spaceship/enemies/EnemySpawner.gd

extends Node2D

@export var min_spawn_interval: float = 3.0
@export var max_spawn_interval: float = 6.0
@export var spawn_margin: float = 150.0
# #96: this spawner is the only place the player meets an enemy off an
# authored map, so a new open-space enemy has to take a share of it or it
# only ever exists in the setup editor. Kept a minority of the wave: the
# lancer is punctuation against a background of chasers, and a screen of
# them would be all telegraph and no fight.
@export var lancer_chance: float = 0.25

@onready var fleet: Node2D = get_node("../Fleet")

var enemy_scene: PackedScene = preload("res://enemies/Enemy.tscn")
var timer: float = 0.0
var next_spawn_time: float = 0.0


func _ready() -> void:
	randomize()
	_reset_timer()


func _process(delta: float) -> void:
	timer += delta
	if timer >= next_spawn_time:
		timer = 0.0
		_reset_timer()
		_spawn_enemy()


func _reset_timer() -> void:
	next_spawn_time = randf_range(min_spawn_interval, max_spawn_interval)


func _spawn_enemy() -> void:
	if fleet.ships.is_empty():
		return

	var visible_rect: Rect2 = ViewUtils.get_visible_world_rect(self)
	var radius: float = visible_rect.size.length() / 2.0 + spawn_margin
	var angle: float = randf() * TAU
	var spawn_pos: Vector2 = fleet.get_centroid() + Vector2(cos(angle), sin(angle)) * radius

	var enemy: Node2D = enemy_scene.instantiate()
	# Set before add_child: Enemy._ready() is what resolves enemy_id into a
	# definition, and it runs the moment the node enters the tree.
	enemy.enemy_id = "lancer" if randf() < lancer_chance else "chaser"
	enemy.position = spawn_pos
	get_parent().add_child(enemy)