create aphid class

scripts/units/aphid.gd

@@ -0,0 +1,36 @@
+extends Unit
+class_name Aphid
+
+enum AphidState {
+	WANDERING,
+}
+
+const MAX_WANDER_DISTANCE: float = 5
+const MIN_WANDER_INTERVAL: float = 0.25
+const MAX_WANDER_INTERVAL: float = 5
+
+var wandering_timer: float = 0
+var state: AphidState = AphidState.WANDERING
+
+@onready var wandering_center: Vector3 = global_position
+
+
+func _process(delta: float) -> void:
+	super._process(delta)
+	_handle_wandering(delta)
+
+
+func _handle_wandering(delta: float) -> void:
+	if state != AphidState.WANDERING:
+		return
+	
+	wandering_timer -= delta
+	if wandering_timer <= 0:
+		var new_pos_offset := Vector3(
+				randf_range(-MAX_WANDER_DISTANCE, MAX_WANDER_DISTANCE),
+				0,
+				randf_range(-MAX_WANDER_DISTANCE, MAX_WANDER_DISTANCE),
+		)
+		var new_pos := wandering_center + new_pos_offset
+		nav_agent.set_target_position(new_pos)
+		wandering_timer = randf_range(-MIN_WANDER_INTERVAL, MAX_WANDER_INTERVAL)