spaceship/enemies/EnemyPursuitComponent.gd

class_name EnemyPursuitComponent
extends Node

# Chases the nearest player ship. Moved out of Enemy.gd verbatim so the
# behaviour is opt-in per definition rather than hardcoded into every enemy.

var capability_id: String = "pursuit"
var velocity: Vector2 = Vector2.ZERO

# #69: used to beeline from anywhere on the map the instant it spawned,
# which read as omniscient rather than alert. Idle until the fleet actually
# comes within this radius. A persistent stalking threat wants the opposite
# of this - see EnemyPursuitComponentMothership.tscn, which overrides it to
# an effectively unlimited value for the mothership's own instance.
@export var detection_range: float = 850.0


func tick(delta: float) -> void:
	var enemy: Node2D = get_parent()
	# #101: a structure is a target now, not scenery. EnemyTargets keeps a
	# ship in the enemy's face ahead of a building further off.
	var target: Node2D = EnemyTargets.nearest_target(self, enemy.global_position)
	if target == null:
		return
	# #113: a wave enemy closes on what the player built from wherever it
	# arrived. Everything else keeps the radius that stops it reading as
	# omniscient (#69).
	if not EnemyTargets.ignores_range(enemy) \
			and enemy.global_position.distance_to(target.global_position) > detection_range:
		return
	var to_target: Vector2 = target.global_position - enemy.global_position

	if to_target.length() > 1.0:
		var desired_velocity: Vector2 = to_target.normalized() * enemy.speed
		velocity = velocity.move_toward(desired_velocity, enemy.acceleration * delta)
		enemy.global_position += velocity * delta

	if velocity.length() > 5.0:
		var target_angle: float = velocity.angle() + PI / 2.0
		enemy.rotation = lerp_angle(enemy.rotation, target_angle, enemy.rotation_speed * delta)


func _nearest_ship(enemy: Node2D) -> Node2D:
	return EnemyTargets.nearest_ship(self, enemy.global_position)