extends SceneTree

## Regression gate for speed-scaled traversal blends, authored stopping, and
## alternating mirrored airborne silhouettes in the Titanfall motion lab.

const DEFAULT_MODEL_PATH := \
	"res://assets/characters/local_reference/titanfall_motion/mannequin.glb"
const SPEED := 13.0

var _failures: Array[String] = []
var _model: SkinnedPlayerModel
var _body: CharacterBody3D
var _model_path := DEFAULT_MODEL_PATH


func _initialize() -> void:
	var args := OS.get_cmdline_user_args()
	if not args.is_empty():
		_model_path = args[0]
	call_deferred("_run")


func _run() -> void:
	_body = CharacterBody3D.new()
	root.add_child(_body)
	current_scene = _body
	_model = SkinnedPlayerModel.new()
	_model.model_path = _model_path
	_body.add_child(_model)
	for _frame in 60:
		await process_frame
	_expect(_model.loaded, "motion-lab mannequin loads")
	if not _model.loaded:
		_finish()
		return

	for clip in ["Stop", "JumpAlt", "FallAlt"]:
		_expect(_model.clip_names_debug().has(clip),
			"rebuilt motion pack contains " + clip)

	# The same transition is deliberately quicker at high speed, while both
	# retain enough time for the skeleton to interpolate rather than cut.
	_body.velocity = Vector3(0.0, -2.0, -4.0)
	await _drive("air", 4.0, 20)
	_model.set_wall_side(-1.0)
	await _drive("wall_run", 4.0, 1)
	var slow_wall_blend := _model._state_trans.xfade_time
	await _drive("ground", 0.0, 24)
	_body.velocity = Vector3(0.0, -2.0, -18.0)
	await _drive("air", 18.0, 20)
	_model.set_wall_side(1.0)
	await _drive("wall_run", 18.0, 1)
	var fast_wall_blend := _model._state_trans.xfade_time
	_expect(slow_wall_blend > 0.0 and fast_wall_blend > 0.0,
		"wall transitions never hard-cut")
	_expect(fast_wall_blend < slow_wall_blend,
		"wall transition shortens with speed (%.3f -> %.3f s)" % [
			slow_wall_blend, fast_wall_blend])

	# Stop owns the full body while physical velocity decays. It must not leave
	# the high-rate Sprint node active during the release glide.
	_model.set_locomotion(0.0, 1.0, 0.0)
	await _drive("ground", 11.0, 45)
	await _drive("stop", 11.0, 1)
	_expect(_model.current_clip_debug() == "Stop",
		"release selects the authored Stop performance")
	var stop_blend := _model._state_trans.xfade_time
	var stop_scale := float(_model._anim_tree.get(
		"parameters/loco_scale/scale"))
	_expect(stop_blend > 0.0 and stop_blend < 0.19,
		"stop enters through a quick nonzero transition (%.3f s)" % stop_blend)
	_expect(stop_scale > 1.0,
		"high-speed stop compresses source timing (%.2fx)" % stop_scale)
	var physical_speed := 11.0
	var stop_distance := 0.0
	var stop_held := true
	var deceleration := MovementParams.new().ground_deceleration
	while physical_speed > 0.6:
		physical_speed *= exp(-deceleration / 60.0)
		stop_distance += physical_speed / 60.0
		await _drive("stop", physical_speed, 1)
		stop_held = stop_held and _model.current_clip_debug() == "Stop"
	_expect(stop_held, "Stop remains active during residual movement")
	await _drive("ground", 0.0, 14)
	_expect(stop_distance > 0.75 and stop_distance < 1.5,
		"physical stop carries a short distance (%.2f m)" % stop_distance)
	_expect(_model.current_clip_debug() == "Idle",
		"stop resolves into Idle instead of a fast run cycle")
	_expect(_model.locomotion_effective_speed_debug() < 0.25,
		"stale sprint playback speed is cleared after stopping")

	# Sample both clips at the same point after their short crossfade. The signed
	# knee lead must reverse, proving the alternate is a true mirrored source
	# performance rather than another phase of the same pose.
	await _drive("ground", 0.0, 30)
	_body.velocity = Vector3(0.0, 8.5, -8.0)
	await _drive("air", 8.0, 12)
	var normal_lead := _knee_lead()
	await _drive("ground", 0.0, 30)
	_body.velocity = Vector3(0.0, 8.5, -8.0)
	await _drive("air_alt", 8.0, 12)
	var alternate_lead := _knee_lead()
	_expect(absf(normal_lead) > 0.04 and absf(alternate_lead) > 0.04 \
			and normal_lead * alternate_lead < 0.0,
		"successive airborne clips swap the leading knee (%.3f / %.3f m)" % [
			normal_lead, alternate_lead])

	# Controller event wiring alternates the presentation state on successive
	# ground jumps and leaves the physics movement state untouched.
	var controller := PlayerMovementController.new()
	controller._machine = MovementStateMachine.new()
	controller._on_movement_event("jump", {})
	var first_air := controller._visual_animation_state("air", 8.0)
	controller._on_movement_event("jump", {})
	var second_air := controller._visual_animation_state("air", 8.0)
	_expect(first_air != second_air and first_air in ["air", "air_alt"] \
			and second_air in ["air", "air_alt"],
		"successive jump events alternate runtime airborne variants")
	controller._machine.free()
	controller.free()
	_body.queue_free()
	await process_frame
	_finish()


func _drive(state: String, speed: float, frames: int) -> void:
	for _frame in frames:
		_model.update_state(state, speed, false)
		await process_frame


func _knee_lead() -> float:
	var rises := {}
	for side in ["L", "R"]:
		var thigh := _model._role_bone("thigh." + side,
			["thigh." + side, "Left thigh" if side == "L" else "Right thigh"])
		var shin := _model._role_bone("shin." + side,
			["shin." + side, "Left shin" if side == "L" else "Right shin"])
		var segment := _model.skeleton.get_bone_global_pose(shin).origin \
			- _model.skeleton.get_bone_global_pose(thigh).origin
		rises[side] = (_model.skeleton.global_transform.basis * segment).y
	return float(rises["R"]) - float(rises["L"])


func _expect(ok: bool, description: String) -> void:
	if ok:
		print("  OK: ", description)
	else:
		_failures.append(description)
		printerr("  FAIL: ", description)


func _finish() -> void:
	print("\n=== MOTION VARIATION SUMMARY ===")
	print("Failures: %d" % _failures.size())
	quit(1 if not _failures.is_empty() else 0)