BtreeTaskExample.cs

public static BuildTask Heal() => () => {
    StrongBox<VehicleTaskManager.ChainHealPoint?> healPoint = new();
    VehicleBody? GetVehicle(AITask _) => healPoint.Value?.Vehicle;
    Vector3 GetPos(AITask _) => healPoint.Value?.Healer.Component.GlobalPosition ?? Vector3.Zero;
    IInteractable? HealPoint(AITask _) => healPoint.Value?.Healer.Interactable;
    return Fallback("Heal", [
        Periodic(Task("Is full health?",
            task => task.Character.DamageComponent.Hitpoints.Proportion.EqualsApprox(1)
                ? TaskResult.Success
                : TaskResult.Fail)
        ),
        Sequence("Heal", [
            Periodic(Task("Locate healer", task => {
                var character = task.Character;
                var pos = character.GlobalPosition;
                healPoint.Value = task.Manager.HealPointsInChain
                    .Where(x => x.Healer.Interactable.InteractionAllowed(character))
                    .OrderBy(x => x.Healer.Component.GlobalPosition.DistanceSquaredTo(pos))
                    .FirstOrDefault();
                return healPoint.Value is not null ? TaskResult.Success : TaskResult.Fail;
            })),
            GotoAndInteract(GetPos, HealPoint, GetVehicle),
        ]),
    ])();
};

public static BuildTask GotoAndInteract(
    Func<AITask, Vector3> getPos,
    Func<AITask, IInteractable?> interactable,
    Func<AITask, VehicleBody?> getVehicle,
    Func<AITask, bool>? shouldInteract = null) => () => {
    shouldInteract ??= _ => true;
    // var interactionAllowed = InteractionAllowed(interactable);
    return Fallback("Go to interaction point and interact", [
        SuccessCooldown(Task("Try interact with", task => {
            var interactableValue = interactable(task);
            if (interactableValue is not null) {
                if (shouldInteract(task)) {
                    task.CharInput.Aiming.LookAtNode(interactableValue.Node);
                    return task.CharInput.TryInteractWith(interactableValue) ? TaskResult.Success : TaskResult.Fail;
                } else {
                    // Fail so we still try to go to the interaction point
                    // Should interact is evaluated after the go to point
                    return TaskResult.Fail;
                }
            } else {
                task.Character.PushError("Interactable is null");
                return TaskResult.Fail;
            }
        })),
        Sequence("Go to and interact", [
            GoToPosition(getPos, getVehicle),
            Task("Should interact", task => shouldInteract(task) ? TaskResult.Success : TaskResult.Running),
            Task("Failed to interact", task => {
                var interactableObj = interactable(task)!;
                var isInRange = task.Character.Interaction.InRangeOf(interactableObj);
                var canInteract = interactableObj.InteractionAllowed(task.Character);
                if (isInRange && canInteract) {
                    task.Assigned.Character.Log(
                        "Failed interact even though is in range and should be able to. This should be unreachable!",
                        LoggingLevel.Warning);
                    return TaskResult.Fail;
                }

                if (isInRange) {
                    task.Assigned.Character.Log(
                        "Interaction is not allowed even though we're in range", LoggingLevel.Warning);
                    return TaskResult.Fail;
                }

                if (canInteract) {
                    task.Assigned.Character.Log("Reached interaction point but still can't interact",
                        LoggingLevel.Warning);
                    return TaskResult.Fail;
                }

                task.Assigned.Character.Log("Failed to interact. This error should be unreachable",
                    LoggingLevel.Warning);
                return TaskResult.Fail;
            }),
        ]),
    ])();

};