ichni_Official/Assets/Scripts/UI/SongSelection/DifficultySelectionContainer.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace Ichni.Menu
{
    public class DifficultySelectionContainer : MonoBehaviour
    {
        public List<DifficultySelectionButton> buttons;
        public DifficultySelectionButton selectedButton;
        
        public void SetUp(List<DifficultyData> difficulties)
        {
            int difficultyCount = difficulties.Count;

            for (var i = 0; i < buttons.Count; i++)
            {
                buttons[i].gameObject.SetActive(i < difficultyCount);
            }

            for (int i = 0; i < difficultyCount; i++)
            {
                buttons[i].SetUp(difficulties[i]);
            }

            SongSelectionRecord songSelectionRecord = MenuInformationRecorder.instance.GetRecordOfThisChapter();
            
            if (songSelectionRecord.difficultyIndex >= difficultyCount)
            {
                songSelectionRecord.difficultyIndex = difficultyCount - 1;
            }
            
            buttons[songSelectionRecord.difficultyIndex].Select();
        }
    }
}