using UnityEngine;
using UnityEngine.XR.Interaction.Toolkit;
using UnityEngine.XR.Interaction.Toolkit.Interactables;

public class OutlineOnHover : MonoBehaviour {
    [Header("References")]
    [SerializeField] private XRBaseInteractable interactable;
    [SerializeField] private Outline outline;

    private int hoverCount = 0;

    private void Awake() {
        // Try to find the XR Interactable on this object.
        if(interactable == null) {
            interactable = GetComponent<XRBaseInteractable>();
        }

        // Try to find the Quick Outline component on this object or its children.
        if(outline == null) {
            outline = GetComponentInChildren<Outline>();
        }

        // Start with the outline turned off.
        SetOutline(false);
    }

    private void OnEnable() {
        if(interactable == null) {
            Debug.LogWarning($"{name} is missing an XRBaseInteractable component.");
            return;
        }

        interactable.hoverEntered.AddListener(OnHoverEntered);
        interactable.hoverExited.AddListener(OnHoverExited);
    }

    private void OnDisable() {
        if(interactable != null) {
            interactable.hoverEntered.RemoveListener(OnHoverEntered);
            interactable.hoverExited.RemoveListener(OnHoverExited);
        }

        hoverCount = 0;
        SetOutline(false);
    }

    private void OnHoverEntered(HoverEnterEventArgs args) {
        hoverCount++;
        SetOutline(true);
    }

    private void OnHoverExited(HoverExitEventArgs args) {
        hoverCount = Mathf.Max(hoverCount - 1, 0);

        if(hoverCount == 0) {
            SetOutline(false);
        }
    }

    private void SetOutline(bool isVisible) {
        if(outline != null) {
            outline.enabled = isVisible;
        }
    }
}