spaceship/ui/TouchJoystick.gd

@tool
class_name TouchJoystick
extends Control

# Touch joystick for steering the fleet. Lives in the bottom-left corner.
#
# Behaves like a "floating" stick within its own rect: the base re-centres
# on wherever the finger first lands, so the player doesn't have to hit an
# exact spot on a phone screen they can't feel. The knob then follows the
# finger out to max_radius, and `direction` reports the offset normalised
# against that radius (so magnitude is 0..1, usable for throttle later).
#
# Releasing puts BOTH the base and the knob back in the middle of the rect, so
# an idle stick always looks the same and always looks idle.
#
# Only claims touches that start inside its own rect - anything else falls
# through untouched, which is what keeps pinch-to-zoom working everywhere
# else on screen.

signal direction_changed(direction: Vector2)
signal released

# How far the knob travels from centre, as a fraction of the control's
# shorter side. Derived rather than a fixed number of pixels so that
# enlarging the stick's rect enlarges the ring the player actually sees -
# otherwise the touch area grows and the visible control stays small.
# The scene zones are deliberately wider than they are tall. Forty percent
# makes the resting ring just over twice its former radius while leaving room
# for the floating base to move inside the touch rect.
const RADIUS_RATIO: float = 0.40

@export var max_radius: float = 90.0
@export var deadzone: float = 0.12
@export var glow_color: Color = Color(0.25, 0.85, 1.0)
@export var core_color: Color = Color(1.0, 1.0, 1.0)

var direction: Vector2 = Vector2.ZERO
var active_touch_index: int = -1
var base_pos: Vector2 = Vector2.ZERO
var knob_pos: Vector2 = Vector2.ZERO


func _ready() -> void:
	# _relayout() writes max_radius, which is @export - under @tool that
	# would persist a computed value into the scene. The preview uses the
	# authored radius instead; only a running game refits.
	if Engine.is_editor_hint():
		return
	# Dialogs release every spring-loaded stick through one compositional
	# contract, without NarrationBanner knowing scene paths or joystick roles.
	add_to_group("touch_joysticks")
	resized.connect(_relayout)
	_relayout()


# Where the stick sits when nobody is touching it: the middle of its own rect.
# The base only moves away from here while a finger is down (see handle_touch),
# and returns the moment it lifts.
func home_pos() -> Vector2:
	return size / 2.0


func _relayout() -> void:
	base_pos = home_pos()
	knob_pos = base_pos
	max_radius = minf(size.x, size.y) * RADIUS_RATIO
	queue_redraw()


func is_active() -> bool:
	return active_touch_index != -1


# Returns true if the event was consumed, so the caller knows not to treat
# it as a world gesture (a fleet move, or one finger of a pinch).
func handle_touch(event: InputEventScreenTouch) -> bool:
	var local: Vector2 = event.position - global_position
	if event.pressed:
		if active_touch_index != -1:
			return false
		if not Rect2(Vector2.ZERO, size).has_point(local):
			return false
		active_touch_index = event.index
		base_pos = local
		knob_pos = local
		_update_direction()
		return true

	if event.index != active_touch_index:
		return false
	release_input()
	return true


# Returns this spring-loaded control to its neutral state. Public and
# idempotent so a dialog can safely release movement and fire sticks before
# pausing their controllers (#182), even when only one is currently held.
func release_input() -> void:
	var was_active: bool = is_active() or direction != Vector2.ZERO
	active_touch_index = -1
	# Back to the middle of the rect, BASE included. This used to reset the
	# knob onto base_pos and leave the base wherever the finger had landed, so
	# a released stick stayed parked off-centre - which reads as a control
	# still in use, and left the ring somewhere different every time.
	base_pos = home_pos()
	knob_pos = base_pos
	direction = Vector2.ZERO
	queue_redraw()
	if was_active:
		direction_changed.emit(direction)
		released.emit()


func handle_drag(event: InputEventScreenDrag) -> bool:
	if event.index != active_touch_index:
		return false
	knob_pos = event.position - global_position
	_update_direction()
	return true


func _update_direction() -> void:
	var offset: Vector2 = knob_pos - base_pos
	if offset.length() > max_radius:
		offset = offset.normalized() * max_radius
		knob_pos = base_pos + offset
	var raw: Vector2 = offset / max_radius
	direction = Vector2.ZERO if raw.length() < deadzone else raw
	queue_redraw()
	direction_changed.emit(direction)


func _draw() -> void:
	var ring: PackedVector2Array = PackedVector2Array()
	var segments: int = 28
	for i in range(segments):
		var a: float = (float(i) / segments) * TAU
		ring.append(base_pos + Vector2(cos(a), sin(a)) * max_radius)
	NeonDraw.draw_glowing_polygon(self, ring, glow_color, 0.55, core_color)

	var knob: PackedVector2Array = PackedVector2Array()
	var knob_radius: float = max_radius * 0.34
	for i in range(segments):
		var a: float = (float(i) / segments) * TAU
		knob.append(knob_pos + Vector2(cos(a), sin(a)) * knob_radius)
	NeonDraw.draw_glowing_polygon(self, knob, glow_color, 1.0 if is_active() else 0.75, core_color)