combo.cs

using UnityEngine;

public class ComboAttack : MonoBehaviour
{
    [SerializeField] private AnimationClip clip;
    private int counter;
    private int tempCounter;
    private float chillDelay;
    private float betweenComboDelay;
    private float chillTimer;
    private float betweenComboTimer;
    private bool isAttack;
    private Animator animator;

    private void Awake()
    {
        betweenComboDelay = clip.length;
        chillDelay = clip.length * 2;
        animator = GetComponent<Animator>();
    }

    private void Update()
    {
        ChillCountdown();

        bool CanAttack = counter < 3;

        if (Input.GetKeyDown(KeyCode.Space) && CanAttack && isAttack == false)
        {
            isAttack = true;
            counter++;
            chillTimer = 0;

            animator.SetInteger("ComboCounter", counter);
        }
        else if (Input.GetKeyDown(KeyCode.Space) && isAttack && CanAttack)
        {
            tempCounter = counter;
            tempCounter++;
            chillTimer = 0;
        }
    }

    private void ChillCountdown()
    {
        if (isAttack && betweenComboTimer >= betweenComboDelay)
        {
            if (tempCounter > 0)
            {
                animator.SetInteger("ComboCounter", tempCounter);
                tempCounter = 0;
                betweenComboTimer = 0;
                counter++;
                return;
            }
        }
        else if(isAttack)
        {
            betweenComboTimer += Time.deltaTime;
        }

        if (isAttack && chillTimer >= chillDelay)
        {
            counter = 0;
            isAttack = false;
            animator.SetInteger("ComboCounter", counter);
        }
        else if (isAttack)
        {
            chillTimer += Time.deltaTime;
        }
    }

    private void OnGUI()
    {
        GUILayout.Label($"ComboCounter: {counter}");
    }
}

comboRefactoring (not work).cs

using UnityEngine;

public class ComboAttack : MonoBehaviour
{
    [SerializeField] private AnimationClip clip;
    private int counter;
    private int tempCounter;
    private bool isAttack;
    private Animator animator;

    private Timer resetComboTimer;
    private Timer nextComboTimer;

    private void Awake()
    {
        resetComboTimer = new Timer(clip.length * 1.2f, ResetState);
        nextComboTimer = new Timer(clip.length, NextState);

        animator = GetComponent<Animator>();
    }

    private void Update()
    {
        bool CanAttack = counter < 3;

        if (Input.GetKeyDown(KeyCode.Space) && CanAttack && isAttack == false)
        {
            isAttack = true;
            counter++;
            resetComboTimer.Reset();

            animator.SetInteger("ComboCounter", counter);
        }
        else if (Input.GetKeyDown(KeyCode.Space) && isAttack && CanAttack)
        {
            tempCounter = counter;
            tempCounter++;
            resetComboTimer.Reset();
        }

        if (isAttack && tempCounter > 0)
        {
            nextComboTimer.Countdown(Time.deltaTime);
        }
        else if (isAttack)
        {
            resetComboTimer.Countdown(Time.deltaTime);
        }
    }

    private void NextState()
    {
        counter++;
        animator.SetInteger("ComboCounter", tempCounter);
        tempCounter = 0;
    }

    private void ResetState()
    {
        counter = 0;
        animator.SetInteger("ComboCounter", counter);
        isAttack = false;
    }

    private void OnGUI()
    {
        GUILayout.Label($"ComboCounter: {counter}");
        GUILayout.Label($"Elapsed RESET: {resetComboTimer.ElapsedTime}");
        GUILayout.Label($"Elapsed NEXT: {nextComboTimer.ElapsedTime}");
    }
}


using System;

public class Timer
{
    private float period;
    public float ElapsedTime;
    private Action action;

    public Timer(float period, Action action)
    {
        this.period = period;
        this.action = action;
    }

    public void Countdown(float deltaTime)
    {
        if (ElapsedTime <= period)
        {
            ElapsedTime += deltaTime;
        }
        else
        {
            action?.Invoke();
            Reset();
        }
    }

    public void Reset()
    {
        ElapsedTime = 0;
    }
}