extends Node
class_name StateMachine

signal state_changed(new_state,old_state)

var state = null setget set_state
var previous_state = null
var states = {}

onready var parent = get_parent()

func _physics_process(delta: float) -> void:
	if state != null:
		_state_logic(delta)
		var transition = _get_transition(delta)
		if transition != null:
			set_state(transition)

func _state_logic(delta):
	pass

func _get_transition(delta):
	return null

func _enter_state(new_state,old_state):
	pass

func _exit_state(old_state,new_state):
	pass

func set_state(new_state):
	previous_state = state
	state = new_state

	if previous_state != null:
		_exit_state(previous_state,new_state)
	if new_state != null:
		_enter_state(new_state,previous_state)

	emit_signal("state_changed",new_state,previous_state)

func add_state(state_name):
	states[state_name] = states.size()