StarsMementoSample

using System;
using Core.Interfaces;
using UnityEngine;

namespace Game
{
    public class Coins : ScriptableObject, IOriginator<IMemento>
    {
        [SerializeField] private int _value;

        public int Value
        {
            get => _value;
            private set
            {
                if (value == _value)
                    return;

                _value = value;
            }
        }

        public bool IsEmpty => Value <= 0;

        public void Add() => Value++;

        public void Add(int amount)
        {
            if (amount < 0)
                throw new ArgumentException("Argument less than zero.", nameof(amount));

            Value += amount;
        }

        #region Memento

        public IMemento SaveState() => new Memento(_value);

        public void RestoreState(IMemento memento) => _value = (int)memento.State;

        public void ResetToDefaultState() => _value = 0;

        [Serializable]
        public struct Memento : IMemento
        {
            private readonly int _value;

            public int Value => _value;

            public object State => Value;

            public Memento(int value) => _value = value;
        }

        #endregion
    }
}