spaceship/Ship.gd

extends Area2D

signal destroyed

const VESSEL_DEFINITIONS = preload("res://VesselDefinitions.gd")

@export var max_speed: float = 460.0
@export var acceleration: float = 450.0
@export var rotation_speed: float = 8.0
@export var arrive_radius: float = 6.0
@export var vessel_type: String = "interceptor"

var definition: Resource
var glow_color: Color = Color(0.25, 0.85, 1.0)
var core_color: Color = Color.WHITE
# The ship's TRUE world velocity - what `position` is actually integrated
# from, and the single source of truth for how fast this vessel is moving.
# Nothing else may contribute motion; see the note in _physics_process.
var velocity: Vector2 = Vector2.ZERO
# The velocity of this ship's formation SLOT (the fleet anchor's own travel).
# Fed forward into the steering below rather than added on top of it: matching
# the slot's speed is most of the job of holding formation, so supplying it
# directly leaves `velocity` free to be a small correction and lets the ship
# sit in its slot with no steady-state lag and no teleporting.
var fleet_velocity: Vector2 = Vector2.ZERO
var move_target: Vector2

# Compatibility accessors keep old saves/tests readable while shield state
# itself belongs exclusively to the optional ShieldComponent.
var shield_charges: int:
	get:
		var component: Node = get_component("shield")
		return component.charges if component != null else 0
	set(value):
		var component: Node = get_component("shield")
		if component != null:
			component.set_charges(value)

var shield_recharge_left: float:
	get:
		var component: Node = get_component("shield")
		return component.recharge_left if component != null else 0.0
	set(value):
		var component: Node = get_component("shield")
		if component != null:
			component.recharge_left = value

var projectile_damage: int:
	get:
		var component: Node = get_component("weapon")
		return component.projectile_damage if component != null else 0


func _ready() -> void:
	move_target = position
	add_to_group("player_ships")
	area_entered.connect(_on_area_entered)
	definition = VESSEL_DEFINITIONS.get_definition(vessel_type)
	if definition == null:
		return
	glow_color = definition.glow_color
	for component_scene in definition.component_scenes:
		var component: Node = component_scene.instantiate()
		add_child(component)
		if component.has_method("setup"):
			component.setup()
	apply_vessel_stats()
	queue_redraw()


func get_component(capability: String) -> Node:
	for child in get_children():
		if child.get("capability_id") == capability:
			return child
	return null


func has_capability(capability: String) -> bool:
	return get_component(capability) != null


func set_move_target(world_pos: Vector2) -> void:
	move_target = world_pos


func apply_vessel_stats() -> void:
	if definition == null:
		definition = VESSEL_DEFINITIONS.get_definition(vessel_type)
	if definition == null:
		return
	max_speed = GameState.vessel_stat(vessel_type, "max_speed")
	acceleration = GameState.vessel_stat(vessel_type, "acceleration")
	for child in get_children():
		if child.has_method("apply_stats"):
			child.apply_stats()


func has_shield() -> bool:
	var component: Node = get_component("shield")
	return component != null and component.is_active()


func _physics_process(delta: float) -> void:
	for child in get_children():
		if child.has_method("tick"):
			child.tick(delta)

	# #59: multiplied here, at the point of use, rather than baked into the
	# cached max_speed/acceleration fields apply_vessel_stats() sets - those
	# stay the true base values, so a stat upgrade researched mid-boost can't
	# corrupt them, and the fader takes effect the instant it moves with no
	# re-apply needed. arrive_radius is scaled too: at N physics ticks/sec a
	# ship's per-tick step is `speed * delta`, and once that step outgrows
	# the (otherwise fixed) arrive_radius it can overshoot the snap-to-target
	# zone every tick while chasing a target that is ALSO now receding N
	# times faster - a small, boost-proportional radius keeps the same
	# "snaps onto its slot" formation tightness at any boost level that
	# 1.0x already has.
	var boost: float = GameState.fleet_speed_multiplier
	var effective_acceleration: float = acceleration * boost
	var to_target: Vector2 = move_target - position
	var distance: float = to_target.length()

