.cross(palm).normalized()
			_curl[side] = curl
			# The whole hand as an ANATOMICAL FRAME, not just the curl axis.
			#
			# Orienting a hand onto something it is gripping is a frame-to-frame
			# problem: the fingers have to wrap AROUND the object, so the curl
			# axis must lie along the object's axis, and the palm has to face it.
			# Both are answered at once by mapping this frame onto the target's.
			# Building the rotation from a shortest arc plus a constant twist —
			# which is what was here — leaves the roll about the barrel
			# unspecified, so the support hand landed upside down.
			_hand_frame[side] = Basis(along, palm, curl)
		if OS.has_environment("HAND_DEBUG"):
			print("HANDS fingers=%d resolved=%d curl=%s" % [
				fingers.size(), _fing.size(), _curl])

	func _process_modification() -> void:
		var skel := get_skeleton()
		if not skel:
			return
		if not _resolved:
			_resolve()
		var delta := get_physics_process_delta_time() if Engine.is_in_physics_frame() \
			else get_process_delta_time()
		var t := 1.0 - exp(-HOLD_SMOOTH * delta)
		_hold_r = lerpf(_hold_r, hold_r_target, t)
		_hold_l = lerpf(_hold_l, hold_l_target, t)

		# Authored clips own the full silhouette. Traversal adds only constraints
		# an offline clip cannot know, such as the live grapple cable.
		_apply_grapple_body(skel, delta)
		if absf(aim_pitch) > 0.01 and not grapple_active:
			_apply_aim_pitch(skel)
		if _hold_r > 0.01 or _hold_l > 0.01:
			_apply_rifle_hold(skel)
			if absf(cheek) > 0.01:
				_apply_cheek(skel)
			_close_hands(skel)
		if recoil > 0.01:
			_apply_recoil(skel)
			recoil = lerpf(recoil, 0.0, 0.25)
		if grapple_active:
			_apply_grapple_arm(skel)

		# Joints LAST, and inside the modification pass: each helper has to track
		# whatever final rotation its child bone ended up with, or it deforms the
		# limb instead of saving it.
		if not joint_helpers.is_empty():
			SkinJointHelper.update(skel, joint_helpers)


	## Rotate the visual body as a pendulum without touching the gameplay
	## CharacterBody/capsule. At low energy the pilot hangs upright under
	## gravity. Speed and angular velocity progressively align the body's long
	## axis with the rope, while tangential velocity controls facing around it.
	func _apply_grapple_body(skel: Skeleton3D, delta: float) -> void:
		var wanted := Quaternion.IDENTITY
		grapple_alignment = 0.0
		if grapple_active:
			var ua: int = _idx.get("DEF-upper_arm.L", -1)
			if ua >= 0:
				var inv := skel.global_transform.affine_inverse()
				var target := inv * grapple_target_world
				var shoulder := skel.get_bone_global_pose(ua).origin
				var rope := target - shoulder
				var rope_length := rope.length()
				if rope_length > 0.01:
					var rope_dir := rope / rope_length
					var velocity := skel.global_transform.basis.inverse() \
						* grapple_velocity_world
					var tangent := velocity - rope_dir * velocity.dot(rope_dir)
					var angular_speed := tangent.length() / rope_length
					# Whole-body cable alignment is a high-energy silhouette.
					# Below 11 m/s the authored hanging pose remains dominant;
					# angular motion can shape a fast swing but cannot bypass
					# the speed gate by itself.
					var speed_factor := smoothstep(
						11.0, 28.0, velocity.length())
					var angular_factor := smoothstep(
						0.8, 2.8, angular_speed)
					grapple_alignment = speed_factor * lerpf(
						0.55, 1.0, angular_factor)

					var up := Vector3.UP.slerp(
						rope_dir, grapple_alignment).normalized()
					var tilt := Quaternion(Vector3.UP, up)
					var forward := tangent - up * tangent.dot(up)
					if forward.length_squared() < 0.0001:
						forward = tilt * Vector3(0.0, 0.0, 1.0)
					else:
						forward = forward.normalized()
					var base_forward := tilt * Vector3(0.0, 0.0, 1.0)
					base_forward = (
						base_forward - up * base_forward.dot(up)
					).normalized()
					var twist := base_forward.signed_angle_to(forward, up)
					wanted = Quaternion(up, twist) * tilt

		var blend := 1.0 - exp(-7.0 * delta)
		_grapple_body = _grapple_body.slerp(wanted.normalized(), blend)
		if _grapple_body.angle_to(Quaternion.IDENTITY) > 0.001:
			_add_space(
				skel, _idx.get("DEF-hips", -1), _grapple_body)


