using System;
using System.Collections;
using UnityEngine;
using UnityEngine.InputSystem;

public class GazeInteractable : MonoBehaviour
{
	[Header("References")]
	public Camera head;
	public Transform snapPoint;
	public InputActionReference rightTrigger;

	[Header("Materials")]
	public Material defaultMaterial;
	public Material hoverMaterial;

	[Header("Settings")]
	public LayerMask snapLayer;
	public LayerMask cubeLayer;
	public float snapDistance = 0.5f;
	public float lerpSpeed = 10.0f;

	private bool grabbed = false;
	private bool hovered = false;
	private float grabDistance = 0.0f;
	private Renderer cubeRenderer;

	void Awake()
	{
		cubeRenderer = GetComponentInChildren<Renderer>();
	}

	void Update()
	{
		CheckHovered();
		Grab();
		Snap();
		cubeRenderer.material = hovered ? hoverMaterial : defaultMaterial;
	}

	private void CheckHovered()
	{
		hovered = Physics.Raycast(head.transform.position, head.transform.forward, out RaycastHit hit, cubeLayer);
	}

	private void Grab()
	{
		bool pressed = rightTrigger.action.ReadValue<float>() > 0.5f;
		if (pressed && !grabbed && hovered) {
			grabDistance = Vector3.Distance(head.transform.position, transform.position);
			grabbed = true;
		} else if (!pressed && grabbed) {
			grabbed = false;
			FindNearestSnapPoint();
		}

		if (grabbed) {
			transform.position = head.transform.position + head.transform.forward * grabDistance;
		}
	}

	private void Snap()
	{
		if (!grabbed && snapPoint != null) {
			transform.position = Vector3.Lerp(transform.position, snapPoint.position, lerpSpeed * Time.deltaTime);
			transform.rotation = Quaternion.Lerp(transform.rotation, snapPoint.rotation, lerpSpeed * Time.deltaTime);
		}
	}

	private void FindNearestSnapPoint()
	{
		Collider[] snapPoints = Physics.OverlapSphere(transform.position, snapDistance, snapLayer);
		if (snapPoints.Length > 0) {
			Transform nearest = null;
			float min = float.MaxValue;
			foreach (var point in snapPoints) {
				float distance = Vector3.Distance(transform.position, point.transform.position);
				if (distance < min) {
					min = distance;
					nearest = point.transform;
				}
			}

			if (nearest != null) {
				snapPoint = nearest;
			}
		}
	}

    private void OnDrawGizmosSelected()
    {
        Gizmos.color = Color.green;
        Gizmos.DrawWireSphere(transform.position, snapDistance);
    }
}