extends Node
class_name BehaviorTree

func tick(actor, blackboard, debug = false) -> int:
	var tick := Tick.new()
	tick.tree = self
	tick.actor = actor
	tick.blackboard = blackboard
	tick.debug = debug
	
	var result := FAILED
	
	for child in get_children():
		var _result = child._execute(tick)
		assert(typeof(_result) == TYPE_INT)
		result = _result
	
	# Close nodes from last tick, if needed
	var last_open_nodes: Array = tick.blackboard.get('openNodes', self)
	var current_open_nodes := tick.open_nodes

	# If node isn't currently open, but was open during last tick, close it
	for node in last_open_nodes:
		if (not current_open_nodes.has(node) 
			and tick.blackboard.get('isOpen', tick.tree, node)):
				node._close(tick)

	# Populate the blackboard
	blackboard.set('openNodes', current_open_nodes, self)
	return result