// ---------------- FocusManager ----------------
using UnityEngine;
using UnityEngine.UI;
using TMPro;
using System.Collections;

public class FocusManager : MonoBehaviour
{
    public static FocusManager Instance { get; private set; }

    [Header("导航按钮")]
    public Button nextFocusButton;
    public Button previousFocusButton;
    public Button firstFocusButton;
    public Button lastFocusButton;

    [Header("下拉菜单控制按钮")]
    public Button dropdownToggleButton;
    public Button dropdownNextButton;
    public Button dropdownPreviousButton;
    public Button dropdownSubmitButton;

    [Header("状态显示")]
    public TextMeshProUGUI dropdownStatusText;
    public TextMeshProUGUI pageStatusText;
    public TextMeshProUGUI inputStatusText;

    [Header("调试")]
    public TextMeshProUGUI debugText;

    public FocusPage currentPage;
    private bool isProcessingInput = false;

    void Awake()
    {
        if (Instance == null) { Instance = this;}
        //else { Destroy(gameObject); return; }
        SetupButtonListeners();
    }

    void Update()
    {
        HandleKeyboardNavigation();
        UpdateStatusDisplay();
        UpdateDebugInfo();
    }

    public void ForceUpdateButtonStates() => UpdateButtonStates();

    public void SetCurrentPage(FocusPage page)
    {
        if (page == null) return;
        currentPage?.ClearFocus();
        currentPage = page;
        ForceUpdateButtonStates();
        UpdateStatusDisplay();
    }

    public FocusPage GetCurrentPage() => currentPage;

    #region 焦点导航
    public void FocusNext() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return;  StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusNext())); }
    public void FocusPrevious() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return; StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusPrevious())); }
    public void FocusFirst() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return; StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusFirst())); }
    public void FocusLast() { if (currentPage == null || isProcessingInput|| currentPage.focusDisabled) return;  StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusLast())); }

    public void DropdownSelectNext() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return; StartCoroutine(ProcessInputCoroutine(() => currentPage.DropdownSelectNext())); }
    public void DropdownSelectPrevious() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return; StartCoroutine(ProcessInputCoroutine(() => currentPage.DropdownSelectPrevious())); }
    public void DropdownSubmit() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return; StartCoroutine(ProcessInputCoroutine(() => currentPage.DropdownSubmit())); }
    public void DropdownToggle() { if (currentPage == null || isProcessingInput || currentPage.focusDisabled) return; StartCoroutine(ProcessInputCoroutine(() => currentPage.DropdownToggle())); }

    private IEnumerator ProcessInputCoroutine(System.Action action)
    {
        if (isProcessingInput) yield break;
        isProcessingInput = true;

        action?.Invoke();

        // 不要等到 EndOfFrame
        yield return null;

        isProcessingInput = false;
        UpdateButtonStates();
    }
    #endregion

    #region 按钮状态
    private void SetupButtonListeners()
    {
        if (nextFocusButton != null) nextFocusButton.onClick.AddListener(FocusNext);
        if (previousFocusButton != null) previousFocusButton.onClick.AddListener(FocusPrevious);
        if (firstFocusButton != null) firstFocusButton.onClick.AddListener(FocusFirst);
        if (lastFocusButton != null) lastFocusButton.onClick.AddListener(FocusLast);

        if (dropdownToggleButton != null) dropdownToggleButton.onClick.AddListener(DropdownToggle);
        if (dropdownNextButton != null) dropdownNextButton.onClick.AddListener(DropdownSelectNext);
        if (dropdownPreviousButton != null) dropdownPreviousButton.onClick.AddListener(DropdownSelectPrevious);
        if (dropdownSubmitButton != null) dropdownSubmitButton.onClick.AddListener(DropdownSubmit);
    }

    // 这里省略其他未改动部分，主要修改按钮状态逻辑
    private void UpdateButtonStates()
    {
        if (currentPage == null)
        {
            SetAllButtonsInteractable(false);
            return;
        }

        bool isDropdownExpanded = currentPage.IsDropdownExpanded();
        bool isOnDropdown = currentPage.IsOnDropdown();
        bool hasInputFocus = currentPage.HasActiveInputField();

        if (previousFocusButton != null)
            previousFocusButton.interactable = currentPage.HasPreviousFocus && !isDropdownExpanded && !hasInputFocus && !isProcessingInput;
        if (nextFocusButton != null)
            nextFocusButton.interactable = currentPage.HasNextFocus && !isDropdownExpanded && !hasInputFocus && !isProcessingInput;

        bool hasElements = currentPage.FocusCount > 0 && !isDropdownExpanded && !hasInputFocus && !isProcessingInput;
        if (firstFocusButton != null) firstFocusButton.interactable = hasElements;
        if (lastFocusButton != null) lastFocusButton.interactable = hasElements;