	## Exact live two-bone constraint for the grapple arm. The target hand point
	## is the farthest reachable point on the cable ray, so shoulder, hand and
	## hook are collinear even when the hook is many metres away.
	func _apply_grapple_arm(skel: Skeleton3D) -> void:
		var ua: int = _idx.get("DEF-upper_arm.L", -1)
		var hand: int = _idx.get("DEF-hand.L", -1)
		if ua < 0 or hand < 0:
			return
		var inv := skel.global_transform.affine_inverse()
		var target := inv * grapple_target_world
		var shoulder := skel.get_bone_global_pose(ua).origin
		var line := target - shoulder
		if line.length_squared() < 0.0001:
			return
		var along := line.normalized()
		var reach := _arm_reach(
			skel, "DEF-upper_arm.L", "DEF-forearm.L", "DEF-hand.L")
		var hand_target := shoulder + along * reach * 0.985
		var gravity_down := skel.global_transform.basis.inverse() * Vector3.DOWN
		var pole := gravity_down + Vector3(0.35, 0.0, 0.0)
		var g_fore := _ik_arm(
			skel,
			"DEF-upper_arm.L",
			"DEF-forearm.L",
			"DEF-hand.L",
			hand_target,
			pole.normalized(),
			1.0,
		)

		# Continue the hand itself down the same ray. This puts the palm socket,
		# not merely the wrist joint, on the cable line.
		if g_fore != Quaternion.IDENTITY and _hand_frame.has("L"):
			var palm := gravity_down - along * gravity_down.dot(along)
			if palm.length_squared() < 0.0001:
				palm = Vector3.RIGHT - along * Vector3.RIGHT.dot(along)
			palm = palm.normalized()
			var curl := along.cross(palm).normalized()
			var want := Basis(along, palm, curl)
			var rest: Basis = _hand_frame["L"]
			var g_hand := (
				want * rest.inverse()
			).get_rotation_quaternion() \
				* skel.get_bone_global_rest(hand).basis.get_rotation_quaternion()
			_set_global_rot(skel, hand, g_fore, g_hand.normalized(), 1.0)
		_close_hand(skel, "L", 1.0)


	# Upper body follows the camera pitch: distributed over spine/neck/head
	# so looking up/down reads on the whole silhouette, not just the head.
	func _apply_aim_pitch(skel: Skeleton3D) -> void:
		# Positive camera pitch (looking up) arches the torso back.
		var per := Quaternion.IDENTITY.slerp(
			Quaternion(Vector3(1, 0, 0), -aim_pitch * 0.55), 1.0 / SPINE.size())
		for n in SPINE:
			_add_space(skel, _idx.get(n, -1), per)
		var head_q := Quaternion(Vector3(1, 0, 0), -aim_pitch * 0.45)
		_add_space(skel, _idx.get("DEF-neck", -1), Quaternion.IDENTITY.slerp(head_q, 0.5))
		_add_space(skel, _idx.get("DEF-head", -1), Quaternion.IDENTITY.slerp(head_q, 0.5))


	# Shot kick: the torso absorbs it. The MUZZLE rise is not applied here —
	# it rides in the hold's aim direction (see `kick` in _apply_rifle_hold),
	# so the IK carries BOTH hands up with the gun. Rotating the arms here
	# instead would shove the support hand straight off the handguard.
	func _apply_recoil(skel: Skeleton3D) -> void:
		var k := recoil
		var back := Quaternion(Vector3(1, 0, 0), -0.05 * k)
		for n in ["DEF-spine.002", "DEF-spine.003"]:
			_add_space(skel, _idx.get(n, -1), back)

	# ── Two-hand rifle hold ──────────────────────────────────────────────────
	# The gun is parented to the RIGHT HAND bone, so where the hands go decides
	# where the gun goes. We therefore place the WEAPON first — stock in the
	# shoulder pocket, barrel down the aim line — then solve both arms with
	# two-bone IK to the resulting grip and foregrip points. That is what makes
	# the stock actually meet the shoulder and the support hand actually touch
	# the handguard, instead of both arms waving at art-directed angles near it.
	# Skeleton space: character faces +Z, up +Y, character-right -X.

