gather-and-defend/Assets/Scripts/LevelConfig/LevelConfig.cs

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

[CreateAssetMenu(menuName = "Gather And Defend/Levels/LevelConfig")]
public class LevelConfig : ScriptableObject
{
    [SerializeField]
    private List<EnemyType> _constantSpawn = new List<EnemyType>();
    [SerializeField]
    private float _gameDuration = 0;
    public List<EnemyType> ConstantSpawn 
    {
        get
        {
            return _constantSpawn;
        }
    }
    public float GetInterval()
    {
        float interval = SumCount().ToFloat() / _gameDuration * 0.01f;
        return interval;
    }
    public EnemyType GetRandomSpawn()
    {
        if (_constantSpawn.Count == 1)
        {
            return _constantSpawn[0];
        }
        return _constantSpawn[Random.Range(0, _constantSpawn.Count - 1)];
    }

    private int SumCount()
    {
        int sum = 0;
        foreach (EnemyType enemy in _constantSpawn)
        {
            sum += enemy.Count;
        }
        return sum;
    }

}