Billboard

using System.Collections.Generic;
using System.Linq;

using UnityEngine;

namespace UIBillboard
{
    public class Billboard : MonoBehaviour
    {
        [SerializeField] private bool _sort = true;
        [SerializeField] private Transform _holder;
        [SerializeField] private BillboardItem _template;
        [Space]
        [SerializeField] private BillboardItem[] _items;

        private Transform _mainCameraTransform;
        private Dictionary<string, BillboardItem> _billboardItems;

        public void SetItemValue(string item, string value) =>
            _billboardItems[item].SetValue(value);

        public void CreateNewItem(string item, string startValue)
        {
            BillboardItem billboardItem = Instantiate(_template, _holder);
            billboardItem.Name = item;
            billboardItem.SetValue(startValue);
            GetAllItems();
        }

        private void GetAllItems()
        {
            _items = _holder.GetComponentsInChildren<BillboardItem>();

            if (_sort)
            {
                _items = _items.OrderBy(ItemNameLength).ToArray();

                foreach(Transform child in _holder)
                    child.SetAsFirstSibling();
            }

            _billboardItems = _items.ToDictionary(item => item.Name);
        }

        private static int ItemNameLength(BillboardItem item) =>
            item.Name.Length;

        private void Start() =>
            _mainCameraTransform = Camera.main.transform;

        private void LateUpdate() =>
            transform.LookAt(
                transform.position + _mainCameraTransform.rotation * Vector3.forward,
                _mainCameraTransform.rotation * Vector3.up);

    }
}