	# Snap only when the slot is STANDING STILL. A stationary target is the
	# one case where converging asymptotically would leave a permanent
	# sub-pixel residue, and settling exactly is what "the fleet has arrived"
	# means everywhere else in the game. While the slot is moving the ship
	# steers continuously instead - a snap there would be a teleport, which
	# is what used to make `velocity` read zero for a ship that was in fact
	# travelling at cruise speed, and that lie is what the whole
	# stop()/fleet_velocity bookkeeping tangle existed to paper over.
	if fleet_velocity == Vector2.ZERO and distance <= arrive_radius * boost:
		position = move_target
		velocity = Vector2.ZERO
	else:
		# Feed-forward plus correction. The ship aims to travel at its slot's
		# velocity, plus whatever extra closes the gap to the slot - so
		# holding formation costs no error, and `velocity` stays the ship's
		# real motion rather than a residual that has to be added to
		# something else to mean anything.
		var correction: Vector2 = Vector2.ZERO
		if distance > 0.001:
			var braking_speed: float = sqrt(2.0 * effective_acceleration * distance)
			correction = to_target.normalized() * min(max_speed * boost, braking_speed)
		var desired_velocity: Vector2 = fleet_velocity + correction
		# HARD BOUND on how fast any single vessel may travel, applied to the
		# total and re-applied every tick. Feed-forward plus correction can
		# ask for more than a vessel can actually fly, and without this the
		# excess was free speed: a ship that had been handed a large velocity
		# kept it, decaying only at `acceleration`. Clamping the REQUEST is
		# not enough - the clamp has to sit on the integrated result, so no
		# sequence of commands can leave a vessel travelling faster than its
		# own top speed.
		desired_velocity = desired_velocity.limit_length(max_speed * boost)
		velocity = velocity.move_toward(desired_velocity, effective_acceleration * delta)
		velocity = velocity.limit_length(max_speed * boost)
		position += velocity * delta

	if velocity.length() > 8.0:
		var target_angle: float = velocity.angle() + PI / 2.0
		rotation = lerp_angle(rotation, target_angle, rotation_speed * delta)


func take_damage(_amount: int) -> bool:
	# Ships have no hit points - any unabsorbed hit is lethal. A shield
	# charge absorbs a hit entirely regardless of its amount, matching
	# VesselShieldComponent's existing all-or-nothing semantics; `_amount`
	# is accepted (not `int`-clamped away) so callers like EnemyProjectile
	# have a normal damage parameter to pass even though it isn't graded here.
	for child in get_children():
		if child.has_method("absorb_hit") and child.absorb_hit():
			return true
	ShipExplosionVFX.spawn(get_tree().root, position)
	destroyed.emit()
	queue_free()
	return false


func _on_area_entered(area: Area2D) -> void:
	if not (area.is_in_group("enemies") or area.is_in_group("asteroids")):
		return
	# The enemy is told about the impact BEFORE this ship resolves its own
	# damage, because resolving it can free this node - and a ship that dies
	# to a ramming chaser must still take the chaser with it. Whether the
	# impact actually destroys the enemy is the enemy's decision (#82).
	if area.is_in_group("enemies") and area.has_method("collide_with_player_vessel"):
		area.collide_with_player_vessel()
	var absorbed: bool = take_damage(1)
	if absorbed and area.is_in_group("asteroids") and is_instance_valid(area):
		area.queue_free()


func _draw() -> void:
	var points: PackedVector2Array = definition.hull_points if definition != null else PackedVector2Array([
		Vector2(0, -22), Vector2(-14, 16), Vector2(14, 16),
	])
	NeonDraw.draw_glowing_polygon(self, points, glow_color, 1.0, core_color)