class_name ExpansionSquarePattern extends ExpansionBase

const EXPANSION_STAGES: int = 3

var expansion_stage: int = 0
var expansion_tiles: Array[Vector2i] = []

func expand_next_tile() -> Vector2i:
	if expansion_tiles.is_empty():
		if expansion_stage < EXPANSION_STAGES:
			expansion_stage += 1
			for x in range(-expansion_stage, expansion_stage + 1):
				for y in range(-expansion_stage, expansion_stage + 1):
					if abs(x) == expansion_stage or abs(y) == expansion_stage:
						expansion_tiles.append(Vector2i(x, y))
	if expansion_stage == EXPANSION_STAGES and expansion_tiles.size() == 1:
		expansion_finished.emit()
	return expansion_tiles.pop_at(randi_range(0, expansion_tiles.size() - 1))