using UnityEngine;
using UnityEngine.UI;

/// <summary>
/// 管理首页 -> 模式选择页 -> 固定方式选择页 -> 实验界面 的切换。
/// 挂在 Canvas 上，与 UIManager 协同工作。
/// </summary>
public class PageController : MonoBehaviour
{
    [Header("=== 三个主页面 ===")]
    [SerializeField] private GameObject _homePagePanel;
    [SerializeField] private GameObject _modeSelectPanel;
    [SerializeField] private GameObject _fixationPanel;

    [Header("=== 实验内 UI（由 UIManager 管理）===")]
    [SerializeField] private UIManager _uiManager;

    [Header("=== 首页控件 ===")]
    [SerializeField] private Button _btnStart;
    [SerializeField] private Button _btnExit;

    [Header("=== 模式选择页控件 ===")]
    [SerializeField] private Button _btnBack;
    [SerializeField] private Button _btnPracticeMode;
    [SerializeField] private Button _btnExamMode;
    [SerializeField] private Text _modeDescText;

    [Header("=== 固定方式选择页控件 ===")]
    [SerializeField] private Button _btnFixationBack;
    [SerializeField] private Button _btnLimbFixation;
    [SerializeField] private Button _btnSplintFixation;

    [Header("=== 模式说明文案 ===")]
    [SerializeField] [TextArea(2, 4)] private string _practiceModeDesc =
        "● 模拟练习模式：不限时长，可反复练习。系统不评分，帮助您熟悉实验流程和操作步骤。";
    [SerializeField] [TextArea(2, 4)] private string _examModeDesc =
        "● 考核评估模式：限定时间，完成后系统自动评分，并提供详细反馈报告。";

    [Header("=== 编辑器预览（仅 Editor 模式有效）===")]
    [SerializeField] private EditorPreviewPage _editorPreview = EditorPreviewPage.None;

    // Page 枚举改为 public，Inspector 中可通过 _editorPreview 切换
    public enum Page { Home, ModeSelect, Fixation, Experiment }
    public enum EditorPreviewPage { None, Home, ModeSelect, Fixation, Experiment }

    private Page _currentPage = Page.Home;
    private ExperimentMode _selectedMode = ExperimentMode.Learn;

    private void Start()
    {
        // 绑定首页按钮
        if (_btnStart != null) _btnStart.onClick.AddListener(OnStartClicked);
        if (_btnExit != null) _btnExit.onClick.AddListener(OnExitClicked);

        // 绑定模式选择页按钮
        if (_btnBack != null) _btnBack.onClick.AddListener(OnModeBackClicked);
        if (_btnPracticeMode != null) _btnPracticeMode.onClick.AddListener(() => OnModeSelected(ExperimentMode.Learn));
        if (_btnExamMode != null) _btnExamMode.onClick.AddListener(() => OnModeSelected(ExperimentMode.Exam));

        // 绑定固定方式选择页按钮
        if (_btnFixationBack != null) _btnFixationBack.onClick.AddListener(OnFixationBackClicked);
        if (_btnLimbFixation != null) _btnLimbFixation.onClick.AddListener(() => OnFixationSelected(FixationMethod.LimbFixation));
        if (_btnSplintFixation != null) _btnSplintFixation.onClick.AddListener(() => OnFixationSelected(FixationMethod.SplintFixation));

        // 初始化模式说明文字
        if (_modeDescText != null)
        {
            _modeDescText.text = _practiceModeDesc + "\n\n" + _examModeDesc;
        }

        // 初始显示首页
        ShowPage(Page.Home);
    }

#if UNITY_EDITOR
    /// <summary>
    /// 在 Inspector 中修改 _editorPreview 下拉框时，立即切换 Scene View 中显示的页面，
    /// 方便编辑不同页面的 UI 布局。仅在非运行状态下生效。
    /// </summary>
    private void OnValidate()
    {
        if (Application.isPlaying) return;

        // 延迟一帧执行，避免在序列化过程中修改场景导致警告
        UnityEditor.EditorApplication.delayCall += () =>
        {
            if (this == null) return;
            if (Application.isPlaying) return;

            switch (_editorPreview)
            {
                case EditorPreviewPage.None:
                    // 不做任何切换，保留当前状态
                    break;
                case EditorPreviewPage.Home:
                    ShowPageEditMode(Page.Home);
                    break;
                case EditorPreviewPage.ModeSelect:
                    ShowPageEditMode(Page.ModeSelect);
                    break;
                case EditorPreviewPage.Fixation:
                    ShowPageEditMode(Page.Fixation);
                    break;
                case EditorPreviewPage.Experiment:
                    ShowPageEditMode(Page.Experiment);
                    break;
            }

            // 切换完成后重置为 None，避免与后续操作冲突
            _editorPreview = EditorPreviewPage.None;
        };
    }

    private void ShowPageEditMode(Page page)
    {
        if (_homePagePanel != null) _homePagePanel.SetActive(page == Page.Home);
        if (_modeSelectPanel != null) _modeSelectPanel.SetActive(page == Page.ModeSelect);
        if (_fixationPanel != null) _fixationPanel.SetActive(page == Page.Fixation);

        if (_uiManager != null)
            _uiManager.enabled = (page == Page.Experiment);

        Debug.Log($"PageController（编辑器预览）: 切换到 [{page}]");
    }
#endif

    #region 页面切换

    private void ShowPage(Page page)
    {
        _currentPage = page;

        if (_homePagePanel != null) _homePagePanel.SetActive(page == Page.Home);
        if (_modeSelectPanel != null) _modeSelectPanel.SetActive(page == Page.ModeSelect);
        if (_fixationPanel != null) _fixationPanel.SetActive(page == Page.Fixation);

        if (_uiManager != null)
            _uiManager.enabled = (page == Page.Experiment);
    }

    #endregion

    #region 按钮回调

    private void OnStartClicked()
    {
        ShowPage(Page.ModeSelect);
    }

    private void OnExitClicked()
    {
#if UNITY_EDITOR
        UnityEditor.EditorApplication.isPlaying = false;
#else
        Application.Quit();
#endif
    }

    private void OnModeBackClicked()
    {
        ShowPage(Page.Home);
    }

    private void OnModeSelected(ExperimentMode mode)
    {
        _selectedMode = mode;

        if (_modeDescText != null)
        {
            _modeDescText.text = mode == ExperimentMode.Learn
                ? _practiceModeDesc + "\n\n✓ 当前已选择「模拟练习模式」"
                : _examModeDesc + "\n\n✓ 当前已选择「考核评估模式」";
        }

        ShowPage(Page.Fixation);
    }

    private void OnFixationBackClicked()
    {
        if (_modeDescText != null)
        {
            _modeDescText.text = _practiceModeDesc + "\n\n" + _examModeDesc;
        }

        ShowPage(Page.ModeSelect);
    }

    private void OnFixationSelected(FixationMethod method)
    {
        var gm = GameManager.Instance;
        if (gm == null)
        {
            Debug.LogError("PageController: GameManager.Instance 为空！");
            return;
        }

        gm.CurrentMode = _selectedMode;
        gm.CurrentFixationMethod = method;

        ShowPage(Page.Experiment);

        var stepManager = FindObjectOfType<StepManager>();
        if (stepManager != null)
        {
            stepManager.InitializeFromGameManager();
        }
    }

    #endregion
}