FsmExample.cs

class Door : MonoBehavior {
    private Fsm _fsmDoor;
    
    private enum State {
        Opened,
        Closed,
        Locked,
        Unlocked,
        ToggleLock,
    }
    
    private void Setup (Player player) {
        var fsmLock = new FsmBuilder(gameObject)
            .State(State.Locked, (locked) => {
                locked.SetAnimatorBool("locked", true);
            })
            .State(State.Unlocked, (unlocked) => {
                unlocked.SetAnimatorBool("locked", false);
            })
            .State(State.ToggleLock, (toggleLock) => {
                toggleLock.SetTransition("unlock", State.Unlocked);
                toggleLock.SetTransition("lock", State.Locked);
               
                toggleLock.Do((@lock) => {
                    switch (@lock.State) {
                        case State.Locked:
                            @lock.Transition("unlock");
                            break;
                        case State.Unlocked:
                            @lock.Transition("lock");
                            break;
                    }
                });
            })
            .Build();
        
        _fsmDoor = new FsmBuilder(gameObject)
            .State(State.Opened, (open) => {
                open.SetTransition("close", State.Closed);
                open.SetAnimatorString("state", "open");
                
                open.TriggerStay("player", (door) => {
                    if (player.Input("open")) {
                        door.Transition("close");
                    }
                });
            })
            .State(State.Closed, (close) => {
                close.SetTransition("open", State.Opened);
                close.SetAnimatorString("state", "close");
                
                close.TriggerStay("player", (door) => {
                    if (player.Input("open") && fsmLock.HasState(State.Unlocked)) {
                        door.Transition("open");
                    } else if (player.Input("key") && player.HasItem("key")) {
                        fsmLock.SetState(State.ToggleLock);
                    }
                });
            })
            .Build();
    }

    private void Update () {
        _fsmDoor.Tick();
    }
}