Programming-Design-Patterns-And-Principles/Assets/Patterns_And_Principles/Patterns/The Singleton Pattern/AdvancedSingleton/Script/AdvancedSingleton.cs

using System;
using UnityEngine;

namespace Patterns_And_Principles.Patterns.The_Singleton_Pattern.AdvanceSingleton.Script
{
    public class AdvancedSingleton : MonoBehaviour
    {
        private static AdvancedSingleton _instance;

        public static AdvancedSingleton Instance
        {
            get
            {
                if (_instance == null)
                {
                    SetupInstance();
                }

                return _instance;
            }
        }

        public int Gem = 0;

        private void Awake()
        {
            if (_instance != null && _instance != this)
            {
                Destroy(gameObject);
                return;
            }

            _instance = this;
            DontDestroyOnLoad(gameObject); // Sahne geçişlerinde yok olmaz
        }

        private static void SetupInstance()
        {
            _instance = FindAnyObjectByType<AdvancedSingleton>();
            if (_instance == null)
            {
                GameObject gameObject = new GameObject(); // Yeni gameobject oluştur.
                gameObject.name = "AdvancedSingleton";
                _instance = gameObject.AddComponent<AdvancedSingleton>();
                DontDestroyOnLoad(gameObject);
            }
        }

        public void AddGem(int amount)
        {
            Gem += amount;
        }
    }
}