using System.Collections;
using UnityEngine;
using UnityEngine.SceneManagement;

/// <summary>
/// 暂停菜单：继续游戏 / 回到 Main 场景。
/// 按钮点击在各自 Button 的 On Click() 里接线（Inspector 配置）。
/// </summary>
[DisallowMultipleComponent]
public class PauseMenu : MonoBehaviour
{
    [Tooltip("「回到Main」要加载的场景名，必须已经加进 Build Settings")]
    [SerializeField] private string mainSceneName = "Main";

    private bool _leaving;

    /// <summary>继续游戏：恢复时间，关掉自己。</summary>
    public void OnContinueClicked()
    {
        Time.timeScale = 1f;
        Destroy(gameObject);
    }

    /// <summary>回到 Main：加载 Main 场景，加载完成后卸载当前场景。</summary>
    public void OnBackToMainClicked()
    {
        if (_leaving) return;
        _leaving = true;
        Time.timeScale = 1f;
        StartCoroutine(LoadMainThenUnloadCurrent());
    }

    private IEnumerator LoadMainThenUnloadCurrent()
    {
        Scene currentScene = gameObject.scene;

        AsyncOperation load = SceneManager.LoadSceneAsync(mainSceneName, LoadSceneMode.Additive);
        if (load == null)
        {
            Debug.LogError("[PauseMenu] 场景 \"" + mainSceneName + "\" 加载失败，确认它已加入 Build Settings。", this);
            _leaving = false;
            yield break;
        }

        yield return load;   // 等 Main 加载完成

        Scene loaded = SceneManager.GetSceneByName(mainSceneName);
        if (loaded.IsValid())
            SceneManager.SetActiveScene(loaded);

        SceneManager.UnloadSceneAsync(currentScene);   // 卸载当前场景
    }
}