using TMPro;
using UnityEngine;

namespace NightclubArcadia.Interaction
{
    /// <summary>
    /// A floating text label that turns to face the camera.
    ///
    /// Lifted out of NPCStandIn, which created its label in Awake and billboarded it in
    /// LateUpdate. That worked, but it meant the text only existed at runtime and could
    /// not be seen or positioned in the Editor. This is a normal component on a normal
    /// child object, so a prefab can show what it will look like.
    /// </summary>
    [RequireComponent(typeof(TextMeshPro))]
    public sealed class WorldSpaceLabel : MonoBehaviour
    {
        [SerializeField] bool billboard = true;

        TextMeshPro text;
        Camera view;

        void Awake() => text = GetComponent<TextMeshPro>();

        public void SetText(string value)
        {
            if (text == null)
            {
                text = GetComponent<TextMeshPro>();
            }
            text.text = value;
        }

        void LateUpdate()
        {
            if (!billboard)
            {
                return;
            }

            // Camera.main is a tagged lookup; cache it, but re-acquire if the camera was
            // destroyed with a scene, which happens when the Systems scene reloads.
            if (view == null)
            {
                view = Camera.main;
                if (view == null)
                {
                    return;
                }
            }

            transform.rotation = Quaternion.LookRotation(transform.position - view.transform.position);
        }
    }
}