State Machine Transition Engine

transition_engine.go

// IMachine machine interface
type IMachine interface {
	Transition() string
	Current() string
}

// Current returns current state
func (m *Machine) Current() string {
	if m.current == "" {
		return m.Initial
	}
	return m.current
}

// Transition transitions to next state
func (m *Machine) Transition(event string) string {
	current := m.Current()
	transitions := m.States[current].On
	next := transitions[event].To
	if next != "" {
	     m.current = next
	     return next
	}
	return current
}