	# Muzzle tilt at low-ready. Kept shallow: at the old 0.38 rad (22 degrees)
	# the gun read as dangling from the hands rather than being carried.
	const GUN_PITCH_HIP := 0.16
	# Where the butt of the stock sits, relative to the right shoulder joint.
	# The pocket is on the FRONT of the shoulder, slightly inboard of the joint.
	# Low-ready used to drop the butt 0.20 m to the ribs, which pulled the whole
	# weapon off the shoulder and out of the arms — it never looked held. It now
	# stays in the pocket and only relaxes slightly out of ADS.
	const POCKET_ADS := Vector3(0.05, 0.01, 0.07)     # in the shoulder pocket
	const POCKET_HIP := Vector3(0.03, -0.07, 0.06)    # still shouldered, relaxed
	# Elbow bend hints (skeleton space). At the hip the firing elbow rides
	# down by the ribs; shouldered it flares OUT and level (the classic
	# "chicken wing"), which is what keeps the tight fold from folding the
	# arm up behind the head. The support elbow always tucks under the gun.
	const POLE_R_HIP := Vector3(-0.55, -0.85, -0.20)
	const POLE_R_ADS := Vector3(-1.0, -0.25, -0.10)
	const POLE_L_HIP := Vector3(0.45, -0.90, -0.10)
	const POLE_L_ADS := Vector3(0.30, -0.95, -0.05)
	const R_HAND_TWIST := 0.0

	func _apply_rifle_hold(skel: Skeleton3D) -> void:
		var ua_r: int = _idx.get("DEF-upper_arm.R", -1)
		var ua_l: int = _idx.get("DEF-upper_arm.L", -1)
		if ua_r < 0:
			return
		# ~7 degrees of muzzle rise per shot, stacking a little on full auto.
		var kick := recoil * 0.12

		# 1. The gun's line: pitched down at low-ready, on the camera line at
		#    ADS, kicked up by recoil.
		#
		#    `pitch` is a low-ready knob only, and deliberately: down the sights
		#    the muzzle follows the CAMERA, so there is nothing there to tune.
		var gun_pitch := lerpf(
			_t("pitch_hip", GUN_PITCH_HIP), -aim_pitch, ads) - kick
		var aim_dir: Vector3 = (Quaternion(Vector3(1, 0, 0), gun_pitch) \
			* Vector3(0, 0, 1)).normalized()
		# Gun's "up" — perpendicular to the barrel in the vertical plane, so the
		# magazine always hangs DOWN.
		var side := aim_dir.cross(Vector3.UP)
		if side.length_squared() < 0.0001:
			side = Vector3(-1, 0, 0)
		side = side.normalized()
		var gun_up := side.cross(aim_dir).normalized()

		# 2. Anchor the stock at the shoulder, then walk out along the barrel.
		var shoulder := skel.get_bone_global_pose(ua_r).origin
		var pocket: Vector3 = _tvp("pocket", POCKET_HIP, POCKET_ADS)
		var stock_pos := shoulder + pocket
		# The gun's own frame: across, up, along the barrel. The hand anchors are
		# nudged in THIS rather than in skeleton space so a sideways offset stays
		# sideways relative to the weapon as it pitches from low ready to ADS,
		# instead of sliding around the gun as it tips.
		var gun_basis := Basis(side, gun_up, aim_dir)
		dbg_gun_basis = gun_basis
		var grip_pos := stock_pos + aim_dir * gun_stock \
			+ gun_basis * _tv("grip_shift", Vector3.ZERO)
		# The support hand rides as far out the handguard as it can actually
		# REACH. Without this a long rifle puts the foregrip past the left
		# arm's limit and the IK yanks the whole arm out straight.
		var fore_dist := gun_fore
		if ua_l >= 0:
			var l_sh := skel.get_bone_global_pose(ua_l).origin
			var reach_l := _arm_reach(skel, "DEF-upper_arm.L", "DEF-forearm.L",
				"DEF-hand.L") * 0.94
			# Slide the support hand back down the handguard until the arm can
			# reach it — but NEVER past this floor. Without one it collapsed to
			# 0.083 m on Taila, which puts the support fist on top of the trigger
			# fist: that reads as a two-handed pistol grip, not a rifle. A support
			# arm that is nearly straight looks far better than no handguard hold.
			var floor_fore: float = gun_fore * 0.55
			for _i in 6:
				if grip_pos.distance_to(l_sh) > reach_l:
					break  # even the grip is out of reach; nothing to slide to
				if (grip_pos + aim_dir * fore_dist).distance_to(l_sh) <= reach_l:
					break
				fore_dist = maxf(fore_dist * 0.8, floor_fore)
				if fore_dist <= floor_fore:
					break
		var fore_pos := grip_pos + aim_dir * fore_dist \
			+ gun_basis * _tv("fore_shift", Vector3.ZERO)
		dbg_grip = grip_pos
		dbg_fore = fore_pos
		dbg_stock = stock_pos

