using System;
using UnityEngine;

namespace Escape_Room_Engine.Portal
{
    public class Portal : MonoBehaviour
    {
        /// <summary>
        /// The portal that is connected with this one.
        /// </summary>
        public Portal other;
        /// <summary>
        /// The main camera to take the position for the portal camera from.
        /// </summary>
        [SerializeField] private Transform playerCamera;
        /// <summary>
        /// The camera that will draw the view for this portal.
        /// </summary>
        [SerializeField] private Transform portalCamera;

        private void Start()
        {
            // check whether the other portal is set up
            if (!other || other.other != this) throw new Exception("Other Portal not set up correctly.");
            // check whether the player camera is set up
            if (!playerCamera) throw new Exception("No camera initialised.");
        }

        private void Update()
        {
            var portalCameraMatrix = transform.localToWorldMatrix * other.transform.worldToLocalMatrix *
                                     playerCamera.localToWorldMatrix;
            portalCamera.SetPositionAndRotation(portalCameraMatrix.GetPosition(), portalCameraMatrix.rotation);
        }
    }
}