        // Submit可用条件
        if (dropdownToggleButton != null) dropdownToggleButton.interactable = isOnDropdown && !hasInputFocus && !isProcessingInput;
        if (dropdownNextButton != null) dropdownNextButton.interactable = isDropdownExpanded && !hasInputFocus && !isProcessingInput;
        if (dropdownPreviousButton != null) dropdownPreviousButton.interactable = isDropdownExpanded && !hasInputFocus && !isProcessingInput;
        if (dropdownSubmitButton != null) dropdownSubmitButton.interactable = (isDropdownExpanded || isOnDropdown) && !hasInputFocus && !isProcessingInput;
    }


    private void SetAllButtonsInteractable(bool interactable)
    {
        if (previousFocusButton != null) previousFocusButton.interactable = interactable;
        if (nextFocusButton != null) nextFocusButton.interactable = interactable;
        if (firstFocusButton != null) firstFocusButton.interactable = interactable;
        if (lastFocusButton != null) lastFocusButton.interactable = interactable;
        if (dropdownToggleButton != null) dropdownToggleButton.interactable = interactable;
        if (dropdownNextButton != null) dropdownNextButton.interactable = interactable;
        if (dropdownPreviousButton != null) dropdownPreviousButton.interactable = interactable;
        if (dropdownSubmitButton != null) dropdownSubmitButton.interactable = interactable;
    }
    #endregion

    #region 状态显示
    private void UpdateStatusDisplay()
    {
        if (currentPage == null)
        {
            if (dropdownStatusText != null) dropdownStatusText.text = "无活动页面";
            if (pageStatusText != null) pageStatusText.text = "";
            if (inputStatusText != null) inputStatusText.text = "";
            return;
        }

        if (pageStatusText != null) pageStatusText.text = $"焦点: {currentPage.CurrentFocusIndex + 1}/{currentPage.FocusCount}";
        if (inputStatusText != null) inputStatusText.text = currentPage.HasActiveInputField() ? "输入模式" : "";

        if (dropdownStatusText != null)
        {
            if (currentPage.IsDropdownExpanded())
            {
                dropdownStatusText.text = $"选择中: {currentPage.GetCurrentDropdownValue()}";
            }
            else if (currentPage.IsOnDropdown())
            {
                dropdownStatusText.text = "按[提交]开始选择";
            }
            else dropdownStatusText.text = "";
        }
    }

    private void UpdateDebugInfo()
    {
        if (debugText != null && currentPage != null)
        {
            debugText.text = $"处理中: {isProcessingInput}\n" +
                             $"输入焦点: {currentPage.HasActiveInputField()}\n" +
                             $"下拉展开: {currentPage.IsDropdownExpanded()}";
        }
    }
    #endregion

    #region 键盘导航
    private void HandleKeyboardNavigation()
    {
        if (currentPage == null) return;

        bool hasInputFocus = currentPage.HasActiveInputField();

        if (hasInputFocus)
        {
            if (Input.GetKeyDown(KeyCode.Escape))
                StartCoroutine(ProcessInputCoroutine(() => currentPage.DeactivateCurrentInputField()));
            return;
        }

        // Dropdown键盘操作，直接调用
        if (currentPage.IsOnDropdown())
        {
            if (Input.GetKeyDown(KeyCode.UpArrow)) currentPage.DropdownSelectPrevious();
            if (Input.GetKeyDown(KeyCode.DownArrow)) currentPage.DropdownSelectNext();

            //if (Input.GetKeyDown(KeyCode.Return) || Input.GetKeyDown(KeyCode.KeypadEnter))
            //    currentPage.DropdownSubmit(); // 内部判断是打开还是提交

            //if (Input.GetKeyDown(KeyCode.Space) || Input.GetKeyDown(KeyCode.Escape))
            //    currentPage.DropdownToggle();
        }
        else
        {
            //// 普通焦点切换用协程限制重复输入
            //if (Input.GetKeyDown(KeyCode.Tab))
            //{
            //    if (Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift))
            //        SafeFocusPrevious();
            //    else
            //        SafeFocusNext();
            //}

            if (Input.GetKeyDown(KeyCode.Home)) FocusFirst();
            if (Input.GetKeyDown(KeyCode.End)) FocusLast();
        }
    }
    #endregion
}