using UnityEngine;

namespace UDE_HAND_INTERACTION
{
    public abstract class InteractDetector<interactor, interactable> : 
                                Interactor<interactor, interactable>
                                where interactor : Interactor<interactor, interactable>
                                where interactable : DetectorInteractable<interactor, interactable>
    {
        protected void GenerateDetectorEvent(DetectorEventType detectorEventType, interactable interactable)
        {
            Pose pose = ComputeDetectorPose();

            if (interactable == null)
            {
                return;
            }

            if (interactable.DetectableElement != null)
            {
                if (detectorEventType == DetectorEventType.Hover)
                {
                    interactable.DetectableElement.WhenDetectorEventRaised +=
                        HandleDetectorEventRaised;
                }
                else if (detectorEventType == DetectorEventType.Unhover)
                {
                    interactable.DetectableElement.WhenDetectorEventRaised -=
                        HandleDetectorEventRaised;
                }
            }

            interactable.PublishDetectorEvent( new DetectorEvent(Identifier, detectorEventType, pose));
        }

        protected virtual void HandleDetectorEventRaised(DetectorEvent evt)
        {
            if (evt.Identifier == Identifier &&
                evt.Type == DetectorEventType.Cancel &&
                Interactable != null)
            {
                interactable interactable = Interactable;
                interactable.RemoveInteractorByIdentifier(Identifier);
                interactable.DetectableElement.WhenDetectorEventRaised -=
                    HandleDetectorEventRaised;
            }
        }

        protected override void InteractableSelected(interactable interactable)
        {
            base.InteractableSelected(interactable);
            GenerateDetectorEvent(DetectorEventType.Select, interactable);
        }

        protected override void DoPostprocess()
        {
            base.DoPostprocess();
            if (_interactable != null)
            {
                GenerateDetectorEvent(DetectorEventType.Move, _interactable);
            }
        }

        protected abstract Pose ComputeDetectorPose();
    }

}