using UnityEngine;
using UnityEngine.UI;
using TMPro;
using System.Collections;
using System.Runtime.InteropServices;

public class FocusManager : MonoBehaviour
{
    // 单例实例
    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;

    private FocusPage currentPage;
    private bool isProcessingInput = false; // 防止重复输入

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

        SetupButtonListeners();
        Debug.Log("FocusManager 初始化完成");
    }

    void Start()
    {
        ForceUpdateButtonStates();
        UpdateStatusDisplay();
    }

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

    #region 公共方法
    public void ForceUpdateButtonStates()
    {
        UpdateButtonStates();
    }
    #endregion

    #region 页面管理
    public void SetCurrentPage(FocusPage page)
    {
        if (page == null) return;

        if (currentPage != null)
        {
            currentPage.ClearFocus();
        }

        currentPage = page;
        Debug.Log($"当前焦点页面更新为: {page.gameObject.name}");

        ForceUpdateButtonStates();
        UpdateStatusDisplay();
    }

    public FocusPage GetCurrentPage()
    {
        return currentPage;
    }
    #endregion

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

    public void FocusPrevious()
    {
        if (currentPage == null || isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusPrevious()));
    }

    public void FocusFirst()
    {
        if (currentPage == null || isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusFirst()));
    }

    public void FocusLast()
    {
        if (currentPage == null || isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage.FocusLast()));
    }

    public void SafeFocusNext()
    {
        if (currentPage == null || isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage.TryMoveToNext()));
    }

    public void SafeFocusPrevious()
    {
        if (currentPage == null || isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage.TryMoveToPrevious()));
    }

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

        isProcessingInput = true;
        action?.Invoke();
        yield return new WaitForEndOfFrame();
        isProcessingInput = false;
        ForceUpdateButtonStates();
    }
    #endregion

    #region 自定义组件控制
    public void ActivateCurrentInput()
    {
        currentPage?.ActivateCurrentInputField();
    }

    public void DeactivateCurrentInput()
    {
        currentPage?.DeactivateCurrentInputField();
    }

    public void InputText(string text)
    {
        var inputField = currentPage?.GetCurrentCustomInputField();
        if (inputField != null)
        {
            TMPInputSimulator.InsertText(inputField, text);
        }
    }

    public void DeleteText()
    {
        var inputField = currentPage?.GetCurrentCustomInputField();
        if (inputField != null)
        {
            TMPInputSimulator.Backspace(inputField);
        }
    }
    #endregion

    #region 下拉菜单控制
    public void DropdownToggle()
    {
        if (isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage?.DropdownToggle()));
    }

    public void DropdownSelectNext()
    {
        if (isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage?.DropdownSelectNext()));
    }

    public void DropdownSelectPrevious()
    {
        if (isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage?.DropdownSelectPrevious()));
    }

    public void DropdownSubmit()
    {
        if (isProcessingInput) return;
        StartCoroutine(ProcessInputCoroutine(() => currentPage?.DropdownSubmit()));
    }
    #endregion

    #region 按钮管理和状态显示
    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);
    }

    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;

        bool dropdownButtonsEnabled = isDropdownExpanded && isOnDropdown && !hasInputFocus && !isProcessingInput;

        if (dropdownToggleButton != null) dropdownToggleButton.interactable = isOnDropdown && !hasInputFocus && !isProcessingInput;
        if (dropdownNextButton != null) dropdownNextButton.interactable = dropdownButtonsEnabled;
        if (dropdownPreviousButton != null) dropdownPreviousButton.interactable = dropdownButtonsEnabled;
        if (dropdownSubmitButton != null) dropdownSubmitButton.interactable = dropdownButtonsEnabled;
    }

    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[打开菜单]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()}";
        }
    }

    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 键盘输入处理
    private void HandleKeyboardNavigation()
    {
        if (currentPage == null || isProcessingInput) return;

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

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

        if (isDropdownExpanded)
        {
            if (Input.GetKeyDown(KeyCode.UpArrow)) DropdownSelectPrevious();
            if (Input.GetKeyDown(KeyCode.DownArrow)) DropdownSelectNext();
            if (Input.GetKeyDown(KeyCode.Return) || Input.GetKeyDown(KeyCode.KeypadEnter)) DropdownSubmit();
            if (Input.GetKeyDown(KeyCode.Space) || Input.GetKeyDown(KeyCode.Escape)) DropdownToggle();
        }
        else
        {
            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
}