		# 3. Where the SUPPORT hand goes, which is most of what tells a viewer
		#    what is being held. See WeaponHoldProfiles.
		#
		#    All four modes reuse the geometry above — the weapon is still placed
		#    first and the arms still solved onto it — they differ in which point
		#    on it the off hand is sent to.
		var l_target := fore_pos
		match support_mode:
			WeaponHoldProfiles.SUPPORT_CUPPED:
				# Both hands together on the grip. Down and to the character's
				# LEFT of the firing fist (`side` is character-right), so the two
				# hands stack rather than collide.
				l_target = grip_pos + gun_basis * Vector3(-0.048, -0.038, 0.012)
			WeaponHoldProfiles.SUPPORT_TUBE:
				# Hooked under the tube from below, forward of the shoulder.
				l_target = fore_pos - gun_up * 0.075
		if reload_phase > 0.001:
			var mag_well := grip_pos + aim_dir * (gun_fore * 0.35) - gun_up * 0.10
			var drop := mag_well - gun_up * 0.22 - aim_dir * 0.05
			var p := reload_phase
			if p < 0.30:        # rip the mag straight down out of the well
				l_target = mag_well.lerp(drop, p / 0.30)
			elif p < 0.55:      # reach down for a fresh one
				l_target = drop
			elif p < 0.80:      # bring it back up and seat it
				l_target = drop.lerp(mag_well, (p - 0.55) / 0.25)
			else:               # hand returns to the handguard
				l_target = mag_well.lerp(fore_pos, (p - 0.80) / 0.20)

		# 4. Solve both arms onto those points.
		var pole_r: Vector3 = _tvp("pole_r", POLE_R_HIP, POLE_R_ADS).normalized()
		var pole_l: Vector3 = _tvp("pole_l", POLE_L_HIP, POLE_L_ADS).normalized()
		var g_fa_r := _ik_arm(skel, "DEF-upper_arm.R", "DEF-forearm.R",
			"DEF-hand.R", grip_pos, pole_r, _hold_r)
		var g_fa_l := _ik_arm(skel, "DEF-upper_arm.L", "DEF-forearm.L",
			"DEF-hand.L", l_target, pole_l, _hold_l)
		if OS.has_environment("GUN_POSE_DEBUG"):
			var hr: int = _idx.get("DEF-hand.R", -1)
			var hl: int = _idx.get("DEF-hand.L", -1)
			print("HOLD st=%s tgtL=%.2f ads=%.2f holdR=%.2f holdL=%.2f rl=%.2f fore=%.3f stock=%.3f foredist=%.3f" % [
					state, hold_l_target, ads, _hold_r, _hold_l, reload_phase,
					gun_fore, gun_stock, fore_dist],
				" sh=", shoulder, " grip=", grip_pos, " fore=", fore_pos,
				" handR=", skel.get_bone_global_pose(hr).origin if hr >= 0 else "-",
				" handL=", skel.get_bone_global_pose(hl).origin if hl >= 0 else "-",
				" reachL=%.3f" % _arm_reach(skel, "DEF-upper_arm.L",
					"DEF-forearm.L", "DEF-hand.L"))

