UI, 소리, 상태를
하나의 흐름으로 묶기

using TMPro;
using UnityEngine;
using UnityEngine.SceneManagement;

public enum GameState
{
    Ready,
    Playing,
    Won,
    Lost
}

public class GameManager : MonoBehaviour
{
    [Header("Rules")]
    [SerializeField, Min(1)] private int targetScore = 3;
    [SerializeField, Min(1f)] private float roundDuration = 30f;

    [Header("UI")]
    [SerializeField] private TMP_Text scoreText;
    [SerializeField] private TMP_Text timerText;
    [SerializeField] private TMP_Text resultText;
    [SerializeField] private GameObject startPanel;
    [SerializeField] private GameObject resultPanel;

    [Header("Audio")]
    [SerializeField] private AudioSource sfxSource;
    [SerializeField] private AudioClip collectClip;
    [SerializeField] private AudioClip winClip;
    [SerializeField] private AudioClip loseClip;

    public GameState CurrentState { get; private set; }

    private int score;
    private float timeRemaining;

    private void Start()
    {
        ShowReady();
    }

    private void Update()
    {
        if (CurrentState != GameState.Playing)
        {
            return;
        }

        timeRemaining = Mathf.Max(
            0f,
            timeRemaining - Time.deltaTime
        );
        UpdateHud();

        if (timeRemaining <= 0f)
        {
            FinishRound(GameState.Lost);
        }
    }

    private void ShowReady()
    {
        CurrentState = GameState.Ready;
        score = 0;
        timeRemaining = roundDuration;
        Time.timeScale = 0f;

        startPanel.SetActive(true);
        resultPanel.SetActive(false);
        UpdateHud();
    }

    public void StartRound()
    {
        if (CurrentState != GameState.Ready)
        {
            return;
        }

        CurrentState = GameState.Playing;
        Time.timeScale = 1f;

        startPanel.SetActive(false);
        resultPanel.SetActive(false);
        UpdateHud();
    }

    public void AddScore(int amount)
    {
        if (CurrentState != GameState.Playing)
        {
            return;
        }

        score = Mathf.Min(score + amount, targetScore);
        PlaySfx(collectClip);
        UpdateHud();

        if (score >= targetScore)
        {
            FinishRound(GameState.Won);
        }
    }

    private void FinishRound(GameState result)
    {
        if (CurrentState != GameState.Playing)
        {
            return;
        }

        CurrentState = result;
        Time.timeScale = 0f;
        resultPanel.SetActive(true);

        bool didWin = result == GameState.Won;
        resultText.text = didWin ? "성공" : "시간 종료";
        PlaySfx(didWin ? winClip : loseClip);
    }

    public void RestartScene()
    {
        Time.timeScale = 1f;
        int currentScene = SceneManager.GetActiveScene().buildIndex;
        SceneManager.LoadScene(currentScene);
    }

    private void UpdateHud()
    {
        scoreText.text = $"{score} / {targetScore}";
        timerText.text = $"{timeRemaining:0.0}";
    }

    private void PlaySfx(AudioClip clip)
    {
        if (clip != null)
        {
            sfxSource.PlayOneShot(clip);
        }
    }
}

using UnityEngine;

public class Collectible : MonoBehaviour
{
    [SerializeField] private GameManager gameManager;

    private bool collected;

    private void OnTriggerEnter2D(Collider2D other)
    {
        if (collected || !other.CompareTag("Player"))
        {
            return;
        }

        if (gameManager.CurrentState != GameState.Playing)
        {
            return;
        }

        collected = true;
        gameManager.AddScore(1);
        gameObject.SetActive(false);
    }
}