using System.Collections;
using System.Reflection;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using TMPro;

[RequireComponent(typeof(TMP_Dropdown))]
public class CustomTMPDropdown : TMP_Dropdown
{
    private FieldInfo dropdownField;
    private FieldInfo blockerField;
    private GameObject dropdownListGO;

    private int currentOptionIndex = 0;

    protected override void Awake()
    {
        base.Awake();
        dropdownField = typeof(TMP_Dropdown).GetField("m_Dropdown", BindingFlags.NonPublic | BindingFlags.Instance);
        blockerField = typeof(TMP_Dropdown).GetField("m_Blocker", BindingFlags.NonPublic | BindingFlags.Instance);

        // 添加Outline
        Outline ol = gameObject.GetComponent<Outline>();
        if (ol == null) ol = gameObject.AddComponent<Outline>();
        ol.effectColor = new Color32(0xFF, 0xAB, 0x00, 255);
        ol.effectDistance = new Vector2(2, -2);
        ol.enabled = false;
    }

    public override void OnPointerClick(PointerEventData eventData) {

        if (FocusManager.Instance.currentPage != null) {
            FocusManager.Instance.currentPage.UpdateFouceByClick(this);

        }
        ToggleDropdown();
    }
    public override void OnSubmit(BaseEventData eventData) {
        SubmitSelection();

    }
    public override void OnCancel(BaseEventData eventData) { }

    private GameObject GetDropdownGO() => dropdownField?.GetValue(this) as GameObject;
    private GameObject GetBlockerGO() => blockerField?.GetValue(this) as GameObject;

    // ---------------- 手动打开/关闭 ----------------
    public void OpenDropdown()
    {
        if (dropdownListGO != null && dropdownListGO.activeSelf) return;
        base.Show();
        StartCoroutine(FixAfterShow());
    }

    public void CloseDropdown()
    {
        if (dropdownListGO != null) Destroy(dropdownListGO);
        GameObject blocker = GetBlockerGO();
        if (blocker != null) Destroy(blocker);
        dropdownListGO = null;
    }

    public void ToggleDropdown()
    {
        if (dropdownListGO != null && dropdownListGO.activeSelf) CloseDropdown();
        else OpenDropdown();
    }

    // ---------------- 上下切换 ----------------
    public void SelectNext()
    {
        if (options.Count == 0) return;
        currentOptionIndex = (currentOptionIndex + 1) % options.Count;
        value = currentOptionIndex;
        RefreshShownValue();
        UpdateHighlight();
    }

    public void SelectPrevious()
    {
        if (options.Count == 0) return;
        currentOptionIndex = (currentOptionIndex - 1 + options.Count) % options.Count;
        value = currentOptionIndex;
        RefreshShownValue();
        UpdateHighlight();
    }

    // ---------------- 提交/打开 ----------------
    public void SubmitSelection()
    {
        if (dropdownListGO == null || !dropdownListGO.activeSelf)
        {
            OpenDropdown();
        }
        else
        {
            value = currentOptionIndex;
            RefreshShownValue();
            onValueChanged?.Invoke(value);
            CloseDropdown();
        }
    }

    // ---------------- 初始化 Dropdown ----------------
    private IEnumerator FixAfterShow()
    {
        yield return null;

        dropdownListGO = GetDropdownGO();
        if (dropdownListGO == null) yield break;

        // 禁用Blocker
        GameObject blocker = GetBlockerGO();
        if (blocker != null)
        {
            Button btn = blocker.GetComponent<Button>();
            if (btn != null) btn.onClick.RemoveAllListeners();
            btn.enabled = false;
            CanvasGroup cg = blocker.GetComponent<CanvasGroup>();
            if (cg == null) cg = blocker.AddComponent<CanvasGroup>();
            cg.blocksRaycasts = false;
        }

        Transform content = dropdownListGO.transform.Find("Viewport/Content");
        if (content != null)
        {
            for (int i = 1; i < content.childCount && i <= options.Count; i++)
            {
                GameObject item = content.GetChild(i).gameObject;
                Toggle toggle = item.GetComponent<Toggle>();
                if (toggle != null)
                {
                    int optionIndex = i - 1;
                    toggle.onValueChanged.RemoveAllListeners();
                    toggle.onValueChanged.AddListener((isOn) =>
                    {
                        if (isOn)
                        {
                            currentOptionIndex = optionIndex;
                            value = currentOptionIndex;
                            RefreshShownValue();
                            onValueChanged?.Invoke(value);
                            CloseDropdown();
                        }
                    });
                }
            }
        }

        currentOptionIndex = value;
        UpdateHighlight();
    }

    private void UpdateHighlight()
    {
        if (dropdownListGO == null) return;

        Transform content = dropdownListGO.transform.Find("Viewport/Content");
        if (content == null) return;

        ScrollRect scrollRect = dropdownListGO.GetComponentInChildren<ScrollRect>();

        for (int i = 1; i < content.childCount && i <= options.Count; i++)
        {
            GameObject item = content.GetChild(i).gameObject;
            Toggle toggle = item.GetComponent<Toggle>();
            if (toggle != null)
            {
                toggle.SetIsOnWithoutNotify((i - 1) == currentOptionIndex);
                if ((i - 1) == currentOptionIndex && scrollRect != null)
                {
                    RectTransform itemRect = item.GetComponent<RectTransform>();
                    RectTransform contentRect = content.GetComponent<RectTransform>();
                    Vector2 localPos = contentRect.InverseTransformPoint(itemRect.position);
                    Vector2 viewportLocalPos = contentRect.InverseTransformPoint(scrollRect.viewport.position);
                    float offset = localPos.y - viewportLocalPos.y;
                    float normalized = 1 - Mathf.Clamp01((offset + itemRect.rect.height) / contentRect.rect.height);
                    scrollRect.verticalNormalizedPosition = normalized;
                }
            }
        }

        // 高亮自己
        Outline ol = gameObject.GetComponent<Outline>();
        if (ol != null) ol.enabled = true;

        RefreshShownValue();
    }


    //上下键直接切换选项
    public void FocusedSelectNext()
    {
        if (options == null || options.Count == 0) return;


        int next = value + 1;
        if (next >= options.Count) next = options.Count - 1;


        if (next != value)
        {
            value = next; // <-- 这里 Unity 会自动触发 onValueChanged
        }
    }


    public void FocusedSelectPrevious()
    {
        if (options == null || options.Count == 0) return;


        int prev = value - 1;
        if (prev < 0) prev = 0;


        if (prev != value)
        {
            value = prev; // <-- 同样自动触发 onValueChanged
        }
    }
}