		# 5. Roll the gun hand so the BARREL lies on the aim line and the
		#    magazine points down — the gun's orientation comes entirely from
		#    this wrist, so it can never end up inverted.
		if _hold_r > 0.001 and g_fa_r != Quaternion.IDENTITY \
				and gun_fwd_hand.length_squared() > 0.5:
			var hand: int = _idx.get("DEF-hand.R", -1)
			if hand >= 0:
				var arc := Quaternion(gun_fwd_hand.normalized(), aim_dir)
				var up_now := arc * gun_up_hand.normalized()
				var up_flat := (up_now - aim_dir * up_now.dot(aim_dir))
				if up_flat.length_squared() > 0.0001:
					var roll := up_flat.normalized().signed_angle_to(gun_up, aim_dir)
					arc = Quaternion(aim_dir, roll + R_HAND_TWIST) * arc
				# The artist's wrist, on top of the solved one. Three axes in the
				# gun's frame rather than the single twist this used to take —
				# the barrel has to lie on the aim line, which fixes two of the
				# hand's three freedoms, but nothing fixes how far the wrist is
				# cocked or broken, and those were unreachable.
				#
				# The gun hangs off THIS bone, so rotating it carries the gun
				# along and the barrel comes off the aim line — which made the
				# knob useless for its actual purpose, since there was then no
				# way to align the hand to a gun that had moved with it. Both
				# outcomes are computed, the hand takes the rotated one, and the
				# difference between them is published as the counter-rotation
				# the weapon mount needs to stay exactly where the solver put it.
				# See `wrist_comp_r`.
				var cur := skel.get_bone_pose_rotation(hand)
				var local_free := (g_fa_r.inverse() * arc).normalized()
				var wrist_q := _wrist("wrist_r", side, gun_up, aim_dir)
				var local_wrist := (g_fa_r.inverse() * (wrist_q * arc)).normalized()
				var applied := cur.slerp(local_wrist, _hold_r)
				wrist_comp_r = applied.inverse() * cur.slerp(local_free, _hold_r)
				skel.set_bone_pose_rotation(hand, applied)

		# 6. Support hand: WRAP the handguard.
		#
		# Built as a frame, not as an arc plus a twist. A hand gripping a
		# cylinder has its fingers curling AROUND that cylinder, which fixes two
		# things at once and leaves nothing free:
		#
		#   curl axis  must lie along the BARREL, or the fingers close across
		#              the handguard instead of around it
		#   palm       must face the barrel — up, for a hand supporting from
		#              underneath
		#
		# The old version aligned the hand's forearm line to the barrel with a
		# shortest arc and then added a constant 0.5 rad twist. A shortest arc
		# says nothing about roll, so the roll came entirely from that constant,
		# and a constant is only ever right for the one rig it was tuned on — the
		# support hand came out upside down.
		if _hold_l > 0.001 and g_fa_l != Quaternion.IDENTITY and ua_l >= 0 \
				and _hand_frame.has("L"):
			var hand_l: int = _idx.get("DEF-hand.L", -1)
			if hand_l >= 0:
				# The hand's target frame, as (along, palm, curl) — the same
				# three axes `_hand_frame` measured off the rest pose.
				#
				# Which way the PALM faces and which axis the fingers CURL about
				# is the whole difference between wrapping a handguard, cupping a
				# fist and hooking under a tube. Sending the hand to a different
				# POSITION without changing its orientation gives a hand that has
				# been teleported to the new spot still shaped for the old one.
				#
				# -aim_dir throughout, so the hand comes at the weapon from the
				# body side rather than reaching over it backwards.
				var palm := gun_up
				var curl := -aim_dir
				match support_mode:
					WeaponHoldProfiles.SUPPORT_CUPPED:
						# Palm presses inward against the grip's exposed panel;
						# fingers still close along the barrel, over the firing
						# hand's.
						palm = side
					WeaponHoldProfiles.SUPPORT_TUBE:
						# A vertical foregrip: the palm faces BACK toward the
						# body and the fingers close about the handle's own
						# up-axis, not about the tube.
						palm = -aim_dir
						curl = gun_up
				var want := Basis(palm.cross(curl).normalized(), palm, curl)
				# Then the artist's wrist. Rolling about the barrel is the one
				# axis a hand wrapping a cylinder is genuinely free in, and it
				# used to be the only one offered — which left no way to cock the
				# wrist forward or break it inward, and those are most of what
				# separates a convincing support hand from a mannequin's.
				# Rotating the whole frame is equivalent to the old roll for the
				# roll component, since -aim_dir is unchanged by a rotation
				# about aim_dir.
				want = Basis(_wrist("wrist_l", side, gun_up, aim_dir)) * want
				var rest: Basis = _hand_frame["L"]
				var g_hand := (want * rest.inverse()).get_rotation_quaternion() \
					* skel.get_bone_global_rest(hand_l).basis.get_rotation_quaternion()
				_set_global_rot(skel, hand_l, g_fa_l, g_hand.normalized(), _hold_l)

	# ── The head against the stock ───────────────────────────────────────────
	#
	# A cheek weld is the single most recognisable thing about how a marksman
	# holds a rifle, and its inverse — the head leaning AWAY — is what says a tube
	# is resting on that shoulder. Both are silhouette at any distance, long after
	# the weapon mesh itself has become a few pixels.
	#
	# Three axes, all toward the right shoulder, because that is where the weapon
	# is: down onto the comb, rolled over it, and turned slightly along it.
	## Full-weld amounts, in radians, at cheek = 1.
	const CHEEK_PITCH := 0.20   # down onto the comb
	const CHEEK_ROLL := 0.26    # over toward the shoulder
	const CHEEK_YAW := 0.09     # turned along the stock
	## How much of the weld is present at low ready. Not zero: the pose has to
	## read before the character shoulders the weapon, and a marksman carrying a
	## rifle already holds their head differently from someone carrying a knife.
	const CHEEK_HIP := 0.35

	func _apply_cheek(skel: Skeleton3D) -> void:
		var k: float = cheek * lerpf(CHEEK_HIP, 1.0, ads) * _hold_r
		if absf(k) < 0.005:
			return
		# Positive X pitches the head DOWN and positive Z rolls it toward the
		# character's right — the same sign conventions as the aim pitch and the
		# wall-run lean respectively.
		var q := Quaternion(Vector3(1, 0, 0), CHEEK_PITCH * k) \
			* Quaternion(Vector3(0, 0, 1), CHEEK_ROLL * k) \
			* Quaternion(Vector3(0, 1, 0), CHEEK_YAW * k)
		# Split across neck and head so the whole column leans rather than the
		# skull hinging off a rigid neck. Weighted toward the head, which is what
		# actually happens when someone lowers a cheek onto a stock.
		_add_space(skel, _idx.get("DEF-neck", -1),
			Quaternion.IDENTITY.slerp(q, 0.35))
		_add_space(skel, _idx.get("DEF-head", -1),
			Quaternion.IDENTITY.slerp(q, 0.65))

	# How far each segment of a finger closes, knuckle -> tip, in radians.
	#
	# Two different grips. The SUPPORT hand wraps a handguard, so all four
	# fingers close hard and evenly. The TRIGGER hand wraps a pistol grip with
	# three fingers while the index lies along the trigger, nearly straight —
	# curling it with the rest is the single thing that most makes a game
	# character look like they are squeezing a bar of soap rather than holding a
	# rifle.
	const CURL_WRAP := [0.85, 1.15, 0.85]
	const CURL_TRIGGER := [0.42, 0.55, 0.35]
	# The thumb opposes rather than curls, so it closes less and it is the one
	# digit whose middle joint barely bends.
	const CURL_THUMB := [0.45, 0.30, 0.25]
	const DIGITS := ["index", "middle", "ring", "pinky"]

	## Close both hands around whatever the IK put them on.
	##
	## Applied AFTER the hold, so the fingers follow wherever the wrists ended up.
	## Weighted by the per-arm hold blend, so a hand the clip has taken back opens
	## again instead of staying clamped shut.
	func _close_hands(skel: Skeleton3D) -> void:
		_close_hand(skel, "R", _hold_r)
		_close_hand(skel, "L", _hold_l)

	func _close_hand(skel: Skeleton3D, side: String, w: float) -> void:
		if w <= 0.01 or not _curl.has(side):
			return
		var axis: Vector3 = _curl[side]
		for digit in DIGITS:
			var bones: PackedInt32Array = _fing.get(digit + "." + side,
				PackedInt32Array())
			if bones.is_empty():
				continue
			# The right index rides the trigger; everything else wraps. A blade
			# has no trigger, and an index left straight along a knife handle
			# reads as a mistake rather than as discipline — so a full fist
			# closes every finger the same.
			var trigger: bool = side == "R" and digit == "index" and not full_fist
			var amount: Array = CURL_TRIGGER if trigger else CURL_WRAP
			var scale: float = _t("curl_trigger", 1.0) if trigger 				else _t("curl_wrap", 1.0)
			for i in bones.size():
				var a: float = amount[i] if i < amount.size() else amount[-1]
				_add_space(skel, bones[i], Quaternion(axis, a * scale * w))
		var thumb: PackedInt32Array = _fing.get("thumb." + side, PackedInt32Array())
		for i in thumb.size():
			var a: float = CURL_THUMB[i] if i < CURL_THUMB.size() else CURL_THUMB[-1]
			_add_space(skel, thumb[i], Quaternion(axis, a * _t("curl_thumb", 1.0) * w))

	## Straight-arm length of an arm chain, from the rest pose.
	func _arm_reach(skel: Skeleton3D, ua_name: String, fa_name: String,
			hand_name: String) -> float:
		var ua: int = _idx.get(ua_name, -1)
		var fa: int = _idx.get(fa_name, -1)
		var hand: int = _idx.get(hand_name, -1)
		if ua < 0 or fa < 0 or hand < 0:
			return 0.5
		var a := skel.get_bone_global_rest(ua).origin
		var b := skel.get_bone_global_rest(fa).origin
		var c := skel.get_bone_global_rest(hand).origin
		return a.distance_to(b) + b.distance_to(c)

	## Two-bone IK: rotate the upper arm + forearm so the HAND JOINT lands on
	## `target` (skeleton space). `pole` biases which way the elbow breaks.
	## Returns the forearm's achieved global rotation (IDENTITY when skipped).
	func _ik_arm(skel: Skeleton3D, ua_name: String, fa_name: String,
			hand_name: String, target: Vector3, pole: Vector3,
			w: float) -> Quaternion:
		if w <= 0.001:
			return Quaternion.IDENTITY
		var ua: int = _idx.get(ua_name, -1)
		var fa: int = _idx.get(fa_name, -1)
		var hand: int = _idx.get(hand_name, -1)
		if ua < 0 or fa < 0 or hand < 0:
			return Quaternion.IDENTITY

		# Segment lengths come from the REST pose so they never drift.
		var ua_rest := skel.get_bone_global_rest(ua).origin
		var fa_rest := skel.get_bone_global_rest(fa).origin
		var hand_rest := skel.get_bone_global_rest(hand).origin
		var l1 := ua_rest.distance_to(fa_rest)
		var l2 := fa_rest.distance_to(hand_rest)
		if l1 < 0.0001 or l2 < 0.0001:
			return Quaternion.IDENTITY

		# The shoulder's CURRENT position (spine lean/aim pitch already moved it).
		var root := skel.get_bone_global_pose(ua).origin
		var to_target := target - root
		var d := to_target.length()
		if d < 0.0001:
			return Quaternion.IDENTITY
		var reach := to_target / d
		d = clampf(d, absf(l1 - l2) + 0.002, l1 + l2 - 0.002)

		# Law of cosines for the shoulder angle, then break the elbow toward
		# the pole to pick one of the infinitely many solutions.
		var cos_a := clampf((l1 * l1 + d * d - l2 * l2) / (2.0 * l1 * d), -1.0, 1.0)
		var axis := reach.cross(pole)
		if axis.length_squared() < 0.000001:
			axis = reach.cross(Vector3.UP)
			if axis.length_squared() < 0.000001:
				axis = reach.cross(Vector3(1, 0, 0))
		axis = axis.normalized()
		var ua_dir := (Quaternion(axis, acos(cos_a)) * reach).normalized()
		var elbow := root + ua_dir * l1
		var fa_dir := target - elbow
		fa_dir = fa_dir.normalized() if fa_dir.length_squared() > 0.00000001 else reach

		var g_fa := _aim_chain(skel, ua_name, fa_name, ua_dir, fa_dir, 0.0, w)
		if OS.has_environment("IK_DEBUG") and ua_name.ends_with(".R"):
			var got_ua := skel.get_bone_global_pose(ua)
			var got_fa := skel.get_bone_global_pose(fa)
			var got_hand := skel.get_bone_global_pose(hand)
			print("IK l1=%.3f l2=%.3f d=%.3f" % [l1, l2, d],
				"\n   root_want=", root, " ua_origin_got=", got_ua.origin,
				"\n   elbow_want=", elbow, " fa_origin_got=", got_fa.origin,
				"\n   hand_want=", target, " hand_got=", got_hand.origin,
				"\n   ua_dir=", ua_dir, " ua_dir_got=",
				(got_fa.origin - got_ua.origin).normalized())
		return g_fa

	# Aim an upper-arm/forearm chain along the given directions with exact FK:
	# desired global orientation = (shortest arc from the bone's rest line to
	# the target dir, plus a twist about that line) ⊕ rest, each local pose
	# derived against the parent's posed global so there is no drift.
	# Returns the forearm's target global rotation (IDENTITY when skipped).
	func _aim_chain(skel: Skeleton3D, ua_name: String, fa_name: String,
			ua_dir: Vector3, fa_dir: Vector3, ua_twist: float,
			w: float) -> Quaternion:
		if w <= 0.001:
			return Quaternion.IDENTITY
		var ua: int = _idx.get(ua_name, -1)
		var fa: int = _idx.get(fa_name, -1)
		if ua < 0 or fa < 0:
			return Quaternion.IDENTITY

		# Bone lines at rest (upper arm -> forearm -> hand joint origins).
		var ua_o := skel.get_bone_global_rest(ua).origin
		var fa_o := skel.get_bone_global_rest(fa).origin
		var fa_children := skel.get_bone_children(fa)
		var fa_tip := skel.get_bone_global_rest(fa_children[0]).origin \
			if fa_children.size() > 0 else fa_o + (fa_o - ua_o)
		var ua_rest_dir := (fa_o - ua_o).normalized()
		var fa_rest_dir := (fa_tip - fa_o).normalized()

		var ua_rest_q := skel.get_bone_global_rest(ua).basis.get_rotation_quaternion()
		var fa_rest_q := skel.get_bone_global_rest(fa).basis.get_rotation_quaternion()

		# Desired global rotations.
		var g_ua := Quaternion(ua_dir, ua_twist) * Quaternion(ua_rest_dir, ua_dir) * ua_rest_q
		var g_fa := Quaternion(fa_rest_dir, fa_dir) * fa_rest_q

		# Convert both to LOCAL pose rotations. Godot composes a bone as
		#   global = parent_global * rest_local * pose_local
		# so pose_local = rest_local⁻¹ * parent_global⁻¹ * global_target.
		# (Dropping the rest_local⁻¹ term silently biases every bone by its
		# rest orientation — which is why hand-tuned angles used to be needed.)
		var parent := skel.get_bone_parent(ua)
		var g_parent := skel.get_bone_global_pose(parent).basis.get_rotation_quaternion() \
			if parent >= 0 else Quaternion.IDENTITY
		_set_global_rot(skel, ua, g_parent, g_ua, w)
		# The forearm hangs off the upper arm we just aimed, so its parent's
		# global IS g_ua (using the cached pose here would lag a frame).
		var fa_parent := skel.get_bone_parent(fa)
		var g_fa_parent := g_ua if fa_parent == ua \
			else skel.get_bone_global_pose(fa_parent).basis.get_rotation_quaternion()
		_set_global_rot(skel, fa, g_fa_parent, g_fa, w)
		if OS.has_environment("GUN_POSE_DEBUG") and ua_name.ends_with(".R"):
			var ua_actual := skel.get_bone_global_pose(ua).basis.get_rotation_quaternion()
			var fa_actual := skel.get_bone_global_pose(fa).basis.get_rotation_quaternion()
			print("CHAIN DEBUG w=", w,
				" ua_t=", g_ua, " ua_a=", ua_actual,
				" | fa_t=", g_fa, " fa_a=", fa_actual,
				" | ua_dir_t=", ua_dir, " ua_dir_a=", ua_actual * (ua_rest_q.inverse() * ua_rest_dir))
		return g_fa

	func _blend_local(skel: Skeleton3D, idx: int, target: Quaternion, w: float) -> void:
		skel.set_bone_pose_rotation(idx,
			skel.get_bone_pose_rotation(idx).slerp(target.normalized(), w))

	## Give a bone the requested GLOBAL rotation, given its parent's global
	## rotation. In Godot 4 a bone's POSE *is* its local transform (rest is
	## merely the default), so this is a plain parent-relative conversion.
	func _set_global_rot(skel: Skeleton3D, idx: int, g_parent: Quaternion,
			g_target: Quaternion, w: float) -> void:
		_blend_local(skel, idx, g_parent.inverse() * g_target, w)

	# Compose a skeleton-space rotation onto a bone's animated local pose.
	func _add_space(skel: Skeleton3D, idx: int, q_space: Quaternion) -> void:
		if idx < 0:
			return
		var b := skel.get_bone_global_rest(idx).basis.get_rotation_quaternion()
		var local := b.inverse() * q_space * b
		skel.set_bone_pose_rotation(idx, skel.get_bone_pose_rotation(idx) * local)